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Author

SHAILENDRA KUMAR VERMA

DISCLAIMER

THIS BOOK HAS BEEN PREPARED FOR EDUCATIONAL, ACADEMIC AND COMPETITIVE-EXAMINATION PREPARATION PURPOSES ONLY.

THE INFORMATION, DEFINITIONS, EXPLANATIONS, FORMULAS, EXAMPLES AND PRACTICE QUESTIONS PROVIDED IN THIS BOOK ARE INTENDED TO HELP STUDENTS UNDERSTAND THE FUNDAMENTAL CONCEPTS OF WORKSHOP TECHNOLOGY AND MANUFACTURING PROCESSES.

WHERE PREVIOUS-YEAR QUESTIONS ARE INCLUDED, THE EXAM NAME AND YEAR SHOULD BE TREATED ACCORDING TO THE AVAILABLE SOURCE/REFERENCE.

SOME QUESTIONS REPRODUCED IN PUBLIC EXAM-PREPARATION RESOURCES MAY BE MEMORY-BASED QUESTIONS RATHER THAN QUESTIONS REPRODUCED FROM AN OFFICIALLY RELEASED QUESTION PAPER. SUCH QUESTIONS SHOULD THEREFORE BE IDENTIFIED SEPARATELY AS MEMORY-BASED QUESTIONS.

THIS BOOK IS NOT AN OFFICIAL PUBLICATION OF SSC, RRB, GATE, UPSC/ESE, ANY STATE PUBLIC SERVICE COMMISSION, PSU, ITI, POLYTECHNIC, UNIVERSITY OR ANY OTHER EXAMINATION AUTHORITY.

THE AUTHOR HAS MADE REASONABLE EFFORTS TO PRESENT TECHNICALLY ACCURATE INFORMATION.

HOWEVER, MANUFACTURING TECHNOLOGY IS A BROAD AND CONTINUOUSLY DEVELOPING FIELD AND TERMINOLOGY, STANDARDS, EXAMINATION PATTERNS, AND TECHNICAL PRACTICES MAY VARY AMONG INSTITUTIONS AND EXAMINATION AUTHORITIES.

READERS ARE ADVISED TO VERIFY CRITICAL TECHNICAL INFORMATION, STANDARDS, CODES, EXAMINATION NOTIFICATIONS AND OFFICIAL EXAMINATION INFORMATION FROM THE RELEVANT OFFICIAL AUTHORITIES.

THE AUTHOR AND PUBLISHER SHALL NOT BE RESPONSIBLE FOR ANY LOSS, DAMAGE, ACADEMIC CONSEQUENCE, EXAMINATION CONSEQUENCE OR OTHER LIABILITY ARISING FROM THE USE OR INTERPRETATION OF THE INFORMATION CONTAINED IN THIS BOOK.

COPYRIGHT NOTICE

THIS BOOK IS INTENDED FOR LAWFUL EDUCATIONAL USE. NO PORTION OF THIS PUBLICATION SHOULD BE REPRODUCED, DISTRIBUTED, UPLOADED, RESOLD OR TRANSMITTED IN ANY FORM WITHOUT APPROPRIATE PERMISSION FROM THE COPYRIGHT HOLDER, EXCEPT WHERE PERMITTED UNDER APPLICABLE LAW.
© Shailendra Kumar Verma

PREFACE

WORKSHOP TECHNOLOGY IS ONE OF THE FUNDAMENTAL SUBJECTS FOR STUDENTS AND CANDIDATES PREPARING FOR EXAMINATIONS RELATED TO MECHANICAL ENGINEERING, MANUFACTURING ENGINEERING, PRODUCTION ENGINEERING, ITI, DIPLOMA, SSC JE, RRB JE, GATE, ESE/IES, STATE JE/AE AND PSU EXAMINATIONS.

THE SUBJECT COVERS THE BASIC PRINCIPLES AND PRACTICAL ASPECTS OF MANUFACTURING, INCLUDING CASTING, METAL FORMING, WELDING, MACHINING, MACHINE TOOLS, GRINDING, HEAT TREATMENT, METROLOGY, WORKSHOP TOOLS AND ADVANCED MANUFACTURING PROCESSES.
THIS BOOK HAS BEEN DESIGNED WITH A DUAL PURPOSE:

TO PROVIDE A CLEAR CONCEPTUAL UNDERSTANDING OF WORKSHOP TECHNOLOGY AND MANUFACTURING PROCESSES.

TO PROVIDE A LARGE COLLECTION OF EXAM-ORIENTED QUESTIONS AND PREVIOUS-YEAR/MEMORY-BASED QUESTIONS WITH ANSWERS AND EXPLANATIONS.

THE BOOK BEGINS WITH FUNDAMENTAL DEFINITIONS BECAUSE A STRONG UNDERSTANDING OF TERMINOLOGY MAKES THE ADVANCED TOPICS MUCH EASIER TO UNDERSTAND.

THE SYLLABUS HAS BEEN ORGANIZED PROGRESSIVELY—FROM BASIC WORKSHOP CONCEPTS AND ENGINEERING MATERIALS TO CASTING, FORMING, JOINING, MACHINING, GRINDING, HEAT TREATMENT AND ADVANCED MANUFACTURING PROCESSES. THESE AREAS BROADLY CORRESPOND WITH ESTABLISHED MANUFACTURING-PROCESS CURRICULA.

TABLE OF CONTENTS

WORKSHOP TOOLS — TYPES & USES

SL NO	CHAPTER
1.	FUNDAMENTAL DEFINITIONS OF WORKSHOP TECHNOLOGY
2.	ENGINEERING MATERIALS
3.	MECHANICAL PROPERTIES OF ENGINEERING MATERIALS
4.	METAL TESTING & TESTING MACHINES
5.	FOUNDRY TECHNOLOGY & CASTING PROCESSES
6.	METAL FORMING PROCESSES
7.	WELDING TECHNOLOGY
8.	FOUNDRY & CASTING TECHNOLOGY
9.	FORGING TECHNOLOGY
10.	SHEET METAL WORKING
11.	METAL CUTTING & MACHINE TOOLS
12.	LATHE & TURNING OPERATIONS
13.	DRILLING MACHINES & DRILLING OPERATIONS
14.	SHAPER, PLANER & SLOTTING MACHINES
15.	MILLING MACHINE & MILLING OPERATIONS
16.	GRINDING MACHINES & ABRASIVE PROCESSES
17.	DRILLING, BORING, REAMING & TAPPING
18.	LATHE MACHINE & TURNING OPERATIONS
19.	SHAPER, PLANER & SLOTTER
20.	MILLING MACHINE & MILLING OPERATIONS
21.	CHAPTER 21 — FULL-LENGTH MOCK TESTS

WORKSHOP TOOLS — TYPES & USES

1. HAMMERS

1.1 Introduction

A hammer is a hand tool consisting mainly of a head mounted on a handle. It is used to apply impact force for operations such as striking, shaping, bending, riveting, assembling, dismantling, and fitting of components.

Hammers used in workshops differ in their shape, weight, face, peen, and application. The selection of a hammer depends on the nature of the job and the amount of impact force required.

1.2 Main Parts of a Hammer

A typical workshop hammer consists of the following parts:

Hammer Head

The hammer head is the working portion of the tool. It is generally made from forged steel and contains the striking face and, in many types, a peen.

Face

The face is the flat or slightly curved striking surface of the hammer. It delivers impact to the workpiece or another tool.

Peen

The peen is the shaped portion opposite the face. Its shape varies according to the intended application.

Eye

The eye is the hole through the hammer head through which the handle is fitted.

Handle

The handle provides a grip and allows the user to control the hammer and generate impact force. Handles are commonly made from wood or other suitable materials.

1.3 Types of Hammers

Workshop hammers can be classified according to their shape and application.

1. Ball Peen Hammer

A ball peen hammer has a flat striking face on one side and a hemispherical ball-shaped peen on the other side.

Uses

Used for general fitting work.

Used for riveting operations.

Used for forming and shaping metal.

Used for peening rivets.

Used for enlarging and shaping metal surfaces.

Used with punches and chisels during workshop operations.

Ball peen hammers are widely used in fitting and engineering workshops.

1.4 Cross Peen Hammer

A cross peen hammer has a flat striking face and a wedge-shaped peen positioned across the handle.

Uses

Used for starting small nails or pins.

Used for working in narrow spaces.

Used for shaping and bending metal.

Used for light forging operations.

Used for forming corners and grooves.

Used in general fitting work.

The narrow cross peen permits impact to be concentrated over a relatively small area.

1.5 Straight Peen Hammer

A straight peen hammer has a wedge-shaped peen positioned in line with the handle.

Uses

Used for shaping and forming metal.

Used for light forging operations.

Used for working in narrow areas.

Used for producing grooves and channels.

Used for general workshop and fitting operations.

The straight peen is particularly useful when the direction of the peen needs to follow the length of the workpiece.

1.6 Sledge Hammer

A sledge hammer is a heavy hammer having a large double-faced or suitable heavy striking head.

Uses

Used for heavy-duty striking operations.
Used for breaking concrete and masonry.
Used for driving heavy stakes.
Used for heavy forging operations.
Used for bending and shaping heavy metal sections.
Used in construction and heavy engineering work.

Sledge hammers are available in different weights according to the force required.

1.7 Club Hammer

A club hammer is a relatively small, heavy hammer with a double-faced head.

Uses

Used for light demolition work.
Used for striking chisels and punches.
Used for masonry work.
Used for breaking small sections of concrete or brick.
Used for general heavy striking operations.

Its compact size provides good control during relatively heavy impact work.

1.8 Mallet

A mallet is a hammer having a head made from a relatively soft material such as wood, rubber, plastic, or similar material.

Uses

Used where the workpiece must not be damaged by a hard steel hammer.

Used for assembling components.

Used for fitting and adjusting parts.

Used for sheet-metal work.

Used for woodworking operations.

Used for positioning components without leaving deep impact marks.

The softer striking surface reduces the possibility of damaging finished surfaces.

1.9 Soft-Faced Hammer

A soft-faced hammer has one or more striking faces made from materials softer than steel, such as copper, brass, nylon, or plastic.

Uses

Used for assembling precision components.

Used for positioning machine parts.

Used for straightening or adjusting components.

Used where surface damage must be avoided.

Used for fitting components with finished surfaces.

The replaceable soft faces on some designs allow the hammer to be adapted to different applications.

1.10 Dead Blow Hammer

A dead blow hammer is a special type of soft-impact hammer designed to reduce rebound after striking.

Its head commonly contains a filling such as metal shot or another suitable material that moves inside the head during impact.

Uses

Used for positioning machine components.

Used for assembling parts.

Used for sheet-metal work.

Used for removing or fitting components without excessive rebound.

Used where controlled impact is required.

Used on finished surfaces where conventional steel hammers may cause damage.

The reduced rebound makes the tool easier to control during precision work.

1.11 Riveting Hammer

A riveting hammer is a light hammer specifically designed for riveting operations.

It generally has a relatively narrow face and a suitable peen for forming rivet heads.

Uses

Used for setting rivets.

Used for forming rivet heads.

Used in sheet-metal work.

Used in fabrication work.

Used for joining metal components by riveting.

The shape and weight of the hammer allow the operator to control the rivet-forming operation accurately.

1.12 Welder’s Hammer

A welder’s hammer, commonly called a chipping hammer, is designed primarily for removing slag from welded joints.

It generally has a pointed or chisel-like end and a flat or suitable striking end.

Uses

Used for removing welding slag.

Used for cleaning weld beads.

Used for removing spatter.

Used for cleaning welded surfaces before inspection.

Used during welding and fabrication operations.

It is commonly used together with a wire brush during weld cleaning.

1.13 Engineer’s Hammer

An engineer’s hammer is a general-purpose workshop hammer having a flat striking face and a peen.

Uses

Used for general fitting work.

Used for striking punches and chisels.

Used for light shaping operations.

Used for assembling and dismantling components.

Used for general maintenance work.

The weight of the hammer is selected according to the job and the required impact force.

1.14 Claw Hammer

A claw hammer has a striking face on one side and a curved claw on the opposite side.

Uses

Used for driving nails.

Used for removing nails.

Used for woodworking.

Used for general maintenance work.

Used for pulling small fasteners.

The claw provides leverage for removing nails and similar fasteners.

1.15 Summary of Hammer Types

Hammer Type	Main Application
Ball Peen Hammer	Riveting, peening and general fitting
Cross Peen Hammer	Narrow-area shaping and light work
Straight Peen Hammer	Shaping and forming metal
Sledge Hammer	Heavy-duty striking
Club Hammer	Heavy striking and chiselling
Mallet	Assembly and work where surface damage must be avoided
Soft-Faced Hammer	Precision assembly and surface protection
Dead Blow Hammer	Controlled impact with reduced rebound
Riveting Hammer	Riveting and sheet-metal work
Welder’s/Chipping Hammer	Removing welding slag
Engineer’s Hammer	General workshop and fitting work
Claw Hammer	Driving and removing nails

CHISELS

2.1 Introduction

A chisel is a hand cutting tool used for cutting, chipping, grooving, removing excess metal, and shaping materials by applying impact force with a hammer.

Chisels used in workshops are generally made from high-carbon steel or alloy tool steel. The cutting edge is hardened and tempered to withstand repeated impact and cutting action.

The selection of a chisel depends on the material, type of operation, shape of the required cut, and accessibility of the work area.

2.2 Main Parts of a Chisel

A typical hand chisel consists of the following parts:

Head

The head is the portion struck by a hammer. It is generally kept strong enough to withstand repeated blows.

Body or Shank

The body is the main portion of the chisel extending between the head and cutting edge.

Cutting Edge

The cutting edge is the sharpened portion that performs the cutting or chipping operation.

Cutting End

The cutting end is formed according to the particular type and application of the chisel.

2.3 Classification of Chisels

Workshop chisels can be classified according to their shape and application.

The important types include:

Flat Chisel

Cape Chisel

Cross-Cut Chisel

Diamond-Point Chisel

Round-Nose Chisel

Side Chisel

Cold Chisel

Hot Chisel

Brick Chisel

Mason’s Chisel

2.4 Flat Chisel

A flat chisel has a broad, flat cutting edge. It is one of the most commonly used chisels in fitting and general metalworking.

Features

Broad cutting edge

Flat cutting surface

Suitable for removing relatively large amounts of material

Available in different sizes

Uses

Used for general chipping operations.

Used for cutting metal sheets and bars.

Used for removing excess metal.

Used for cutting rivet heads.

Used for removing unwanted material from castings.

Used for general fitting work.

The broad cutting edge makes the flat chisel suitable for general-purpose metal cutting and chipping.

2.5 Cape Chisel

A cape chisel has a narrow, wedge-shaped cutting edge. It is used where a narrow cut or groove is required.

Features

Narrow cutting edge

Wedge-shaped point

Suitable for concentrated cutting action

Uses

Used for cutting narrow grooves.

Used for cutting keyways.

Used for making slots.

Used for cutting narrow channels.

Used for starting larger grooves.

Used for removing material from confined areas.

Cape chisels are particularly useful where a narrow and controlled cut is required.

2.6 Cross-Cut Chisel

A cross-cut chisel has a narrow cutting edge that is wider than the body in the cutting region. It is used primarily for producing grooves and channels.

Features

Narrow cutting edge

Wedge-shaped cutting portion

Suitable for narrow grooves

Uses

Used for cutting grooves.

Used for cutting keyways.

Used for making narrow channels.

Used for removing material from restricted areas.

Used for cutting slots in metal components.

2.7 Diamond-Point Chisel

A diamond-point chisel has a cutting end with a diamond-shaped cross-section.

Features

Diamond-shaped cutting end

Pointed cutting profile

Suitable for V-shaped grooves and special cuts

Uses

Used for cutting V-grooves.

Used for cutting narrow angular grooves.

Used for removing material from corners.

Used for making grooves in metal surfaces.

Used for working in confined locations.

The pointed profile allows the chisel to reach areas where a broad flat chisel cannot work effectively.

2.8 Round-Nose Chisel

A round-nose chisel has a rounded or semicircular cutting edge.

Features

Rounded cutting edge

Suitable for producing curved grooves

Designed for controlled material removal

Uses

Used for cutting oil grooves.

Used for making semicircular grooves.

Used for producing curved channels.

Used for removing material from curved surfaces.

Used in special fitting operations.

2.9 Side Chisel

A side chisel has a cutting edge designed for cutting grooves or slots from the side.

Features

Specially shaped cutting end

Suitable for side cutting

Useful in restricted areas

Uses

Used for cutting narrow slots.

Used for cutting grooves from the side.

Used for removing material from confined locations.

Used for special fitting operations.

2.10 Cold Chisel

A cold chisel is a general-purpose metalworking chisel used for cutting and chipping metal without heating the workpiece.

Features

Made from hardened and tempered tool steel.

Has a suitable wedge-shaped cutting edge.

Designed to withstand hammer blows.

Available in several shapes and sizes.

Uses

Used for cutting cold metal.

Used for removing excess metal.

Used for cutting bolts and rivets.

Used for removing welds and unwanted material.

Used for chipping castings.

Used in fitting and maintenance work.

Flat, cape, diamond-point, and round-nose chisels are commonly used forms of cold chisels for different operations.

2.11 Hot Chisel

A hot chisel is used for cutting and shaping metal while it is heated to a high temperature.

Features

Designed for hot metalworking.

Cutting edge is suitable for cutting heated metal.

Used primarily in forging operations.

Uses

Used for cutting heated metal bars.

Used for hot forging operations.

Used for cutting heated rods and sections.

Used for separating heated metal pieces.

Used for preparing metal stock during forging.

A hot chisel is used with heated metal, whereas a cold chisel is generally used on metal at normal temperature.

2.12 Brick Chisel

A brick chisel is a broad, strong chisel designed primarily for cutting and splitting bricks and similar masonry materials.

Features

Broad cutting edge

Strong construction

Suitable for masonry applications

Uses

Used for cutting bricks.

Used for splitting masonry materials.

Used for removing sections of brickwork.

Used for light masonry repair work.

2.13 Mason’s Chisel

A mason’s chisel is designed for cutting, shaping, and removing masonry materials such as brick, stone, and concrete.

Features

Strong cutting edge

Suitable for impact work

Available in different shapes for masonry applications

Uses

Used for cutting stone.

Used for cutting bricks.

Used for removing mortar.

Used for making grooves in masonry.

Used for demolition and repair work.

Used for shaping masonry surfaces.

2.14 Chisel Selection

The selection of a chisel depends on:

Type of material being cut

Thickness of the material

Shape of the required cut

Width and depth of the groove

Accessibility of the work area

Nature of the operation

Required cutting accuracy

For example, a flat chisel is suitable for general chipping, while a cape or cross-cut chisel is preferred for narrow grooves and slots.

2.15 Important Workshop Practices for Chisels

A chisel should be selected according to the job and kept properly sharpened. The cutting edge should be free from cracks and excessive damage.

During repeated hammering, the head of a chisel can develop a mushroomed shape. Such a condition can be hazardous because pieces of metal may break away during striking. Therefore, damaged or mushroomed chisel heads should be properly maintained or replaced.

The workpiece should also be securely held before beginning a cutting or chipping operation.

2.16 Summary of Chisel Types

Type of Chisel	Main Uses
Flat Chisel	General cutting and chipping
Cape Chisel	Narrow grooves, slots and keyways
Cross-Cut Chisel	Grooves and narrow channels
Diamond-Point Chisel	V-grooves and angular cuts
Round-Nose Chisel	Curved and semicircular grooves
Side Chisel	Side cutting and restricted areas
Cold Chisel	Cutting and chipping cold metal
Hot Chisel	Cutting heated metal during forging
Brick Chisel	Cutting and splitting bricks
Mason’s Chisel	Cutting and shaping masonry

FILES

3.1 Introduction

A file is a multi-point cutting tool used to remove a small amount of material from a workpiece by rubbing its cutting teeth against the surface.

Files are widely used in fitting, bench work, toolmaking, fabrication, and maintenance operations. They are mainly used for removing excess material, producing the required shape and size, smoothing surfaces, and finishing edges.

A file consists of a hardened steel body provided with a series of cutting teeth. The file is generally operated by moving it over the workpiece with suitable pressure.

3.2 Main Parts of a File

A typical file consists of the following parts:

Point

The point is the extreme end of the file opposite the handle.

Face

The face is the broad surface containing the cutting teeth.

Edge

The edge is the narrow longitudinal surface of the file. In some files, the edge may also contain cutting teeth.

Heel

The heel is the portion of the file near the tang where the teeth generally terminate.

Tang

The tang is the tapered portion used for fitting the handle.

Shoulder

The shoulder is the portion between the body of the file and the tang.

Handle

The handle provides a safe and comfortable grip during filing operations.

3.3 Classification of Files

Files can be classified according to:

Shape
Cut of teeth
Grade or coarseness
Length
Special application

3.4 Types of Files According to Shape

3.4.1 Flat File

A flat file has a rectangular cross-section and parallel or slightly tapered sides.

Features

Broad flat face

Rectangular cross-section

Suitable for general-purpose filing

Uses

Used for filing flat surfaces.

Used for reducing the size of metal components.

Used for finishing flat surfaces.

Used for removing burrs.

Used for general fitting work.

3.4.2 Hand File

A hand file is similar to a flat file but generally has a safe edge on one side.

Features

Rectangular cross-section

One edge may be uncut

Suitable for filing surfaces close to another surface

Uses

Used for general fitting work.

Used for filing flat surfaces.

Used for finishing edges.

Used where an adjacent surface must not be cut.

Used for producing accurate dimensions.

3.4.3 Square File

A square file has a square cross-section and is generally tapered toward the point.

Uses

Used for filing square holes.

Used for enlarging rectangular openings.

Used for producing square grooves.

Used for filing keyways.

Used for internal corners.

3.4.4 Round File

A round file has a circular cross-section and is also commonly called a round file or rat-tail file when used in a tapered form.

Uses

Used for enlarging round holes.

Used for filing curved surfaces.

Used for producing semicircular grooves.

Used for finishing concave surfaces.

Used for filing internal radii.

3.4.5 Half-Round File

A half-round file has one flat face and one curved face.

Uses

Used for filing concave surfaces.

Used for filing flat surfaces.

Used for producing curved profiles.

Used for internal curved surfaces.

Used for general fitting work.

Its two different surfaces make it suitable for both flat and curved filing operations.

3.4.6 Triangular File

A triangular file has a triangular cross-section.

It is also commonly known as a three-square file.

Uses

Used for filing V-shaped grooves.

Used for sharpening saw teeth.

Used for filing angular grooves.

Used for producing internal angles.

Used for finishing triangular openings.

3.4.7 Knife-Edge File

A knife-edge file has a very thin wedge-shaped cross-section.

Uses

Used for filing narrow slots.

Used for producing sharp internal angles.

Used for filing narrow grooves.

Used for working in confined spaces.

Used for precision fitting operations.

3.4.8 Pillar File

A pillar file is a relatively narrow rectangular file with parallel sides.

Uses

Used for precision filing.

Used for filing narrow flat surfaces.

Used for producing slots.

Used for toolmaking and fitting operations.

Used where greater control is required.

3.4.9 Warding File

A warding file is a thin, narrow file designed for working in narrow slots and restricted spaces.

Uses

Used for filing narrow slots.

Used in lock and key work.

Used for precision fitting.

Used for working in confined areas.

3.5 Types of Files According to Cut

The cut of a file refers to the arrangement and form of its teeth.

3.5.1 Single-Cut File

A single-cut file has one series of parallel teeth across its surface.

Features

The teeth are arranged in a single direction.

Uses

Used for light material removal.

Used for finishing surfaces.

Used for sharpening cutting edges.

Used where a relatively smooth finish is required.

Used for soft and relatively ductile materials.

3.5.2 Double-Cut File

A double-cut file has two sets of intersecting teeth.

Features

The first set of teeth is known as the overcut and the second set crosses it.

Uses

Used for faster material removal.

Used for rough and general-purpose filing.

Used for reducing large amounts of material.

Used for shaping metal components.

Used in general fitting work.

Double-cut files generally remove material faster than single-cut files.

3.5.3 Rasp-Cut File

A rasp-cut file has individual, raised teeth formed by a special cutting process.

Uses

Used mainly on wood.

Used on soft materials.

Used for shaping and removing material from softer workpieces.

Used in woodworking and related applications.

3.5.4 Curved-Cut File

A curved-cut file has curved rows of teeth across its surface.

Uses

Used for rapid material removal.

Used for filing soft materials.

Used for aluminium and similar materials.

Used where clogging of the file needs to be reduced.

Used for producing a relatively smooth finish.

3.6 Types of Files According to Grade

The grade of a file indicates the relative coarseness or fineness of its teeth.

The common grades are:

Rough
Bastard
Second Cut
Smooth
Dead Smooth

3.6.1 Rough File

A rough file has relatively large and coarse teeth.

Uses

Used for rapid removal of material.

Used for rough shaping.

Used when a large amount of material has to be removed.

Used on relatively soft materials.

It is not normally used when a fine surface finish is required.

3.6.2 Bastard File

A bastard file has teeth finer than a rough file but coarser than a second-cut file.

Uses

Used for general-purpose filing.

Used for removing moderate amounts of material.

Used for shaping workpieces.

Used for general fitting operations.

3.6.3 Second-Cut File

A second-cut file has finer teeth than a bastard file.

Uses

Used for intermediate filing.

Used after rough filing.

Used for improving surface finish.

Used for bringing a workpiece closer to its final size.

3.6.4 Smooth File

A smooth file has relatively fine teeth.

Uses

Used for finishing surfaces.

Used for accurate fitting.

Used for removing small amounts of material.

Used where a smoother surface is required.

3.6.5 Dead-Smooth File

A dead-smooth file has very fine teeth.

Uses

Used for fine finishing.

Used for precision fitting.

Used for producing a smooth surface.

Used for removing very small amounts of material.

3.7 Types of Files According to Application

Needle Files

Needle files are small files with relatively fine teeth and are usually supplied in sets of different shapes.

Common Types

Flat

Square

Round

Half-Round

Triangular

Knife-Edge

Uses

Used for precision filing.

Used for small components.

Used for dies and moulds.

Used for toolmaking.

Used for intricate and delicate work.

Swiss Pattern Files

Swiss pattern files are precision files having fine teeth and are used for detailed and accurate filing operations.

Uses

Used for precision engineering.

Used for tool and die work.

Used for fine finishing.

Used for small and intricate components.

3.8 File Selection

The correct file should be selected according to:

Shape of the workpiece

Amount of material to be removed

Required surface finish

Required accuracy

Material being filed

Accessibility of the surface

Type of filing operation

For example, a flat file is suitable for flat surfaces, a round file for curved surfaces and holes, and a triangular file for V-grooves and saw-tooth work.

3.9 Proper Use of a File

During filing, the workpiece should be held securely in a suitable vice or fixture.

The file should be fitted with a proper handle when it has a tang. The operator should apply suitable pressure during the forward cutting stroke and avoid excessive pressure during the return stroke.

The file should be kept clean so that material particles do not clog the teeth.

Files should not be used as hammers, levers, or pry tools because they are designed specifically for cutting and finishing operations.

3.10 File Card

A file card is a cleaning tool fitted with short wire bristles.

Uses

Used for cleaning clogged file teeth.

Used for removing metal particles from the file.

Used for maintaining the cutting effectiveness of the file.

3.11 Summary of File Types

Classification	Type
According to Shape	Flat File
	Hand File
	Square File
	Round File
	Half-Round File
	Triangular File
	Knife-Edge File
	Pillar File
	Warding File
According to Cut	Single-Cut File
	Double-Cut File
	Rasp-Cut File
	Curved-Cut File
According to Grade	Rough
	Bastard
	Second Cut
	Smooth
	Dead Smooth
Special Files	Needle File
	Swiss Pattern File

HACKSAWS

4.1 Introduction

A hacksaw is a hand or power-operated cutting tool used for cutting metal, plastic, pipes, rods, bars, sheets, and other materials.

A hacksaw consists mainly of a frame and a replaceable toothed blade. The blade is fitted under tension in the frame, and cutting takes place when the teeth move against the workpiece.

Hacksaws are widely used in fitting, maintenance, fabrication, plumbing, machine shops, and general workshop operations.

4.2 Main Parts of a Hand Hacksaw

A typical hand hacksaw consists of:

Frame

The frame holds the blade and maintains the required blade tension.

Handle

The handle provides a firm grip and allows the operator to move the saw safely.

Blade

The blade is the cutting member and contains a series of teeth along one edge.

Blade Tensioning Screw

It is used to adjust the tension of the blade.

Wing Nut

The wing nut or tensioning mechanism helps secure and tension the blade.

Blade Pins

The pins or pegs at the ends of the frame hold the blade in position.

4.3 Types of Hacksaws

Hacksaws can be classified according to their construction, operation, and application.

The important types are:

Hand Hacksaw
Junior Hacksaw
Fixed Frame Hacksaw
Adjustable Frame Hacksaw
Power Hacksaw
Electric Hacksaw
Reciprocating Hacksaw

4.4 Hand Hacksaw

A hand hacksaw is a manually operated saw consisting of a frame and a removable toothed blade.

Features

Manually operated

Replaceable blade

Blade fitted under tension

Available with different blade lengths and tooth pitches

Uses

Used for cutting metal bars.

Used for cutting rods and pipes.

Used for cutting bolts and screws.

Used for cutting small sections and strips.

Used for general fitting work.

Used for maintenance and repair operations.

The hand hacksaw is one of the most commonly used cutting tools in a general workshop.

4.5 Junior Hacksaw

A junior hacksaw is a small and lightweight hacksaw designed for light cutting operations.

Features

Small frame

Narrow blade

Lightweight construction

Suitable for small and delicate work

Uses

Used for cutting small metal sections.

Used for cutting thin rods and tubes.

Used for cutting small plastic components.

Used for light maintenance work.

Used where access is restricted.

4.6 Fixed Frame Hacksaw

A fixed frame hacksaw has a frame of fixed dimensions designed to accommodate a particular blade length.

Features

Rigid frame

Simple construction

Blade held securely

Suitable for regular cutting work

Uses

Used for general workshop cutting.

Used for cutting rods, bars and pipes.

Used for routine fitting operations.

Used for maintenance work.

4.7 Adjustable Frame Hacksaw

An adjustable frame hacksaw has a frame that can be adjusted to accommodate blades of different lengths.

Features

Adjustable frame

Can accommodate different blade sizes

More versatile than a fixed frame

Uses

Used for general-purpose cutting.

Used where different blade lengths are required.

Used in maintenance workshops.

Used for cutting materials of different sizes.

4.8 Power Hacksaw

A power hacksaw is a machine-operated hacksaw in which the blade is moved mechanically rather than manually.

Features

Mechanically operated

Suitable for repetitive cutting

Can cut larger sections than a hand hacksaw

Provides more consistent cutting action

Uses

Used for cutting metal bars.

Used for cutting pipes.

Used for cutting rods and structural sections.

Used for production and workshop cutting.

Used where repeated cutting operations are required.

4.9 Electric Hacksaw

An electric hacksaw uses an electric motor to provide the cutting motion.

Features

Reduces manual effort

Suitable for repeated cutting operations

Provides relatively consistent cutting action

Uses

Used for cutting metal sections.

Used for workshop maintenance.

Used for fabrication work.

Used for repeated cutting operations.

Used where manual hacksawing would require excessive effort.

4.10 Reciprocating Hacksaw

A reciprocating hacksaw uses a back-and-forth movement of the blade to perform the cutting operation.

Features

Reciprocating blade motion

Mechanically powered

Suitable for cutting relatively large sections

Used for continuous or repeated cutting operations

Uses

Used for cutting metal bars.

Used for cutting pipes and sections.

Used in fabrication shops.

Used in machine and maintenance workshops.

4.11 Hacksaw Blades

The hacksaw blade is the actual cutting element of a hacksaw.

Hacksaw blades are generally made from high-carbon steel, high-speed steel, or other suitable tool materials, depending on the application.

They are available with different tooth pitches.

4.12 Types of Hacksaw Blades According to Tooth Pitch

The common tooth pitches include:

Coarse

Medium

Fine

Very Fine

The selection depends mainly on the thickness and type of material being cut.

Coarse-Tooth Blade

Used for:

Thick sections

Soft materials

Rapid material removal

Medium-Tooth Blade

Used for:

General-purpose cutting

Medium-thickness materials

General workshop operations

Fine-Tooth Blade

Used for:

Thin sections

Thin sheets

Small tubes

Small components

Very Fine-Tooth Blade

Used for:

Very thin materials

Fine cutting operations

Small and delicate sections

4.13 Hacksaw Blade Tooth Arrangement

Hacksaw blades may also differ in the arrangement and design of their teeth.

Regular Tooth Blade

The teeth are arranged in a conventional uniform pattern.

Uses:

General-purpose cutting

Common workshop materials

Variable-Tooth Blade

The tooth spacing varies along the blade.

Uses:

Reducing vibration

Cutting difficult sections

Cutting materials where smoother cutting action is desirable

4.14 Selection of Hacksaw Blade

The correct blade should be selected according to:

Material being cut

Thickness of material

Shape of the workpiece

Required cutting speed

Type of cutting operation

Accessibility of the workpiece

A general rule is that thin materials require finer teeth, while thicker materials can generally be cut with coarser teeth.

4.15 Proper Use of a Hacksaw

The workpiece should be firmly held in a vice or suitable fixture before cutting.

The blade should be fitted with its teeth pointing in the forward cutting direction for a conventional hand hacksaw.

The blade should be tensioned properly. Excessive tension can damage the blade or frame, while insufficient tension can cause poor cutting and blade bending.

During cutting, the operator should use controlled, steady strokes and avoid excessive force.

4.16 Applications of Hacksaws

Hacksaws are commonly used for:

Cutting rods

Cutting pipes

Cutting metal bars

Cutting bolts

Cutting screws

Cutting strips

Cutting tubes

Cutting small structural sections

General fitting work

Maintenance and repair work

Fabrication operations

4.17 Summary of Hacksaw Types

Type	Main Uses
Hand Hacksaw	General manual cutting
Junior Hacksaw	Light and small cutting work
Fixed Frame Hacksaw	Routine workshop cutting
Adjustable Frame Hacksaw	Cutting with different blade lengths
Power Hacksaw	Mechanically powered heavy/repetitive cutting
Electric Hacksaw	Motor-powered cutting
Reciprocating Hacksaw	Repeated cutting of metal sections

SNIPS & SHEARS

5.1 Introduction

Snips and shears are cutting tools used mainly for cutting sheet metal, thin metal plates, wires, strips, and other thin materials.

They work on the principle of shearing, in which two cutting edges move past each other and separate the material.

The selection of snips or shears depends on the thickness, shape, and type of material, as well as the required cutting direction.

5.2 SNIPS

A snip is a hand-operated cutting tool having two sharp cutting blades joined at a pivot. It is mainly used for cutting thin sheets and light materials.

Snips are particularly useful where the material has to be cut manually along straight or curved lines.

5.3 Types of Snips

The important types of snips are:

Straight Snips
Curved Snips
Duckbill Snips
Combination Snips
Aviation Snips
Offset Snips
Tinner’s Snips

5.4 Straight Snips

Straight snips have relatively straight cutting blades.

Features

Straight cutting edges

Designed mainly for straight cuts

Hand-operated

Uses

Used for cutting sheet metal in straight lines.

Used for trimming sheet-metal edges.

Used for cutting thin metal strips.

Used for general sheet-metal work.

5.5 Curved Snips

Curved snips have blades designed to follow curved cutting paths.

Features

Curved or specially shaped cutting edges

Suitable for curved profiles

Uses

Used for cutting curved lines.

Used for cutting circular or irregular shapes.

Used for trimming curved sheet-metal edges.

Used in sheet-metal fabrication.

5.6 Duckbill Snips

Duckbill snips have blades with a distinctive broad, curved shape resembling a duck’s bill.

Features

Broad curved blades

Suitable for controlled cutting of sheet material

Provides better access for certain curved cuts

Uses

Used for cutting curves in sheet metal.

Used for trimming sheet-metal components.

Used for cutting irregular shapes.

Used in fabrication and sheet-metal work.

5.7 Combination Snips

Combination snips are general-purpose hand snips designed for both straight and curved cutting.

Uses

Used for straight cuts.

Used for curved cuts.

Used for trimming sheet metal.

Used for general sheet-metal fabrication.

5.8 Aviation Snips

Aviation snips are specially designed hand-operated snips commonly used for cutting sheet metal.

They are generally available in different configurations for different cutting directions.

Types of Aviation Snips

Straight-Cut Aviation Snips

Usually identified as snips intended primarily for straight cutting.

Uses:

Cutting straight lines in sheet metal.

Trimming sheet edges.

General sheet-metal work.

Left-Cut Aviation Snips

Designed to make left-hand or left-direction curved cuts.

Uses:

Cutting curves toward the left.

Cutting irregular sheet-metal profiles.

Trimming curved edges.

Right-Cut Aviation Snips

Designed to make right-hand or right-direction curved cuts.

Uses:

Cutting curves toward the right.

Cutting irregular profiles.

Trimming sheet-metal edges.

The different blade configurations make aviation snips more suitable for controlled curved cutting than ordinary straight snips.

5.9 Offset Snips

Offset snips have handles or blades arranged so that the operator’s hand is positioned away from the sheet being cut.

Features

Offset blade arrangement

Improved hand clearance

Suitable for longer cuts

Uses

Used for cutting sheet metal.

Used for making longer cuts.

Used where hand clearance is required.

Used for cutting curved and straight profiles depending on design.

5.10 Tinner’s Snips

Tinner’s snips are strong hand-operated cutting tools traditionally used by tinsmiths for cutting thin sheet metal.

Types

Straight Pattern

Curved Pattern

Combination Pattern

Uses

Used for cutting thin sheet metal.

Used for trimming metal sheets.

Used for fabrication work.

Used for making straight and curved cuts.

5.11 SHEARS

A shear is a cutting tool in which two cutting edges pass one another to cut sheet material. Shears may be operated manually, mechanically, or by power.

Compared with ordinary snips, shears are generally used when greater cutting capacity, improved control, or repeated cutting is required.

5.12 Types of Shears

Important workshop shears include:

Hand Shears
Bench Shears
Lever Shears
Throatless Shears
Guillotine Shears
Power Shears
Foot-Operated Shears
Pneumatic Shears

5.13 Hand Shears

Hand shears are manually operated cutting tools used for thin sheet material.

Uses

Used for cutting sheet metal.

Used for trimming edges.

Used for cutting small sheet-metal components.

Used for general fabrication work.

5.14 Bench Shears

Bench shears are mounted on a bench or worktable and provide greater stability than ordinary hand snips.

Features

Fixed to a bench

Lever-operated

Provides better cutting control

Uses

Used for cutting sheet metal.

Used for trimming sheets.

Used for cutting strips.

Used for repetitive workshop operations.

5.15 Lever Shears

Lever shears use a lever mechanism to increase the cutting force applied by the operator.

Features

Long operating lever

Greater mechanical advantage

Suitable for thicker sheet material than ordinary hand snips

Uses

Used for cutting sheet metal.

Used for cutting metal strips.

Used for trimming larger sheets.

Used for repeated cutting operations.

5.16 Throatless Shears

A throatless shear is designed so that the workpiece can move freely around the cutting area without being restricted by a fixed throat.

Features

Open working area

Allows the sheet to be moved in different directions

Suitable for irregular shapes

Uses

Used for cutting irregular shapes.

Used for curved profiles.

Used for circular patterns.

Used for sheet-metal fabrication.

5.17 Guillotine Shears

A guillotine shear uses a blade arrangement in which the cutting action takes place across the width of the sheet.

Features

Straight cutting blade

Suitable for accurate straight cuts

Available in manual and powered forms

Uses

Used for cutting large sheets.

Used for making straight cuts.

Used for cutting sheet-metal strips.

Used in fabrication and production work.

5.18 Power Shears

Power shears use an electric motor or another power source to produce the cutting action.

Features

Power operated

Reduces manual effort

Suitable for repetitive cutting

Provides faster cutting than hand-operated tools

Uses

Used for cutting sheet metal.

Used for fabrication work.

Used for repeated production cutting.

Used for trimming metal sheets.

5.19 Foot-Operated Shears

Foot-operated shears use a foot pedal or treadle to operate the cutting mechanism.

Features

Operated by foot

Hands remain available for controlling the workpiece

Suitable for sheet-metal work

Uses

Used for cutting sheet metal.

Used for straight cutting.

Used for repeated fabrication work.

Used where both hands are needed to control the sheet.

5.20 Pneumatic Shears

Pneumatic shears are operated using compressed air.

Features

Suitable for repeated cutting

Reduces operator effort

Uses

Used for sheet-metal fabrication.

Used for repetitive cutting operations.

Used in industrial workshops.

Used where compressed-air equipment is available.

5.21 Selection of Snips and Shears

The correct tool should be selected according to:

Thickness of sheet

Type of material

Straight or curved cut

Size of workpiece

Required accuracy

Frequency of cutting

Available operating space

Snips are generally preferred for light manual cutting, while shears are selected when greater cutting capacity, stability, or production efficiency is required.

5.22 Summary

Tool / Type	Main Use
Straight Snips	Straight sheet-metal cuts
Curved Snips	Curved cuts
Duckbill Snips	Curved and irregular cuts
Combination Snips	Straight and curved cuts
Aviation Snips	Controlled straight and curved cuts
Offset Snips	Cutting with improved hand clearance
Tinner’s Snips	General sheet-metal cutting
Hand Shears	Light manual sheet cutting
Bench Shears	Stable bench-mounted cutting
Lever Shears	Higher-force sheet cutting
Throatless Shears	Irregular and curved profiles
Guillotine Shears	Straight sheet cutting
Power Shears	Fast and repeated cutting
Foot-Operated Shears	Controlled sheet cutting
Pneumatic Shears	Powered industrial cutting

PLIERS

6.1 Introduction

Pliers are hand-operated workshop tools used mainly for gripping, holding, bending, twisting, cutting, and manipulating wires, small components, rods, and other materials.

They consist generally of two metal levers joined at a pivot. The jaws are operated by opening and closing the handles. The lever action multiplies the force applied by the operator, allowing a relatively small hand force to produce a greater gripping or cutting force at the jaws.

Pliers are widely used in fitting, electrical work, mechanical maintenance, automotive repair, sheet-metal work, fabrication, assembly, and general workshop operations.

6.2 Construction and Main Parts of Pliers

A typical pair of pliers consists of the following parts:

1. Jaws

The jaws are the working portions of the pliers. They grip, hold, bend, or cut the workpiece depending on the type of pliers.

2. Pivot

The pivot connects the two halves of the pliers and allows them to rotate relative to each other.

3. Handles

Handles provide the means of applying hand force. They may have insulated or non-slip coverings for improved grip and operator comfort.

4. Cutting Edges

Certain pliers are provided with hardened cutting edges for cutting wires, cables, pins, and similar materials.

5. Nose

The nose is the forward portion of the pliers containing the jaws. Its shape varies according to the intended application.

6.3 Working Principle of Pliers

Pliers operate according to the principle of the lever.

The pivot acts as the fulcrum. When force is applied to the handles, the jaws move in the opposite direction and exert a gripping or cutting force on the workpiece.

The mechanical advantage depends on the relative distances between:

The hand force and the pivot

The working jaws or cutting edges and the pivot

A longer handle generally allows greater force to be produced at the jaws, while the jaw shape determines the type of operation that can be performed.

6.4 Types of Pliers

Important workshop pliers include:

Combination Pliers
Long-Nose Pliers
Needle-Nose Pliers
Round-Nose Pliers
Flat-Nose Pliers
Bent-Nose Pliers
Side-Cutting Pliers
Diagonal Cutting Pliers
End-Cutting Pliers
Slip-Joint Pliers
Groove-Joint Pliers
Water-Pump Pliers
Locking Pliers
Linesman’s Pliers
Circlip Pliers
Internal Circlip Pliers
External Circlip Pliers
Snap-Ring Pliers
Retaining-Ring Pliers

6.5 Combination Pliers

Definition

Combination pliers are general-purpose pliers designed for gripping, holding, bending, twisting, and cutting wires.

Features

They normally have:

Serrated gripping jaws

A cutting section near the pivot

Strong handles

A central pivot joint

The jaws may include a relatively flat gripping area and a cutting edge.

Uses

Combination pliers are used for:

Holding wires

Bending wires

Twisting wires

Cutting small and medium wires

Gripping nuts and small components

General maintenance work

Electrical and mechanical workshop operations

They are one of the most commonly used general-purpose pliers.

6.6 Long-Nose Pliers

Definition

Long-nose pliers have long, narrow jaws designed for reaching and manipulating components in confined spaces.

Features

The jaws are considerably longer and narrower than those of combination pliers.

Uses

They are used for:

Holding small components

Bending wires

Positioning wires

Reaching into narrow spaces

Electrical assembly

Instrument work

Removing or positioning small parts

They are particularly useful where ordinary pliers cannot reach.

6.7 Needle-Nose Pliers

Definition

Needle-nose pliers are precision gripping pliers having very narrow, tapered jaws.

Features

Their long tapered nose allows access to small and restricted areas.

Uses

They are used for:

Holding thin wires

Bending small wires

Forming wire loops

Handling small components

Electrical work

Electronic assembly

Precision mechanical work

They are especially suitable for delicate manipulation rather than heavy gripping.

6.8 Round-Nose Pliers

Definition

Round-nose pliers have smooth, rounded jaws used mainly for forming and bending wire into curves and loops.

Features

The jaws are generally tapered and circular in cross-section.

Uses

They are used for:

Making wire loops

Forming circular bends

Producing curved wire shapes

Electrical wiring

Jewellery and fine wire work

Small component forming

They are selected when smooth curved bends are required.

6.9 Flat-Nose Pliers

Definition

Flat-nose pliers have broad, flat jaws used for gripping, bending, and positioning small components.

Features

Their jaws provide relatively large flat contact surfaces.

Uses

They are used for:

Holding flat components

Bending sheet material

Straightening wires

Forming wires

Positioning components

General assembly work

They are useful where a firm, controlled grip is required without using serrated jaws.

6.10 Bent-Nose Pliers

Definition

Bent-nose pliers have jaws that are angled or curved relative to the handles.

Features

The angled nose improves visibility and access in restricted locations.

Uses

They are used for:

Reaching around obstacles

Holding small components

Bending wires

Positioning parts

Electrical work

Assembly and maintenance operations

6.11 Side-Cutting Pliers

Definition

Side-cutting pliers are pliers equipped with cutting edges positioned on the side of the jaws.

Features

They are designed primarily for cutting rather than heavy gripping.

Uses

They are used for:

Cutting wires

Cutting small cables

Cutting pins and leads

Electrical installation

Assembly work

General maintenance

The correct cutting capacity must always be considered before cutting a material.

6.12 Diagonal Cutting Pliers

Definition

Diagonal cutting pliers have cutting edges arranged diagonally to the handles and are designed primarily for cutting wire.

Features

The angled cutting edges allow the tool to cut close to a surface in many applications.

Uses

They are used for:

Cutting electrical wires

Cutting component leads

Cutting small pins

Trimming wire ends

Electrical and electronic work

General workshop maintenance

They should not be used to cut materials harder than their specified capacity.

6.13 End-Cutting Pliers

Definition

End-cutting pliers have cutting edges located at the end of the jaws.

Features

The cutting edges meet at the end of the tool, allowing cutting close to the surface of the workpiece.

Uses

They are used for:

Cutting nails

Cutting wire

Removing pins

Cutting protruding material

Trimming wire close to a surface

Construction and maintenance work

They are particularly useful when a flush or near-surface cut is required.

6.14 Slip-Joint Pliers

Definition

Slip-joint pliers have an adjustable pivot that allows the jaws to be set at different openings.

Features

The pivot can be moved between different positions to accommodate different sizes of workpieces.

Uses

They are used for:

Gripping pipes

Holding nuts and fittings

General maintenance

Holding irregular components

Plumbing operations

Mechanical repair

They provide greater versatility than fixed-joint gripping pliers.

6.15 Groove-Joint Pliers

Definition

Groove-joint pliers are adjustable pliers in which the pivot mechanism moves through a series of grooves or positions.

Features

They provide a wide range of jaw openings while maintaining useful gripping capability.

Uses

They are used for:

Holding pipes

Gripping large fittings

Plumbing work

Mechanical maintenance

Holding irregularly shaped components

General repair work

6.16 Water-Pump Pliers

Definition

Water-pump pliers are adjustable gripping pliers designed for gripping objects of different sizes, particularly pipes and fittings.

Features

They have:

Long handles

Adjustable jaw positions

Serrated jaws

Strong gripping capability

Uses

They are commonly used for:

Pipes

Plumbing fittings

Nuts and couplings

Mechanical maintenance

General workshop repair

They are also commonly known as groove-joint or tongue-and-groove pliers depending on their construction.

6.17 Locking Pliers

Definition

Locking pliers are pliers that can be locked onto a workpiece and maintain gripping force without continuous hand pressure.

Features

They generally include:

Adjustable screw mechanism

Locking mechanism

Serrated jaws

Release lever

Uses

They are used for:

Holding workpieces securely

Clamping components

Holding parts during welding

Removing damaged fasteners

Temporary clamping

Mechanical maintenance

They are particularly useful when the operator needs to keep both hands available.

6.18 Linesman’s Pliers

Definition

Linesman’s pliers are heavy-duty pliers designed for gripping, twisting, and cutting electrical conductors and wires.

Features

They generally have:

Strong serrated jaws

Hardened cutting edges

Robust construction

Long handles for increased leverage

Uses

They are used for:

Electrical wiring

Cutting wires

Twisting conductors

Pulling wires

Gripping cables

General electrical maintenance

6.19 Circlip Pliers

Definition

Circlip pliers are specialized pliers used for installing and removing circlips or retaining rings.

Features

Their tips fit into the holes provided in a circlip.

Depending on their design, the pliers may expand an external circlip or compress an internal circlip.

Uses

They are used for:

Removing circlips

Installing circlips

Servicing shafts

Servicing bearings

Automotive repair

Machinery maintenance

6.20 Internal Circlip Pliers

Definition

Internal circlip pliers are designed to remove and install circlips located inside a bore or housing.

Working Action

When the handles are operated, the jaws move in a direction that allows the internal retaining ring to be compressed for removal or installation.

Uses

They are used in:

Bearing housings

Gearboxes

Mechanical assemblies

Automotive components

Machinery maintenance

6.21 External Circlip Pliers

Definition

External circlip pliers are designed for circlips mounted on shafts or outside cylindrical components.

Working Action

The tips engage the holes of the external circlip and move the ring outward or inward as required for installation or removal.

Uses

They are used for:

Shafts

Bearings

Gear assemblies

Automotive components

Mechanical equipment

6.22 Snap-Ring Pliers

Definition

Snap-ring pliers are specialized tools for installing and removing snap rings used as retaining elements in mechanical assemblies.

Features

They are available in different forms depending on whether the ring is internal or external and whether straight or angled access is required.

Uses

They are used in:

Bearings

Shafts

Gearboxes

Automotive assemblies

Hydraulic and mechanical equipment

6.23 Retaining-Ring Pliers

Definition

Retaining-ring pliers are designed specifically for installing and removing retaining rings used to prevent components from moving axially.

Uses

They are used in:

Machinery

Automotive systems

Bearings

Gear assemblies

Pumps

Mechanical equipment

The pliers must match the retaining-ring design and size.

6.24 Selection of Pliers

The correct pliers should be selected according to the operation and workpiece.

Important factors include:

1. Type of Operation

Determine whether the tool is required for:

Gripping

Bending

Cutting

Clamping

Wire forming

Circlip removal

2. Material

Consider the material and hardness of the wire or component before cutting or gripping it.

3. Size of Workpiece

Adjustable pliers should be selected when the workpiece size varies considerably.

4. Accessibility

Long-nose, needle-nose, or bent-nose pliers are suitable for restricted areas.

5. Required Force

Heavy-duty pliers should be selected for high-force applications.

6. Precision

Fine work requires appropriately sized precision pliers with suitable jaw geometry.

6.25 Proper Use of Pliers

For safe and effective operation:

Select the correct type of pliers.

Use pliers of suitable size and capacity.

Keep the jaws clean.

Apply force smoothly.

Keep fingers away from the closing area.

Do not use ordinary pliers as a hammer.

Do not use cutting pliers for materials harder than their rated capacity.

Do not extend handles with pipes or other objects to increase leverage unless the tool is specifically designed for such use.

Do not use insulated handles as protection against electrical voltage unless the pliers are specifically rated and certified for that purpose.

Keep the pivot properly lubricated where appropriate.

Replace damaged or excessively worn pliers.

6.26 Maintenance of Pliers

Proper maintenance increases tool life and reliability.

Cleaning

Remove dirt, grease, metal particles, and other contaminants after use.

Lubrication

Apply suitable lubricant to the pivot when required.

Inspection

Check for:

Cracked handles

Damaged jaws

Worn cutting edges

Loose pivots

Corrosion

Damaged insulation

Storage

Store pliers in a dry location and protect them from excessive moisture and corrosion.

6.27 Applications of Pliers in Workshops

Pliers are used extensively in:

Fitting shops

Machine shops

Electrical workshops

Automobile workshops

Plumbing work

Sheet-metal work

Welding and fabrication

Maintenance departments

Assembly operations

Mechanical repair

Electronics and instrument work

6.28 Summary Table

Type of Pliers	Main Feature	Principal Uses
Combination Pliers	General-purpose gripping and cutting	Holding, bending, cutting wires
Long-Nose Pliers	Long narrow jaws	Confined spaces, wire work
Needle-Nose Pliers	Very narrow tapered jaws	Precision gripping and forming
Round-Nose Pliers	Rounded jaws	Wire loops and curved bends
Flat-Nose Pliers	Flat jaws	Holding and bending
Bent-Nose Pliers	Angled jaws	Restricted access
Side-Cutting Pliers	Side cutting edges	Wire cutting
Diagonal Cutting Pliers	Diagonal cutting edges	Wire and lead cutting
End-Cutting Pliers	Cutting edges at end	Nails, pins, flush cutting
Slip-Joint Pliers	Adjustable pivot	General gripping
Groove-Joint Pliers	Multiple jaw positions	Pipes and fittings
Water-Pump Pliers	Wide adjustable grip	Plumbing and maintenance
Locking Pliers	Locking mechanism	Clamping and holding
Linesman’s Pliers	Heavy-duty construction	Electrical and wire work
Circlip Pliers	Special tips for circlips	Installing/removing circlips
Internal Circlip Pliers	For internal rings	Bore and housing assemblies
External Circlip Pliers	For external rings	Shafts and external assemblies
Snap-Ring Pliers	Snap-ring handling	Mechanical assemblies
Retaining-Ring Pliers	Retaining-ring handling	Bearings, shafts and machinery

6.29 Conclusion

Pliers are essential workshop hand tools based on the lever principle. Different jaw shapes, cutting arrangements, adjustment mechanisms, and specialized tips allow them to perform a wide range of operations. Proper selection according to the material, size, accessibility, and required operation improves efficiency, accuracy, and safety in workshop practice.

SCREWDRIVERS

7.1 Introduction

A screwdriver is a hand tool used for tightening and loosening screws. It consists mainly of a handle, shank, and working tip or blade.

Screwdrivers are widely used in fitting, assembly, electrical work, automobile maintenance, machine repair, appliance servicing, and general workshop operations.

The correct screwdriver must be selected according to the type, size, and head design of the screw. Using an unsuitable screwdriver can damage both the screw head and the tool.

7.2 Construction of a Screwdriver

A typical screwdriver consists of the following main parts:

1. Handle

The handle is the portion held by the operator. It is commonly made from plastic, composite material, wood, or other suitable materials.

The handle provides:

Comfortable gripping

Torque transmission

Control during operation

Some handles are designed with textured or non-slip surfaces to improve grip.

2. Shank

The shank is the metal shaft connecting the handle to the working tip.

It is generally manufactured from hardened steel or alloy steel suitable for transmitting torque.

3. Tip or Blade

The tip engages with the screw head.

Its shape must correspond to the screw-head recess or slot.

4. Ferrule

Some screwdrivers have a ferrule between the handle and shank. It provides additional support and strength to the connection.

7.3 Working Principle of a Screwdriver

A screwdriver operates by converting the turning force applied to the handle into rotational motion of the screw.

When the operator rotates the handle:

Torque is transmitted through the shank.
The tip engages with the screw head.
The screw rotates.
The screw moves into or out of the threaded hole depending on the direction of rotation.

A properly fitting tip provides good contact with the screw head and reduces the possibility of slipping or damaging the recess.

7.4 Types of Screwdrivers

Important types of workshop screwdrivers include:

Flat-Blade Screwdriver
Slotted Screwdriver
Phillips Screwdriver
Pozidriv Screwdriver
Torx Screwdriver
Hex Screwdriver
Robertson Screwdriver
JIS Screwdriver
Precision Screwdriver
Stubby Screwdriver
Offset Screwdriver
Ratcheting Screwdriver
Insulated Screwdriver
Electrician’s Screwdriver
Nut Driver
Interchangeable-Bit Screwdriver

7.5 Flat-Blade Screwdriver

Definition

A flat-blade screwdriver has a flat, straight working tip designed to engage a screw having a straight slot.

Features

The tip is generally rectangular or blade-shaped.

The width and thickness of the tip must be appropriate for the screw slot.

Uses

It is used for:

Slotted screws

General assembly

Machine maintenance

Electrical equipment

Appliances

Workshop repair

7.6 Slotted Screwdriver

Definition

A slotted screwdriver is specifically designed for screws with a single straight slot across the head.

It is commonly considered the standard flat-tip screwdriver.

Uses

It is used for:

Slotted machine screws

Wood screws

Electrical terminals

General maintenance

Equipment assembly

Fitting work

The tip should fit the slot closely to prevent damage to the screw head.

7.7 Phillips Screwdriver

Definition

A Phillips screwdriver has a cross-shaped tip designed for Phillips-head screws.

Features

The tip has four primary driving surfaces arranged in a cross pattern.

Different sizes are available to match different screw-head sizes.

Uses

Phillips screwdrivers are commonly used in:

Machine assembly

Electrical equipment

Electronic equipment

Automotive components

Appliances

General maintenance

Using the correct Phillips size is important to prevent slipping and damage to the screw recess.

7.8 Pozidriv Screwdriver

Definition

A Pozidriv screwdriver is designed for Pozidriv screws, which have a modified cross-shaped recess.

Features

The recess provides additional driving surfaces compared with a standard Phillips design.

A Pozidriv tip should be used with a Pozidriv screw rather than relying on a Phillips screwdriver.

Uses

It is commonly used in:

Furniture assembly

Machinery

Construction

Electrical equipment

General mechanical assembly

7.9 Torx Screwdriver

Definition

A Torx screwdriver has a six-point star-shaped tip designed for Torx screws.

Features

The star-shaped interface provides good contact between the driver and screw.

Uses

Torx screwdrivers are widely used in:

Automotive components

Machinery

Electronics

Appliances

Computer equipment

Mechanical assemblies

They are useful where controlled torque transmission is required.

7.10 Hex Screwdriver

Definition

A hex screwdriver is designed to drive screws having a hexagonal recess.

Features

The working tip has a six-sided profile.

It provides positive engagement with a matching hexagonal socket.

Uses

It is used in:

Machinery

Furniture

Mechanical assemblies

Equipment maintenance

Automotive applications

Hex drivers are also commonly available in the form of L-shaped hex keys or socket-type tools.

7.11 Robertson Screwdriver

Definition

A Robertson screwdriver has a square-shaped driving tip designed for screws with square recesses.

Features

The square recess provides positive engagement between the driver and screw.

Uses

It is used in:

Construction

Woodworking

Furniture assembly

Mechanical applications

General fastening

7.12 JIS Screwdriver

Definition

A JIS screwdriver is designed for screws manufactured according to the Japanese Industrial Standard cross-recess design.

Features

Its tip geometry is different from a standard Phillips design and is intended to provide proper engagement with JIS screws.

Uses

It is particularly useful for:

Japanese machinery

Motorcycles

Automotive equipment

Electronics

Precision mechanical assemblies

7.13 Precision Screwdriver

Definition

Precision screwdrivers are small screwdrivers designed for working with small screws and delicate components.

Features

They generally have:

Small tips

Small handles

Fine control

Various tip profiles

Some precision screwdriver handles include a rotating end that allows controlled finger operation.

Uses

They are used for:

Electronic devices

Instruments

Watches

Small appliances

Computers

Small mechanical assemblies

7.14 Stubby Screwdriver

Definition

A stubby screwdriver has a short shank and compact handle.

Features

Its small overall length allows operation where normal screwdrivers cannot fit.

Uses

It is used in:

Restricted spaces

Automotive repair

Machinery maintenance

Appliance repair

Tight assemblies

Its compact size is its main advantage.

7.15 Offset Screwdriver

Definition

An offset screwdriver has a working tip positioned at an angle to the main body or handle.

Features

The angled arrangement allows screws to be accessed from the side.

Uses

It is used for:

Confined locations

Machinery

Automotive maintenance

Electrical equipment

Assemblies where straight access is difficult

7.16 Ratcheting Screwdriver

Definition

A ratcheting screwdriver contains a mechanism that permits the handle to rotate in one direction while the tip remains engaged with the screw.

Features

The ratchet mechanism allows repeated tightening or loosening without removing the tip from the screw head after every partial turn.

Many designs include a direction selector for:

Tightening

Loosening

Locked position

Uses

It is used for:

Fast assembly

Maintenance

Repeated screw operations

Mechanical work

Electrical installation

General workshop applications

7.17 Insulated Screwdriver

Definition

An insulated screwdriver has a protective insulating covering over the handle and shank area.

Purpose

The insulation is intended to reduce the risk of electrical contact when the tool is specifically rated for electrical work.

Uses

It is used by electricians for:

Electrical terminals

Switchgear

Control panels

Wiring systems

Electrical equipment maintenance

Only screwdrivers specifically designed and appropriately rated for electrical work should be used on energized or potentially energized equipment, following the applicable safety procedures.

7.18 Electrician’s Screwdriver

Definition

An electrician’s screwdriver is designed primarily for electrical installation and maintenance work.

Features

Depending on the design, it may include:

Insulated handle

Insulated shank

Slotted or cross-type tip

Ergonomic grip

Uses

It is used for:

Terminal screws

Switches

Circuit accessories

Electrical panels

Wiring installations

Electrical maintenance

7.19 Nut Driver

Definition

A nut driver is a screwdriver-style tool having a socket at the end instead of a conventional screwdriver tip.

Features

The socket fits over a hexagonal nut or bolt head.

Uses

It is used for:

Small hex nuts

Machine assembly

Electrical equipment

Appliance repair

Automotive components

Fastener installation

Nut drivers are especially useful where a screwdriver-like handle provides convenient access and control.

7.20 Interchangeable-Bit Screwdriver

Definition

An interchangeable-bit screwdriver has a holder that accepts replaceable screwdriver bits of different profiles and sizes.

Features

A single handle can accommodate multiple bit types, such as:

Slotted

Phillips

Pozidriv

Torx

Hex

Uses

It is used for:

General maintenance

Assembly

Electrical work

Appliance servicing

Mechanical repair

It reduces the number of separate handles required for different screw types.

7.21 Screwdriver Tip Selection

The tip should be selected according to the screw head.

Important considerations include:

1. Tip Profile

The tip must match the recess:

Slotted → Flat/slotted tip

Phillips → Phillips tip

Pozidriv → Pozidriv tip

Torx → Torx tip

Hex → Hex tip

Square recess → Robertson/square tip

2. Tip Size

The screwdriver should be correctly matched to the screw size.

An undersized tip may slip, while an oversized tip may not enter the recess correctly.

3. Tip Condition

The tip should not be excessively worn, rounded, chipped, or damaged.

7.22 Proper Use of Screwdrivers

For efficient and safe operation:

Select the correct screwdriver type.

Match the tip size to the screw.

Keep the screwdriver aligned with the screw axis.

Apply steady pressure while turning.

Keep the workpiece secure.

Avoid excessive force.

Do not use a screwdriver as a chisel.

Do not use a screwdriver as a pry bar unless it is specifically designed for that purpose.

Do not strike an ordinary screwdriver with a hammer.

Keep the tip clean and undamaged.

Use electrically rated insulated screwdrivers when required for electrical work.

7.23 Maintenance of Screwdrivers

Proper maintenance improves tool life and performance.

Cleaning

Remove oil, grease, dirt, and metal particles from the tool.

Tip Inspection

Check for:

Rounded edges

Chipped tips

Cracks

Excessive wear

Distortion

Handle Inspection

Check for:

Cracks

Loose components

Damaged insulation

Excessive wear

Storage

Store screwdrivers in a dry and organized location to prevent corrosion and tip damage.

7.24 Applications of Screwdrivers

Screwdrivers are extensively used in:

Fitting shops

Machine shops

Electrical workshops

Automobile workshops

Electronics

Appliance repair

Machinery assembly

Maintenance departments

Construction

Furniture assembly

Instrument servicing

7.25 Advantages of Screwdrivers

Screwdrivers offer several advantages:

Simple construction

Easy operation

Low cost

Portable

Available in many sizes and profiles

Suitable for assembly and maintenance

Easy to replace or interchange

Useful in confined spaces with specialized designs

7.26 Limitations of Screwdrivers

Some limitations include:

Incorrect tip selection can damage the screw.

Excessive force can damage the tool or fastener.

Ordinary screwdrivers should not be used as chisels or levers.

Manual screwdrivers are slower for very large quantities of fastening.

Damaged tips may slip and reduce control.

Electrical work requires appropriately rated insulated tools and proper safety procedures.

7.27 Summary Table

Type of Screwdriver	Main Feature	Principal Uses
Flat-Blade	Flat straight tip	Slotted screws
Slotted	Straight-slot engagement	General fastening
Phillips	Cross-shaped tip	Machinery, electrical and assembly work
Pozidriv	Modified cross-shaped tip	Construction and assembly
Torx	Six-point star tip	Automotive, machinery and electronics
Hex	Hexagonal tip	Mechanical assemblies
Robertson	Square tip	Construction and furniture
JIS	Japanese-standard cross tip	Japanese equipment and electronics
Precision	Small fine tip	Small components and instruments
Stubby	Short compact design	Confined spaces
Offset	Angled access	Restricted locations
Ratcheting	One-way ratchet mechanism	Fast repetitive fastening
Insulated	Electrical protective insulation	Electrical maintenance
Electrician’s	Electrical-work design	Wiring and terminals
Nut Driver	Socket-type end	Hex nuts and small fasteners
Interchangeable-Bit	Replaceable bits	Multiple fastening types

7.28 Conclusion

A screwdriver is a fundamental workshop hand tool used for tightening and loosening screws. Different screwdriver designs are developed to match different screw-head profiles, sizes, working conditions, and accessibility requirements.

Correct selection of the screwdriver improves torque transmission, fastening accuracy, tool life, and safety. The tool should always be used only for its intended purpose, with particular attention to proper tip selection and electrical safety when working on electrical equipment.

SPANNERS & WRENCHES

8.1 Introduction

Spanners and wrenches are hand tools used for tightening and loosening nuts, bolts, screws, pipe fittings, and other threaded fasteners.

They are widely used in:

Fitting shops

Machine shops

Automobile workshops

Maintenance departments

Plumbing work

Assembly operations

Construction work

Mechanical engineering workshops

The correct spanner or wrench must be selected according to the size, shape, location, and type of fastener.

8.2 Difference Between Spanners and Wrenches

The terms spanner and wrench are sometimes used interchangeably.

Generally:

A spanner is commonly used for gripping and turning nuts and bolts.

A wrench is a broader term used for various tools designed to apply torque for turning fasteners, pipes, and mechanical components.

Both perform similar basic functions but are available in different designs for specific applications.

8.3 Main Parts of a Spanner or Wrench

Depending on the type, a spanner or wrench may consist of:

Jaw

The jaw engages with the nut, bolt, or fitting.

Opening

The opening is the space between the jaws of an open-ended spanner.

Ring

A ring spanner has a closed ring-shaped end that surrounds the fastener.

Handle or Shank

The handle provides leverage and allows torque to be applied.

Adjustable Mechanism

Some wrenches have an adjustable jaw mechanism to accommodate different sizes.

Socket

Socket-type wrenches use interchangeable sockets that fit over nuts and bolt heads.

8.4 Types of Spanners and Wrenches

Important types include:

Open-End Spanner
Double Open-End Spanner
Ring Spanner
Double-Ended Ring Spanner
Combination Spanner
Adjustable Spanner
Box Spanner
Socket Wrench
Torque Wrench
Pipe Wrench
Hook Spanner
C-Spanner
Crowfoot Wrench
Allen Key
T-Wrench
Strap Wrench
Chain Wrench
Lug Wrench
Cone Wrench
Flare Nut Wrench

8.5 Open-End Spanner

Definition

An open-end spanner has an open jaw at one or both ends designed to fit over the flats of a nut or bolt head.

Features

Open jaws

Fixed size

Usually made from alloy steel

Available in different sizes

Uses

It is used for:

Tightening nuts

Loosening nuts

Tightening bolts

General fitting work

Machine maintenance

Assembly operations

An open-end spanner is useful where the fastener cannot be accessed from directly above.

8.6 Double Open-End Spanner

Definition

A double open-end spanner has open jaws at both ends.

The two ends are generally designed for different sizes.

Uses

It is used for:

General mechanical work

Tightening and loosening nuts

Assembly operations

Maintenance work

Machine fitting

Having two different sizes increases its usefulness.

8.7 Ring Spanner

Definition

A ring spanner has a closed ring-shaped end that fits around a nut or bolt head.

Features

Closed ring

Provides greater contact with the fastener

Reduces the possibility of slipping

Available in different sizes

Uses

It is used for:

Tightening nuts and bolts

Loosening tight fasteners

Automobile repair

Machine assembly

Mechanical maintenance

A ring spanner generally provides better grip than an open-end spanner.

8.8 Double-Ended Ring Spanner

Definition

A double-ended ring spanner has a ring-shaped opening at both ends.

Uses

It is used for:

Mechanical assembly

Machine maintenance

Automobile work

General workshop operations

Tightening and loosening different sizes of fasteners

The two ends generally provide different sizes.

8.9 Combination Spanner

Definition

A combination spanner has an open-end jaw at one end and a ring end at the other end.

Both ends are generally designed for the same fastener size.

Uses

It is used for:

General fitting work

Tightening nuts and bolts

Machine maintenance

Automobile repair

Assembly work

The open end provides convenient side access, while the ring end provides improved grip.

8.10 Adjustable Spanner

Definition

An adjustable spanner has one fixed jaw and one movable jaw.

The opening can be adjusted to fit different sizes of nuts and bolts.

Main Parts

Fixed jaw

Movable jaw

Adjusting screw

Handle

Uses

It is used for:

Different sizes of nuts

Different sizes of bolts

Maintenance work

Plumbing fittings

General repair work

The adjustable spanner is versatile because one tool can handle several fastener sizes.

8.11 Box Spanner

Definition

A box spanner is a tubular wrench with openings designed to fit around nuts and bolts.

Features

Tubular construction

Usually has openings at both ends

Provides access to recessed fasteners

Uses

It is used for:

Recessed nuts

Spark plugs in suitable designs

Mechanical assemblies

Automobile work

Maintenance operations

8.12 Socket Wrench

Definition

A socket wrench uses removable sockets of different sizes.

The socket fits over the nut or bolt head and is turned using a handle, ratchet, or other drive mechanism.

Main Parts

Socket

Ratchet handle

Drive mechanism

Extension bar, where required

Types of Socket Wrenches

Ratchet Socket Wrench

Fixed Handle Socket Wrench

T-Handle Socket Wrench

Flexible Socket Wrench

Uses

Socket wrenches are used for:

Tightening nuts and bolts

Automobile repair

Machine assembly

Maintenance work

Recessed fasteners

They provide efficient operation and good engagement with suitable fasteners.

8.13 Ratchet Socket Wrench

Definition

A ratchet socket wrench contains a ratchet mechanism that allows repeated turning without removing the socket after each movement.

Uses

It is used for:

Fast assembly

Automobile maintenance

Machine repair

Repeated tightening and loosening operations

Work in restricted spaces

The direction of operation can generally be changed for tightening or loosening.

8.14 Torque Wrench

Definition

A torque wrench is a special wrench designed to apply a specified amount of torque to a fastener.

Types

Important types include:

Beam-Type Torque Wrench

Click-Type Torque Wrench

Dial-Type Torque Wrench

Electronic Torque Wrench

Uses

It is used for:

Tightening critical bolts

Engine assembly

Automobile maintenance

Machine assembly

Precision mechanical work

A torque wrench helps ensure that fasteners are tightened to the required specification.

8.15 Beam-Type Torque Wrench

A beam-type torque wrench indicates the applied torque through the deflection of a beam and a scale.

Uses

General torque measurement

Mechanical maintenance

Assembly work

Fastener tightening where specified torque is required

8.16 Click-Type Torque Wrench

A click-type torque wrench produces an indication, commonly a click, when the preset torque value is reached.

Uses

Automobile work

Machine assembly

Controlled tightening

Production and maintenance operations

It is widely used where a specified tightening torque must be applied.

8.17 Pipe Wrench

Definition

A pipe wrench is a heavy-duty adjustable wrench designed mainly for gripping and turning pipes and round fittings.

Features

Serrated jaws

Adjustable opening

Strong handle

High gripping force

Uses

It is used for:

Tightening pipes

Loosening pipes

Plumbing work

Pipe fitting

Maintenance work

Pipe wrenches are primarily intended for round surfaces and may damage finished surfaces.

8.18 Hook Spanner

Definition

A hook spanner has a hook-shaped end designed to engage with notches or slots on circular nuts.

Uses

It is used for:

Round nuts

Bearing locknuts

Slotted retaining nuts

Mechanical assemblies

Machine maintenance

8.19 C-Spanner

Definition

A C-spanner is a wrench with a C-shaped or hook-shaped design for engaging circular nuts or fittings.

Uses

It is used for:

Circular locknuts

Slotted nuts

Bearing adjustments

Mechanical assemblies

8.20 Crowfoot Wrench

Definition

A crowfoot wrench is an open-ended wrench head designed to attach to a ratchet handle or extension.

Features

Open-end design

Socket-drive connection

Useful in restricted locations

Uses

It is used for:

Difficult-to-reach fasteners

Pipe fittings

Automotive work

Mechanical maintenance

8.21 Allen Key

Definition

An Allen key is an L-shaped tool with a hexagonal cross-section.

It is designed for screws and bolts having a hexagonal socket.

Types

L-Shaped Allen Key

T-Handle Allen Key

Ball-End Allen Key

Folding Allen Key Set

Uses

It is used for:

Socket-head screws

Machinery

Furniture assembly

Bicycle maintenance

Mechanical equipment

8.22 L-Shaped Allen Key

The standard Allen key has two arms of different lengths.

Uses

General hex-socket screws

Machinery assembly

Furniture

Mechanical maintenance

The longer arm provides greater leverage.

8.23 T-Handle Allen Key

A T-handle Allen key has a handle arranged in the shape of the letter T.

Uses

Faster turning

Repeated assembly

Machinery maintenance

Workshop applications

8.24 Ball-End Allen Key

A ball-end Allen key has a rounded end that can engage a suitable hex socket at a limited angle.

Uses

Restricted access

Angled operation

Machinery assembly

Difficult-to-reach fasteners

8.25 T-Wrench

Definition

A T-wrench has a T-shaped handle that provides convenient manual turning.

Uses

It is used for:

Socket operations

Tap holding in suitable designs

Fasteners

Workshop maintenance

The T-shaped handle provides balanced manual control.

8.26 Strap Wrench

Definition

A strap wrench uses a flexible strap to grip round objects.

Features

Flexible strap

Suitable for cylindrical surfaces

Reduces surface damage compared with serrated jaws

Uses

It is used for:

Pipes

Filters

Cylindrical components

Delicate finished surfaces

Plumbing and maintenance

8.27 Chain Wrench

Definition

A chain wrench uses a metal chain to grip large round objects.

Features

Chain gripping mechanism

Suitable for large diameters

High gripping capability

Uses

It is used for:

Large pipes

Cylindrical components

Industrial maintenance

Heavy mechanical work

8.28 Lug Wrench

Definition

A lug wrench is designed primarily for tightening and loosening wheel lug nuts.

Types

L-Shaped Lug Wrench

Cross Lug Wrench

Telescopic Lug Wrench

Uses

It is used for:

Vehicle wheel maintenance

Removing wheel nuts

Installing wheel nuts

8.29 Cone Wrench

Definition

A cone wrench is a thin spanner designed for narrow nuts, particularly those found in adjustable bearing assemblies.

Features

Thin profile

Narrow jaw thickness

Suitable for restricted spaces

Uses

It is used for:

Bicycle hub adjustments

Bearing cone adjustments

Thin locknuts

Precision mechanical assemblies

8.30 Flare Nut Wrench

Definition

A flare nut wrench has a partially enclosed ring designed to grip flare nuts while allowing access around a tube or pipe.

Uses

It is used for:

Brake lines

Hydraulic tubing

Fuel lines

Refrigeration systems

Plumbing connections

The design provides better contact with the nut than a standard open-end spanner.

8.31 Selection of Spanners and Wrenches

The correct tool should be selected according to:

Size of the fastener

Shape of the fastener

Required torque

Available access

Type of application

Material and condition of the fastener

A properly fitting tool reduces slipping and damage to the nut or bolt.

8.32 Proper Use of Spanners and Wrenches

The following practices should be followed:

Select the correct size.

Ensure proper contact with the fastener.

Apply force smoothly.

Avoid excessive force.

Do not use damaged jaws.

Avoid extending the handle with a pipe unless the tool is specifically designed for such use.

Pull the tool where practical instead of placing the body in an unsafe position.

Use a torque wrench when specified tightening torque is required.

Keep tools clean and properly maintained.

8.33 Applications

Spanners and wrenches are extensively used in:

Machine fitting

Automobile repair

Mechanical assembly

Plumbing

Industrial maintenance

Construction

Manufacturing

Equipment servicing

Workshop operations

8.34 Summary of Spanners and Wrenches

Type	Main Use
Open-End Spanner	General nuts and bolts
Double Open-End Spanner	Two different fastener sizes
Ring Spanner	Secure gripping of nuts and bolts
Combination Spanner	Open and ring operations
Adjustable Spanner	Different fastener sizes
Box Spanner	Recessed nuts and bolts
Socket Wrench	Efficient fastening operations
Ratchet Socket Wrench	Fast repetitive work
Torque Wrench	Controlled tightening torque
Pipe Wrench	Pipes and round fittings
Hook Spanner	Circular slotted nuts
C-Spanner	Locknuts and circular fittings
Crowfoot Wrench	Difficult-to-reach fasteners
Allen Key	Hex-socket screws
T-Wrench	Controlled manual turning
Strap Wrench	Delicate cylindrical objects
Chain Wrench	Large pipes and round components
Lug Wrench	Vehicle wheel nuts
Cone Wrench	Thin nuts and bearing adjustments
Flare Nut Wrench	Tubing and hydraulic fittings

8.35 Conclusion

Spanners and wrenches are essential tools for workshop assembly and maintenance. Their different jaw designs, gripping mechanisms, adjustable features, and specialized forms allow them to handle a wide variety of fasteners and mechanical components.

Proper selection and correct use of the appropriate spanner or wrench improve efficiency, safety, fastening accuracy, and the service life of both the tool and the fastener.

FILES

9.1 Introduction

A file is a hand cutting tool used for removing small amounts of material from a workpiece. It is one of the most important tools used in fitting and workshop operations.

Files are commonly used for:

Removing excess material

Smoothing surfaces

Finishing edges

Shaping components

Enlarging holes

Removing burrs

Producing accurate dimensions

Files are widely used in fitting shops, machine shops, fabrication workshops, automobile workshops, maintenance departments, and general engineering work.

9.2 Main Parts of a File

A typical hand file consists of the following parts:

1. Point

The point is the end of the file opposite to the handle.

2. Face

The face is the broad surface of the file containing cutting teeth.

3. Edge

The edge is the narrow side surface of the file.

4. Heel

The heel is the portion of the file near the tang where the teeth generally begin.

5. Tang

The tang is the narrow extension that fits into the handle.

6. Handle

The handle provides a safe and comfortable grip during filing.

7. Teeth

The teeth are small cutting projections that remove material from the workpiece.

9.3 Working Principle of a File

A file removes material through the cutting action of its teeth.

During the forward stroke, the teeth cut and remove small particles from the workpiece.

The amount of material removed depends on:

Type of file

Size of file

Tooth pattern

Material being filed

Pressure applied

Filing technique

9.4 Classification of Files

Files can be classified according to:

Shape
Tooth pattern
Grade or coarseness
Length
Special application

9.5 Types of Files According to Shape

Important types include:

Flat File
Hand File
Square File
Round File
Half-Round File
Triangular File
Knife File
Warding File
Pillar File
Mill File
Crossing File
Barrette File

9.6 Flat File

Definition

A flat file has a broad rectangular cross-section.

It is one of the most commonly used files in general workshop practice.

Features

Flat broad surfaces

Rectangular shape

Suitable for flat surfaces

Available in different grades

Uses

A flat file is used for:

Filing flat surfaces

Removing excess material

Smoothing edges

General fitting work

Finishing metal components

9.7 Hand File

Definition

A hand file is similar to a flat file but generally has one or more safe edges depending on its design.

Features

Flat rectangular shape

Suitable for accurate filing

Convenient for general hand operations

Uses

It is used for:

Filing flat surfaces

Finishing components

Filing edges

General fitting work

Producing accurate surfaces

9.8 Square File

Definition

A square file has a square cross-section.

Features

Four filing surfaces

Square shape

Suitable for square openings

Uses

It is used for:

Enlarging square holes

Filing square corners

Filing rectangular openings

Producing internal corners

General fitting operations

9.9 Round File

Definition

A round file has a circular cross-section.

Features

Round shape

Tapered or parallel design depending on type

Suitable for curved surfaces

Uses

It is used for:

Enlarging circular holes

Filing curved surfaces

Producing rounded profiles

Finishing internal circular surfaces

Round files are commonly known as rat-tail files when they are relatively narrow and tapered.

9.10 Half-Round File

Definition

A half-round file has one flat surface and one curved surface.

Features

Flat on one side

Curved on the other side

Versatile design

Uses

It is used for:

Filing flat surfaces

Filing curved surfaces

Enlarging curved openings

General fitting work

The two different surfaces make it useful for a variety of operations.

9.11 Triangular File

Definition

A triangular file has a triangular cross-section.

Features

Three filing surfaces

Suitable for angles and corners

Uses

It is used for:

Filing internal angles

Filing triangular openings

Filing V-shaped grooves

Sharpening certain saw teeth

It is also commonly called a three-square file.

9.12 Knife File

Definition

A knife file has a thin wedge-shaped cross-section.

Features

Thin profile

Sharp edge

Suitable for narrow grooves

Uses

It is used for:

Filing narrow slots

Filing acute angles

Finishing fine grooves

Precision fitting work

9.13 Warding File

Definition

A warding file is a thin file designed for filing narrow spaces and small openings.

Uses

It is used for:

Narrow slots

Small openings

Fine fitting

Locksmith work

Precision operations

9.14 Pillar File

Definition

A pillar file is a narrow parallel-sided file commonly used for precision filing.

Features

Parallel edges

Relatively narrow shape

Suitable for accurate work

Uses

It is used for:

Precision fitting

Filing narrow surfaces

Toolmaking

Fine mechanical work

9.15 Mill File

Definition

A mill file is generally a flat file with a specific tooth pattern suitable for general finishing and sharpening operations.

Uses

It is used for:

General filing

Finishing metal surfaces

Sharpening suitable tools

Removing small amounts of material

9.16 Crossing File

Definition

A crossing file has curved surfaces with different radii.

Features

Two curved filing surfaces

Different curvature on each side

Uses

It is used for:

Filing curved surfaces

Enlarging curved openings

Finishing internal curves

Special shaping operations

9.17 Barrette File

Definition

A barrette file generally has one working face and non-cutting surfaces on other sides.

Features

One primary cutting surface

Safe surfaces help protect adjacent areas

Uses

It is used for:

Precision filing

Filing selected surfaces

Fine finishing

Tool and die work

9.18 Types of Files According to Tooth Pattern

Files may have different tooth arrangements.

The main types include:

Single-Cut File
Double-Cut File
Rasp-Cut File
Curved-Tooth File

9.19 Single-Cut File

Definition

A single-cut file has one series of parallel rows of teeth.

Features

Teeth arranged in one direction

Produces a smoother cutting action

Removes material at a controlled rate

Uses

It is used for:

Finishing work

Fine filing

Sharpening operations

Producing smoother surfaces

9.20 Double-Cut File

Definition

A double-cut file has two sets of teeth crossing each other.

Features

Crossed tooth pattern

Higher material-removal capability

Suitable for faster filing

Uses

It is used for:

Rapid material removal

Rough filing

General workshop fitting

Removing excess metal

9.21 Rasp-Cut File

Definition

A rasp-cut file has individually formed teeth.

Features

Large individual teeth

Aggressive cutting action

Suitable mainly for softer materials

Uses

It is commonly used for:

Wood

Leather

Soft materials

Rough shaping operations

9.22 Curved-Tooth File

Definition

A curved-tooth file has teeth arranged in curved patterns.

Features

Curved cutting teeth

Efficient material removal

Suitable for certain soft materials

Uses

It may be used for:

Soft metals

Aluminium

Lead

Plastic

Other materials that may clog ordinary files

9.23 Types of Files According to Grade

Files are also classified according to the coarseness of their teeth.

Common grades include:

Rough
Bastard
Second Cut
Smooth
Dead Smooth

9.24 Rough File

A rough file has relatively coarse teeth.

Uses

Rapid material removal

Rough shaping

Initial filing operations

Soft materials

9.25 Bastard File

A bastard file has teeth that are finer than a rough file but coarser than a second-cut file.

Uses

General filing

Medium material removal

Workshop fitting

Initial and intermediate finishing

9.26 Second-Cut File

A second-cut file has finer teeth than a bastard file.

Uses

General finishing

Intermediate filing

Accurate fitting work

Producing smoother surfaces

9.27 Smooth File

A smooth file has fine teeth.

Uses

Fine finishing

Accurate fitting

Surface finishing

Final shaping operations

9.28 Dead Smooth File

A dead smooth file has very fine teeth.

Uses

Very fine finishing

Precision work

Fine mechanical components

Final surface finishing

9.29 Types of Filing Operations

Different filing methods are used depending on the required result.

Important filing operations include:

Straight Filing
Cross Filing
Draw Filing
Diagonal Filing

9.30 Straight Filing

In straight filing, the file is moved generally in a straight direction over the workpiece.

Uses

General material removal

Flat surfaces

Initial filing operations

9.31 Cross Filing

Cross filing involves moving the file diagonally across the surface.

Uses

Removing material quickly

Rough filing

Flattening surfaces

9.32 Draw Filing

In draw filing, the file is held across the workpiece and moved sideways.

Uses

Fine finishing

Producing smooth surfaces

Final surface finishing

Draw filing generally produces a smoother finish than rough filing methods.

9.33 Selection of a File

The correct file should be selected according to:

Shape of Workpiece

Flat surface → Flat file

Round hole → Round file

Square opening → Square file

Curved surface → Half-round file

Amount of Material to Be Removed

Large amount → Rough or double-cut file

Moderate amount → Bastard or second-cut file

Fine finishing → Smooth or dead smooth file

Material

The file should be suitable for the material being worked.

Different materials may require different tooth patterns to avoid excessive clogging and improve cutting efficiency.

9.34 Proper Use of Files

The following practices should be followed:

Use a suitable file handle.

Select the correct file type.

Hold the workpiece firmly.

Apply pressure mainly during the cutting stroke.

Avoid excessive force.

Keep the file clean.

Do not use a damaged file.

Do not strike a file with a hammer.

Do not use a file as a lever.

Store files separately to prevent tooth damage.

9.35 File Cleaning

Files may become clogged with particles during use.

A file card or file brush is commonly used to remove material from between the teeth.

Keeping the teeth clean improves cutting performance and reduces damage to the workpiece.

9.36 Maintenance of Files

Proper maintenance includes:

Cleaning after use

Removing particles from teeth

Protecting against moisture

Preventing corrosion

Avoiding contact between files during storage

Inspecting handles

Replacing damaged files

Files should be stored carefully because contact between their teeth can cause damage.

9.37 Applications of Files in Workshops

Files are widely used for:

Fitting operations

Removing burrs

Surface finishing

Shaping metal

Enlarging holes

Finishing edges

Toolmaking

Machine maintenance

Automobile repair

Fabrication work

9.38 Summary Table

Type of File	Shape / Feature	Main Uses
Flat File	Flat rectangular	Flat surfaces and general filing
Hand File	Flat precision design	Accurate fitting
Square File	Square cross-section	Square holes and corners
Round File	Circular cross-section	Round holes and curved surfaces
Half-Round File	Flat and curved surfaces	Flat and curved work
Triangular File	Three-sided	Angles and V-grooves
Knife File	Thin wedge-shaped	Narrow grooves
Warding File	Thin and narrow	Small openings and slots
Pillar File	Narrow parallel form	Precision filing
Mill File	Flat general-purpose	Finishing and sharpening
Crossing File	Different curved surfaces	Curved work
Barrette File	One main cutting face	Precision finishing

9.39 Summary of File Grades

Grade	Main Application
Rough	Rapid material removal
Bastard	General filing
Second Cut	Intermediate and finishing work
Smooth	Fine finishing
Dead Smooth	Very fine precision finishing

9.40 Conclusion

Files are essential hand tools used for cutting, shaping, smoothing, and finishing materials. They are available in many shapes, tooth patterns, and grades to perform different workshop operations.

Correct selection of the file according to the workpiece shape, material, and required finish is important for efficient and accurate work.

Proper use and maintenance of files improve their service life, cutting efficiency, surface quality, and workshop safety.

CHISELS

10.1 Introduction

A chisel is a cutting hand tool used for cutting, chipping, shaping, removing material, and finishing workpieces.

Chisels are widely used in workshops for working on:

Metals

Wood

Stone

Masonry materials

In workshop technology and manufacturing processes, metalworking chisels, especially cold chisels, are very important hand tools.

A chisel generally works by applying force to its cutting edge. The force may be applied manually, usually with a suitable hammer, depending on the type of chisel and operation.

10.2 Main Parts of a Chisel

A typical metalworking chisel consists of the following parts:

1. Cutting Edge

The cutting edge is the working portion that cuts into the material.

2. Cutting Angle

The cutting angle is formed at the cutting end of the chisel. The angle depends on the material being worked.

3. Bevel

The bevel is the inclined surface formed near the cutting edge.

4. Body

The body forms the main portion of the chisel and transmits the applied force.

5. Head

The head is the striking end of the chisel where force is applied by a hammer.

10.3 Classification of Chisels

Chisels can be classified according to their application and shape.

The main types include:

Cold Chisel
Hot Chisel
Flat Chisel
Cape Chisel
Round-Nose Chisel
Diamond-Point Chisel
Cross-Cut Chisel
Side Chisel
Wood Chisel
Firmer Chisel
Mortise Chisel
Paring Chisel
Bevel-Edge Chisel

10.4 Cold Chisel

Definition

A cold chisel is used for cutting and chipping metals at normal or room temperature.

Cold chisels are generally manufactured from suitable hardened and tempered tool steel.

Uses

A cold chisel is used for:

Cutting metal

Removing unwanted material

Chipping surfaces

Cutting rivets

Removing burrs

Cutting thin metal sections

General fitting operations

Cold chisels are available in several different shapes according to the required operation.

10.5 Types of Cold Chisels

The four most important types of cold chisels used in fitting workshops are:

Flat Chisel
Cape Chisel
Round-Nose Chisel
Diamond-Point Chisel

These are among the most important chisels for workshop and fitting operations.

10.6 Flat Chisel

Definition

A flat chisel has a broad, straight cutting edge.

It is the most commonly used type of cold chisel.

Features

Broad cutting edge

Straight cutting edge

Strong construction

Suitable for general-purpose chipping

Uses

A flat chisel is used for:

General chipping

Cutting metal sheets

Removing excess metal

Cutting rivet heads

Removing burrs

Removing unwanted projections

Chipping large flat surfaces

General fitting work

The flat chisel is generally the first choice for ordinary metal chipping operations.

10.7 Cape Chisel

Definition

A cape chisel has a narrow cutting edge.

It is specially designed for cutting narrow grooves and slots.

Features

Narrow cutting edge

Suitable for confined cutting

Strong side support

Uses

A cape chisel is used for:

Cutting narrow grooves

Cutting keyways

Cutting slots

Making narrow channels

Cleaning corners

It should not be used for cutting large flat surfaces because its narrow cutting edge is designed specifically for narrow work.

10.8 Round-Nose Chisel

Definition

A round-nose chisel has a curved or semicircular cutting edge.

Features

Rounded cutting edge

Suitable for curved grooves

Designed for semicircular shapes

Uses

A round-nose chisel is used for:

Cutting semicircular grooves

Making oil grooves

Forming curved channels

Producing rounded internal shapes

It is commonly used where a curved groove is required.

10.9 Diamond-Point Chisel

Definition

A diamond-point chisel has a pointed cutting end with a diamond-shaped form.

Features

Sharp pointed end

Suitable for corners and narrow areas

Useful for detailed chipping

Uses

A diamond-point chisel is used for:

Cleaning sharp corners

Making V-shaped grooves

Removing material from narrow areas

Producing sharp internal angles

Fine chipping work

It is especially useful where a flat or cape chisel cannot reach properly.

10.10 Cross-Cut Chisel

Definition

A cross-cut chisel is designed mainly for cutting narrow grooves across a metal surface.

Depending on the design, it may be similar in application to a cape chisel.

Uses

It is used for:

Cutting narrow channels

Cutting grooves

Making slots

Removing material from restricted areas

10.11 Side Chisel

Definition

A side chisel is designed for operations where material must be removed from the side of a workpiece or from locations with restricted access.

Uses

It may be used for:

Side cutting operations

Cleaning restricted areas

Removing excess material

Special fitting operations

10.12 Hot Chisel

Definition

A hot chisel is designed for cutting metal when the metal is in a heated condition.

It is commonly used in forging and blacksmithing operations.

Uses

A hot chisel is used for:

Cutting heated metal

Forging operations

Blacksmith work

Separating hot metal sections

Shaping heated workpieces

A hot chisel should be selected according to the conditions for which it is designed.

10.13 Wood Chisel

Definition

A wood chisel is a cutting tool used mainly for cutting and shaping wood.

Wood chisels are different from metalworking chisels because their cutting edges and construction are designed specifically for woodworking operations.

Uses

Wood chisels are used for:

Cutting wood

Shaping wooden components

Making joints

Removing unwanted wood

Finishing wooden surfaces

10.14 Types of Wood Chisels

Important types of wood chisels include:

Firmer Chisel
Bevel-Edge Chisel
Mortise Chisel
Paring Chisel

10.15 Firmer Chisel

Definition

A firmer chisel is a general-purpose woodworking chisel.

Features

Relatively strong blade

Straight cutting edge

Suitable for general woodworking

Uses

It is used for:

General wood cutting

Shaping wood

Making joints

Removing material

Workshop woodworking operations

10.16 Bevel-Edge Chisel

Definition

A bevel-edge chisel has bevelled sides that allow the tool to enter narrow corners.

Features

Bevelled edges

Narrow side profile

Suitable for detailed work

Uses

It is used for:

Fine woodworking

Cleaning corners

Making joints

Working in narrow spaces

Detailed shaping

10.17 Mortise Chisel

Definition

A mortise chisel is a strong chisel designed specifically for cutting mortises in wood.

Features

Thick blade

Strong construction

Designed to withstand higher forces

Uses

It is used for:

Cutting mortises

Making mortise-and-tenon joints

Removing wood from deep openings

Joinery work

10.18 Paring Chisel

Definition

A paring chisel is designed for removing thin layers of wood with controlled hand pressure.

Features

Long blade

Fine cutting edge

Suitable for precision finishing

Uses

It is used for:

Fine finishing

Removing thin layers

Fitting wooden joints

Accurate shaping

Surface finishing

10.19 Selection of a Chisel

The correct chisel should be selected according to:

Type of Material

Different chisels are designed for:

Metal

Heated metal

Wood

Type of Operation

The operation may involve:

General cutting

Chipping

Groove cutting

Slot cutting

Corner cleaning

Curved groove formation

Fine finishing

Shape of Required Cut

The required shape determines the type of chisel:

Required Work	Suitable Chisel
General metal cutting	Flat Chisel
Narrow groove	Cape Chisel
Semicircular groove	Round-Nose Chisel
Sharp corners	Diamond-Point Chisel
Hot metal cutting	Hot Chisel
General woodworking	Firmer Chisel
Narrow corners in wood	Bevel-Edge Chisel
Mortises	Mortise Chisel
Fine wood finishing	Paring Chisel

10.20 Proper Use of Chisels

The following practices should be followed when using chisels:

Select the correct type of chisel.

Ensure the cutting edge is properly maintained.

Hold the workpiece securely.

Use a suitable hammer where required.

Apply controlled force.

Avoid excessive striking force.

Keep hands away from the cutting area.

Do not use a damaged chisel.

Do not use a chisel with a badly mushroomed head.

Maintain the correct cutting edge for efficient operation.

10.21 Maintenance of Chisels

Proper maintenance includes:

Cleaning

Remove dirt, oil, and metal particles after use.

Cutting Edge Maintenance

The cutting edge should be maintained in proper condition.

A damaged or dull edge reduces cutting efficiency.

Head Inspection

The striking head should be checked regularly for deformation or mushrooming.

Storage

Chisels should be stored in a dry location to prevent corrosion and damage.

10.22 Applications of Chisels in Workshops

Chisels are used in:

Fitting shops

Machine shops

Forging shops

Woodworking shops

Maintenance departments

Fabrication workshops

Automobile workshops

General engineering work

10.23 Summary Table — Types of Chisels and Their Uses

Type of Chisel	Main Use
Cold Chisel	Cutting metal at normal temperature
Flat Chisel	General metal cutting and chipping
Cape Chisel	Narrow grooves and slots
Round-Nose Chisel	Semicircular grooves
Diamond-Point Chisel	Sharp corners and V-grooves
Cross-Cut Chisel	Narrow channels and grooves
Side Chisel	Restricted and side cutting operations
Hot Chisel	Cutting heated metal
Wood Chisel	Cutting and shaping wood
Firmer Chisel	General woodworking
Bevel-Edge Chisel	Fine work and narrow corners
Mortise Chisel	Cutting mortises
Paring Chisel	Fine finishing of wood

10.24 Conclusion

Chisels are important cutting and shaping tools used in workshop operations. Different types are designed for specific materials and applications.

In a fitting workshop, the flat chisel, cape chisel, round-nose chisel, and diamond-point chisel are particularly important.

Correct selection of the chisel according to the material, required shape, and type of operation improves cutting efficiency, accuracy, safety, and tool life.

PUNCHES

11.1 Introduction

A punch is a hand tool used for marking, locating, driving, removing, or forming holes and impressions on a workpiece.

Punches are commonly used in:

Fitting shops

Machine shops

Sheet-metal workshops

Fabrication shops

Automobile workshops

Maintenance work

Most punches are struck with a suitable hammer to perform their operation.

11.2 Main Parts of a Punch

A typical punch consists of:

1. Point

The point is the working end that contacts the workpiece.

2. Body

The body forms the main portion of the punch and transmits the striking force.

3. Shank

The shank provides strength and connects the working end with the head.

4. Head

The head is the striking end of the punch where force is applied.

11.3 Types of Punches

The important types of punches used in workshop practice include:

Prick Punch
Centre Punch
Dot Punch
Automatic Centre Punch
Pin Punch
Drift Punch
Taper Punch
Hollow Punch
Transfer Punch
Letter Punch
Number Punch
Belt Punch
Gasket Punch

11.4 Prick Punch

Definition

A prick punch is used for making small, light indentations on a marked line.

It is commonly used during marking-out operations before more permanent marks are made.

Features

Sharp pointed end

Fine marking point

Used for accurate initial marking

Uses

A prick punch is used for:

Making small reference marks

Marking layout lines

Indicating points on a workpiece

Preliminary marking before centre punching

11.5 Centre Punch

Definition

A centre punch is used for making an indentation at the centre of a hole location before drilling.

The indentation helps the drill point locate correctly and reduces the tendency of the drill to move away from the marked position.

Uses

A centre punch is used for:

Marking hole centres

Preparing a location for drilling

Locating drill points

Marking important reference positions

It is one of the most commonly used punches in fitting work.

11.6 Dot Punch

Definition

A dot punch is used for making permanent dot marks on layout lines.

Uses

It is used for:

Marking layout lines

Making reference points

Indicating boundaries

Producing permanent identification marks

A series of dots can be made along a marked line to preserve the layout during further workshop operations.

11.7 Automatic Centre Punch

Definition

An automatic centre punch is a spring-operated punch that produces an indentation without requiring a hammer.

Features

Spring-operated mechanism

Adjustable striking force in some designs

Convenient one-hand operation

Uses

It is used for:

Marking drilling locations

Making centre marks

Layout work

Precision marking

It is particularly useful when repeated centre marks are required.

11.8 Pin Punch

Definition

A pin punch is designed for driving pins, dowel pins, and similar components out of holes.

Features

Straight, narrow working end

Available in different diameters

Designed to fit the size of the pin

Uses

It is used for:

Removing pins

Driving dowel pins

Removing retaining pins

Assembly and disassembly work

Mechanical maintenance

The punch diameter should be slightly smaller than the hole containing the pin.

11.9 Drift Punch

Definition

A drift punch is generally tapered and is used for aligning holes or positioning components.

It is not primarily intended for producing accurate holes.

Uses

A drift punch is used for:

Aligning bolt holes

Aligning machine components

Positioning parts

Assisting assembly operations

11.10 Taper Punch

Definition

A taper punch has a gradually tapered working end.

Features

Tapered shape

Available in different sizes

Suitable for alignment operations

Uses

It is used for:

Aligning holes

Positioning components

Assisting assembly

Enlarging openings slightly in suitable operations

11.11 Hollow Punch

Definition

A hollow punch is a tubular punch with a circular cutting edge.

It is used for producing circular holes in suitable soft materials.

Uses

It is commonly used for making holes in:

Leather

Rubber

Gaskets

Plastic sheets

Soft materials

Hollow punches are available in different diameters.

11.12 Transfer Punch

Definition

A transfer punch is used to transfer the location of an existing hole from one component to another workpiece.

Uses

It is used for:

Transferring hole locations

Accurate layout work

Assembly operations

Jig and fixture work

Mechanical fitting

It helps maintain accurate correspondence between mating components.

11.13 Letter Punch

Definition

A letter punch is used for permanently marking alphabetical characters on suitable workpieces.

Uses

It is used for:

Identification marking

Component marking

Workshop identification

Serial information

Manufacturing marks

11.14 Number Punch

Definition

A number punch is used for permanently marking numerical characters.

Uses

It is used for:

Serial numbers

Component identification

Production numbers

Equipment marking

Workshop records

11.15 Belt Punch

Definition

A belt punch is used for making holes in belts and similar flexible materials.

Uses

It is commonly used for:

Leather belts

Rubber materials

Flexible straps

Similar soft materials

Different punch sizes are available according to the required hole diameter.

11.16 Gasket Punch

Definition

A gasket punch is designed for producing holes in gasket materials.

Uses

It is used for:

Rubber gaskets

Fibre gaskets

Soft gasket sheets

Maintenance and repair work

It is commonly used when preparing or modifying gasket materials.

11.17 Selection of Punches

The correct punch should be selected according to the required operation.

Operation	Suitable Punch
Preliminary marking	Prick Punch
Hole centre marking	Centre Punch
Permanent layout dots	Dot Punch
Hammer-free centre marking	Automatic Centre Punch
Removing pins	Pin Punch
Aligning holes	Drift Punch
Alignment and positioning	Taper Punch
Cutting circular holes	Hollow Punch
Transferring hole positions	Transfer Punch
Alphabetical identification	Letter Punch
Numerical identification	Number Punch
Holes in belts	Belt Punch
Holes in gasket material	Gasket Punch

11.18 Proper Use of Punches

The following practices should be followed:

Select the correct type of punch.

Use a suitable hammer where required.

Hold the punch correctly.

Keep the workpiece securely supported.

Strike the punch accurately.

Avoid excessive force.

Keep hands away from the striking area.

Do not use a damaged punch.

Replace punches with badly mushroomed heads.

Select the correct punch diameter for pins and holes.

11.19 Maintenance of Punches

Proper maintenance includes:

Cleaning

Remove dirt, grease, and metal particles after use.

Point Inspection

Check the working point for:

Damage

Excessive wear

Bending

Deformation

Head Inspection

Check the striking head for mushrooming or cracks.

Storage

Store punches in a dry location and preferably in an organized tool holder.

11.20 Applications of Punches in Workshops

Punches are widely used for:

Marking operations

Drilling preparation

Hole alignment

Pin removal

Component assembly

Component identification

Sheet and gasket work

Maintenance operations

Mechanical fitting

11.21 Summary Table — Types of Punches

Type of Punch	Main Use
Prick Punch	Preliminary marking
Centre Punch	Marking drilling centres
Dot Punch	Permanent layout marks
Automatic Centre Punch	Spring-operated centre marking
Pin Punch	Driving and removing pins
Drift Punch	Aligning holes
Taper Punch	Alignment and positioning
Hollow Punch	Cutting circular holes
Transfer Punch	Transferring hole locations
Letter Punch	Marking letters
Number Punch	Marking numbers
Belt Punch	Making holes in belts
Gasket Punch	Making holes in gasket material

11.22 Conclusion

Punches are essential workshop tools used for marking, locating, aligning, driving, removing, and forming operations.

Each type of punch has a specific purpose. For example, a centre punch is used before drilling, while a pin punch is used for removing pins, and a transfer punch is used for transferring hole locations.

Correct selection and proper use of punches improve accuracy, efficiency, safety, and the quality of workshop operations.

MARKING & MEASURING TOOLS

12.1 Introduction

Marking and measuring tools are essential workshop instruments used to determine dimensions, establish reference points and lines, transfer measurements, check accuracy, and guide manufacturing operations.

Marking tools are mainly used to transfer or indicate dimensions and locations on a workpiece, while measuring tools are used to determine or verify dimensions.

They are widely used in:

Fitting shops

Machine shops

Fabrication workshops

Tool rooms

Sheet-metal work

Inspection departments

Manufacturing industries

Accurate marking and measurement are essential for producing components according to the required dimensions and tolerances.

12.2 Classification of Marking and Measuring Tools

Important workshop tools in this category include:

Marking Tools

Scriber
Marking Knife
Surface Gauge
Height Gauge
Divider
Odd-Leg Caliper
Prick Punch
Centre Punch
Marking Block
Surface Plate

Measuring Tools

Steel Rule
Measuring Tape
Outside Caliper
Inside Caliper
Vernier Caliper
Vernier Height Gauge
Vernier Depth Gauge
Micrometer
Depth Micrometer
Screw Pitch Gauge
Feeler Gauge
Radius Gauge
Bevel Protractor
Combination Set
Dial Indicator
Slip Gauges
Thread Plug Gauge
Thread Ring Gauge

PART A — MARKING TOOLS

12.3 Scriber

Definition

A scriber is a pointed marking tool used for making fine lines on metal surfaces.

Construction

A scriber is generally made from hardened steel and has one or more sharp pointed ends.

Uses

It is used for:

Marking straight lines

Transferring dimensions

Marking centres and boundaries

Layout work

Marking lines before cutting or machining

The line produced by a scriber is fine and relatively permanent.

12.4 Marking Knife

Definition

A marking knife is a sharp-edged tool used to produce precise marking lines, particularly on wood and certain soft materials.

Uses

It is used for:

Accurate layout

Marking dimensions

Marking joints

Producing fine reference lines

It is particularly useful where a narrow and precise line is required.

12.5 Surface Gauge

Definition

A surface gauge is a marking and measuring instrument used to transfer dimensions from a reference surface to a workpiece.

Main Parts

A typical surface gauge consists of:

Base

Spindle

Scriber

Clamp

Fine adjustment arrangement

Uses

It is used for:

Marking parallel lines

Transferring dimensions

Checking parallelism

Locating positions relative to a datum surface

Layout work on a surface plate

12.6 Height Gauge

Definition

A height gauge is a precision measuring and marking instrument used to measure or mark vertical dimensions from a reference surface.

Features

It generally consists of:

Rigid base

Vertical beam or column

Sliding carriage

Fine adjustment

Scriber or measuring attachment

Uses

It is used for:

Measuring heights

Marking lines at specified heights

Comparing dimensions

Layout work

Checking component positions

12.7 Divider

Definition

A divider is a marking instrument having two pointed legs used for transferring distances, dividing lines, and marking arcs or circles.

Uses

It is used for:

Transferring dimensions

Marking circles

Marking arcs

Dividing lines

Locating equal distances

Layout work

Dividers are particularly useful for transferring dimensions from a scale to a workpiece.

12.8 Odd-Leg Caliper

Definition

An odd-leg caliper, also called a Jenny caliper, has one straight leg and one leg with a bent or offset point.

Uses

It is used for:

Marking parallel lines

Marking lines from an edge

Locating the centre of round workpieces

Layout operations

12.9 Marking Block

Definition

A marking block is a simple layout tool used to support and position a scriber or marking point at a desired height.

Uses

It is used for:

Marking lines

Transferring heights

Basic layout operations

Positioning reference lines

12.10 Surface Plate

Definition

A surface plate is a precision flat reference surface used for marking, measuring, inspection, and layout operations.

Features

It is manufactured with a highly accurate flat surface.

Uses

It is used for:

Supporting workpieces

Precision marking

Inspection

Checking flatness

Using height gauges and surface gauges

Layout operations

A surface plate is a reference tool rather than a direct measuring instrument.

PART B — MEASURING TOOLS

12.11 Steel Rule

Definition

A steel rule is a simple linear measuring instrument used to measure or transfer dimensions.

Features

Graduated scale

Straight rigid construction

Usually made from steel

Uses

It is used for:

Measuring lengths

Checking dimensions

Marking distances

General workshop measurement

Steel rules are suitable for ordinary measurements but are less precise than precision instruments such as micrometers.

12.12 Measuring Tape

Definition

A measuring tape is a flexible measuring instrument used mainly for measuring longer dimensions.

Uses

It is used for:

Measuring large components

Workshop layout

Construction work

Fabrication

General dimensional measurement

It is convenient for large dimensions but is not normally used where very high precision is required.

12.13 Outside Caliper

Definition

An outside caliper is used to compare or transfer the external dimensions of a workpiece.

Features

It has two legs that contact the outside surfaces of the component.

Uses

It is used for:

Checking outside diameters

Comparing external dimensions

Transferring measurements

Checking thickness

A caliper normally requires a separate scale or reference instrument when an actual numerical dimension is required.

12.14 Inside Caliper

Definition

An inside caliper is used to compare or transfer internal dimensions.

Uses

It is used for:

Checking internal diameters

Measuring internal widths

Comparing openings

Transferring internal dimensions

It is commonly used for holes, slots, and other internal features.

12.15 Vernier Caliper

Definition

A Vernier caliper is a precision measuring instrument used for measuring external dimensions, internal dimensions, and depths.

Main Parts

A typical vernier caliper consists of:

Main scale

Vernier scale

Outside jaws

Inside jaws

Depth rod

Locking screw

Fine adjustment mechanism in suitable designs

Uses

It is used for measuring:

Outside diameter

Inside diameter

Thickness

Length

Depth

Step dimensions

The vernier principle allows measurements to be read more precisely than with an ordinary steel rule.

12.16 Vernier Height Gauge

Definition

A vernier height gauge is a precision instrument used to measure and mark vertical dimensions from a reference surface.

Features

It normally has:

Base

Graduated vertical beam

Sliding carriage

Vernier scale

Scriber or measuring attachment

Fine adjustment

Uses

It is used for:

Measuring heights

Marking accurate lines

Comparing heights

Layout work

Inspection

It is commonly used on a surface plate.

12.17 Vernier Depth Gauge

Definition

A vernier depth gauge is a precision instrument used to measure the depth of holes, slots, recesses, and steps.

Features

It generally consists of:

Base

Main scale

Vernier scale

Depth blade or rod

Uses

It is used for:

Measuring hole depth

Measuring slot depth

Measuring recesses

Measuring steps

Precision inspection

12.18 Micrometer

Definition

A micrometer is a precision measuring instrument used for measuring small dimensions with high accuracy.

It operates using a precision screw mechanism.

Main Parts

A typical outside micrometer consists of:

Frame

Anvil

Spindle

Sleeve

Thimble

Ratchet stop

Lock

Working Principle

The spindle moves axially when the thimble is rotated because of the precision screw thread.

The amount of spindle movement corresponds to the pitch of the screw and the angular movement of the thimble.

Uses

It is used for measuring:

Outside diameter

Thickness

Small external dimensions

Shafts

Precision components

12.19 Outside Micrometer

Definition

An outside micrometer is specifically designed to measure external dimensions.

Uses

It is used for:

Shaft diameter

Rod diameter

Component thickness

External dimensions

12.20 Inside Micrometer

Definition

An inside micrometer is designed for measuring internal dimensions.

Uses

It is used for:

Internal diameters

Bores

Internal widths

Precision internal measurements

12.21 Depth Micrometer

Definition

A depth micrometer is a precision instrument used to measure the depth of holes, slots, recesses, and steps.

Uses

It is used for:

Deep holes

Slots

Recesses

Steps

Precision depth inspection

12.22 Screw Pitch Gauge

Definition

A screw pitch gauge is a measuring tool used to determine the pitch or thread spacing of a screw thread.

Construction

It consists of a set of thin leaves, each having teeth corresponding to a particular thread pitch.

Uses

It is used for:

Identifying thread pitch

Checking screw threads

Selecting a matching thread

Thread inspection

The gauge is available in different metric and imperial thread standards.

12.23 Feeler Gauge

Definition

A feeler gauge consists of a set of thin metal blades of known thickness used for measuring or checking small gaps.

Features

Each blade has a specified thickness.

Uses

It is used for:

Checking clearances

Valve clearance adjustment

Checking gaps between components

Machine maintenance

Precision fitting

12.24 Radius Gauge

Definition

A radius gauge is used to check the radius of convex and concave curved surfaces.

Construction

It consists of a set of blades or leaves having accurately formed radii.

Uses

It is used for:

Checking internal radii

Checking external radii

Inspecting curved profiles

Toolmaking

Machine component inspection

12.25 Bevel Protractor

Definition

A bevel protractor is a precision angular measuring instrument used to measure and set angles.

Main Parts

It generally consists of:

Protractor scale

Blade

Stock

Adjustable mechanism

Vernier scale in precision designs

Uses

It is used for:

Measuring angles

Setting angles

Checking inclined surfaces

Machine setup

Inspection work

12.26 Combination Set

Definition

A combination set is a versatile measuring and marking instrument consisting of a graduated rule and interchangeable heads.

Common Heads

Square head

Protractor head

Centre head

Uses

It is used for:

Checking 90° angles

Checking 45° angles

Measuring depths

Marking lines

Finding centres

Measuring angles

12.27 Dial Indicator

Definition

A dial indicator is a precision comparative measuring instrument used to detect and measure small linear movements.

Working Principle

The movement of the contact point is transferred through a mechanical mechanism to a pointer that moves over a graduated dial.

Uses

It is used for:

Checking runout

Checking alignment

Checking parallelism

Checking flatness

Comparing dimensions

Machine setup

Precision inspection

12.28 Slip Gauges

Definition

Slip gauges, also called gauge blocks, are precision blocks of accurately known dimensions used as standards for measurement and calibration.

Features

They are manufactured to very high dimensional accuracy.

Uses

They are used for:

Setting measuring instruments

Checking dimensions

Calibration

Precision inspection

Setting machine tools

Establishing reference dimensions

Several blocks can be wrung together to obtain a required dimension.

12.29 Thread Plug Gauge

Definition

A thread plug gauge is a limit gauge used for checking the internal thread of a component.

Features

It generally has:

GO portion

NO-GO portion

Uses

It is used for:

Checking internal threads

Production inspection

Verifying thread acceptability

The GO and NO-GO principles allow rapid inspection without determining the exact thread dimension.

12.30 Thread Ring Gauge

Definition

A thread ring gauge is a limit gauge used for checking external threads.

Uses

It is used for:

Checking external threads

Production inspection

Verifying threaded shafts

Checking manufactured components

12.31 Accuracy and Precision

Accuracy and precision are important concepts in workshop measurement.

Accuracy

Accuracy indicates how close a measured value is to the true or accepted value.

Precision

Precision indicates the degree of consistency or repeatability of measurements.

A good measuring instrument should provide appropriate accuracy, repeatability, and resolution for the required application.

12.32 Selection of Measuring Tools

The measuring instrument should be selected according to:

1. Required Accuracy

General dimensions may be measured using a steel rule, while precision dimensions may require a vernier caliper or micrometer.

2. Type of Dimension

Different instruments are required for:

External dimensions

Internal dimensions

Depths

Angles

Gaps

Radii

Thread pitch

3. Size of Workpiece

The measuring range of the instrument must be suitable for the component.

4. Shape and Accessibility

The instrument must be capable of reaching the feature being measured.

5. Measurement Resolution

The smallest readable increment should be suitable for the required tolerance.

12.33 Proper Use of Measuring Instruments

The following practices should be followed:

Select the correct instrument.

Clean the measuring surfaces.

Clean the workpiece before measurement.

Avoid excessive measuring force.

Check zero setting where applicable.

Hold the instrument correctly.

Read the scale carefully.

Avoid measuring a moving workpiece.

Protect precision instruments from impact.

Store instruments in suitable protective cases.

12.34 Maintenance of Measuring Instruments

Precision measuring instruments require careful handling.

Important practices include:

Clean instruments after use.

Protect measuring surfaces from scratches.

Prevent corrosion.

Do not drop precision instruments.

Check calibration at appropriate intervals.

Store instruments in dry, protected locations.

Do not force measuring mechanisms.

Keep precision instruments away from excessive heat and contamination.

12.35 Summary — Important Marking Tools

Tool	Main Use
Scriber	Fine marking lines
Marking Knife	Precise layout marking
Surface Gauge	Marking from a datum surface
Height Gauge	Measuring and marking heights
Divider	Circles, arcs and transferring dimensions
Odd-Leg Caliper	Parallel marking and centre finding
Marking Block	Basic layout and height marking
Surface Plate	Precision reference surface

12.36 Summary — Important Measuring Tools

Tool	Main Use
Steel Rule	General linear measurement
Measuring Tape	Long dimensions
Outside Caliper	External dimension comparison
Inside Caliper	Internal dimension comparison
Vernier Caliper	External, internal and depth measurement
Vernier Height Gauge	Height measurement and marking
Vernier Depth Gauge	Depth measurement
Micrometer	Precision measurement
Inside Micrometer	Internal dimensions
Depth Micrometer	Precision depth measurement
Screw Pitch Gauge	Thread pitch identification
Feeler Gauge	Small gap measurement
Radius Gauge	Checking radii
Bevel Protractor	Angle measurement
Combination Set	Squaring, angle and centre work
Dial Indicator	Comparative precision measurement
Slip Gauges	Precision standards and calibration
Thread Plug Gauge	Internal thread inspection
Thread Ring Gauge	External thread inspection

12.37 Conclusion

Marking and measuring tools are fundamental to accurate workshop practice. Marking tools establish the required geometry and reference locations, while measuring instruments determine or verify dimensions and conditions.

The correct instrument must be selected according to the required accuracy, dimension, range, feature geometry, and tolerance.

Proper handling, cleaning, calibration, and storage of measuring instruments are essential for maintaining measurement accuracy and ensuring reliable manufacturing results.

HOLDING & CLAMPING TOOLS

13.1 INTRODUCTION

Holding and clamping tools are essential workshop devices used to securely hold, support, position, or restrain a workpiece during manufacturing and maintenance operations.

A workpiece must remain stable during operations such as cutting, filing, drilling, tapping, marking, assembly, welding, and machining. Proper holding prevents unwanted movement and improves accuracy, safety, and surface finish.

Holding and clamping devices range from simple hand-operated clamps to heavy-duty machine-workholding systems.

13.2 DEFINITION

A holding tool is a device used to support or grip a workpiece so that it remains in a stable position during an operation.

A clamping tool is a device used to apply a controlled force to hold a workpiece firmly against a supporting surface or fixture.

The main purposes are:

To prevent workpiece movement

To maintain correct position

To improve dimensional accuracy

To improve operator safety

To facilitate accurate machining and assembly

To reduce vibration

To provide repeatable positioning

13.3 IMPORTANT REQUIREMENTS OF A GOOD HOLDING DEVICE

A good holding or clamping device should:

Hold the workpiece firmly.
Avoid unnecessary deformation.
Provide adequate accessibility to the working area.
Allow quick loading and unloading.
Maintain accurate positioning.
Resist vibration and cutting forces.
Be suitable for the shape and size of the workpiece.
Be strong enough for the intended operation.
Permit safe operation.
Minimize damage to finished surfaces.

13.4 CLASSIFICATION OF HOLDING & CLAMPING TOOLS

Important workshop holding and clamping devices include:

Bench Vice
Machine Vice
Hand Vice
Pin Vice
Pipe Vice
Leg Vice
Toolmaker’s Vice
Angle Vice
Cross-Slide Vice
Quick-Release Vice
Chain Clamp
C-Clamp
G-Clamp
F-Clamp
Bar Clamp
Toggle Clamp
Parallel Clamp
Edge Clamp
Strap Clamp
Sash Clamp
Magnetic Clamp
Welding Clamp
Locking Clamp
Spring Clamp
V-Block with Clamp
Step Clamp
Hold-Down Clamp
Workholding Fixture

13.5 VICES

A vice is a mechanical holding device consisting mainly of fixed and movable jaws. The workpiece is held between the jaws by applying clamping force.

Vices are among the most commonly used holding devices in fitting and machine workshops.

13.5.1 BENCH VICE

A bench vice is a vice permanently or semi-permanently mounted on a workbench.

Construction

The main parts include:

Fixed jaw

Movable jaw

Jaw plates

Spindle

Handle

Slide

Body

Base

Swivel mechanism in swivel types

Working

The workpiece is placed between the jaws. Rotating the spindle moves the movable jaw toward the fixed jaw and clamps the workpiece.

Uses

Filing

Sawing

Chiseling

Drilling small workpieces

Assembly and dismantling

General fitting work

13.5.2 SWIVEL BASE BENCH VICE

A swivel-base vice is mounted on a base that permits the vice body to rotate through a required angle.

Advantages

Work can be positioned conveniently.

Different working orientations can be obtained.

Operator accessibility is improved.

Applications

Used in fitting, maintenance, fabrication, and general workshop operations.

13.5.3 QUICK-RELEASE VICE

A quick-release vice allows the movable jaw to be repositioned rapidly without continuously rotating the spindle.

Advantages

Faster workpiece loading

Faster unloading

Reduced setup time

Suitable for repetitive work

13.5.4 HAND VICE

A hand vice is a small portable vice operated by hand.

Features

Compact construction

Lightweight

Small jaws

Portable design

Uses

Holding small components

Small filing operations

Small fitting work

Holding thin sections

Light assembly work

13.5.5 PIN VICE

A pin vice is a small hand-operated holding device having a small chuck or collet for gripping very small components.

Uses

Holding small drills

Small reaming tools

Fine hand work

Jewelry and instrument work

Precision small-component operations

13.5.6 PIPE VICE

A pipe vice is specially designed to hold cylindrical pipes and tubes.

Features

Its jaws are shaped to grip round work securely.

Uses

Cutting pipes

Threading pipes

Filing pipe ends

Pipe fitting

Plumbing operations

13.5.7 LEG VICE

A leg vice is a heavy-duty vice traditionally used in blacksmithing and forging work.

It has a long leg that transfers load to the floor or supporting structure.

Uses

Heavy forging work

Hot and cold metalworking

Holding heavy sections

Chiseling and bending operations

13.5.8 TOOLMAKER’S VICE

A toolmaker’s vice is a precision vice used for accurately holding small components.

Features

High accuracy

Hardened jaws

Compact construction

Precise alignment

Uses

Toolmaking

Precision fitting

Inspection work

Small machining operations

Precision assembly

13.5.9 ANGLE VICE

An angle vice holds a workpiece at a fixed or adjustable angle.

Uses

Angular filing

Angular machining

Drilling at an angle

Precision fitting

13.5.10 CROSS-SLIDE VICE

A cross-slide vice permits controlled movement of the workpiece in two perpendicular horizontal directions.

Uses

Milling operations

Drilling operations

Positioning workpieces

Repeated machining operations

13.6 CLAMPS

Clamps are devices used to apply holding force to workpieces, components, fixtures, or supporting surfaces.

They are available in many forms depending on the application.

13.6.1 C-CLAMP

A C-clamp has a C-shaped frame and a threaded screw used to apply clamping force.

Features

Simple construction

Strong clamping action

Adjustable opening

Suitable for temporary holding

Uses

Fabrication

Welding

Assembly

Holding plates

Temporary workholding

13.6.2 G-CLAMP

A G-clamp is essentially a screw-operated clamp having a frame shaped approximately like the letter G.

Uses

Holding workpieces

Assembly

Welding

Woodworking

Fabrication

13.6.3 F-CLAMP

An F-clamp consists of a long bar with a fixed head and a sliding jaw operated by a screw.

Advantages

Large clamping capacity

Adjustable throat depth

Suitable for long workpieces

Uses

Fabrication

Assembly

Woodworking

General workshop work

13.6.4 BAR CLAMP

A bar clamp uses a long bar to provide a large clamping span.

Uses

Holding large components

Assembly work

Fabrication

Frame construction

13.6.5 TOGGLE CLAMP

A toggle clamp uses a mechanical linkage mechanism to quickly apply and release clamping force.

Advantages

Rapid operation

Consistent clamping

Easy release

Suitable for repetitive production

Uses

Jigs and fixtures

Production work

Welding fixtures

Assembly operations

13.6.6 SPRING CLAMP

A spring clamp uses spring force to grip a workpiece.

Features

Quick operation

Lightweight

Portable

Easy to release

Uses

Temporary holding

Light assembly

Small fabrication work

Holding materials during adhesive setting

13.6.7 WELDING CLAMP

A welding clamp is designed to hold components securely during welding.

Requirements

A welding clamp should:

Resist heat

Maintain alignment

Provide sufficient clamping force

Permit access for welding

Be easy to remove after welding

Uses

Holding plates

Pipe alignment

Fabrication

Welding assemblies

13.6.8 LOCKING CLAMP

A locking clamp uses a locking mechanism to maintain clamping pressure after adjustment.

Advantages

Hands-free holding

Adjustable grip

Suitable for repetitive operations

Uses

Fabrication

Assembly

Temporary workholding

Component positioning

13.7 STRAP CLAMPS

A strap clamp uses a rigid strap or bar to press a workpiece against a supporting surface.

They are commonly used with machine tables and fixtures.

Uses

Holding large workpieces

Machine-shop workholding

Milling setups

Drilling setups

Fixture applications

13.8 STEP CLAMP

A step clamp is used with stepped blocks or supporting arrangements to clamp workpieces at different heights.

Advantages

Adjustable height

Strong holding force

Suitable for machine-table workholding

Applications

Milling machines

Drilling machines

Machine fixtures

Production setups

13.9 HOLD-DOWN CLAMP

A hold-down clamp applies force downward to press a workpiece against a supporting surface.

Uses

Fixture work

Machining

Drilling

Routing

Fabrication

13.10 EDGE CLAMP

An edge clamp is designed to apply force to the edge or side of a workpiece.

Uses

Holding plates

Machining thin components

Welding

Fabrication

Fixture applications

13.11 PARALLEL CLAMP

A parallel clamp has jaws that remain substantially parallel during clamping.

Advantages

Uniform gripping

Reduced risk of tilting

Suitable for accurately holding components

Applications

Precision assembly

Fabrication

Woodworking

Toolmaking

13.12 MAGNETIC CLAMP

A magnetic clamp uses magnetic force to hold ferromagnetic workpieces.

Advantages

Rapid positioning

No mechanical screw adjustment in many designs

Easy repositioning

Useful for steel components

Limitations

It is generally unsuitable for non-magnetic materials and applications where magnetic holding force is insufficient.

Uses

Welding

Fabrication

Steel positioning

Assembly

13.13 V-BLOCK WITH CLAMP

A V-block is a precision supporting device used to hold cylindrical or round workpieces.

A clamp is commonly used with the V-block to prevent the cylindrical component from moving.

Uses

Shaft inspection

Marking

Drilling

Machining

Measurement

Layout work

13.14 CHAIN CLAMP

A chain clamp uses a chain arrangement to grip cylindrical or irregularly shaped components.

Uses

Pipe work

Large cylindrical components

Welding

Fabrication

Heavy maintenance operations

13.15 SELECTION OF HOLDING & CLAMPING TOOLS

Selection should be based on:

1. Workpiece Size

The device must have adequate capacity for the workpiece.

2. Workpiece Shape

Flat, round, irregular, thin, and delicate components may require different holding arrangements.

3. Required Clamping Force

Heavy machining requires stronger workholding than light hand operations.

4. Operation

The holding device should suit filing, drilling, machining, welding, assembly, or other operations.

5. Surface Condition

Finished surfaces may require protective jaw covers or soft contact surfaces.

6. Accessibility

The clamp should not obstruct cutting tools, measuring instruments, or other equipment.

7. Accuracy

Precision operations require accurate and rigid holding devices.

8. Production Requirement

Repetitive production often benefits from quick-action or toggle-type clamps.

13.16 PROPER USE OF VICES

The following practices should be followed:

Select a vice suitable for the workpiece.
Keep the workpiece properly supported.
Position the workpiece securely between the jaws.
Apply sufficient clamping force.
Do not use excessive force.
Keep the workpiece at a suitable height.
Use soft jaw covers for finished surfaces when required.
Avoid striking the vice handle with another hammer.
Do not use the vice as an anvil unless specifically designed for that purpose.
Keep the vice properly secured to its mounting surface.

13.17 PROPER USE OF CLAMPS

Select the correct clamp size.
Position the clamp properly.
Ensure the contact surfaces are clean.
Apply sufficient but controlled force.
Avoid excessive tightening.
Protect finished surfaces when necessary.
Ensure the clamp cannot interfere with the operation.
Check the workpiece before beginning the operation.
Release the clamp carefully.
Inspect clamps regularly for damage.

13.18 MAINTENANCE OF HOLDING & CLAMPING TOOLS

Proper maintenance increases service life and reliability.

Important maintenance practices

Keep jaws clean.

Remove chips and dirt regularly.

Lubricate vice spindles when required.

Keep threads clean and lubricated.

Inspect clamps for cracks or deformation.

Replace damaged jaw plates.

Keep sliding surfaces clean.

Prevent unnecessary corrosion.

Store portable clamps properly.

Check mounting bolts periodically.

Do not use damaged holding devices.

13.19 SAFETY PRECAUTIONS

Safety is essential when using holding and clamping equipment.

Always select a device appropriate for the work.
Ensure the workpiece is securely held.
Never exceed the rated capacity.
Avoid excessive tightening.
Keep hands away from pinch points.
Check clamps before use.
Do not use cracked or damaged clamps.
Ensure the vice is securely mounted.
Keep the working area free from chips and oil.
Use appropriate personal protective equipment.
Confirm that the workpiece cannot rotate or eject during machining.
Release stored clamping force carefully.

13.20 ADVANTAGES OF PROPER WORKHOLDING

Proper workholding provides:

Increased safety

Improved accuracy

Better surface finish

Reduced vibration

Better repeatability

Reduced setup errors

Improved productivity

Reduced workpiece damage

Easier machining and assembly

13.21 COMMON APPLICATIONS

Holding and clamping tools are used in:

Fitting workshops

Machine shops

Welding shops

Fabrication shops

Automotive workshops

Maintenance departments

Tool rooms

Production industries

Assembly operations

Inspection and layout work

13.22 SUMMARY TABLE

Tool	Main Function	Typical Application
Bench Vice	General workholding	Fitting
Swivel Vice	Adjustable positioning	General workshop
Quick-Release Vice	Rapid workholding	Repetitive work
Hand Vice	Small workholding	Light fitting
Pin Vice	Very small components	Precision work
Pipe Vice	Pipe holding	Pipe work
Leg Vice	Heavy holding	Forging
Toolmaker’s Vice	Precision holding	Toolmaking
Angle Vice	Angular holding	Machining/fitting
Cross-Slide Vice	Controlled positioning	Drilling/milling
C/G-Clamp	General clamping	Fabrication
F-Clamp	Long-span clamping	Assembly
Toggle Clamp	Quick clamping	Production fixtures
Spring Clamp	Light temporary holding	Assembly
Welding Clamp	Welding alignment	Fabrication
Strap Clamp	Machine-table holding	Machining
Step Clamp	Adjustable machine holding	Fixtures
Hold-Down Clamp	Downward holding force	Machining
Edge Clamp	Edge holding	Fabrication
Magnetic Clamp	Magnetic holding	Steel fabrication
V-Block with Clamp	Cylindrical workholding	Inspection/machining
Chain Clamp	Cylindrical/irregular holding	Pipe/fabrication

13.23 CONCLUSION

Holding and clamping tools are fundamental to safe and accurate workshop operations. They prevent unwanted movement, maintain workpiece position, reduce vibration, and improve the quality of manufacturing and maintenance work.

Vices are mainly used for gripping and supporting workpieces, while clamps provide temporary or specialized holding force. Correct selection depends on workpiece size, shape, material, required force, operation, accuracy, and accessibility.

Proper use, regular maintenance, and safe handling of holding and clamping equipment are essential for achieving reliable workshop performance and extending tool life.

DRILLING & HOLE-MAKING TOOLS

14.1 INTRODUCTION

Drilling and hole-making tools are used to produce, enlarge, finish, or modify holes in engineering components and workpieces.

Hole-making is an important workshop operation used in fitting, fabrication, machine shops, maintenance, automotive work, tool rooms, and manufacturing industries.

Different tools are selected according to the required hole diameter, depth, accuracy, surface finish, material, and production requirement.

14.2 DEFINITION

A drilling tool is a cutting tool designed primarily to produce a hole by removing material as it rotates and advances into a workpiece.

A hole-making tool is a cutting or forming tool used to create, enlarge, finish, or modify an existing hole.

Common hole-making tools include:

Twist drills

Centre drills

Step drills

Flat drills

Reamers

Countersinks

Counterbores

Core drills

Hole saws

Annular cutters

Trepanning tools

4.3 BASIC PRINCIPLE OF DRILLING

Drilling is generally performed by rotating a cutting tool while applying axial feed toward the workpiece.

The cutting edges remove material and form a hole.

The main motions are:

Cutting Motion

The drill rotates around its axis.

Feed Motion

The drill moves axially into the workpiece.

Material Removal

The cutting edges shear material from the workpiece and form chips.

The cutting conditions must be selected according to tool material, workpiece material, drill diameter, and machine capability.

4.4 MAIN PARTS OF A TWIST DRILL

A conventional twist drill consists of several important features.

1. Shank

The shank is the portion held by the machine spindle, chuck, or tool holder.

Common shank arrangements include:

Straight shank

Taper shank

2. Body

The body is the working portion between the shank and the point.

3. Flutes

Flute are helical grooves running along the body of the drill.

Their functions include:

Providing cutting edges

Providing chip space

Helping remove chips

Allowing cutting fluid to reach the cutting zone

4. Lands

The lands are the raised portions between adjacent flutes.

5. Margins

Margins are narrow raised surfaces near the outer diameter that help guide the drill in the hole.

6. Web

The web is the central portion separating the flutes.

7. Point

The point is the cutting end of the drill.

8. Cutting Edges

The cutting edges remove material from the workpiece.

14.5 CLASSIFICATION OF DRILLS

Important workshop drills include:

Twist Drill
Straight-Flute Drill
Jobber-Length Drill
Stub-Length Drill
Long-Series Drill
Centre Drill
Step Drill
Flat Drill
Taper Drill
Core Drill
Oil-Hole Drill
Deep-Hole Drill
Gun Drill
Masonry Drill
Carbide Drill

14.6 TWIST DRILL

A twist drill is the most commonly used drill for producing cylindrical holes.

It normally has two helical flutes and two principal cutting edges.

Features

Helical flutes

Two main cutting edges

Central web

Point angle

Straight or taper shank

Uses

General hole drilling

Fitting work

Machine-shop operations

Automotive maintenance

Fabrication

Production work

14.7 STRAIGHT-FLUTE DRILL

A straight-flute drill has flutes running substantially parallel to the drill axis rather than being strongly helical.

Advantages

Useful for certain brittle materials

Provides controlled cutting action

Suitable for specialized applications

Applications

Used for selected materials and machining conditions where straight flutes provide an advantage.

14.8 JOBBER-LENGTH DRILL

A jobber-length drill is a general-purpose drill with a commonly used length-to-diameter proportion.

Features

General-purpose design

Good balance between rigidity and reach

Widely available in standard sizes

Uses

General machine-shop drilling

Fitting

Maintenance

Production work

14.9 STUB-LENGTH DRILL

A stub drill has a shorter body than a conventional jobber-length drill.

Advantages

Higher rigidity

Reduced tendency to deflect

Suitable for shallow holes

Uses

Precision drilling

Production work

Short-hole applications

14.10 LONG-SERIES DRILL

A long-series drill has an extended length for applications requiring greater drilling depth.

Advantages

Greater reach

Suitable for deep or inaccessible locations

Limitation

Because of its greater length, it is more susceptible to deflection and vibration than a shorter drill.

14.11 CENTRE DRILL

A centre drill is a short, rigid drill used to produce a starting hole or centre hole.

It commonly has a pilot portion and a countersinking portion.

Uses

Starting holes for conventional drilling

Preparing centre holes for lathe work

Producing centre holes in shafts

Providing accurate starting locations

14.12 STEP DRILL

A step drill contains multiple cutting diameters arranged in steps along the tool.

Advantages

Several hole diameters can be produced with one tool

Reduces tool changes

Useful for thin sheet materials

Applications

Sheet metal

Electrical panels

Fabrication

Thin plates

14.13 FLAT DRILL

A flat drill has a relatively simple flat cutting form and is used in certain traditional or specialized drilling applications.

Uses

General workshop work

Woodworking applications

Selected metalworking operations depending on design

14.14 TAPER DRILL

A taper drill is designed for producing holes associated with tapered requirements or specialized machining conditions.

Applications

Tapered holes

Tool and machine components

Specialized engineering applications

14.15 CORE DRILL

A core drill is designed to enlarge or finish an existing hole, particularly where a smaller pilot hole or cast opening already exists.

Features

Multiple cutting edges

Relatively rigid construction

Suitable for enlarging existing holes

Uses

Enlarging holes

Machining cast holes

Preparing holes for further operations

14.16 OIL-HOLE DRILL

An oil-hole drill incorporates internal passages or specialized geometry to deliver cutting fluid closer to the cutting zone.

Advantages

Improved cooling

Better lubrication

Improved chip evacuation

Useful in deeper drilling

Applications

Used particularly in production and difficult drilling operations.

14.17 DEEP-HOLE DRILL

Deep-hole drills are designed specifically for producing holes whose depth is large compared with their diameter.

Requirements

Deep-hole drilling requires:

Accurate alignment

Effective chip removal

Adequate cooling

Appropriate cutting conditions

Suitable tool geometry

Applications

Shafts

Hydraulic components

Automotive components

Precision engineering parts

14.18 GUN DRILL

A gun drill is a specialized deep-hole drilling tool designed for producing long, straight, accurately positioned holes.

Features

Single effective cutting arrangement in many designs

Internal or external coolant arrangements

Specialized guide geometry

High capability for deep-hole work

Applications

Die manufacturing

Hydraulic components

Automotive parts

Precision engineering

14.19 MASONRY DRILL

A masonry drill is designed for drilling materials such as:

Concrete

Brick

Stone

Masonry

Its cutting tip commonly incorporates a hard, wear-resistant insert.

Uses

Construction work

Building maintenance

Installation work

14.20 CARBIDE DRILL

A carbide drill uses cemented carbide cutting material or carbide cutting elements.

Advantages

High hardness

High wear resistance

Suitable for high cutting speeds

Good performance on difficult materials

Applications

Hardened or abrasive materials

High-production machining

Precision drilling

14.21 DRILL POINT GEOMETRY

Drill performance depends strongly on point geometry.

Important parameters include:

Point angle

Helix angle

Lip clearance

Chisel edge

Web thickness

Cutting-edge geometry

Correct geometry depends on the workpiece material and drilling application.

14.22 DRILL POINT ANGLE

The point angle is the included angle between the principal cutting edges at the drill point.

Different materials may require different point geometries.

A commonly used general-purpose twist drill has a point angle around 118°, although specialized drills may use other geometries.

The correct point geometry influences:

Cutting force

Heat generation

Hole quality

Tool life

Chip formation

14.23 DRILL SIZE SELECTION

Drill size is selected according to:

Required hole diameter

Material

Hole depth

Required accuracy

Subsequent operation

Threading requirements

For example, when preparing a hole for tapping, the drill diameter must be selected according to the required thread and tapping allowance rather than simply using the nominal thread diameter.

14.24 REAMERS

A reamer is a multi-edge cutting tool used primarily to accurately size and finish an existing hole.

Reaming normally removes a relatively small amount of material.

Main purposes

Improve hole dimensional accuracy

Improve surface finish

Correct slight inaccuracies

Produce a more uniform hole

Reamers should not normally be used to create a completely new hole from solid material.

14.25 TYPES OF REAMERS

Important reamers include:

Hand Reamer
Machine Reamer
Straight Reamer
Taper Reamer
Adjustable Reamer
Expansion Reamer
Shell Reamer
Chucking Reamer
Bridge Reamer

14.25.1 HAND REAMER

A hand reamer is designed for manual operation.

Features

Long lead

Usually has a square end for a tap wrench or similar driving tool

Suitable for controlled hand operation

Uses

Finishing holes manually

Fitting work

Maintenance

Precision fitting

14.25.2 MACHINE REAMER

A machine reamer is designed to be driven by a machine.

Uses

Drill press operations

Lathe operations

Milling-machine applications

Production machining

14.25.3 TAPER REAMER

A taper reamer produces or finishes a tapered hole.

Uses

Taper pin holes

Tapered machine components

Precision assembly

14.25.4 ADJUSTABLE REAMER

An adjustable reamer permits limited adjustment of its effective cutting diameter.

Advantages

Can compensate for wear

Provides diameter adjustment

Useful for maintenance work

14.25.5 EXPANSION REAMER

An expansion reamer permits a limited increase in diameter through an expansion mechanism.

Uses

Correcting wear

Maintenance

Finishing holes where limited adjustment is beneficial

14.25.6 SHELL REAMER

A shell reamer consists of a hollow cutting body designed to be mounted on a suitable arbor.

Advantages

Suitable for larger holes

Can be used with interchangeable arbors

Economical for certain applications

14.25.7 CHUCKING REAMER

A chucking reamer is designed for machine operation and is commonly used in production machining.

Features

Rigid construction

Accurate cutting diameter

Suitable for machine tool holding

14.25.8 BRIDGE REAMER

A bridge reamer is used for enlarging and aligning holes, particularly in fabrication and structural work.

Uses

Structural fabrication

Shipbuilding

Heavy engineering

Alignment of holes

14.26 COUNTERSINK

A countersink is a cutting tool used to produce a conical recess at the mouth of a hole.

Purpose

It allows a countersunk-head screw or similar fastener to sit flush or nearly flush with the surface.

Uses

Screw seating

Deburring

Removing sharp edges

Producing conical recesses

14.27 COUNTERBORE

A counterbore produces a cylindrical recess around an existing hole.

Purpose

It provides space for:

Socket-head screws

Bolt heads

Other cylindrical fastener heads

Advantages

Provides flush or recessed fastening

Produces a flat-bottomed recess

Improves component appearance

14.28 SPOT-FACING TOOL

A spot-facing tool produces a flat seating surface around a hole.

Purpose

It provides a suitable flat surface for a bolt head, nut, washer, or similar component.

Applications

Cast surfaces

Forged components

Machine parts

Bolt seating areas

14.29 HOLE SAW

A hole saw is a cylindrical cutting tool with teeth around its circumference.

It removes an annular section of material while leaving a central core.

Advantages

Produces relatively large holes

Requires less material removal than a solid drill of the same diameter

Uses

Sheet metal

Wood

Plastics

Building materials

Installation work

14.30 ANNULAR CUTTER

An annular cutter removes material around the circumference of the hole rather than cutting the entire hole area.

Advantages

Efficient material removal

Lower power requirement for large holes compared with solid drilling in suitable applications

Produces relatively accurate holes

Applications

Structural steel

Fabrication

Portable magnetic drilling machines

Heavy engineering

14.31 TREPANNING TOOL

A trepanning tool cuts along a circular path and removes a ring of material.

Advantages

Suitable for large-diameter holes

Reduces material removal

Can save cutting power compared with full-area cutting

Applications

Large holes

Heavy machining

Specialized machine-shop operations

14.32 HOLE-MAKING OPERATIONS

Important hole-making operations include:

Drilling

Producing a new hole in solid material.

Reaming

Accurately sizing and finishing an existing hole.

Counterboring

Producing a cylindrical recess around a hole.

Countersinking

Producing a conical recess around a hole.

Spot Facing

Producing a flat seating surface around a hole.

Trepanning

Producing a large circular opening by removing an annular section.

Boring

Increasing the diameter and improving the accuracy of an existing hole using a single-point or specialized boring tool.

14.33 DRILLING DEFECTS

Common drilling problems include:

Oversized holes

Undersized holes

Rough hole surface

Hole deviation

Burr formation

Drill breakage

Excessive heat

Chattering

Poor chip evacuation

Uneven hole geometry

14.34 CAUSES OF POOR DRILLING PERFORMANCE

Possible causes include:

Incorrect Speed

Excessive speed can increase heat and tool wear.

Incorrect Feed

Improper feed can cause poor chip formation, vibration, or excessive cutting forces.

Dull Tool

A worn cutting edge increases cutting force and heat.

Poor Workholding

Workpiece movement can cause inaccurate or unsafe drilling.

Improper Alignment

Misalignment can cause hole deviation.

Insufficient Cooling

Excessive heat can reduce tool life and damage the workpiece.

Poor Chip Removal

Blocked flutes can cause overheating and tool failure.

14.35 PROPER DRILLING PRACTICE

Select the correct drill.
Check the drill for damage or excessive wear.
Secure the workpiece properly.
Select suitable cutting speed.
Select suitable feed.
Align the drill correctly.
Use cutting fluid when appropriate.
Ensure effective chip evacuation.
Avoid excessive force.
Withdraw the drill periodically when required for deep-hole chip removal.
Stop the machine before removing chips manually.
Inspect the finished hole.

14.36 TOOL SELECTION

The correct drilling or hole-making tool depends on:

Workpiece material

Hole diameter

Hole depth

Hole tolerance

Surface-finish requirement

Production quantity

Machine type

Tool material

Cutting conditions

Required subsequent operation

14.37 DRILL MATERIALS

Common drill materials include:

High-Speed Steel

Widely used because of its combination of toughness, hardness, and cost.

Cobalt High-Speed Steel

Provides improved hot hardness and is useful for difficult-to-machine materials.

Carbide

Provides high hardness and wear resistance and supports high cutting speeds under suitable conditions.

14.38 MAINTENANCE OF DRILLING TOOLS

Proper maintenance includes:

Keep drills clean.

Protect cutting edges.

Store drills systematically.

Prevent corrosion.

Inspect cutting edges regularly.

Sharpen worn drills correctly.

Use suitable grinding methods.

Avoid dropping drills.

Check reamers for damage.

Protect precision cutting surfaces.

Store large tools securely.

14.39 SAFETY PRECAUTIONS

Wear suitable eye protection.
Secure the workpiece properly.
Never hold a workpiece by hand during machine drilling when proper workholding is required.
Remove the chuck key before starting the machine.
Keep hands away from rotating tools.
Do not touch chips with bare hands.
Use a brush or suitable tool for chip removal after stopping the machine.
Avoid loose clothing near rotating equipment.
Use appropriate cutting fluid where required.
Stop the machine before making adjustments.
Do not force a damaged or dull drill.
Use the correct tool for the material and operation.

14.40 APPLICATIONS

Drilling and hole-making tools are widely used in:

Fitting shops

Machine shops

Automotive industries

Fabrication workshops

Tool rooms

Construction

Maintenance departments

Aerospace manufacturing

General engineering

Production industries

14.41 SUMMARY TABLE

Tool	Primary Function
Twist Drill	General hole production
Jobber Drill	General-purpose drilling
Stub Drill	Rigid shallow-hole drilling
Long-Series Drill	Extended-reach drilling
Centre Drill	Starting and centre-hole preparation
Step Drill	Producing different diameters in thin material
Core Drill	Enlarging existing holes
Deep-Hole Drill	Deep-hole production
Gun Drill	Accurate deep-hole drilling
Masonry Drill	Drilling masonry materials
Carbide Drill	High-performance drilling
Hand Reamer	Manual hole finishing
Machine Reamer	Machine hole finishing
Taper Reamer	Tapered-hole finishing
Adjustable Reamer	Adjustable hole finishing
Expansion Reamer	Limited diameter adjustment
Shell Reamer	Larger-hole finishing
Bridge Reamer	Hole enlargement and alignment
Countersink	Conical recess
Counterbore	Cylindrical recess
Spot-Facing Tool	Flat seating surface
Hole Saw	Large circular holes
Annular Cutter	Efficient large-hole cutting
Trepanning Tool	Large circular openings

14.42 CONCLUSION

Drilling and hole-making tools are essential for producing and finishing holes in engineering components. The twist drill is the most widely used tool for general drilling, while specialized tools such as centre drills, step drills, deep-hole drills, reamers, countersinks, counterbores, hole saws, and annular cutters serve specific requirements.

Correct tool selection, suitable cutting conditions, proper workholding, effective cooling and chip removal, and regular tool maintenance are essential for obtaining accurate holes, good surface finish, long tool life, and safe workshop oper

THREADING TOOLS

15.1 INTRODUCTION

Threading is the process of producing helical ridges or grooves on the internal or external surface of a workpiece. Threads are widely used for fastening, adjustment, power transmission, and movement between mechanical components.

Threading tools are used in fitting shops, machine shops, maintenance workshops, tool rooms, automotive industries, and manufacturing plants.

Threads may be produced manually or by machine, depending on the required accuracy, size, production quantity, and application.

15.2 DEFINITION OF THREAD

A thread is a continuous helical ridge formed on the internal or external surface of a cylindrical or conical component.

External Thread

An external thread is formed on the outside surface of a component.

Example: Bolt thread.

Internal Thread

An internal thread is formed inside a hole.

Example: Nut thread.

15.3 THREADING TOOLS

Important workshop threading tools include:

Taps
Hand Taps
Machine Taps
Spiral-Point Taps
Spiral-Flute Taps
Pipe Taps
Forming Taps
Tap Sets
Dies
Solid Dies
Adjustable Dies
Split Dies
Die Nuts
Die Stocks
Thread Chasers
Threading Taps for Specialized Applications
Threading Tools for Machine Operations

15.4 TAPS

A tap is a cutting or forming tool used to produce an internal thread in a previously prepared hole.

The tap contains cutting edges and thread-forming geometry corresponding to the required thread.

15.5 MAIN PARTS OF A TAP

A typical tap consists of:

1. Shank

The shank is the portion above the threaded cutting section.

2. Square

The square portion at the end of many hand taps provides a means for driving the tap.

3. Flutes

Flutes provide cutting edges and spaces for chip accommodation.

4. Cutting Edges

The cutting edges remove material during cutting-type tapping.

5. Threaded Portion

This portion contains the thread form used to produce the internal thread.

6. Chamfer

The chamfered portion provides the gradual introduction of cutting edges into the hole.

7. Tang

The tang is the terminal portion behind the square in many tap designs.

15.6 TYPES OF TAPS

Important types include:

Hand Taps
Taper Tap
Intermediate Tap
Plug Tap
Bottoming Tap
Machine Tap
Spiral-Point Tap
Spiral-Flute Tap
Forming Tap
Pipe Tap
Extension Tap

15.7 HAND TAP

A hand tap is designed primarily for manually producing internal threads.

Traditional hand-tap sets commonly contain three taps:

Taper tap

Intermediate tap

Bottoming tap

Modern tap sets and standards may use different configurations depending on the application.

15.8 TAPER TAP

A taper tap has a relatively long chamfered section, allowing the cutting action to begin gradually.

Advantages

Easy starting

Reduced cutting load at the beginning

Suitable for starting a new internal thread

Uses

General hand tapping

Through holes

Initial thread formation

15.9 INTERMEDIATE TAP

An intermediate tap has a shorter chamfer than a taper tap and provides a stage between initial and final threading.

Uses

General hand tapping

Following a taper tap

Producing more complete threads

15.10 PLUG TAP

A plug tap has a shorter chamfer than a taper tap and is widely used for general-purpose tapping.

Uses

Through holes

General engineering work

Machine and hand tapping

15.11 BOTTOMING TAP

A bottoming tap has a very short chamfer and is designed to produce threads close to the bottom of a blind hole.

Uses

Blind holes

Deep internal threads

Completing threads after a starting tap

15.12 MACHINE TAP

A machine tap is designed for tapping using a machine tool.

Advantages

Faster operation

Better production consistency

Suitable for repetitive manufacturing

Can be used with controlled machine feeds

Applications

Production machining

Drill presses

Tapping machines

CNC machines

15.13 SPIRAL-POINT TAP

A spiral-point tap has a geometry that directs chips forward during tapping.

Advantages

Good chip control

Effective for through holes

Reduced risk of chip accumulation in suitable applications

Applications

Production tapping

Through-hole threading

Machine tapping

15.14 SPIRAL-FLUTE TAP

A spiral-flute tap has helical flutes that help transport chips backward and out of the hole.

Advantages

Effective chip evacuation from blind holes

Smooth cutting action in suitable materials

Applications

Blind-hole tapping

Machine tapping

Materials requiring improved chip evacuation

15.15 FORMING TAP

A forming tap produces a thread by plastically deforming material rather than cutting chips.

Advantages

No cutting chips

Strong thread profile

Good surface finish

Suitable for ductile materials

Limitations

It requires suitable material ductility and appropriate hole size.

Applications

Production manufacturing

Automotive components

Aluminum and other ductile materials

High-volume threading

15.16 PIPE TAP

A pipe tap is used to produce internal pipe threads.

Pipe threads may be designed for mechanical fastening, sealing, or both depending on the thread standard and application.

Uses

Plumbing

Hydraulic systems

Pneumatic systems

Pipe fittings

Industrial piping

15.17 EXTENSION TAP

An extension tap has an extended shank to reach internal threads located deeper inside a component.

Applications

Deep or inaccessible holes

Maintenance work

Specialized tapping operations

15.18 TAP SET

A tap set contains taps intended to produce an internal thread progressively or for specific applications.

A traditional hand set may contain:

Taper tap

Intermediate tap

Bottoming tap

The exact configuration depends on the manufacturer and thread standard.

15.19 DIES

A die is a threading tool used primarily to produce or restore external threads on cylindrical workpieces.

Dies are commonly used on:

Rods

Bolts

Studs

Shafts

Pipes

15.20 MAIN FEATURES OF A DIE

Important features include:

Cutting edges

Threaded opening

Flutes or chip spaces

Chamfer

Die body

Driving notches in applicable designs

15.21 TYPES OF DIES

Important types include:

Solid Die
Adjustable Die
Split Die
Die Nut
Circular Die

15.22 SOLID DIE

A solid die is a fixed-size threading tool.

Advantages

Simple construction

Rigid

Suitable for producing consistent threads

Limitation

Its cutting diameter has limited or no adjustment.

Uses

General external threading

Maintenance

Production work

15.23 ADJUSTABLE DIE

An adjustable die permits limited adjustment of the thread diameter.

Advantages

Thread size can be adjusted

Useful for correcting minor dimensional differences

Can be used for initial and finishing passes

Applications

Maintenance

Fitting work

General workshop threading

15.24 SPLIT DIE

A split die contains a split or adjustment arrangement that allows limited dimensional adjustment.

Uses

External thread production

Thread correction

Maintenance operations

15.25 DIE NUT

A die nut is a solid threading tool commonly used for cleaning, repairing, or restoring existing external threads.

It is generally not intended for heavy initial thread cutting.

Uses

Thread cleaning

Thread repair

Maintenance

Restoring damaged external threads

15.26 DIE STOCK

A die stock is a holder used to securely grip and operate a die during manual threading.

Main Parts

Body

Die holding arrangement

Handles

Clamping or adjustment mechanism

Functions

Holds the die securely

Provides leverage

Maintains alignment

Facilitates controlled rotation

15.27 THREAD CHASER

A thread chaser is a tool designed primarily to clean, restore, or refine existing threads rather than remove large amounts of material.

Uses

Thread restoration

Cleaning damaged threads

Maintenance

Removing dirt and minor deformation

15.28 TAP WRENCHES

A tap wrench is used to hold and rotate a tap during manual tapping.

Important types include:

Adjustable T-Handle Tap Wrench

Provides good control and is suitable for many general tapping operations.

Bar-Type Tap Wrench

Uses a crossbar arrangement to provide leverage.

Ratchet Tap Wrench

Allows rotation in confined spaces while reducing the need to reposition the handle continuously.

Small Tap Wrench

Used for small taps and precision work.

15.29 THREADING OPERATION USING A TAP

The general procedure for manual tapping is:

Step 1 — Prepare the Hole

Produce a correctly sized tapping hole.

Step 2 — Chamfer the Hole

A small chamfer helps the tap enter the hole smoothly.

Step 3 — Align the Tap

The tap should be aligned correctly with the hole axis.

Step 4 — Start the Tap

Apply controlled downward pressure while rotating the tap.

Step 5 — Cut the Thread

Rotate the tap steadily while maintaining alignment.

Step 6 — Control Chips

For cutting taps, appropriate reversing or chip-breaking practice may be required depending on the tap and material.

Step 7 — Complete the Thread

Continue until the required thread depth is reached.

Step 8 — Remove the Tap

Reverse the tap carefully and inspect the finished thread.

15.30 EXTERNAL THREADING USING A DIE

The general procedure is:

Prepare the workpiece to the correct diameter.
Chamfer the end of the workpiece.
Select the correct die.
Mount the die in the die stock.
Align the die squarely with the workpiece.
Apply suitable cutting lubricant when required.
Rotate the die steadily.
Break chips appropriately for the material and die design.
Continue to the required thread length.
Reverse and remove the die.
Clean and inspect the finished thread.

15.31 TAP DRILL SIZE

The tap drill size is the diameter of the hole prepared before cutting an internal thread.

For a metric cutting thread, a commonly used approximate relationship is:

Tap Drill Size ≈ Major Diameter − Pitch

For example:

For an M10 × 1.5 thread:

Major diameter = 10 mm

Pitch = 1.5 mm

Approximate tap drill size:

10 − 1.5 = 8.5 mm

Actual recommended values should be selected from the appropriate standard or tooling manufacturer’s data, especially for special materials and thread forms.

15.32 THREADING LUBRICANTS

Suitable cutting fluids or lubricants can:

Reduce friction

Reduce heat

Improve surface finish

Extend tool life

Improve chip control

Reduce the possibility of tool seizure

The appropriate lubricant depends on:

Workpiece material

Tool material

Thread size

Tapping method

Machine conditions

15.33 THREADING TOOL MATERIALS

Threading tools may be manufactured from:

High-Speed Steel

Widely used for general-purpose taps and dies.

Carbide

Used for specialized high-performance applications and suitable machine conditions.

Powder Metallurgy High-Speed Steel

Used for applications requiring improved performance and wear resistance.

Tool material selection depends on workpiece material, production requirements, cutting conditions, and tool design.

15.34 COMMON THREADING PROBLEMS

Threading operations may suffer from:

Oversized threads

Undersized threads

Damaged thread profile

Rough thread surface

Broken tap

Broken die

Misaligned thread

Chipped cutting edges

Excessive cutting torque

Poor chip evacuation

Tool seizure

15.35 CAUSES OF THREADING FAILURES

Incorrect Hole Size

An undersized tapping hole can cause excessive torque and tool breakage.

Incorrect Alignment

Poor alignment can produce inaccurate or damaged threads.

Dull Tool

A worn tool increases cutting forces.

Incorrect Lubrication

Insufficient lubrication may increase friction and heat.

Incorrect Tool Selection

The tap or die must match the thread standard, size, material, and application.

Excessive Force

Excessive force can damage the tool or workpiece.

Poor Chip Control

Improper chip evacuation can cause jamming and tool failure.

15.36 THREAD GAUGING

Thread gauges are used to check whether produced threads conform to specified limits.

Common examples include:

Plug thread gauges

Ring thread gauges

A thread plug gauge is generally used for checking internal threads, while a thread ring gauge is generally used for checking external threads.

These gauges are inspection devices rather than thread-cutting tools.

15.37 SELECTION OF THREADING TOOLS

The correct tool should be selected according to:

Thread standard
Thread diameter
Thread pitch
Internal or external thread
Blind or through hole
Workpiece material
Required accuracy
Production quantity
Machine capability
Required surface finish

15.38 MAINTENANCE OF TAPS AND DIES

Proper maintenance includes:

Clean tools after use.

Remove chips carefully.

Prevent corrosion.

Protect cutting edges.

Store tools systematically.

Avoid dropping taps and dies.

Keep dies properly supported.

Inspect cutting edges for wear.

Do not use damaged tools.

Use suitable lubricant during operation.

Keep tap and die sets properly organized.

15.39 SAFETY PRECAUTIONS

Select the correct tap or die.
Ensure the workpiece is securely held.
Maintain correct alignment.
Do not force a tap excessively.
Use suitable cutting lubricant.
Remove chips safely.
Keep hands away from sharp cutting edges.
Wear suitable eye protection.
Do not use damaged threading tools.
Avoid excessive torque.
Stop the machine before making adjustments.
Keep the work area clean.

15.40 APPLICATIONS OF THREADING TOOLS

Threading tools are widely used in:

Automotive manufacturing

General engineering

Machine shops

Fitting workshops

Maintenance departments

Pipe industries

Fabrication

Tool rooms

Hydraulic systems

Pneumatic systems

Machinery assembly

15.41 COMPARISON OF TAPS AND DIES

Feature	Tap	Die
Main Purpose	Internal threading	External threading
Used On	Holes	Rods, shafts, bolts, pipes
Common Holder	Tap wrench	Die stock
Typical Operation	Tapping	Die threading
Thread Produced	Internal	External

15.42 SUMMARY TABLE

Tool	Primary Function
Taper Tap	Starting internal thread
Intermediate Tap	Intermediate internal threading
Plug Tap	General internal threading
Bottoming Tap	Threading near bottom of blind hole
Machine Tap	Machine-based internal threading
Spiral-Point Tap	Through-hole machine tapping
Spiral-Flute Tap	Blind-hole machine tapping
Forming Tap	Chipless thread forming
Pipe Tap	Internal pipe threading
Extension Tap	Deep/inaccessible internal threading
Solid Die	Fixed external threading
Adjustable Die	Adjustable external threading
Split Die	Limited adjustment of external thread
Die Nut	Thread cleaning and restoration
Die Stock	Holds and drives a die
Thread Chaser	Restores or cleans existing threads
Tap Wrench	Holds and drives taps

15.43 CONCLUSION

Threading tools are essential for producing and maintaining internal and external threads used throughout mechanical engineering.

Taps are primarily used for internal threading, while dies are used for external threading. Different tap and die designs are selected according to hole type, thread size, material, chip evacuation requirements, accuracy, and production conditions.

Correct hole preparation, proper alignment, suitable lubrication, controlled cutting force, and appropriate tool selection are essential for producing accurate and reliable threads.

EXAM-WISE QUESTION BANK

The book will also contain separate question collections, wherever reliable exam attribution is available, for:
SSC JE
RRB JE
GATE
ESE/IES
State JE
State AE
PSU Examinations
ITI Examinations
Diploma/Polytechnic Examinations
Other Technical Examinations

MCQ FORMAT USED IN THIS BOOK

Question
Q1. What is the primary purpose of a workshop?
A. Only to store raw materials
B. To carry out technical and manufacturing activities
C. Only to sell finished products
D. Only to transport materials
Answer: B. To carry out technical and manufacturing activities
Explanation:
A workshop is a designated working environment where manufacturing, machining, fabrication, repair, maintenance, assembly, measurement and other technical activities are performed using appropriate tools, machines and equipment.
Exam Question
Note: This is an original exam-oriented question and is not claimed as a previous-year question.

CHAPTER 1FUNDAMENTAL DEFINITIONS OF WORKSHOP TECHNOLOGY

1.1 Introduction

Workshop Technology is a branch of engineering knowledge concerned with the methods, tools, machines, materials and processes used to manufacture, modify, assemble, inspect and maintain engineering components and products.
A student cannot properly understand advanced manufacturing processes without first understanding basic workshop terminology.
For this reason, this book begins with fundamental definitions.

1.2 Workshop

Definition
A workshop is a designated place where manufacturing, machining, fabrication, repair, maintenance, assembly, inspection and other technical activities are carried out using appropriate tools, machines and equipment.
Examples
Fitting workshop
Machine shop
Welding workshop
Foundry
Carpentry shop
Sheet-metal shop
Exam Point
A workshop is not merely a place containing machines. It is an organized working environment where engineering operations are performed.

1.3 Workshop Technology

Definition
Workshop Technology is the systematic study of materials, tools, machines and manufacturing processes used to convert raw materials into useful engineering products.
Main Areas
Workshop Technology includes:
Fitting
Carpentry
Welding
Foundry
Sheet-metal work
Forging
Machining
Grinding
Measurement
Inspection
Heat treatment

1.4 Manufacturing

Definition
Manufacturing is the process of converting raw materials into useful products or components through physical, chemical, mechanical or other controlled processes.
Example
Steel bar → Cutting → Turning → Drilling → Finishing → Finished component
Exam Point
Manufacturing involves more than material removal. It can include:
Casting
Forming
Joining
Machining
Heat treatment
Surface finishing
Additive manufacturing

1.5 Manufacturing Process

Definition
A manufacturing process is a planned sequence of operations by which raw material is converted into a component or product having the required shape, size, properties and surface quality.
Manufacturing processes are commonly classified into major groups such as:
Casting
Forming
Machining
Joining
Heat treatment
Surface treatment
Additive manufacturing
This broad classification is consistent with the way manufacturing-process curricula organize the subject.

1.6 Production

Definition
Production is the overall activity of creating goods or services by utilizing resources such as materials, machines, labour, energy, information and capital.
Difference
Manufacturing mainly concerns the transformation of materials into products.
Production is a broader concept that includes manufacturing along with planning, material handling, inspection, assembly and other activities.

1.7 Production System

Definition
A production system is an organized arrangement of people, machines, materials, methods and other resources used to produce goods efficiently.
Major Types
Job production
Batch production
Mass production
Continuous production

1.8 Process

Definition
A process is a planned method or sequence of actions through which a desired change is produced in a material, component or product.
Example
Turning is a machining process used to remove material from a rotating workpiece.

1.9 Operation

Definition
An operation is a specific manufacturing activity performed to achieve a particular change in a workpiece.
Example
In manufacturing a shaft:
Facing
Turning
Grooving
Threading
Each can be considered a separate operation.

1.10 Job

Definition
A job is a particular workpiece or manufacturing task assigned to a worker, machine or production system.

1.11 Workpiece

Definition
A workpiece is the piece of material on which a manufacturing operation is performed.
Example
During turning, the metal bar mounted on the lathe is the workpiece.

1.12 Raw Material

Definition
Raw material is the basic material used as an input for manufacturing a product.
Examples
Steel bar
Aluminium sheet
Copper rod
Cast iron casting
Metal plate

1.13 Finished Product

Definition
A finished product is a manufactured item that has completed all required production operations and satisfies the specified requirements.

1.14 Semi-Finished Product

Definition
A semi-finished product is a product that has undergone some manufacturing operations but requires additional processing before becoming a final product.
Examples
Rolled steel plate
Forged blank
Rough casting
Extruded section

1.15 Machine

Definition
A machine is a mechanical, electrical or other device that uses energy to perform useful work.

1.16 Machine Tool

Definition
A machine tool is a power-driven machine used to hold and control a workpiece and/or cutting tool to perform manufacturing operations with controlled movement.
Examples
Lathe
Milling machine
Drilling machine
Shaper
Planer
Grinding machine
Important Point
A machine tool is specifically designed for manufacturing operations.

1.17 Cutting Tool

Definition
A cutting tool is a tool used to remove unwanted material from a workpiece in the form of chips during machining.
Examples
Single-point turning tool
Drill
Milling cutter
Reamer

1.18 Hand Tool

Definition
A hand tool is a tool primarily operated manually without direct power-driven cutting action.
Examples
Hammer
File
Hacksaw
Chisel
Screwdriver
Spanner

1.19 Power Tool

Definition
A power tool is a tool operated using an external power source such as electricity, compressed air or hydraulic power.

1.20 Jig

Definition
A jig is a work-holding and tool-guiding device used to locate and hold a workpiece and guide the cutting tool during an operation.
Key Point
Jig = Holds work + Guides tool

1.21 Fixture

Definition
A fixture is a device used to accurately locate and securely hold a workpiece during a manufacturing operation.
Key Point
Fixture = Holds and locates workpiece
Unlike a jig, a conventional fixture does not normally guide the cutting tool.

1.22 Gauge

Definition
A gauge is a measuring or checking device used to determine whether a dimension or characteristic of a component falls within specified limits.

1.23 Inspection

Definition
Inspection is the process of examining a component or product to determine whether it conforms to specified requirements.

1.24 Measurement

Definition
Measurement is the process of determining the numerical value of a physical quantity by comparison with an accepted standard.

1.25 Accuracy

Definition
Accuracy indicates how close a measured value is to the true or accepted value.
Example
If the actual diameter is 50.00 mm and the measured value is 50.01 mm, the measurement has a small error and is relatively accurate.

1.26 Precision

Definition
Precision indicates the degree of agreement among repeated measurements.
Important Difference
Accuracy → Closeness to true value
Precision → Repeatability/consistency
This distinction is extremely important in technical examinations.

1.27 Tolerance

Definition
Tolerance is the permissible variation in a specified dimension.
For a dimension:
50.00 ± 0.02 mm
the total tolerance is:
0.04 mm

1.28 Allowance

Definition
Allowance is the intentional difference between the dimensions of mating parts designed to obtain a desired fit.
Important Difference
Tolerance = Permissible variation
Allowance = Intentional difference between mating dimensions

1.29 Surface Finish

Definition
Surface finish refers to the quality or texture of a manufactured surface resulting from the manufacturing process.
Surface finish is important for:
Friction
Wear
Sealing
Appearance
Fatigue performance
Proper functioning of mating components

1.30 Machining

Definition
Machining is a manufacturing process in which unwanted material is removed from a workpiece to obtain the required shape, size and surface finish.
Examples
Turning
Milling
Drilling
Shaping
Grinding

1.31 Metal Cutting

Definition
Metal cutting is a material-removal process in which a cutting tool removes unwanted material from a metal workpiece, generally in the form of chips.

1.32 Casting

Definition
Casting is a manufacturing process in which molten material is poured into a mould cavity and allowed to solidify to obtain the desired shape.
Basic Steps
Melting → Pouring → Solidification → Removal → Cleaning/Finishing

1.33 Forming

Definition
Metal forming is a manufacturing process in which a metal workpiece is plastically deformed to obtain the desired shape without significant removal of material.
Examples
Forging
Rolling
Extrusion
Drawing
Sheet-metal forming

1.34 Forging

Definition
Forging is a metal-forming process in which a workpiece is plastically deformed by the application of compressive forces using tools, dies, hammers or presses.

1.35 Rolling

Definition
Rolling is a metal-forming process in which metal is passed between rotating rolls to reduce its thickness or change its cross-sectional shape.

1.36 Extrusion
Definition
Extrusion is a metal-forming process in which a billet is forced through a die opening to produce a component or section having a desired cross-sectional profile.

1.37 Drawing

Definition
Drawing is a metal-forming process in which a material is pulled through a die to reduce its cross-sectional area or modify its shape.

1.38 Welding

Definition
Welding is a joining process used to produce a permanent joint between materials by applying suitable heat, pressure, or a combination of heat and pressure, with or without filler material depending on the process.

1.39 Brazing

Definition.

Brazing is a joining process in which a filler metal is melted and distributed between closely fitted surfaces by capillary action, while the base metals are not melted.

1.40 Soldering

Definition
Soldering is a joining process in which a relatively low-melting-point filler metal is used to join components without melting the base materials.

1.41 Fitting

Definition
Fitting is a bench-work operation involving the accurate shaping, sizing, finishing and assembly of components using hand tools and related equipment.

CHAPTER 1 — QUICK REVISION

Term Key Meaning

Workshop Place for technical/manufacturing activities

Manufacturing Conversion of raw material into useful products

Process Planned method of producing a desired change

Operation Specific manufacturing activity

Workpiece Material being processed

Raw Material Basic input material

Machine Tool Power-driven manufacturing machine

Cutting Tool Removes material during machining

Jig Holds work and guides tool

Fixture Holds and locates work

Gauge Checks dimensions/limits

Accuracy Closeness to true value

Precision Repeatability

Tolerance Permissible dimensional variation

Allowance Intentional difference between mating dimensions

Machining Removal of unwanted material

Casting Shaping by pouring molten material into mould

Forging Plastic deformation by compressive forces

Rolling Passing metal between rotating rolls

Extrusion Forcing material through a die

Drawing Pulling material through a die

Welding Permanent joining process

Brazing Joining with filler metal without melting base metal

Soldering Low-temperature filler-metal joining

Fitting Accurate bench-work shaping and assembly

Q51. Which of the following best defines a manufacturing process?

A. A method of transporting raw materials
B. A planned sequence of activities used to convert material into a desired product
C. A method of selling products
D. A method of storing finished goods
Answer: B. A planned sequence of activities used to convert material into a desired product
Explanation: A manufacturing process consists of planned activities that transform raw material into a component or finished product having the required shape, dimensions and properties.
Question

Q52. Which of the following is a primary manufacturing process?

A. Casting
B. Inspection
C. Measurement
D. Transportation
Answer: A. Casting
Explanation: Casting is generally considered a primary manufacturing process because a useful shape is produced directly from molten material.
Question

Q53. Which of the following is primarily a material-removal process?
A. Forging
B. Rolling
C. Machining
D. Casting
Answer: C. Machining
Explanation: Machining removes unwanted material from a workpiece to obtain the required dimensions, geometry and surface finish.
Question

Q54. Which manufacturing process changes the shape mainly by plastic deformation?

A. Metal forming
B. Grinding
C. Drilling
D. Turning
Answer: A. Metal forming
Explanation: Forming processes change the geometry of a material through plastic deformation, generally without significant material removal.
Question

Q55. Which of the following is an example of a metal-forming process?
A. Forging
B. Drilling
C. Grinding
D. Boring
Answer: A. Forging
Explanation: Forging changes the shape of metal through plastic deformation caused mainly by compressive forces.
Question

Q56. Which process involves passing a workpiece between rotating rolls?

A. Extrusion
B. Rolling
C. Drawing
D. Forging
Answer: B. Rolling
Explanation: Rolling uses rotating rolls to reduce thickness or alter the cross-sectional profile of the material.
Question

Q57. Which process forces a billet through a die?
A. Drawing
B. Extrusion
C. Rolling
D. Welding
Answer: B. Extrusion
Explanation: In extrusion, compressive force pushes the billet through a die opening to obtain the desired profile.
Question

Q58. Which process pulls material through a die?
A. Extrusion
B. Drawing
C. Forging
D. Casting
Answer: B. Drawing
Explanation: Drawing reduces the cross-sectional area of a material by pulling it through a die.
Question

Q59. Which of the following is a permanent joining process?

A. Welding
B. Turning
C. Milling
D. Grinding
Answer: A. Welding
Explanation: Welding produces a permanent joint between two or more components.
Question

Q60. In which joining process is a filler metal generally used without melting the base metals?

A. Welding
B. Brazing
C. Forging
D. Rolling
Answer: B. Brazing
Explanation: During brazing, the filler metal melts and flows into the joint while the base materials remain below their melting temperatures.
Question

Q61. Which joining process generally uses a lower-temperature filler metal than brazing?

A. Welding
B. Soldering
C. Forging
D. Casting
Answer: B. Soldering
Explanation: Soldering uses a relatively low-melting-point filler metal and normally does not melt the base materials.
Question

Q62. Which of the following is NOT a material-removal process?

A. Turning
B. Milling
C. Forging
D. Drilling
Answer: C. Forging
Explanation: Forging is a metal-forming process. It changes the shape of the workpiece mainly through plastic deformation rather than removing material.
Question

Q63. Which machine tool is mainly used for producing cylindrical surfaces by turning?

A. Lathe
B. Shaper
C. Planer
D. Slotter
Answer: A. Lathe
Explanation: The lathe is primarily used for turning operations in which the workpiece rotates relative to the cutting tool.
Question

Q64. A machine tool used primarily for producing flat surfaces with a reciprocating cutting tool is:

A. Shaper
B. Lathe
C. Milling machine
D. Grinding machine
Answer: A. Shaper
Explanation: A shaper produces surfaces using the reciprocating motion of a single-point cutting tool.
Question

Q65. Which machine uses a rotating multi-point cutting tool?

A. Milling machine
B. Shaper
C. Planer
D. Lathe
Answer: A. Milling machine
Explanation: A milling cutter rotates and has multiple cutting edges.
Question

Q66. Which of the following is primarily an abrasive machining process?
A. Grinding
B. Forging
C. Casting
D. Welding
Answer: A. Grinding
Explanation: Grinding removes material using abrasive grains contained in a grinding wheel or other abrasive tool.
Question

Q67. Which term describes the amount by which a dimension is allowed to vary?
A. Allowance
B. Tolerance
C. Accuracy
D. Precision
Answer: B. Tolerance
Explanation: Tolerance is the permissible variation in a specified dimension.
Question

Q68. For a dimension of 25.00 ± 0.02 mm, the upper limit is:
A. 24.98 mm
B. 25.00 mm
C. 25.02 mm
D. 25.04 mm
Answer: C. 25.02 mm
Explanation:
Upper limit = 25.00 + 0.02
= 25.02 mm
Question

Q69. For a dimension of 25.00 ± 0.02 mm, the lower limit is:
A. 24.96 mm
B. 24.98 mm
C. 25.02 mm
D. 25.04 mm
Answer: B. 24.98 mm
Explanation:
Lower limit = 25.00 − 0.02
= 24.98 mm
Question

Q70. The total tolerance for 25.00 ± 0.02 mm is:
A. 0.01 mm
B. 0.02 mm
C. 0.04 mm
D. 25.02 mm
Answer: C. 0.04 mm
Explanation:
Total tolerance = Upper limit − Lower limit
= 25.02 − 24.98
= 0.04 mm
Question

Q71. Which term indicates closeness of a measured value to the true value?
A. Precision
B. Accuracy
C. Tolerance
D. Allowance
Answer: B. Accuracy
Explanation: Accuracy indicates how close a measurement is to the true or accepted value.
Question

Q72. Repeated measurements that are very close to one another indicate high:
A. Accuracy only
B. Precision
C. Tolerance
D. Allowance
Answer: B. Precision
Explanation: Precision is associated with repeatability or consistency of measurements.
Question

Q73. A set of measurements may be precise but not accurate when:
A. They are close to one another but far from the true value
B. They are all exactly equal to the true value
C. There is no measurement
D. The instrument has no scale
Answer: A. They are close to one another but far from the true value
Explanation: Precision concerns consistency, whereas accuracy concerns closeness to the true value.
Question

Q74. Which instrument is commonly used for accurate measurement of external dimensions?
A. Hammer
B. Micrometer
C. Chisel
D. Hacksaw
Answer: B. Micrometer
Explanation: A micrometer is a precision measuring instrument used for measuring dimensions such as external diameter or thickness within its range.
Question

Q75. Which instrument can commonly measure external dimensions, internal dimensions and depth?
A. Vernier caliper
B. Hammer
C. File
D. Scriber
Answer: A. Vernier caliper
Explanation: A standard Vernier caliper can measure external and internal dimensions and depth.
Question

Q76. Which tool is primarily used for marking lines on a metal workpiece?
A. Scriber
B. Hammer
C. Spanner
D. File
Answer: A. Scriber
Explanation: A scriber is used to mark fine lines on metal surfaces during layout and marking operations.
Question

Q77. Which tool is commonly used to check whether two surfaces are at right angles?
A. Try square
B. Divider
C. Scriber
D. File
Answer: A. Try square
Explanation: A try square is used to check and mark approximately 90° angles.
Question

Q78. Which tool is used to remove small amounts of material by rubbing its abrasive surface against the workpiece?
A. File
B. Hammer
C. Spanner
D. Scriber
Answer: A. File
Explanation: A file is a hand tool having abrasive teeth used mainly for sizing, shaping and finishing.
Question

Q79. Which tool is commonly used to cut metal manually?
A. Hacksaw
B. Try square
C. Divider
D. Micrometer
Answer: A. Hacksaw
Explanation: A hacksaw is a hand-operated cutting tool used for cutting metal and other materials.
Question

Q80. Which of the following is a marking tool?
A. Divider
B. Lathe
C. Grinding wheel
D. Drill press
Answer: A. Divider
Explanation: A divider is commonly used for transferring measurements and marking arcs or circles on a workpiece.
Question

Q81. Which operation involves producing an external cylindrical surface on a lathe?
A. Turning
B. Milling
C. Grinding
D. Broaching
Answer: A. Turning
Explanation: Turning removes material from the external surface of a rotating workpiece using a single-point cutting tool.
Question

Q82. Which lathe operation produces a flat surface at the end of a cylindrical workpiece?
A. Facing
B. Knurling
C. Threading
D. Grooving
Answer: A. Facing
Explanation: Facing produces a flat surface perpendicular to the axis of rotation.
Question

Q83. Which operation is used to produce a helical thread on a workpiece?
A. Thread cutting
B. Facing
C. Filing
D. Grinding only
Answer: A. Thread cutting
Explanation: Thread cutting on a lathe produces helical threads by coordinating spindle rotation with longitudinal tool movement.
Question

Q84. Which operation produces a roughened pattern on a cylindrical surface?
A. Knurling
B. Facing
C. Boring
D. Reaming
Answer: A. Knurling
Explanation: Knurling produces a patterned surface, commonly to improve grip.
Question

Q85. Which operation is used to enlarge an existing hole accurately?
A. Boring
B. Forging
C. Rolling
D. Casting
Answer: A. Boring
Explanation: Boring enlarges and improves an existing hole using a single-point or suitable boring tool.
Question

Q86. Which operation is generally used to improve the dimensional accuracy and finish of an existing hole?
A. Reaming
B. Forging
C. Rolling
D. Welding
Answer: A. Reaming
Explanation: Reaming is a finishing operation used to bring an existing hole closer to the required size and improve its surface finish.
Question

Q87. Which process is used to produce a hole initially in a solid workpiece?
A. Drilling
B. Boring
C. Reaming
D. Honing
Answer: A. Drilling
Explanation: Drilling is normally used to produce a new circular hole in a solid workpiece.
Question

Q88. Which of the following is a surface-finishing process?
A. Grinding
B. Forging
C. Casting
D. Extrusion
Answer: A. Grinding
Explanation: Grinding can produce accurate dimensions and improved surface finish.
Question

Q89. Which process uses a mould cavity?
A. Casting
B. Turning
C. Milling
D. Drilling
Answer: A. Casting
Explanation: Casting uses a mould cavity into which molten material is introduced.
Question

Q90. The cavity in a mould generally represents the:
A. Cutting-tool geometry
B. Desired external shape of the casting
C. Machine-bed shape
D. Measuring-instrument shape
Answer: B. Desired external shape of the casting
Explanation: The mould cavity provides the required geometry into which molten material solidifies.
Question

Q91. Which component of a casting system helps compensate for shrinkage during solidification?
A. Riser
B. Cutting tool
C. Fixture
D. Micrometer
Answer: A. Riser
Explanation: A riser acts as a reservoir of molten metal and helps feed the casting during solidification to compensate for shrinkage.
Question

Q92. A pattern is primarily used in:
A. Casting
B. Turning
C. Grinding
D. Welding
Answer: A. Casting
Explanation: A pattern is used to produce the mould cavity required for casting.
Question

Q93. Which of the following is associated with moulding?
A. Foundry
B. Machine shop only
C. Fitting bench only
D. Metrology laboratory only
Answer: A. Foundry
Explanation: Moulding is a major activity in foundry work, where mould cavities are prepared for casting.
Question

Q94. Which of the following is primarily a joining operation?
A. Welding
B. Turning
C. Drilling
D. Milling
Answer: A. Welding
Explanation: Welding is used to create a permanent joint between components.
Question

Q95. Which process can join metals using a filler metal while keeping the base metals below their melting temperature?
A. Brazing
B. Turning
C. Milling
D. Drilling
Answer: A. Brazing
Explanation: Brazing relies on melting and flowing of the filler metal while the base metals remain solid.
Question

Q96. Which term describes the ability of a material to return to its original shape after removal of load, within its elastic limit?
A. Elasticity
B. Plasticity
C. Brittleness
D. Hardness
Answer: A. Elasticity
Explanation: Elasticity is the property by which a material tends to regain its original shape after the deforming load is removed, provided the elastic limit has not been exceeded.
Question

Q97. A material that fractures with little plastic deformation is described as:
A. Ductile
B. Brittle
C. Malleable
D. Elastic
Answer: B. Brittle
Explanation: Brittle materials generally undergo little plastic deformation before fracture.
Question

Q98. The ability of a material to withstand deformation under load is related to:
A. Strength
B. Colour
C. Density only
D. Thermal conductivity only
Answer: A. Strength
Explanation: Strength is the ability of a material to withstand applied loads without failure.
Question

Q99. Which term represents resistance to deformation under elastic loading?
A. Stiffness
B. Ductility
C. Plasticity
D. Brittleness
Answer: A. Stiffness
Explanation: Stiffness is the resistance offered by a material or component to elastic deformation.
Question

Q100. Which sequence represents a typical basic manufacturing transformation?
A. Finished product → raw material → manufacturing
B. Raw material → manufacturing processes → finished product
C. Product → advertising → raw material
D. Inspection → raw material → transportation
Answer: B. Raw material → manufacturing processes → finished product
Explanation: Manufacturing begins with raw or semi-finished material and applies suitable processes to obtain a product meeting the required specifications.
Question

Important Process Differences

Process Basic Principle

Casting Molten material → mould → solidification

Forging Plastic deformation by compressive force

Rolling Material passes between rotating rolls

Extrusion Material forced through die

Drawing Material pulled through die

Machining Unwanted material removed

Welding Permanent joining

Brazing Filler metal joins parts without melting base metals

Soldering Lower-temperature filler-metal joining

Grinding Abrasive material removal

CHAPTER 2 — ENGINEERING MATERIALS

2.1 Introduction

Engineering materials are the basic materials used for manufacturing machines, tools, structures, components and other engineering products.
A proper understanding of engineering materials is essential in Workshop Technology, because the selection of a material depends on its strength, hardness, toughness, ductility, machinability, corrosion resistance, cost, availability and intended application.
Engineering materials can broadly be classified into:
Metallic materials
Non-metallic materials
Composite materials
Metallic materials are further divided into:
Ferrous materials
Non-ferrous materials

2.2 Engineering Material

Definition
An engineering material is a material having suitable physical, mechanical, chemical or thermal properties that can be used for manufacturing engineering components, machines, tools or structures.
Examples
Steel
Cast iron
Aluminium
Copper
Brass
Bronze
Plastics
Ceramics
Composites
Exam Point
Material selection depends on the required properties and application of the component.

2.3 Metals

Definition
A metal is an element or material generally characterized by good electrical and thermal conductivity, metallic lustre, ductility and malleability.
Common Engineering Metals
Iron
Copper
Aluminium
Zinc
Nickel
Magnesium
Titanium

2.4 Ferrous Materials

Definition
Ferrous materials are materials in which iron is the principal constituent.
Major Examples
Cast iron
Steel
Carbon steel
Alloy steel
Stainless steel
Important Point
The word ferrous is derived from ferrum, the Latin word for iron.

2.5 Non-Ferrous Materials

Definition
Non-ferrous materials are metals and alloys in which iron is not the principal constituent.
Examples
Aluminium
Copper
Zinc
Magnesium
Titanium
Brass
Bronze
Major Characteristics
Many non-ferrous metals offer:
Good corrosion resistance
Low density
Good electrical conductivity
Good thermal conductivity

2.6 Alloy

Definition
An alloy is a metallic material formed by combining two or more elements, at least one of which is generally a metal, to obtain desirable properties.
Examples
Brass = Copper + Zinc
Bronze = Copper + Tin
(as the conventional/basic definition)
Steel = Iron + Carbon, with other elements possibly present.
Why Are Alloys Used?
Alloying can improve:
Strength
Hardness
Wear resistance
Corrosion resistance
Machinability
Heat resistance

2.7 Steel

Definition
Steel is an iron-based alloy containing carbon as an important alloying element, generally with carbon content below that of cast irons and with possible additions of other alloying elements.
Common Types
Plain carbon steel
Low-carbon steel
Medium-carbon steel
High-carbon steel
Alloy steel
Stainless steel

2.8 Carbon Steel

Definition
Carbon steel is steel in which carbon is the principal alloying element and the properties are primarily controlled by carbon content, with other elements present in relatively limited amounts.
Classification
Depending on carbon content, carbon steels are commonly classified as:
Low-carbon steel
Medium-carbon steel
High-carbon steel

2.9 Low-Carbon Steel

Definition
Low-carbon steel is steel containing a relatively low percentage of carbon.
General Characteristics
Good ductility
Good weldability
Good machinability
Relatively low hardness
Relatively low strength compared with higher-carbon steels
Applications

Sheets
Structural components
Automobile components
Nuts and bolts
General fabrication

2.10 Medium-Carbon Steel

Definition
Medium-carbon steel contains more carbon than low-carbon steel and generally provides a balance between strength, hardness and ductility.
Applications
Shafts
Axles
Gears
Machine components

2.11 High-Carbon Steel

Definition
High-carbon steel contains a relatively high percentage of carbon and generally has higher hardness and strength but lower ductility than low-carbon steel.
Applications
Cutting tools
Springs
High-strength wires
Dies
Wear-resistant components

2.12 Cast Iron

Definition
Cast iron is an iron-carbon alloy containing a relatively high carbon content, generally above the carbon content range of steels.
General Characteristics
Good castability
Good compressive strength
Good wear resistance in many grades
Good vibration-damping capacity
Generally brittle compared with steels
Applications
Machine beds
Engine blocks
Pump bodies
Pipes
Housings

2.13 Grey Cast Iron

Definition
Grey cast iron is cast iron in which carbon is present predominantly in the form of graphite flakes, giving the fractured surface a grey appearance.
Characteristics
Good machinability
Good damping capacity
Good castability
Relatively brittle
Applications
Machine beds
Engine blocks
Housings
Bases

2.14 White Cast Iron

Definition
White cast iron is cast iron in which carbon is predominantly present in combined form, mainly as cementite, giving a white appearance on fracture.
Characteristics
High hardness
High wear resistance
Poor machinability
Brittle

2.15 Malleable Cast Iron

Definition
Malleable cast iron is produced by heat treating suitable white cast iron to improve its ductility and toughness.
Applications
Pipe fittings
Brackets
Small machine components

2.16 Ductile Cast Iron

Definition
Ductile cast iron, also called nodular cast iron, is cast iron in which graphite occurs mainly in spheroidal or nodular form.
Characteristics
Better ductility than grey cast iron
Good strength
Good toughness
Good wear resistance
2.17 Alloy Steel
Definition
Alloy steel is steel containing deliberate additions of alloying elements such as chromium, nickel, molybdenum, manganese or vanadium to obtain specific properties.
Applications
Automobile components
Gears
Shafts
Pressure vessels
Aerospace components
Dies and tools

2.18 Stainless Steel

Definition
Stainless steel is a group of alloy steels containing sufficient chromium to provide substantial resistance to corrosion through formation of a protective chromium-rich oxide film.
Applications
Kitchen equipment
Chemical-processing equipment
Medical instruments
Food-processing equipment
Architectural applications
Exam Point
Chromium is the key alloying element associated with stainless-steel corrosion resistance.

2.19 Copper

Definition
Copper is a non-ferrous metal known for its excellent electrical and thermal conductivity, ductility and corrosion resistance.
Applications
Electrical wires
Electrical components
Heat exchangers
Pipes
Conductors

2.20 Aluminium

Definition
Aluminium is a lightweight non-ferrous metal having good corrosion resistance, good thermal and electrical conductivity and good formability.
Applications
Aircraft components
Automobile components
Electrical applications
Window frames
Packaging
Heat exchangers

2.21 Brass

Definition
Brass is a copper-zinc alloy.
Characteristics
Good machinability
Good corrosion resistance
Attractive appearance
Good electrical and thermal conductivity compared with many other engineering materials
Applications
Valves
Fittings
Fasteners
Electrical components
Decorative components
Exam Point
Brass → Copper + Zinc

2.22 Bronze

Definition
Bronze is traditionally a copper-tin alloy, although the term is also used for several copper-based alloys containing other elements.
Applications
Bearings
Bushes
Gears
Marine components
Valves
Exam Point
Traditional bronze → Copper + Tin

2.23 Zinc

Definition
Zinc is a non-ferrous metal commonly used for corrosion protection of steel and in the production of alloys such as brass.
Major Application
Galvanizing uses zinc coating to protect steel or iron from corrosion.
2.24 Magnesium
Definition
Magnesium is a very lightweight structural metal used where low weight is important.
Applications
Aerospace components
Automobile components
Portable equipment
Lightweight structural parts

2.25 Titanium

Definition
Titanium is a strong, relatively lightweight metal with excellent corrosion resistance and a high strength-to-weight ratio.
Applications
Aerospace
Chemical processing
Medical implants
Marine applications

2.26 Mechanical Properties

Definition
Mechanical properties describe how a material behaves when subjected to mechanical forces or loads.
Important mechanical properties include:
Strength
Hardness
Toughness
Ductility
Malleability
Elasticity
Plasticity
Stiffness
Resilience
Fatigue strength
Creep resistance

2.27 Strength

Definition
Strength is the ability of a material to withstand an applied load without failure.
Important types include:
Tensile strength
Compressive strength
Shear strength
Bending strength

2.28 Hardness

Definition
Hardness is the resistance of a material to localized plastic deformation such as indentation, scratching or wear.
Common Hardness Tests
Brinell
Rockwell
Vickers

2.29 Toughness

Definition
Toughness is the ability of a material to absorb energy and undergo deformation before fracture.
Important Point
A tough material can generally withstand impact or sudden loading better than a brittle material.

2.30 Ductility

Definition
Ductility is the ability of a material to undergo significant plastic deformation under tensile loading before fracture.
Example
Copper is generally considered a highly ductile engineering metal.

2.31 Malleability

Definition
Malleability is the ability of a material to undergo plastic deformation under compressive loading and be formed into thin sheets without cracking.
Exam Point
Ductility → tensile deformation
Malleability → compressive deformation

2.32 Brittleness

Definition
Brittleness is the tendency of a material to fracture with little or limited plastic deformation.
Example
Many forms of cast iron are relatively brittle compared with ductile steels.

2.33 Elasticity

Definition
Elasticity is the property by which a material tends to return to its original shape and dimensions after removal of the applied load, provided the elastic limit has not been exceeded.

2.34 Plasticity

Definition
Plasticity is the ability of a material to undergo permanent deformation without fracture.

2.35 Stiffness

Definition
Stiffness is the resistance offered by a material or component to elastic deformation.
Exam Point
A material may have high strength but a component’s deformation under load is also strongly related to its stiffness.

2.36 Resilience
Definition

Resilience is the ability of a material to absorb energy within its elastic limit and release that energy when the load is removed.

2.37 Fatigue

Definition
Fatigue is the progressive failure of a material caused by repeated or fluctuating stresses, often at stress levels below the material’s static strength.
Common Examples
Rotating shafts
Springs
Aircraft components
Connecting rods

2.38 Creep

Definition
Creep is the slow, time-dependent deformation of a material under sustained load, particularly at elevated temperature.
Important Point
Creep is especially important in:
Boilers
Turbines
Engines
High-temperature piping
Power-plant components

2.39 Wear

Definition
Wear is the progressive loss or displacement of material from a surface due to interaction with another surface or environment.
Common Types
Adhesive wear
Abrasive wear
Corrosive wear
Fatigue wear

2.40 Corrosion Resistance

Definition
Corrosion resistance is the ability of a material to resist deterioration caused by chemical or electrochemical interaction with its environment.
Example
Stainless steel generally has much better corrosion resistance than ordinary carbon steel because of its chromium-containing passive surface film.

QUICK REVISION TABLE

Material/Property Key Point

Ferrous material Iron is principal constituent

Non-ferrous material Iron is not principal constituent

Steel Iron-based alloy with carbon as an important constituent

Cast iron High-carbon iron alloy

Brass Copper + Zinc

Bronze Traditionally Copper + Tin

Stainless steel Chromium-containing corrosion-resistant steel

Copper Excellent electrical conductivity

Aluminium Lightweight and corrosion resistant

Strength Resistance to applied load

Hardness Resistance to indentation/wear

Toughness Energy absorption before fracture

Ductility Plastic deformation in tension

Malleability Plastic deformation in compression

Elasticity Recovery after removal of load

Plasticity Permanent deformation

Stiffness Resistance to elastic deformation

Resilience Elastic energy absorption

Fatigue Failure under repeated/fluctuating stress

Creep Time-dependent deformation under sustained load

Wear Progressive material loss

Corrosion resistance Resistance to environmental deterioration

CHAPTER 2 — IMPORTANT EXAM POINTS

Remember These Combinations

Brass → Cu + Zn

Bronze → Cu + Sn

Stainless Steel → Cr is essential for corrosion resistance

Ferrous → Iron-based

Ductility → Tensile deformation

Malleability → Compressive deformation

Hardness → Indentation

Toughness → Energy absorption before fracture

Elasticity → Returns after load removal

Plasticity → Permanent deformation

Fatigue → Repeated/fluctuating load

Creep → Time + sustained load

Q1. Which of the following is a ferrous material?
A. Aluminium
B. Copper
C. Cast iron
D. Brass
Answer: C. Cast iron
Explanation: Ferrous materials are iron-based materials. Cast iron contains iron as its principal constituent.
Question

Q2. Which of the following is a non-ferrous metal?
A. Mild steel
B. Cast iron
C. Aluminium
D. Carbon steel
Answer: C. Aluminium
Explanation: Aluminium is a non-ferrous metal because iron is not its principal constituent.
Question

Q3. Brass is primarily an alloy of:
A. Copper and tin
B. Copper and zinc
C. Iron and carbon
D. Aluminium and copper
Answer: B. Copper and zinc
Explanation: Brass is conventionally defined as a copper-zinc alloy.
Question
Q4. Bronze is tr

aditionally an alloy of:
A. Copper and zinc
B. Copper and tin
C. Iron and carbon
D. Aluminium and magnesium
Answer: B. Copper and tin
Explanation: Traditional bronze is a copper-tin alloy. There are also many other copper-based alloys commercially called bronzes.
Question

Q5. The principal alloying element responsible for the corrosion resistance of stainless steel is:
A. Carbon
B. Chromium
C. Sulphur
D. Silicon
Answer: B. Chromium
Explanation: Chromium promotes formation of a thin, protective passive oxide film that provides stainless steels with their characteristic corrosion resistance.
Question

Q6. Which material is generally known for excellent electrical conductivity?
A. Copper
B. Cast iron
C. High-carbon steel
D. Glass
Answer: A. Copper
Explanation: Copper has very high electrical conductivity and is widely used for electrical conductors and cables.
Question

Q7. Which of the following is a major advantage of aluminium?
A. Very high density
B. Low density
C. Extremely high hardness in pure form
D. Poor corrosion resistance
Answer: B. Low density
Explanation: Aluminium is lightweight and has good corrosion resistance, making it useful in transport and aerospace applications.
Question

Q8. Which material is commonly used for electrical wires?
A. Copper
B. Cast iron
C. Tool steel
D. White cast iron
Answer: A. Copper
Explanation: Copper combines excellent electrical conductivity with good ductility and is therefore widely used for electrical wiring.
Question

Q9. Which of the following is a ferrous alloy?
A. Brass
B. Bronze
C. Steel
D. Aluminium alloy
Answer: C. Steel
Explanation: Steel is an iron-based alloy and is therefore classified as a ferrous material.
Question

Q10. Which of the following is generally considered a lightweight engineering metal?
A. Aluminium
B. Lead
C. Cast iron
D. Steel
Answer: A. Aluminium
Explanation: Aluminium has relatively low density compared with steel and many other structural metals.
Question

Q11. Which property represents resistance to indentation?
A. Ductility
B. Hardness
C. Elasticity
D. Plasticity
Answer: B. Hardness
Explanation: Hardness is commonly evaluated through resistance to indentation, scratching or localized plastic deformation.
Question

Q12. Which property represents the ability to absorb energy before fracture?
A. Toughness
B. Hardness
C. Stiffness
D. Brittleness
Answer: A. Toughness
Explanation: Toughness is the ability to absorb energy and undergo deformation before fracture.
Question

Q13. The ability of a material to undergo plastic deformation in tension before fracture is called:
A. Ductility
B. Malleability
C. Hardness
D. Stiffness
Answer: A. Ductility
Explanation: Ductility is particularly associated with plastic deformation under tensile loading.
Question

Q14. The ability of a material to be formed into thin sheets by compressive deformation is called:
A. Ductility
B. Malleability
C. Toughness
D. Hardness
Answer: B. Malleability
Explanation: Malleability is the ability to undergo plastic deformation under compression without cracking.

Question
Q15. Which property allows a material to regain its original shape after removal of load?
A. Plasticity
B. Elasticity
C. Brittleness
D. Toughness
Answer: B. Elasticity
Explanation: Within its elastic limit, an elastic material returns approximately to its original dimensions after removal of the load.

Question
Q16. Which property represents resistance to elastic deformation?
A. Stiffness
B. Ductility
C. Malleability
D. Plasticity
Answer: A. Stiffness
Explanation: Stiffness indicates resistance to elastic deformation.

Question
Q17. A brittle material generally undergoes:
A. Large plastic deformation before fracture
B. Little plastic deformation before fracture
C. Unlimited elastic deformation
D. No deformation at all
Answer: B. Little plastic deformation before fracture
Explanation: Brittle materials generally fracture with relatively little plastic deformation.

Question
Q18. Which of the following is generally more ductile?
A. Glass
B. Copper
C. White cast iron
D. Ceramics
Answer: B. Copper
Explanation: Copper is a highly ductile metal and can undergo considerable plastic deformation before fracture.

Question
Q19. Which property is particularly important for materials subjected to impact loading?
A. Toughness
B. Density
C. Thermal expansion
D. Electrical resistance
Answer: A. Toughness
Explanation: Toughness is the ability to absorb energy before fracture, making it particularly important under impact or shock loading.

Question
Q20. Fatigue failure is generally associated with:
A. Repeated or fluctuating stresses
B. Constant temperature only
C. Static pressure only
D. Melting
Answer: A. Repeated or fluctuating stresses
Explanation: Fatigue is progressive failure caused by repeated or fluctuating stresses.

Question
Q21. Creep is:
A. Sudden fracture due to impact
B. Time-dependent deformation under sustained load
C. Surface scratching
D. Plastic deformation during forging only
Answer: B. Time-dependent deformation under sustained load
Explanation: Creep is a slow, time-dependent deformation that becomes particularly important at elevated temperatures.

Question
Q22. Creep is particularly important in:
A. High-temperature components
B. Room-temperature wooden furniture only
C. Measuring instruments only
D. Hand tools only
Answer: A. High-temperature components
Explanation: Creep becomes significant in components subjected to sustained stress at elevated temperatures, such as turbine and boiler components.

Question
Q23. Which of the following is a common hardness test?
A. Brinell test
B. Tensile test
C. Compression test
D. Impact-only test
Answer: A. Brinell test
Explanation: Brinell, Rockwell and Vickers are widely used hardness-testing methods.

Question
Q24. Which hardness test commonly uses a diamond pyramid indenter?
A. Vickers
B. Brinell
C. Charpy
D. Izod
Answer: A. Vickers
Explanation: The Vickers hardness test uses a diamond pyramid-shaped indenter.

Question
Q25. The Brinell hardness test commonly uses:
A. A steel or carbide ball indenter
B. A diamond cone only
C. A flat plate only
D. A cutting tool
Answer: A. A steel or carbide ball indenter
Explanation: Brinell testing uses a spherical indenter, traditionally hardened steel and commonly tungsten carbide in modern practice.

Question
Q26. Which of the following is an example of a mechanical property?
A. Hardness
B. Colour
C. Density only
D. Electrical conductivity
Answer: A. Hardness
Explanation: Hardness describes material response to mechanical loading and localized deformation.

Question
Q27. Which of the following is a physical property?
A. Density
B. Toughness
C. Hardness
D. Ductility
Answer: A. Density
Explanation: Density is a physical property, whereas hardness, toughness and ductility are mechanical properties.

Question
Q28. Which material is commonly used for machine beds because of its good vibration-damping capacity?
A. Grey cast iron
B. Aluminium foil
C. Copper wire
D. Glass
Answer: A. Grey cast iron
Explanation: Grey cast iron has good vibration-damping characteristics and is therefore widely used for machine-tool beds and bases.

Question
Q29. The graphite in ordinary grey cast iron is predominantly present as:
A. Spherical particles
B. Flakes
C. Needles only
D. Fibres
Answer: B. Flakes
Explanation: Grey cast iron characteristically contains graphite flakes in its microstructure.

Question
Q30. In ductile cast iron, graphite is predominantly present in:
A. Flake form
B. Nodular/spheroidal form
C. Continuous sheet form
D. Powder form
Answer: B. Nodular/spheroidal form
Explanation: The graphite in ductile or nodular cast iron is mainly spheroidal, improving ductility and toughness compared with grey cast iron.

Question
Q31. Which type of cast iron generally has high hardness and poor machinability?
A. White cast iron
B. Grey cast iron
C. Ductile cast iron
D. Malleable cast iron
Answer: A. White cast iron
Explanation: White cast iron contains carbon predominantly in combined form, especially cementite, making it hard and wear-resistant but difficult to machine.

Question
Q32. Malleable cast iron is produced by heat treatment of:
A. Grey cast iron
B. White cast iron
C. Pure aluminium
D. Brass
Answer: B. White cast iron
Explanation: Suitable white cast iron is heat treated to produce malleable cast iron with improved ductility and toughness.

Question
Q33. Which cast iron generally has the best combination of strength and ductility among common cast irons?
A. Ductile cast iron
B. White cast iron
C. Grey cast iron
D. Chilled cast iron
Answer: A. Ductile cast iron
Explanation: The nodular graphite structure of ductile cast iron gives it substantially better ductility and toughness than grey or white cast iron.

Question
Q34. Which material is commonly used for machine-tool beds?
A. Grey cast iron
B. Pure zinc
C. Brass sheet
D. Lead
Answer: A. Grey cast iron
Explanation: Grey cast iron combines good castability, machinability and vibration damping, making it suitable for machine beds.

Question
Q35. Which of the following is a low-carbon steel application?
A. General fabrication and structural components
B. High-speed cutting tools only
C. Grinding-wheel abrasives
D. Glass manufacturing
Answer: A. General fabrication and structural components
Explanation: Low-carbon steels are ductile, weldable and suitable for many general fabrication and structural applications.
Question

Q36. As carbon content in plain carbon steel generally increases, which property tends to increase?
A. Hardness
B. Ductility
C. Weldability
D. Formability
Answer: A. Hardness
Explanation: Increasing carbon content generally increases hardness and strength after suitable processing, while ductility and weldability tend to decrease.
Question

Q37. Which type of steel generally has the highest carbon content among the following?
A. Low-carbon steel
B. Medium-carbon steel
C. High-carbon steel
D. Mild steel
Answer: C. High-carbon steel
Explanation: High-carbon steel contains more carbon than low- and medium-carbon steels.
Question

Q38. Which material is commonly used for springs because of its ability to withstand elastic deformation?
A. Spring steel
B. Grey cast iron
C. Pure lead
D. Glass
Answer: A. Spring steel
Explanation: Spring steels are designed to provide suitable strength and elastic properties for repeated spring action.
Question

Q39. Which alloying element is strongly associated with improved wear and corrosion resistance in many alloy steels?
A. Chromium
B. Oxygen
C. Hydrogen
D. Sulphur only
Answer: A. Chromium
Explanation: Chromium can improve hardness, wear resistance and corrosion resistance depending on composition and heat treatment.
Question

Q40. Nickel in steel can contribute to:
A. Toughness and corrosion resistance
B. Complete loss of strength
C. Zero ductility in every case
D. Elimination of all heat treatment
Answer: A. Toughness and corrosion resistance
Explanation: Nickel is used in alloy steels to improve properties such as toughness and corrosion resistance.
Question

Q41. Which of the following is a non-ferrous alloy?
A. Brass
B. Carbon steel
C. Cast iron
D. Stainless steel
Answer: A. Brass
Explanation: Brass is a copper-zinc alloy and does not have iron as its principal constituent.
Question

Q42. Which material is commonly used for bearings and bushes?
A. Bronze
B. Glass
C. Pure iron only
D. Concrete
Answer: A. Bronze
Explanation: Several bronze alloys have good wear resistance and suitable friction characteristics and are used for bearings and bushes.
Question

Q43. Which metal is commonly used as a coating for protecting steel against atmospheric corrosion?
A. Zinc
B. Copper
C. Tin only
D. Lead only
Answer: A. Zinc
Explanation: Zinc coating, known as galvanizing, is widely used to protect iron and steel from corrosion.

Question
Q44. Galvanizing generally involves coating steel with:
A. Zinc
B. Copper
C. Aluminium only
D. Carbon
Answer: A. Zinc
Explanation: Galvanizing is the application of a zinc coating to iron or steel for corrosion protection.

Question
Q45. Which metal has a high strength-to-weight ratio and excellent corrosion resistance?
A. Titanium
B. Lead
C. Grey cast iron
D. Pure zinc
Answer: A. Titanium
Explanation: Titanium and its alloys are valued for high specific strength and excellent corrosion resistance.

Question
Q46. Which material is widely used in aerospace applications because of its low density?
A. Aluminium alloys
B. Grey cast iron
C. Lead
D. White cast iron
Answer: A. Aluminium alloys
Explanation: Aluminium alloys provide relatively low density with useful strength and corrosion resistance.

Question
Q47. Which of the following is generally a good conductor of both heat and electricity?
A. Copper
B. Rubber
C. Glass
D. Wood
Answer: A. Copper
Explanation: Copper has excellent electrical and thermal conductivity.

Question
Q48. Which material is generally characterized by good castability and vibration damping?
A. Grey cast iron
B. Pure aluminium
C. Copper
D. Titanium
Answer: A. Grey cast iron
Explanation: Grey cast iron flows well during casting and its graphite structure provides useful vibration damping.

Question
Q49. Which property is most directly associated with resistance to scratching?
A. Hardness
B. Ductility
C. Malleability
D. Plasticity
Answer: A. Hardness
Explanation: Hardness is commonly associated with resistance to scratching, indentation and wear.

Question
Q50. Which property is most important when a material must withstand repeated loading for a long period?
A. Fatigue strength
B. Colour
C. Density alone
D. Melting point alone
Answer: A. Fatigue strength
Explanation: Components subjected to repeated or fluctuating loads require adequate fatigue strength to resist fatigue failure.

Question
Q51. Which of the following is NOT a ferrous material?
A. Steel
B. Cast iron
C. Stainless steel
D. Brass
Answer: D. Brass
Explanation: Brass is a copper-zinc alloy and is classified as a non-ferrous material.

Question
Q52. Which of the following is a copper-based alloy?
A. Brass
B. Mild steel
C. Cast iron
D. Stainless steel
Answer: A. Brass
Explanation: Brass is primarily composed of copper and zinc.

Question
Q53. Which material is particularly suitable for electrical conductors?
A. Copper
B. White cast iron
C. High-carbon steel
D. Grey cast iron
Answer: A. Copper
Explanation: Copper’s high electrical conductivity and ductility make it suitable for electrical conductors.

Question
Q54. Which property is particularly desirable in a material used for a cutting tool?
A. High hardness
B. Very low hardness
C. Very high ductility only
D. Very low wear resistance
Answer: A. High hardness
Explanation: Cutting tools must resist deformation and wear at the cutting edge, so high hardness is essential.

Question
Q55. Which material property is most closely associated with resistance to wear?
A. Hardness
B. Malleability
C. Elasticity
D. Thermal expansion
Answer: A. Hardness
Explanation: Hardness generally contributes significantly to resistance against abrasive and surface wear, although wear behavior depends on several factors.

Q56. Which material is generally easier to plastically deform?
A. Ductile material
B. Brittle material
C. Glass
D. White cast iron
Answer: A. Ductile material
Explanation: Ductile materials can undergo significant plastic deformation before fracture.

Question
Q57. Which property is important for a material used in sheet-metal forming?
A. Malleability
B. Brittleness
C. Extremely low ductility
D. Poor formability
Answer: A. Malleability
Explanation: Malleability enables materials to undergo compressive plastic deformation and be formed into sheets.

Question
Q58. Which of the following materials is generally brittle?
A. Grey cast iron
B. Copper
C. Aluminium
D. Mild steel
Answer: A. Grey cast iron
Explanation: Grey cast iron is relatively brittle because of its flake-graphite structure.

Question
Q59. Which property is associated with resistance to sudden impact?
A. Toughness
B. Density
C. Conductivity
D. Thermal expansion
Answer: A. Toughness
Explanation: Toughness measures a material’s ability to absorb energy before fracture and is important under impact loading.

Question
Q60. Which property is particularly important in a material subjected to high temperature for a long time?
A. Creep resistance
B. Colour
C. Electrical resistance only
D. Surface appearance only
Answer: A. Creep resistance
Explanation: Components under sustained stress at high temperatures can undergo creep, so creep resistance is important.

Question
Q61. Which of the following is a common alloying element in stainless steel?
A. Chromium
B. Sodium
C. Calcium
D. Potassium
Answer: A. Chromium
Explanation: Chromium is essential to the corrosion resistance of stainless steels.

Question
Q62. Which of the following is a lightweight non-ferrous metal?
A. Aluminium
B. Cast iron
C. Steel
D. High-carbon steel
Answer: A. Aluminium
Explanation: Aluminium has relatively low density and is widely used where weight reduction is important.

Question
Q63. Which material is commonly used for engine blocks?
A. Cast iron
B. Glass
C. Copper wire
D. Rubber
Answer: A. Cast iron
Explanation: Cast irons, particularly grey cast iron, have good castability, machinability and vibration-damping characteristics. Aluminium alloys are also widely used for engine blocks.
Question

Q64. Which type of cast iron has graphite in nodular form?
A. Ductile cast iron
B. Grey cast iron
C. White cast iron
D. Chilled cast iron
Answer: A. Ductile cast iron
Explanation: Ductile cast iron is characterized by spheroidal or nodular graphite.

Question
Q65. Which cast iron has graphite predominantly in flake form?
A. Grey cast iron
B. Ductile cast iron
C. Malleable cast iron
D. White cast iron
Answer: A. Grey cast iron
Explanation: Graphite flakes give grey cast iron its characteristic appearance and contribute to good vibration damping.

Question
Q66. Which cast iron contains carbon mainly in combined form?
A. White cast iron
B. Grey cast iron
C. Ductile cast iron
D. Malleable cast iron
Answer: A. White cast iron
Explanation: White cast iron contains carbon primarily as cementite and therefore has high hardness and poor machinability.

Question
Q67. Which material is generally preferred for a component requiring good corrosion resistance and relatively low weight?
A. Aluminium alloy
B. Grey cast iron
C. White cast iron
D. Plain carbon steel without protection
Answer: A. Aluminium alloy
Explanation: Aluminium alloys combine low density with good corrosion resistance.

Question
Q68. Which of the following is an example of an alloy?
A. Brass
B. Pure oxygen
C. Pure nitrogen
D. Distilled water
Answer: A. Brass
Explanation: Brass is an alloy of copper and zinc.
Question

Q69. Why are alloying elements added to metals?
A. To obtain desirable properties
B. Always to reduce strength
C. Always to increase weight
D. Only to change colour
Answer: A. To obtain desirable properties
Explanation: Alloying can be used to modify strength, hardness, corrosion resistance, toughness, machinability and other properties.

Question
Q70. Which of the following is generally associated with increasing carbon content in plain carbon steel?
A. Increased hardness and strength
B. Increased ductility in all cases
C. Improved weldability in all cases
D. Elimination of brittleness
Answer: A. Increased hardness and strength
Explanation: Increasing carbon generally raises hardness and strength, while ductility and weldability tend to decrease.

Question
Q71. Which type of steel is generally used where good weldability is required?
A. Low-carbon steel
B. High-carbon steel
C. Extremely high-carbon steel
D. White cast iron
Answer: A. Low-carbon steel
Explanation: Low-carbon steels generally have good weldability because of their relatively low carbon content.

Question
Q72. Which steel is commonly suitable for gears and shafts where greater strength is required than low-carbon steel?
A. Medium-carbon steel
B. Pure copper
C. Aluminium foil
D. Grey cast iron only
Answer: A. Medium-carbon steel
Explanation: Medium-carbon steels provide a useful balance of strength, hardness and ductility and are commonly used for shafts, gears and axles.

Question
Q73. Which steel is commonly used for high-strength wires and springs?
A. High-carbon steel
B. Low-carbon steel only
C. Pure aluminium
D. Grey cast iron
Answer: A. High-carbon steel
Explanation: High-carbon steels can provide high strength and hardness and are used in springs and high-strength wire applications.

Question
Q74. Which property is especially important for a spring material?
A. Resilience
B. Brittleness
C. Very low elasticity
D. Poor fatigue resistance
Answer: A. Resilience
Explanation: Springs must store and release elastic energy, making resilience an important property.

Question
Q75. Which phenomenon is strongly associated with repeated cyclic loading?
A. Fatigue
B. Creep
C. Casting
D. Galvanizing
Answer: A. Fatigue
Explanation: Fatigue failure develops under repeated or fluctuating stresses.

Question
Q76. Which phenomenon is strongly associated with sustained stress at elevated temperature?
A. Creep
B. Fatigue only
C. Hardening
D. Tempering
Answer: A. Creep
Explanation: Creep is time-dependent deformation under sustained stress and is especially significant at elevated temperatures.

Question
Q77. Which property is associated with the ability to resist permanent deformation?
A. Hardness
B. Colour
C. Thermal conductivity
D. Density
Answer: A. Hardness
Explanation: Hardness is commonly associated with resistance to localized permanent deformation such as indentation.

Question
Q78. Which material is commonly selected for a bearing because of suitable wear and friction characteristics?
A. Bronze
B. Glass
C. Concrete
D. Pure iron only
Answer: A. Bronze
Explanation: Several bronze alloys are used for bearings and bushes because of their wear and friction characteristics.

Question
Q79. Which material is widely used for corrosion-resistant kitchen utensils and equipment?
A. Stainless steel
B. White cast iron
C. Plain carbon steel without coating
D. High-carbon steel only
Answer: A. Stainless steel
Explanation: Stainless steel offers good corrosion resistance and is widely used in food-processing and kitchen applications.
Question

Q80. Which metal is commonly used as the base metal in brass and bronze?
A. Copper
B. Iron
C. Aluminium
D. Titanium
Answer: A. Copper
Explanation: Brass and bronze are both copper-based alloys.

Question
Q81. Which of the following is a major advantage of copper?
A. High electrical conductivity
B. Very low electrical conductivity
C. Extremely high brittleness
D. Poor thermal conductivity
Answer: A. High electrical conductivity
Explanation: Copper is one of the most widely used engineering materials for electrical conductors because of its excellent conductivity.

Question
Q82. Which material is commonly used for lightweight automobile components?
A. Aluminium alloy
B. White cast iron
C. Lead
D. Glass
Answer: A. Aluminium alloy
Explanation: Aluminium alloys provide useful strength at relatively low weight.

Question
Q83. Which material is commonly associated with galvanizing?
A. Zinc
B. Copper
C. Tin
D. Nickel
Answer: A. Zinc
Explanation: Galvanizing protects iron and steel by applying a zinc coating.

Question
Q84. Which property allows a metal to be drawn into wires?
A. Ductility
B. Malleability
C. Brittleness
D. Hardness
Answer: A. Ductility
Explanation: Ductility is the ability of a material to undergo tensile plastic deformation and is important in wire drawing.

Question
Q85. Which property allows a metal to be rolled into thin sheets?
A. Malleability
B. Brittleness
C. Hardness only
D. Fatigue
Answer: A. Malleability
Explanation: Malleability allows a material to undergo compressive plastic deformation, making it suitable for sheet formation.

Question
Q86. Which material property is important for a cutting tool to maintain its cutting edge?
A. Hardness
B. High ductility only
C. Malleability
D. Low wear resistance
Answer: A. Hardness
Explanation: Cutting tools require high hardness and wear resistance to retain their cutting edges during machining.

Question
Q87. Which of the following is a thermal property?
A. Thermal conductivity
B. Hardness
C. Toughness
D. Ductility
Answer: A. Thermal conductivity
Explanation: Thermal conductivity describes a material’s ability to conduct heat.

Question
Q88. Which of the following is an electrical property?
A. Electrical conductivity
B. Toughness
C. Hardness
D. Ductility
Answer: A. Electrical conductivity
Explanation: Electrical conductivity indicates how readily a material conducts electric current.

Question
Q89. Which material is commonly preferred where high corrosion resistance and high specific strength are required?
A. Titanium alloy
B. Grey cast iron
C. Plain carbon steel
D. Lead
Answer: A. Titanium alloy
Explanation: Titanium alloys combine high strength-to-weight ratio with excellent corrosion resistance.

Question
Q90. Which of the following is generally NOT a desired property for a cutting tool?
A. High hardness
B. Good wear resistance
C. High hot hardness where appropriate
D. Very low hardness
Answer: D. Very low hardness
Explanation: A cutting tool must retain adequate hardness and resistance to wear and deformation during cutting.

Question
Q91. Which property is most closely associated with the ability to resist elastic deformation?
A. Stiffness
B. Ductility
C. Malleability
D. Brittleness
Answer: A. Stiffness
Explanation: Stiffness represents resistance to elastic deformation.
Question

Q92. Which property describes the ability of a material to absorb energy elastically?
A. Resilience
B. Brittleness
C. Hardness
D. Creep
Answer: A. Resilience
Explanation: Resilience is the capacity to absorb energy within the elastic range.

Question
Q93. Which material generally has good vibration-damping capacity?
A. Grey cast iron
B. Copper wire
C. Aluminium foil
D. Glass
Answer: A. Grey cast iron
Explanation: Graphite flakes in grey cast iron contribute to good vibration damping.

Question
Q94. Which of the following is a major characteristic of white cast iron?
A. High hardness
B. Excellent ductility
C. Very high machinability
D. High malleability
Answer: A. High hardness
Explanation: White cast iron contains hard carbide phases and is highly wear resistant but brittle and difficult to machine.

Question
Q95. Which cast iron is produced by suitable heat treatment of white cast iron?
A. Malleable cast iron
B. Grey cast iron
C. Ductile cast iron
D. Alloy steel
Answer: A. Malleable cast iron
Explanation: Malleable cast iron is produced through heat treatment of suitable white cast iron.

Question
Q96. Which material is most suitable among the following for a component requiring excellent electrical conductivity?
A. Copper
B. Grey cast iron
C. High-carbon steel
D. White cast iron
Answer: A. Copper
Explanation: Copper has excellent electrical conductivity and is widely used in electrical applications.

Question
Q97. Which of the following is an alloy of iron and carbon?
A. Steel
B. Brass
C. Bronze
D. Pure aluminium
Answer: A. Steel
Explanation: Steel is an iron-based alloy in which carbon is an important constituent.

Question
Q98. Which of the following is generally a desirable property for a material used in a machine component exposed to corrosive surroundings?
A. Corrosion resistance
B. High brittleness
C. Very low strength
D. Very poor surface quality
Answer: A. Corrosion resistance
Explanation: Corrosion-resistant materials maintain their useful properties better in corrosive environments.
Question

Q99. Which statement is correct?
A. Ductility is mainly associated with tensile plastic deformation
B. Malleability is only electrical conductivity
C. Toughness means resistance to corrosion only
D. Hardness means electrical conductivity
Answer: A. Ductility is mainly associated with tensile plastic deformation
Explanation: Ductility describes the capacity for plastic deformation under tensile loading before fracture.

Question
Q100. Which of the following correctly matches the material with its conventional composition?
A. Brass — Copper + Zinc
B. Bronze — Iron + Carbon
C. Steel — Copper + Zinc
D. Cast iron — Copper + Tin
Answer: A. Brass — Copper + Zinc
Explanation: Brass is a copper-zinc alloy. Bronze is traditionally copper-tin, while steel and cast iron are iron-carbon-based materials.
Question

CHAPTER 2 — FINAL REVISION CAPSULE

Most Important Material Combinations

Brass → Copper + Zinc

Traditional Bronze → Copper + Tin

Steel → Iron + Carbon-based alloy

Stainless Steel → Chromium-containing steel

Ferrous → Iron is principal constituent

Non-ferrous → Iron is not principal constituent

Galvanizing → Zinc coating

Grey Cast Iron → Graphite flakes

Ductile Cast Iron → Nodular graphite

White Cast Iron → Carbon mainly in combined form

Most Important Properties

Strength → Resistance to applied load

Hardness → Resistance to indentation/scratching

Toughness → Energy absorption before fracture

Ductility → Tensile plastic deformation

Malleability → Plastic deformation under compression

Elasticity → Recovery after unloading

Plasticity → Permanent deformation

Stiffness → Resistance to elastic deformation

Resilience → Elastic energy absorption

Fatigue → Repeated/fluctuating stresses

Creep → Time-dependent deformation under sustained stress

Wear → Progressive material loss

CHAPTER 3 — MECHANICAL PROPERTIES OF ENGINEERING MATERIALS

3.1 Introduction

Mechanical properties describe how an engineering material behaves when subjected to an external force or load.
For Workshop Technology, understanding these properties is important because the selection of material for a machine component depends heavily on its mechanical behaviour.
For example:
A shaft requires adequate strength and toughness.
A spring requires high resilience and fatigue strength.
A cutting tool requires high hardness and wear resistance.
A wire requires good ductility.
A sheet-metal component requires good malleability and formability.
A machine bed benefits from good stiffness and vibration damping.

3.2 Load

Definition
A load is an external force or system of forces acting on a body.
Common Types of Loading
Tensile load
Compressive load
Shear load
Bending load
Torsional load

3.3 Tensile Load

A tensile load tends to pull a body apart.
Example
A rod being pulled from both ends is subjected to tensile loading.
Effect: Increase in length and reduction in cross-sectional dimensions.

3.4 Compressive Load

A compressive load tends to shorten or compress a body.
Example
A column carrying a vertical load is subjected primarily to compression.
Effect: Reduction in length and possible increase in lateral dimensions.

3.5 Shear Load

A shear load tends to cause one part of a body to slide relative to another part.
Example
A rivet or bolt subjected to transverse loading can experience shear.

3.6 Bending Load

A bending load causes a component to curve or bend.
Examples
Beams
Shafts
Levers
Machine components
A bending load can produce both tensile and compressive stresses in different regions of a component.

3.7 Torsional Load

A torsional load produces twisting about the longitudinal axis of a component.
Examples
Shafts
Drive axles
Transmission components

3.8 Stress

Definition
Stress is the internal resisting force developed per unit area of a material when an external load is applied.
For normal stress:
σ=P/A

Where:
σ= stress
P= applied load
A= cross-sectional area
SI Unit
Pascal (Pa)
In engineering applications, MPa and N/mm² are commonly used.
Important Relation
1″ ” N/mm^2=1″ ” MPa

3.9 Tensile Stress

Tensile stress is produced when a member is subjected to a tensile load.
σ_t=P/A

It tends to elongate the material.

3.10 Compressive Stress

Compressive stress is produced when a member is subjected to compressive loading.
σ_c=P/A

It tends to shorten the member.

3.11 Shear Stress

Shear stress acts tangentially to a surface and tends to cause sliding between adjacent layers.
It is commonly represented by:
τ=P/A

for the simple average shear-stress case.

3.12 Strain

Definition
Strain is the deformation produced per unit original dimension.
For linear tensile strain:
ϵ=ΔL/L

Where:
ΔL= change in length
L= original length
Important Point
Strain has no unit because it is a ratio of two lengths.

3.13 Tensile Strain

Tensile strain is produced when a material is subjected to tensile stress.
ϵ_t=”Increase in length” /”Original length”

3.14 Compressive Strain

Compressive strain is produced when a material is subjected to compressive stress.
ϵ_c=”Decrease in length” /”Original length”

3.15 Hooke’s Law

Definition
Hooke’s Law states that, within the elastic limit, stress is directly proportional to strain.
σ∝ϵ

Therefore:
σ=Eϵ

where Eis Young’s modulus.
Important Condition
Hooke’s law is applicable only within the proportional/elastic range as appropriate to the material and loading condition.

3.16 Young’s Modulus

Young’s modulus is the ratio of normal stress to corresponding normal strain within the linear elastic region.
E=σ/ϵ
SI Unit
Pa or N/m²
In engineering:
GPa is commonly used.
Important Point
A higher Young’s modulus generally indicates a stiffer material in axial loading.

3.17 Modulus of Rigidity

The modulus of rigidity, also called shear modulus, is the ratio of shear stress to shear strain within the elastic range.
G=τ/γ
where:
G= modulus of rigidity
τ= shear stress
γ= shear strain

3.18 Bulk Modulus

The bulk modulus is the ratio of hydrostatic pressure to the corresponding volumetric strain.
K=p/(ΔV/V)

It represents resistance to uniform volumetric deformation.

3.19 Poisson’s Ratio

Definition
Poisson’s ratio is the ratio of lateral strain to longitudinal strain in a material under axial loading, with sign convention depending on the formulation.
In magnitude form:
ν=”lateral strain” /”longitudinal strain”

Because a tensile-loaded specimen generally becomes narrower laterally, the signed lateral strain is opposite in sign to the longitudinal strain.

3.20 Elastic Limit

Definition
The elastic limit is the maximum stress up to which a material can return essentially to its original dimensions after removal of the load.
Beyond this region, permanent deformation may remain.

3.21 Proportional Limit

Definition
The proportional limit is the highest stress up to which stress remains directly proportional to strain.
Difference
Proportional limit: stress-strain relationship remains linear.
Elastic limit: material can still substantially recover its original dimensions after unloading.
The two limits may be very close for many engineering materials, but they are conceptually different.

3.22 Yield Point

Definition
The yield point is the stress region at which significant plastic deformation begins without a corresponding large increase in stress, in materials that exhibit a distinct yield phenomenon.
Some materials do not show a sharply defined yield point; in such cases, an offset yield strength may be specified.

3.23 Yield Strength

Definition
Yield strength is the stress at which a specified amount of permanent/plastic deformation begins to be considered significant.
For many metals without a distinct yield point, a 0.2% proof stress is commonly used.

3.24 Ultimate Tensile Strength

Definition
Ultimate tensile strength (UTS) is the maximum engineering tensile stress reached by a specimen during a tensile test.
UTS=”Maximum load” /”Original cross-sectional area”

3.25 Fracture Stress

Fracture stress is the stress associated with the load at which the specimen finally fractures.
In an engineering stress-strain curve, fracture may occur after the ultimate tensile strength has been reached because of necking.

3.26 Plastic Deformation

Definition
Plastic deformation is permanent deformation that remains after the external load is removed.
It occurs when the material is loaded beyond its elastic range.

3.27 Elastic Deformation

Definition
Elastic deformation is recoverable deformation that disappears when the load is removed, provided the material remains within its elastic range.

3.28 Ductility

Ductility is the ability of a material to undergo substantial plastic deformation in tension before fracture.
Common Measures
Percentage elongation
Percentage reduction in area
A higher percentage elongation generally indicates greater ductility.

3.29 Percentage Elongation

Percentage elongation is given by:
%” ” Elongation=(L_f-L_0)/L_0 ×100

Where:
L_0= original gauge length
L_f= final gauge length
3.30 Percentage Reduction in Area
%” ” Reduction” ” in” ” Area=(A_0-A_f)/A_0 ×100

Where:
A_0= original cross-sectional area
A_f= final cross-sectional area
It is also commonly used as an indicator of ductility.

3.31 Toughness

Definition
Toughness is the ability of a material to absorb energy and undergo plastic deformation before fracture.
Important Point
Toughness combines aspects of strength and ductility.
3.32 Resilience

Definition
Resilience is the ability of a material to absorb and store energy elastically.
Modulus of Resilience
The modulus of resilience represents the elastic strain energy absorbed per unit volume up to the elastic limit or relevant yield point.

3.33 Stiffness

Definition
Stiffness is the resistance offered by a body or material to deformation under load.
For axial loading, Young’s modulus is an important material parameter related to stiffness.

3.34 Hardness

Hardness is resistance to localized permanent deformation, commonly measured through indentation tests.
Common Tests
Brinell
Rockwell
Vickers

3.35 Rockwell Hardness Test

The Rockwell test determines hardness based on the depth of indentation produced under specified loading conditions.
Important Point
Rockwell testing is widely used because it is relatively rapid and does not require measuring the indentation diameter optically.

3.36 Brinell Hardness Test

The Brinell test uses a spherical indenter and determines hardness from the size of the indentation produced under a specified load.
Suitable For
It is often useful for relatively large or coarse-grained metallic specimens.

3.37 Vickers Hardness Test

The Vickers test uses a diamond pyramid indenter.
It is suitable for a wide range of materials and can be used for relatively small or thin specimens when appropriate testing conditions are selected.

3.38 Impact Strength

Definition
Impact strength represents the ability of a material to absorb energy under sudden or impact loading.
Common Tests
Charpy impact test
Izod impact test

3.39 Fatigue Strength

Definition
Fatigue strength is the ability of a material to withstand repeated or fluctuating stresses without failure for a specified number of cycles or under specified fatigue conditions.

3.40 Endurance Limit

For some materials, particularly certain steels, an endurance limit is the stress level below which the material can withstand a very large or effectively indefinite number of cycles under specified conditions.
Not all materials exhibit a true endurance limit.

3.41 Creep

Creep is the progressive, time-dependent deformation of a material under sustained stress.
It becomes especially important at elevated temperatures.

3.42 Wear

Wear is the progressive removal, displacement or degradation of material from a surface due to interaction with another surface or environment.
Major Types
Adhesive wear
Abrasive wear
Fatigue wear
Corrosive wear

3.43 Adhesive Wear

Adhesive wear occurs when material is transferred between contacting surfaces due to localized adhesion and subsequent shearing.

3.44 Abrasive Wear

Abrasive wear occurs when a hard surface or hard particles remove material from a softer surface.

3.45 Fatigue Wear

Fatigue wear occurs due to repeated loading and unloading of contacting surfaces, eventually causing surface damage and material removal.

3.46 Corrosive Wear

Corrosive wear occurs when chemical or electrochemical reactions contribute to material removal from a surface.
3.47 Factor of Safety

Definition
The factor of safety (FOS) provides a margin between the strength of a component/material and the allowable working condition.
A simplified form is:
FOS=”Failure strength” /”Allowable working stress”

The precise definition depends on the design criterion and material behavior.
Purpose
It accounts for uncertainties such as:
Variations in material properties
Manufacturing defects
Uncertainty in loading
Service conditions
Design assumptions

3.48 Working Stress

Definition
Working stress, or allowable stress, is the stress level permitted in a component during normal operation according to the applicable design standard and safety considerations.

3.49 Stress Concentration

Definition
Stress concentration is the localized increase in stress around discontinuities such as:
Holes
Notches
Sharp corners
Keyways
Grooves
Important Point
Sharp corners generally produce greater stress concentration than smoothly rounded transitions.

3.50 Engineering Stress vs True Stress

Engineering Stress
σ_e=P/A_0

where A_0is the original cross-sectional area.
True Stress
σ_t=P/A_i

where A_iis the instantaneous cross-sectional area.
Exam Point
Engineering stress uses the original area, while true stress uses the instantaneous area.

QUICK REVISION TABLE

Property/Term Meaning

Load External force/system of forces

Stress Internal force per unit area

Strain Deformation per unit original dimension

Tensile stress Stress due to pulling

Compressive stress Stress due to pushing

Shear stress Stress causing sliding

Young’s modulus Normal stress / normal strain

Shear modulus Shear stress / shear strain

Bulk modulus Hydrostatic stress / volumetric strain

Poisson’s ratio Lateral strain / longitudinal strain

Elasticity Recovery after unloading

Plasticity Permanent deformation

Yield strength Stress associated with specified plastic deformation

UTS Maximum engineering tensile stress

Ductility Plastic deformation in tension

Malleability Plastic deformation under compression

Toughness Energy absorption before fracture

Resilience Elastic energy absorption

Stiffness Resistance to deformation

Hardness Resistance to localized deformation

Fatigue Failure under repeated/fluctuating loading

Creep Time-dependent deformation

Wear Progressive surface/material loss

FOS Margin between failure and allowable condition

Stress concentration Localized increase in stress

IMPORTANT FORMULAS

Normal Stress
σ=P/A

Strain
ϵ=ΔL/L

Young’s Modulus
E=σ/ϵ

Shear Modulus
G=τ/γ

Percentage Elongation
%EL=(L_f-L_0)/L_0 ×100

Percentage Reduction in Area
%RA=(A_0-A_f)/A_0 ×100

Factor of Safety
FOS=”Failure strength” /”Allowable working stress”

Q1. The internal resisting force developed per unit area of a material subjected to an external load is called:
A. Strain
B. Stress
C. Deformation
D. Toughness
Answer: B. Stress
Explanation: Stress represents the internal resistance developed in a material against an applied load. For direct normal loading:
σ=P/A

Q2. The SI unit of stress is:
A. Newton
B. Joule
C. Pascal
D. Watt
Answer: C. Pascal
Explanation: Stress is force per unit area, so its SI unit is N/m², which is called the Pascal (Pa).

Q3. Which of the following is equivalent to 1 MPa?
A. 1 N/m²
B. 1 N/mm²
C. 1000 N/mm²
D. 1 kN/mm²
Answer: B. 1 N/mm²
Explanation:
1″ ” MPa=10^6 “ ” N/m^2=1″ ” N/mm^2

Q4. Strain is defined as:
A. Force per unit area
B. Deformation per unit original dimension
C. Force × distance
D. Energy per unit volume
Answer: B. Deformation per unit original dimension
Explanation: For linear deformation:
ϵ=ΔL/L

Therefore, strain is dimensionless.

Q5. The unit of strain is:
A. N
B. Pa
C. mm
D. No unit
Answer: D. No unit
Explanation: Strain is a ratio of two lengths and therefore has no physical unit.

Q6. A tensile load tends to:
A. Shorten a component
B. Twist a component only
C. Elongate a component
D. Produce no deformation
Answer: C. Elongate a component
Explanation: Tensile loading pulls a component apart and generally increases its length.

Q7. A compressive load tends to:
A. Increase length
B. Decrease length
C. Produce only twisting
D. Produce no stress
Answer: B. Decrease length
Explanation: Compressive loading tends to shorten a component.

Q8. A load acting tangentially to a surface primarily produces:
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Hydrostatic stress
Answer: C. Shear stress
Explanation: Shear stress acts tangentially to the surface and tends to cause relative sliding between adjacent layers.

Q9. The ratio of normal stress to normal strain within the elastic range is:
A. Bulk modulus
B. Young’s modulus
C. Modulus of rigidity
D. Poisson’s ratio
Answer: B. Young’s modulus
Explanation:
E=σ/ϵ

Young’s modulus is an important measure of stiffness in axial loading.

Q10. The SI unit of Young’s modulus is:
A. N
B. N/m²
C. m/N
D. N·m
Answer: B. N/m²
Explanation: Since Young’s modulus is stress divided by dimensionless strain, its unit is the same as stress: Pa or N/m².

Q11. Hooke’s law states that, within the proportional limit:
A. Stress is inversely proportional to strain
B. Stress is directly proportional to strain
C. Stress is independent of strain
D. Strain is always zero
Answer: B. Stress is directly proportional to strain
Explanation:
σ∝ϵ

or
σ=Eϵ

within the applicable linear elastic range.
Q12. Which property indicates resistance to elastic deformation?
A. Stiffness
B. Ductility
C. Plasticity
D. Malleability
Answer: A. Stiffness
Explanation: Stiffness is the resistance offered by a material or component to elastic deformation.

Q13. A material that returns to its original shape after removal of load, within its elastic range, possesses:
A. Plasticity
B. Elasticity
C. Brittleness
D. Creep
Answer: B. Elasticity
Explanation: Elasticity is the ability of a material to recover its original shape and dimensions after the load is removed, provided the elastic range is not exceeded.

Q14. Permanent deformation remaining after removal of load is called:
A. Elastic deformation
B. Plastic deformation
C. Thermal deformation
D. Volumetric deformation only
Answer: B. Plastic deformation
Explanation: Plastic deformation is permanent deformation and does not disappear completely after unloading.

Q15. The maximum stress up to which a material substantially returns to its original dimensions after unloading is called:
A. Ultimate stress
B. Elastic limit
C. Breaking stress
D. Working stress
Answer: B. Elastic limit
Explanation: Beyond the elastic limit, permanent deformation can remain after the load is removed.

Q16. The maximum stress up to which stress is directly proportional to strain is called:

A. Proportional limit
B. Ultimate stress
C. Fracture stress
D. Breaking stress
Answer: A. Proportional limit
Explanation: Up to the proportional limit, stress and strain have a linear relationship.

Q17. The beginning of significant permanent deformation in a ductile material is associated with:
A. Yielding
B. Elastic recovery
C. Hardening only
D. Creep only
Answer: A. Yielding
Explanation: Yielding marks the transition from predominantly elastic behavior to significant plastic deformation.
Q18. Yield strength represents:

A. Stress at which specified plastic deformation occurs
B. Density of the material
C. Melting temperature
D. Thermal conductivity
Answer: A. Stress at which specified plastic deformation occurs
Explanation: For materials without a distinct yield point, a proof or offset yield strength, commonly 0.2%, may be specified.

Q19. The maximum engineering stress reached during a tensile test is called:
A. Yield stress
B. Ultimate tensile strength
C. Working stress
D. Shear stress
Answer: B. Ultimate tensile strength
Explanation: UTS is calculated using the maximum load divided by the original cross-sectional area.
UTS=P_max/A_0

Q20. Which property represents the ability of a material to undergo plastic deformation in tension before fracture?
A. Ductility
B. Hardness
C. Stiffness
D. Brittleness
Answer: A. Ductility
Explanation: Ductility indicates the capacity for plastic deformation under tensile loading.
Q21. Percentage elongation is commonly used as a measure of:

A. Hardness
B. Ductility
C. Stiffness
D. Thermal conductivity
Answer: B. Ductility
Explanation: A greater percentage elongation generally indicates greater ductility.
%EL=(L_f-L_0)/L_0 ×100

Q22. A material capable of being drawn into wires is generally:
A. Ductile
B. Brittle
C. Extremely hard and brittle
D. Non-metallic only
Answer: A. Ductile
Explanation: Wire drawing requires substantial tensile plastic deformation, which is characteristic of ductile materials.

Q23. The ability of a material to be formed into thin sheets by compressive deformation is:

A. Ductility
B. Malleability
C. Toughness
D. Resilience
Answer: B. Malleability
Explanation: Malleability refers particularly to plastic deformation under compressive loading.

Q24. Which property is most closely associated with resistance to indentation?
A. Hardness
B. Ductility
C. Resilience
D. Plasticity
Answer: A. Hardness
Explanation: Hardness is commonly evaluated through resistance to indentation.

Q25. Which of the following is a hardness test?
A. Brinell
B. Charpy
C. Izod
D. Tensile test
Answer: A. Brinell
Explanation: Brinell is a standard indentation hardness test.

Q26. The Rockwell hardness test primarily measures:
A. Indentation depth
B. Tensile elongation
C. Impact energy
D. Percentage reduction in area
Answer: A. Indentation depth
Explanation: Rockwell hardness is determined from the depth of indentation produced under specified loads.

Q27. The Vickers hardness test uses a:
A. Steel ball only
B. Diamond pyramid indenter
C. Cutting tool
D. Flat punch only
Answer: B. Diamond pyramid indenter
Explanation: The Vickers test uses a diamond pyramid, traditionally with a square base.

Q28. The Brinell hardness test commonly uses:
A. A spherical indenter
B. A diamond pyramid only
C. A sharp cutting tool
D. A cylindrical punch only
Answer: A. A spherical indenter
Explanation: Brinell hardness is determined from the indentation made by a spherical indenter.

Q29. Toughness is the ability of a material to:
A. Resist only indentation
B. Absorb energy before fracture
C. Conduct electricity
D. Conduct heat
Answer: B. Absorb energy before fracture
Explanation: Toughness represents the capacity to absorb mechanical energy before fracture.

Q30. Which property is particularly important for a component subjected to shock loading?
A. Toughness
B. Colour
C. Density only
D. Thermal expansion only
Answer: A. Toughness
Explanation: Tough materials can absorb significant energy before fracture and are therefore valuable under impact or shock loading.

Q31. Resilience refers to the ability of a material to:
A. Absorb energy elastically
B. Resist corrosion only
C. Resist melting
D. Undergo permanent deformation only
Answer: A. Absorb energy elastically
Explanation: Resilience is associated with elastic strain-energy storage.

Q32. A spring material should have high:
A. Resilience
B. Brittleness
C. Creep only
D. Thermal expansion
Answer: A. Resilience
Explanation: Springs store and release elastic energy, so high resilience is desirable.

Q33. Fatigue failure occurs mainly due to:
A. Repeated or fluctuating stresses
B. A single static load only
C. Melting
D. Corrosion only
Answer: A. Repeated or fluctuating stresses
Explanation: Fatigue is progressive damage caused by cyclic stress variations.

Q34. Which component is particularly susceptible to fatigue failure?
A. Rotating shaft
B. Stationary brick wall
C. Glass window with no loading
D. Wooden table under no load
Answer: A. Rotating shaft
Explanation: Rotating shafts can experience fluctuating bending and torsional stresses, making fatigue an important design consideration.

Q35. Creep is most significant when a component is subjected to:
A. Sustained load, particularly at elevated temperature
B. No load
C. Only one impact
D. Zero temperature
Answer: A. Sustained load, particularly at elevated temperature
Explanation: Creep is time-dependent deformation under sustained stress and becomes particularly important at elevated temperatures.

Q36. Which of the following is a typical creep-related application?
A. Steam turbine component
B. Hand file at room temperature only
C. Measuring scale
D. Wooden ruler
Answer: A. Steam turbine component
Explanation: Turbine components operate under sustained stress and elevated temperatures, making creep resistance important.

Q37. Wear is best described as:
A. Progressive material loss or surface degradation
B. Elastic recovery
C. Plastic elongation only
D. Increase in mass due to loading
Answer: A. Progressive material loss or surface degradation
Explanation: Wear occurs due to interaction between surfaces or with the environment and may involve material removal or displacement.

Q38. Abrasive wear occurs when:
A. Hard particles or surfaces remove material from a softer surface
B. A material melts completely
C. A component returns to its original shape
D. A material undergoes only elastic deformation
Answer: A. Hard particles or surfaces remove material from a softer surface
Explanation: Abrasive wear results from cutting, ploughing or scratching by harder asperities or particles.
Q39. Adhesive wear is associated with:

A. Material transfer between contacting surfaces
B. Only thermal expansion
C. Only elastic deformation
D. Absence of contact
Answer: A. Material transfer between contacting surfaces
Explanation: Localized adhesion between contacting surfaces can lead to material transfer and subsequent removal.

Q40. Which property is generally important for a cutting tool?
A. High hardness
B. Very low hardness
C. Very high malleability
D. Very low wear resistance
Answer: A. High hardness
Explanation: Cutting tools need adequate hardness and wear resistance to maintain their cutting edge.

Q41. A component has a load of 20,000 N and a cross-sectional area of 1,000 mm². The normal stress is:
A. 2 N/mm²
B. 20 N/mm²
C. 200 N/mm²
D. 20,000 N/mm²
Answer: B. 20 N/mm²
Explanation:
σ=P/A
=20,000/1,000=20″ ” N/mm^2

Therefore, stress = 20 MPa.
Numerical
Q42. A steel rod of original length 500 mm elongates by 1 mm. Its strain is:
A. 0.002
B. 0.02
C. 2
D. 500
Answer: A. 0.002
Explanation:
ϵ=ΔL/L
=1/500=0.002

Numerical
Q43. If the strain in a specimen is 0.005, the percentage strain is:
A. 0.05%
B. 0.5%
C. 5%
D. 50%
Answer: C. 0.5%
Explanation:
0.005×100=0.5%

Therefore, the correct answer is B. 0.5%.
Correction: The options contain the correct answer as B, not C.
Final Answer: B. 0.5%
Numerical
Q44. If stress is 200 MPa and strain is 0.001, Young’s modulus is:
A. 20 MPa
B. 200 MPa
C. 200 GPa
D. 2 GPa
Answer: C. 200 GPa
Explanation:
E=σ/ϵ
E=200/0.001=200,000″ ” MPa

Since:
1000″ ” MPa=1″ ” GPa
E=200″ ” GPa

Numerical
Q45. A rod has an original gauge length of 100 mm and final gauge length of 110 mm. Percentage elongation is:
A. 1%
B. 5%
C. 10%
D. 20%
Answer: C. 10%
Explanation:
%EL=(110-100)/100×100
=10%

Numerical
Q46. A specimen has an original cross-sectional area of 200 mm² and a final area of 150 mm². Percentage reduction in area is:
A. 10%
B. 20%
C. 25%
D. 50%
Answer: C. 25%
Explanation:
%RA=(200-150)/200×100
=50/200×100=25%

Numerical
Q47. If a material has a Young’s modulus of 200 GPa and is subjected to a stress of 100 MPa, its elastic strain is:
A. 0.0005
B. 0.005
C. 0.05
D. 0.5
Answer: A. 0.0005
Explanation:
ϵ=σ/E

Convert:
200″ ” GPa=200,000″ ” MPa

Therefore:
ϵ=100/200000=0.0005

Numerical
Q48. If the failure strength of a component is 600 MPa and its allowable stress is 150 MPa, the factor of safety is:
A. 2
B. 3
C. 4
D. 6
Answer: C. 4
Explanation:
FOS=600/150=4

Numerical
Q49. Which stress-strain region is associated with recoverable deformation?
A. Elastic region
B. Plastic region only
C. Fracture region
D. Necking region only
Answer: A. Elastic region
Explanation: Deformation within the elastic range is substantially recoverable after unloading.
Q50. In an engineering stress-strain curve for a ductile metal, necking generally begins after:
A. The proportional limit
B. The ultimate tensile strength
C. Zero stress
D. The origin
Answer: B. The ultimate tensile strength
Explanation: In a conventional tensile test of a ductile metal, localized necking generally begins after the maximum engineering stress, i.e., the UTS, has been reached.

Q51. Which modulus represents the ratio of shear stress to shear strain?
A. Young’s modulus
B. Bulk modulus
C. Modulus of rigidity
D. Resilience modulus
Answer: C. Modulus of rigidity
Explanation:
G=τ/γ

It is also called the shear modulus.

Q52. Which modulus represents resistance to uniform volumetric deformation?
A. Young’s modulus
B. Bulk modulus
C. Shear modulus
D. Section modulus
Answer: B. Bulk modulus
Explanation: Bulk modulus relates hydrostatic pressure to volumetric strain.

Q53. Poisson’s ratio relates:
A. Longitudinal stress and lateral stress
B. Lateral strain and longitudinal strain
C. Shear stress and normal stress
D. Load and area
Answer: B. Lateral strain and longitudinal strain
Explanation: Poisson’s ratio describes the lateral contraction/expansion associated with longitudinal deformation.
Q54. Which of the following is dimensionless?
A. Young’s modulus
B. Stress
C. Strain
D. Load
Answer: C. Strain
Explanation: Strain is a ratio of two dimensions of the same type and therefore has no unit.

Q55. The stress corresponding to the maximum engineering load in a tensile test is:
A. Yield stress
B. Ultimate tensile stress
C. Proof stress
D. Working stress
Answer: B. Ultimate tensile stress
Explanation: UTS is based on the maximum load divided by the original cross-sectional area.

Q56. Which property is generally associated with a brittle material?
A. Large plastic deformation before fracture
B. Little plastic deformation before fracture
C. Very high ductility
D. Very high malleability
Answer: B. Little plastic deformation before fracture
Explanation: Brittle materials generally fracture with little plastic deformation.

Q57. Which material property is desirable in a shaft subjected to shock loading?
A. Toughness
B. Brittleness
C. Low strength
D. Low fatigue resistance
Answer: A. Toughness
Explanation: Toughness allows a component to absorb significant energy before fracture.

Q58. Which property is especially important for a shaft under repeated rotational loading?
A. Fatigue strength
B. Colour
C. Density only
D. Melting point only
Answer: A. Fatigue strength
Explanation: Rotating shafts can experience cyclic stresses and therefore require adequate fatigue strength.

Q59. Which type of stress is mainly associated with a component subjected to twisting?
A. Tensile stress
B. Compressive stress
C. Shear stress
D. Hydrostatic stress
Answer: C. Shear stress
Explanation: Torsion primarily produces shear stresses in a shaft.

Q60. Which type of loading causes twisting of a shaft?
A. Tensile loading
B. Torsional loading
C. Compressive loading
D. Uniform pressure only
Answer: B. Torsional loading
Explanation: Torsional loading produces a twisting moment about the longitudinal axis.

Q61. Which type of load is primarily responsible for bending a beam?
A. Bending load
B. Torsional load only
C. Pure thermal load
D. Electrical load
Answer: A. Bending load
Explanation: Bending loading causes curvature of the beam and produces tensile and compressive stresses across its section.

Q62. A sharp corner in a machine component can cause:
A. Stress concentration
B. Zero stress
C. Zero deformation
D. Elimination of fatigue
Answer: A. Stress concentration
Explanation: Geometric discontinuities such as sharp corners, holes and keyways can cause localized increases in stress.

Q63. Which feature generally reduces stress concentration compared with a sharp corner?
A. Fillet radius
B. Sharp notch
C. Sudden section change
D. Crack
Answer: A. Fillet radius
Explanation: A smooth fillet reduces the severity of abrupt geometric changes and can lower stress concentration.

Q64. Engineering stress is calculated using:
A. Instantaneous area
B. Original cross-sectional area
C. Final area only
D. Surface area
Answer: B. Original cross-sectional area
Explanation:
σ_e=P/A_0

Engineering stress uses the original cross-sectional area.
Q65. True stress is calculated using:
A. Original area only
B. Instantaneous cross-sectional area
C. Gauge length only
D. Volume only
Answer: B. Instantaneous cross-sectional area
Explanation:
σ_t=P/A_i

where A_iis the instantaneous cross-sectional area.
Q66. A material with high Young’s modulus is generally:
A. More resistant to elastic deformation
B. More ductile in every case
C. More brittle in every case
D. Less stiff
Answer: A. More resistant to elastic deformation
Explanation: Higher Young’s modulus means greater stiffness for a given axial loading condition.

Q67. Young’s modulus primarily indicates:
A. Elastic stiffness
B. Corrosion resistance
C. Electrical conductivity
D. Melting point
Answer: A. Elastic stiffness
Explanation: Young’s modulus is a measure of resistance to elastic deformation in tension or compression.

Q68. Which of the following is NOT a mechanical property?
A. Toughness
B. Hardness
C. Ductility
D. Thermal conductivity
Answer: D. Thermal conductivity
Explanation: Thermal conductivity is a thermal property, while toughness, hardness and ductility are mechanical properties.

Q69. Which of the following is a mechanical property?
A. Ductility
B. Electrical conductivity
C. Thermal expansion
D. Density
Answer: A. Ductility
Explanation: Ductility describes mechanical behavior under loading.

Q70. Which test is commonly used to determine impact toughness?
A. Charpy test
B. Brinell test
C. Rockwell test
D. Vickers test
Answer: A. Charpy test
Explanation: Charpy and Izod are standard impact tests used to evaluate energy absorption under sudden loading.

Q71. The Izod test is used primarily to determine:
A. Impact toughness
B. Hardness
C. Young’s modulus
D. Thermal conductivity
Answer: A. Impact toughness
Explanation: Izod is an impact test in which a notched specimen is struck by a pendulum.

Q72. Which property is generally associated with the area under the complete engineering stress-strain curve up to fracture?
A. Toughness
B. Stiffness only
C. Hardness
D. Resilience only
Answer: A. Toughness
Explanation: The area under the complete stress-strain curve up to fracture represents the energy absorbed per unit volume, associated with toughness.

Q73. The area under the elastic portion of the stress-strain curve represents:
A. Modulus of resilience
B. Ultimate strength
C. Hardness
D. Fatigue strength
Answer: A. Modulus of resilience
Explanation: The elastic area represents elastic strain energy per unit volume.

Q74. Which property is particularly important for a material used in a forming operation?
A. Ductility/formability
B. Brittleness
C. Extremely low plasticity
D. Very low elongation
Answer: A. Ductility/formability
Explanation: Forming operations require sufficient plastic deformation without cracking.

Q75. Which material behavior is associated with permanent shape change?
A. Plasticity
B. Elasticity
C. Resilience
D. Stiffness
Answer: A. Plasticity
Explanation: Plasticity allows permanent deformation without immediate fracture.

Q76. Which property is important in a material used for a punch or die?
A. Hardness and wear resistance
B. Very low hardness
C. Very high malleability only
D. Low strength
Answer: A. Hardness and wear resistance
Explanation: Punches and dies are subjected to contact stresses and wear and therefore require suitable hardness and wear resistance.

Q77. Which of the following can cause premature fatigue failure?
A. Stress concentration
B. Smooth fillet
C. Proper surface finish
D. Correct material selection
Answer: A. Stress concentration
Explanation: Stress concentrations can significantly increase local cyclic stresses and promote fatigue crack initiation.

Q78. Which surface condition generally improves fatigue performance compared with a severely rough surface?
A. Smooth surface
B. Deep scratches
C. Sharp notches
D. Cracks
Answer: A. Smooth surface
Explanation: Surface defects and scratches can act as stress raisers and fatigue-crack initiation sites.

Q79. Which factor is important in creep?
A. Time
B. Time-independent load only
C. Colour
D. Electrical resistance only
Answer: A. Time
Explanation: Creep is fundamentally a time-dependent deformation process.

Q80. Which factor is especially important in high-temperature creep?

A. Temperature
B. Colour
C. Surface polish only
D. Electrical conductivity only
Answer: A. Temperature
Explanation: Creep rates generally increase strongly with temperature for many engineering materials.

Q81. A tensile specimen has an original length of 200 mm and elongates to 204 mm. Its percentage elongation is:
A. 1%
B. 2%
C. 4%
D. 20%
Answer: B. 2%
Explanation:
%EL=(204-200)/200×100
=2%

Numerical
Q82. A component carries 50 kN load over an area of 500 mm². Its average stress is:
A. 10 N/mm²
B. 50 N/mm²
C. 100 N/mm²
D. 500 N/mm²
Answer: C. 100 N/mm²
Explanation:
σ=50,000/500=100″ ” N/mm^2

Therefore, stress = 100 MPa.
Numerical
Q83. A rod of 2 m length elongates by 2 mm. The strain is:
A. 0.001
B. 0.01
C. 0.1
D. 1
Answer: A. 0.001
Explanation:
Convert 2 m to 2000 mm.
ϵ=2/2000=0.001

Numerical
Q84. If Young’s modulus is 210 GPa and the strain is 0.001, the stress is:
A. 21 MPa
B. 210 MPa
C. 2.1 MPa
D. 2100 MPa
Answer: B. 210 MPa
Explanation:
σ=Eϵ
=210×0.001=0.210″ ” GPa
=210″ ” MPa

Numerical
Q85. A material has a failure strength of 800 MPa and a factor of safety of 4. Its allowable stress is:
A. 100 MPa
B. 200 MPa
C. 400 MPa
D. 3200 MPa
Answer: B. 200 MPa
Explanation:
FOS=(Failure” ” strength)/(Allowable” ” stress)

Therefore:
Allowable” ” stress=800/4=200″ ” MPa

Numerical
Q86. A specimen has an original area of 400 mm² and final area of 300 mm². The percentage reduction in area is:
A. 10%
B. 20%
C. 25%
D. 40%
Answer: C. 25%
Explanation:
%RA=(400-300)/400×100
=25%

Numerical
Q87. If the original length of a specimen is 250 mm and the final length is 275 mm, percentage elongation is:
A. 5%
B. 10%
C. 15%
D. 25%
Answer: B. 10%
Explanation:
%EL=(275-250)/250×100=10%

Numerical
Q88. A stress of 150 MPa produces a strain of 0.00075 in a linearly elastic material. Young’s modulus is:
A. 100 GPa
B. 150 GPa
C. 200 GPa
D. 250 GPa
Answer: C. 200 GPa
Explanation:
E=σ/ϵ
=150/0.00075=200,000″ ” MPa=200″ ” GPa

Numerical
Q89. Which of the following statements about ductility is correct?
A. It is measured only by hardness
B. Percentage elongation can be used as an indicator of ductility
C. It means resistance to indentation
D. It means resistance to creep only
Answer: B. Percentage elongation can be used as an indicator of ductility
Explanation: Percentage elongation and percentage reduction in area are commonly used measures of ductility.

Q90. Which of the following statements about toughness is correct?
A. Toughness is identical to hardness
B. Toughness concerns energy absorption before fracture
C. Toughness means only electrical conductivity
D. Toughness means zero deformation
Answer: B. Toughness concerns energy absorption before fracture
Explanation: Toughness represents the capacity to absorb energy and deform before fracture.

Q91. Which of the following statements about hardness is correct?
A. Hardness is resistance to localized deformation
B. Hardness means ductility
C. Hardness means elastic recovery only
D. Hardness means creep rate
Answer: A. Hardness is resistance to localized deformation
Explanation: Indentation hardness tests measure resistance to localized permanent deformation.

Q92. Which statement about fatigue is correct?
A. Fatigue can occur under repeated stresses
B. Fatigue occurs only above the melting point
C. Fatigue is identical to creep
D. Fatigue occurs only under static loading
Answer: A. Fatigue can occur under repeated stresses
Explanation: Fatigue is progressive damage resulting from cyclic or fluctuating stresses.

Q93. Which statement about creep is correct?
A. It is time-dependent deformation
B. It is always instantaneous
C. It is identical to hardness
D. It requires no load
Answer: A. It is time-dependent deformation
Explanation: Creep is the progressive deformation of a material with time under sustained stress, especially at elevated temperature.

Q94. Which property is most desirable for a material used in a cable or wire?
A. Ductility
B. Brittleness
C. Very low tensile strength
D. Very high brittleness
Answer: A. Ductility
Explanation: Wire manufacturing involves drawing, which requires substantial plastic deformation without fracture.

Q95. Which property is particularly desirable in a material used for pressure vessels?
A. Adequate strength and toughness
B. Extreme brittleness
C. Very low ductility
D. Zero fatigue resistance
Answer: A. Adequate strength and toughness
Explanation: Pressure vessels must safely withstand pressure and potential service loads without catastrophic fracture.

Q96. Which property is particularly important for a machine bed?
A. Stiffness
B. Extreme ductility
C. High malleability only
D. Low strength
Answer: A. Stiffness
Explanation: Machine beds must resist deformation and maintain alignment during operation.

Q97. Which of the following is a common cause of stress concentration?
A. Keyway
B. Smooth uniform section
C. Large fillet radius
D. Uniform straight surface
Answer: A. Keyway
Explanation: Keyways create geometric discontinuities and can produce local stress concentration.

Q98. Which of the following is generally used to reduce stress concentration?
A. Sharp notch
B. Fillet
C. Crack
D. Sudden section change
Answer: B. Fillet
Explanation: A properly designed fillet provides a smoother transition and reduces the severity of stress concentration.

Q99. Which statement correctly distinguishes elasticity and plasticity?
A. Elasticity produces permanent deformation; plasticity produces recovery
B. Elasticity is recoverable deformation; plasticity is permanent deformation
C. Both mean exactly the same thing
D. Neither involves deformation
Answer: B. Elasticity is recoverable deformation; plasticity is permanent deformation
Explanation: Elastic deformation disappears substantially after unloading, while plastic deformation remains.
Q100. Which combination is correctly matched?

A. Ductility — ability to absorb impact energy only
B. Hardness — resistance to indentation
C. Creep — repeated cyclic loading only
D. Fatigue — time-dependent deformation under sustained load
Answer: B. Hardness — resistance to indentation
Explanation: Hardness is associated with resistance to localized deformation such as indentation. Fatigue concerns cyclic loading, while creep is time-dependent deformation under sustained stress.

CHAPTER 3 — EXAM REVISION BOX

⭐ Remember These

Stress = Load / Area

Strain = Change in dimension / Original dimension

Young’s Modulus = Stress / Strain

Ductility → Wire drawing

Malleability → Sheet forming

Hardness → Indentation resistance

Toughness → Energy absorption before fracture

Resilience → Elastic energy absorption

Stiffness → Resistance to elastic deformation

Fatigue → Repeated/fluctuating stress

Creep → Time-dependent deformation

Brinell → Ball indenter

Rockwell → Indentation depth

Vickers → Diamond pyramid

Charpy/Izod → Impact testing

Stress concentration → Holes, keyways, notches, sharp corners

CHAPTER 4 — METAL TESTING & TESTING MACHINES

4.1 Introduction

Metal testing is the systematic examination of metals and engineering materials to determine their mechanical properties, physical characteristics, defects, quality and suitability for a particular application.
In Workshop Technology and Manufacturing Processes, testing is important because the material selected for a component must be capable of safely performing under the expected service conditions.

For example:

Shafts → tensile, torsion and fatigue considerations
Pressure vessels → tensile, toughness and NDT
Gears → hardness, wear and fatigue
Springs → tensile, fatigue and resilience
Welded components → tensile and NDT
Machine tools → hardness, strength and dimensional accuracy
4.2 Classification of Material Tests
Material testing can broadly be classified into:

Destructive Testing (DT)
In destructive testing, the specimen is damaged or destroyed during the test.
Examples:
Tensile test
Compression test
Impact test
Torsion test
Fatigue test
Bend test
Non-Destructive Testing (NDT)
In NDT, the component is inspected without causing significant damage to its serviceability.
Examples:
Visual testing
Liquid penetrant testing
Magnetic particle testing
Ultrasonic testing
Radiographic testing
4.3 Destructive Testing
Definition
A destructive test is a test in which the specimen undergoes permanent deformation, damage or fracture during testing.
Main Purpose
To determine properties such as:
Yield strength
Ultimate tensile strength
Ductility
Toughness
Elongation
Reduction in area
Fatigue behaviour
4.4 Non-Destructive Testing
Definition
Non-destructive testing (NDT) is a group of inspection methods used to detect surface or internal discontinuities without significantly damaging the component.
Advantages
Component can often remain in service
Defects can be detected without destroying the part
Useful for quality control
Useful for weld inspection
Useful for detecting hidden defects
4.5 Tensile Test
The tensile test is one of the most important mechanical tests performed on engineering materials.
It determines properties such as:
Yield strength
Ultimate tensile strength
Percentage elongation
Percentage reduction in area
Young’s modulus, within the appropriate elastic range
4.6 Universal Testing Machine
A Universal Testing Machine (UTM) is a machine used to perform several mechanical tests by applying controlled loads to specimens.
Depending on its configuration, a UTM can be used for:
Tensile testing
Compression testing
Bending testing
Shear testing
The machine generally includes:
Loading system
Grips/fixtures
Load-measuring system
Specimen holding arrangement
Control and recording system
4.7 Tensile Test Specimen
A standard tensile specimen generally consists of:
Grip ends
Gauge length
Reduced section
The reduced section is intended to provide a controlled region in which deformation occurs.
4.8 Gauge Length
Definition
The gauge length is the specified length over which elongation is measured during a tensile test.
Initial gauge length is usually represented by:
L_0

Final gauge length after fracture is represented by:
L_f

4.9 Tensile Test Results

A tensile test can provide:

Yield strength
Stress associated with the onset of specified plastic deformation.
Ultimate tensile strength
Maximum engineering tensile stress.
Percentage elongation
%EL=(L_f-L_0)/L_0 ×100
Percentage reduction in area
%RA=(A_0-A_f)/A_0 ×100
4.10 Engineering Stress-Strain Curve
A typical tensile test produces an engineering stress-strain curve.
Important regions/points include:
Proportional limit
Elastic limit
Yield region
Strain-hardening region
Ultimate tensile strength
Necking
Fracture
The exact appearance varies with the material.
4.11 Proportional Region
In the proportional region:
σ∝ϵ

Therefore:
σ=Eϵ

The slope of the linear portion of the engineering stress-strain curve represents Young’s modulus.

4.12 Yielding

Yielding represents the onset of significant plastic deformation.
Some materials, particularly certain low-carbon steels under appropriate conditions, may show a distinct upper and lower yield point.
Other materials do not show a sharply defined yield point

4.13 Strain Hardening

After yielding, some ductile metals become stronger as plastic deformation continues.
This phenomenon is called:
Strain hardening or work hardening.

4.14 Necking

After the maximum engineering stress is reached in a conventional tensile test of a ductile specimen, localized reduction in cross-sectional area may begin.
This is called:
Necking.
The specimen eventually fractures.

4.15 Compression Test

A compression test determines the behavior of a material under compressive loading.
It is particularly useful for materials such as:
Cast iron
Concrete
Ceramics
Certain polymers
Materials that are difficult to test in tension
Important Point
Ductile metals can undergo large compressive deformation without a clear fracture, making interpretation different from tensile testing.
4.16 Compression Testing Machine
A compression test may be performed using:
Universal Testing Machine
Dedicated compression testing machine
The specimen is placed between compression platens and subjected to increasing compressive load.
4.17 Compression Stress
Average compressive stress can be expressed as:
σ_c=P/A

where:
P= compressive load
A= relevant cross-sectional area
4.18 Shear Test
A shear test determines the resistance of a material to shear loading.
The basic average shear stress relationship is:
τ=P/A

depending on the test configuration.
Shear testing is useful for evaluating:
Riveted joints
Bolted joints
Welded joints
Pins
Fasteners
Materials subjected to direct shear

4.19 Torsion Test

The torsion test determines the behavior of a material under twisting.
It is especially important for:
Shafts
Axles
Drive components
Transmission elements
Important properties can include:
Torsional strength
Shear modulus
Angle of twist behavior
Torsional failure characteristics

4.20 Torsion Testing Machine

A torsion testing machine applies a controlled torque to a specimen and measures the resulting angular deformation.
The relationship between torque and angle of twist can be used to evaluate torsional behaviour.

4.21 Impact Test

Impact testing determines the ability of a material to absorb energy under sudden loading.
Two widely used impact tests are:
Charpy test
Izod test

4.22 Charpy Impact Test

In the Charpy test, a notched specimen is supported horizontally, and a pendulum strikes the specimen.
The absorbed impact energy is determined from the energy lost by the pendulum.
Key Point
Charpy → Horizontal specimen

4.23 Izod Impact Test

In the Izod test, the notched specimen is generally held vertically as a cantilever, and the pendulum strikes it.
Key Point
Izod → Vertical specimen

4.24 Importance of the Notch

A notch acts as a stress concentration.
The notch helps create a controlled location for crack initiation and allows comparison of the material’s resistance to impact fracture.

4.25 Impact Energy

Impact energy is the energy absorbed by the specimen during fracture under impact loading.
A higher absorbed impact energy generally indicates greater resistance to sudden fracture under the specified test conditions.

4.26 Hardness Testing

Hardness testing determines resistance to localized deformation, generally by indentation or related methods.
Major hardness tests include:
Brinell
Rockwell
Vickers

4.27 Brinell Hardness Test

The Brinell test uses a spherical indenter to produce an indentation.
The hardness number is related to the applied load and the size of the indentation.
Important
Brinell → Ball/Spherical indenter

4.28 Brinell Hardness Number

The Brinell hardness number is based on:
Applied load
Diameter of indenter
Diameter of indentation
The indentation diameter is measured after the test.

4.29 Advantages of Brinell Test

Suitable for many bulk metallic materials
Useful for relatively coarse or heterogeneous materials
Large indentation can provide a representative measurement
Limitation
The relatively large indentation may make the test unsuitable for very thin or finished surfaces where indentation damage is unacceptable.

4.30 Rockwell Hardness Test

The Rockwell test determines hardness from the depth of penetration of an indenter under specified loads.
Major Advantage
It is rapid and convenient for production inspection.

4.31 Rockwell Indenters

Depending on the Rockwell scale, indenters can include:
Diamond cone
Hardened steel ball
Carbide ball
The selected indenter and load depend on the particular Rockwell scale.

4.32 Vickers Hardness Test

The Vickers test uses a diamond pyramid indenter.
The two diagonals of the indentation are measured and used to determine the Vickers hardness value.
Important
Vickers → Diamond pyramid

4.33 Advantages of Vickers Test

Can be used over a wide hardness range
Suitable for small areas when properly prepared
Useful for thin sections and microhardness applications with suitable loads
Uses the same basic geometric indenter principle across its scales

4.34 Fatigue Test

Fatigue testing evaluates a material’s behavior under repeated or fluctuating stress.
The specimen is subjected to cyclic loading until:
Failure occurs, or
A specified number of cycles is reached.

4.35 S-N Curve

The relationship between cyclic stress amplitude and number of cycles to failure is commonly represented by an:
S-N curve
where:
S = stress amplitude
N = number of cycles to failure
It is also called a Wohler curve.

4.36 Fatigue Failure

Fatigue failure can occur at stress levels significantly below the static tensile strength.
Typical stages include:
Crack initiation
Crack propagation
Final fracture

4.37 Creep Test

A creep test determines the deformation of a material with time under sustained stress, usually at a controlled elevated temperature.
Important parameters include:
Stress
Temperature
Time
Strain

4.38 Creep Curve

A typical creep curve has three stages:
Stage I — Primary Creep
Creep rate decreases with time.
Stage II — Secondary Creep
Creep rate is approximately steady.
Stage III — Tertiary Creep
Creep rate accelerates, often leading to rupture.

4.39 Non-Destructive Testing — Major Methods

The major NDT methods are:
Visual Testing — VT
Liquid Penetrant Testing — PT
Magnetic Particle Testing — MT
Ultrasonic Testing — UT
Radiographic Testing — RT

4.40 Visual Testing

Visual testing is the simplest NDT method.
It can detect visible defects such as:
Surface cracks
Undercuts
Corrosion
Poor weld appearance
Dimensional abnormalities

4.41 Liquid Penetrant Testing

Liquid penetrant testing is used primarily for detecting surface-breaking discontinuities.
Basic Procedure
Clean the surface.
Apply penetrant.
Allow penetration time.
Remove excess penetrant.
Apply developer.
Inspect indications.
Important
It can be used on many non-porous materials, not only ferromagnetic materials.

4.42 Magnetic Particle Testing

Magnetic particle testing is used for detecting surface and near-surface discontinuities in ferromagnetic materials.
The component is magnetized and magnetic particles are applied.
Defects disturb the magnetic field and produce visible particle accumulations.
Important
MT → Ferromagnetic materials

4.43 Ultrasonic Testing

Ultrasonic testing uses high-frequency sound waves to detect internal and surface-connected discontinuities.
It can be used to detect:
Cracks
Inclusions
Lack of fusion
Internal discontinuities
Thickness variations

4.44 Principle of Ultrasonic Testing

An ultrasonic transducer sends high-frequency sound waves into the component.
When waves encounter an interface or discontinuity, part of the energy is reflected.
The reflected signal can be analyzed to determine information about the defect.

4.45 Radiographic Testing

Radiographic testing uses penetrating radiation, commonly X-rays or gamma rays, to produce an image showing internal variations in the component.
It is commonly used for inspection of:
Welds
Castings
Pressure-containing components

4.46 Advantages of Radiography

Radiography can reveal certain internal discontinuities and provides a permanent image/record when conventional film radiography is used.
Limitation
Radiographic testing involves radiation hazards and requires appropriate safety controls.

4.47 Selection of NDT Method

The appropriate NDT method depends on:
Material
Type of defect
Defect location
Component geometry
Thickness
Accessibility
Required sensitivity
Safety considerations

4.48 Weld Testing

Welds can be inspected using:
Visual testing
Liquid penetrant testing
Magnetic particle testing
Ultrasonic testing
Radiographic testing
The method selected depends on the weld material, geometry and suspected defect type.

4.49 Destructive vs Non-Destructive Testing

Destructive Testing Non-Destructive Testing

Specimen may be damaged/destroyed Component is generally preserved
Gives mechanical properties Mainly detects discontinuities
Tensile test Ultrasonic test
Compression test Radiography
Impact test Liquid penetrant
Torsion test Magnetic particle
Fatigue test Visual inspection

4.50 Key Examination Points

Remember:

Tensile Test → Strength + Ductility

UTM → Tensile/Compression/Bending and related tests

Charpy → Horizontal specimen

Izod → Vertical cantilever specimen

Brinell → Spherical indenter

Rockwell → Depth of indentation

Vickers → Diamond pyramid

Fatigue → Cyclic loading

S-N Curve → Stress vs Number of cycles

Creep → Time-dependent deformation

PT → Surface-breaking defects

MT → Ferromagnetic materials

UT → High-frequency sound waves

.
Q1. The main purpose of material testing is to determine:
A. Only colour
B. Mechanical properties and suitability
C. Only weight
D. Only electrical resistance
Answer: B. Mechanical properties and suitability
Explanation: Material testing helps determine properties and performance characteristics needed for engineering applications.

Q2. Which of the following is a destructive test?
A. Visual inspection
B. Tensile test
C. Ultrasonic test
D. Liquid penetrant test
Answer: B. Tensile test
Explanation: In a tensile test, the specimen is normally permanently deformed and eventually fractured.

Q3. Which is a non-destructive test?
A. Tensile test
B. Impact test
C. Ultrasonic testing
D. Compression test
Answer: C. Ultrasonic testing
Explanation: Ultrasonic testing detects discontinuities without significantly damaging the component.

Q4. A Universal Testing Machine can commonly perform:

A. Only hardness testing
B. Tensile and compression tests
C. Only chemical analysis
D. Only radiography
Answer: B. Tensile and compression tests
Explanation: A UTM can be configured for several mechanical tests including tensile, compression and bending tests.

Q5. The elongation of a tensile specimen is measured over its:
A. Head
B. Grip
C. Gauge length
D. Shoulder only
Answer: C. Gauge length
Explanation: Gauge length is the specified length over which elongation is measured.

Q6. The maximum engineering stress in a tensile test is called:
A. Yield strength
B. Ultimate tensile strength
C. Proof stress
D. Shear strength
Answer: B. Ultimate tensile strength
Explanation: UTS corresponds to the maximum engineering stress reached during the tensile test.

Q7. Which test is primarily used to determine impact toughness?
A. Charpy test
B. Brinell test
C. Vickers test
D. Rockwell test
Answer: A. Charpy test
Explanation: The Charpy test measures energy absorbed by a specimen under impact loading.

Q8. In the Charpy impact test, the specimen is generally:
A. Held vertically as a cantilever
B. Supported horizontally
C. Suspended freely
D. Rotated continuously
Answer: B. Supported horizontally
Explanation: A standard Charpy specimen is supported horizontally and struck by a pendulum.

Q9. In the Izod test, the specimen is generally:
A. Horizontally simply supported
B. Vertically supported as a cantilever
C. Freely suspended
D. Placed under compression
Answer: B. Vertically supported as a cantilever
Explanation: The Izod specimen is held vertically and struck by the pendulum.

Q10. The notch in an impact-test specimen mainly acts as:
A. A cooling device
B. A stress concentrator
C. A lubricant reservoir
D. A measuring scale
Answer: B. A stress concentrator
Explanation: The notch creates a controlled region of high local stress where fracture can initiate.

Q11. Brinell hardness testing uses:
A. A spherical indenter
B. A diamond cone only
C. A pendulum
D. Ultrasonic waves
Answer: A. A spherical indenter
Explanation: The Brinell method uses a ball-type indenter and measures the resulting indentation.

Q12. Rockwell hardness testing is primarily based on:
A. Indentation depth
B. Tensile elongation
C. Impact energy
D. Reduction in area
Answer: A. Indentation depth
Explanation: Rockwell hardness is determined from the depth of penetration under specified loading conditions.

Q13. The Vickers hardness test uses:
A. Steel ball
B. Diamond pyramid
C. Pendulum
D. Cylindrical roller
Answer: B. Diamond pyramid
Explanation: The Vickers indenter is a diamond pyramid, traditionally with a square base.

Q14. Which test is particularly suitable for determining hardness rapidly in production environments?
A. Rockwell test
B. Tensile test
C. Impact test
D. Creep test
Answer: A. Rockwell test
Explanation: Rockwell testing is relatively rapid because hardness is obtained directly from indentation depth.

Q15. Which test is commonly used for detecting surface-breaking cracks on a non-porous component?
A. Liquid penetrant testing
B. Tensile testing
C. Compression testing
D. Torsion testing
Answer: A. Liquid penetrant testing
Explanation: Penetrant testing is designed to reveal surface-breaking discontinuities in suitable non-porous materials.

Q16. Magnetic particle testing is primarily applicable to:
A. Ferromagnetic materials
B. All plastics
C. Wood only
D. Glass only
Answer: A. Ferromagnetic materials
Explanation: The method depends on magnetization and magnetic flux leakage.

Q17. Ultrasonic testing uses:
A. High-frequency sound waves
B. Visible light only
C. Magnetic particles only
D. X-rays only
Answer: A. High-frequency sound waves
Explanation: UT introduces high-frequency acoustic waves into the component and analyzes reflected signals.

Q18. Radiographic testing commonly uses:
A. X-rays or gamma rays
B. Water pressure
C. Magnetic particles
D. Mechanical indentation
Answer: A. X-rays or gamma rays
Explanation: Radiography uses penetrating radiation to produce an image showing internal variations.

Q19. Which NDT method is particularly useful for detecting internal discontinuities using reflected sound waves?
A. Ultrasonic testing
B. Visual testing
C. Liquid penetrant testing
D. Magnetic particle testing
Answer: A. Ultrasonic testing
Explanation: UT detects discontinuities through reflections of high-frequency sound waves.

Q20. The S-N curve is associated with:
A. Fatigue testing
B. Hardness testing
C. Compression testing
D. Brinell testing
Answer: A. Fatigue testing
Explanation: An S-N curve relates cyclic stress level to the number of cycles to failure

Q21. In an S-N curve, N generally represents:
A. Newton
B. Number of cycles
C. Normal stress
D. Notch depth
Answer: B. Number of cycles
Explanation: In fatigue testing, N represents the number of loading cycles.

Q22. Creep is:
A. Instantaneous elastic deformation only
B. Time-dependent deformation under sustained stress
C. Impact fracture only
D. Hardness measurement
Answer: B. Time-dependent deformation under sustained stress
Explanation: Creep develops progressively with time under sustained loading, particularly at elevated temperatures.

Q23. During secondary creep, the creep rate is approximately:
A. Constant
B. Infinite
C. Always zero
D. Increasing rapidly
Answer: A. Constant
Explanation: Secondary creep is characterized approximately by a steady creep rate.

Q24. During tertiary creep:
A. Creep rate generally accelerates
B. Creep stops completely
C. Stress becomes zero
D. The specimen becomes perfectly elastic
Answer: A. Creep rate generally accelerates
Explanation: Tertiary creep is associated with accelerating deformation and often culminates in rupture.
Q25. Which test determines a material’s behavior under twisting?

A. Torsion test
B. Brinell test
C. Charpy test
D. Radiographic test
Answer: A. Torsion test
Explanation: A torsion test applies torque and measures the resulting angular deformation and torsional response.

Q26. The tensile test is mainly performed to determine:
A. Melting point
B. Tensile properties
C. Electrical resistance
D. Thermal conductivity
Answer: B. Tensile properties
Explanation: A tensile test provides information about yield strength, ultimate tensile strength, elongation, reduction in area and elastic behavior.

Q27. Which property can be determined from the percentage elongation obtained in a tensile test?
A. Ductility
B. Hardness
C. Thermal conductivity
D. Density
Answer: A. Ductility
Explanation: Percentage elongation is one of the common measures of ductility.

Q28. The percentage reduction in area in a tensile test is calculated using:
A. Original and final cross-sectional areas
B. Original and final lengths
C. Load and time
D. Stress and temperature
Answer: A. Original and final cross-sectional areas
Explanation:
%RA=(A_0-A_f)/A_0 ×100

where A_0is the original area and A_fis the final area.
Q29. The slope of the initial straight portion of a stress-strain curve represents:
A. Toughness
B. Young’s modulus
C. Hardness
D. Fatigue strength
Answer: B. Young’s modulus
Explanation: In the linear elastic region:
E=σ/ϵ

Thus, the slope is Young’s modulus.
Q30. In a tensile test of a ductile metal, necking normally begins:
A. Before loading
B. At or after the maximum engineering stress
C. At zero stress
D. Before the elastic region
Answer: B. At or after the maximum engineering stress
Explanation: Localized necking generally begins after the maximum engineering stress, i.e., after UTS has been reached.

Q31. Which machine is commonly used for tensile testing of metallic specimens?
A. Universal Testing Machine
B. Lathe machine
C. Drilling machine
D. Shaper
Answer: A. Universal Testing Machine
Explanation: A UTM is designed to apply controlled loads for tests such as tension and compression.

Q32. The load applied during a tensile test is measured by the:
A. Load-measuring system of the testing machine
B. Vernier caliper
C. Micrometer only
D. Thermometer
Answer: A. Load-measuring system of the testing machine
Explanation: The testing machine incorporates a load cell or other calibrated load-measuring mechanism.

Q33. A tensile specimen normally has a reduced section mainly to:
A. Control the region of deformation
B. Increase its weight
C. Prevent any deformation
D. Increase its temperature
Answer: A. Control the region of deformation
Explanation: The reduced gauge section promotes deformation in a defined region and facilitates measurement.

Q34. Which of the following is NOT normally obtained directly from a tensile test?
A. Ultimate tensile strength
B. Percentage elongation
C. Reduction in area
D. Melting point
Answer: D. Melting point
Explanation: Melting point is a thermal property and is not determined by a standard tensile test.

Q35. The area under the complete stress-strain curve up to fracture is associated with:
A. Toughness
B. Hardness
C. Stiffness only
D. Yield strength only
Answer: A. Toughness
Explanation: It represents the energy absorbed per unit volume before fracture.

Q36. The area under the elastic portion of the stress-strain curve represents:
A. Modulus of resilience
B. Ultimate strength
C. Hardness number
D. Fatigue limit
Answer: A. Modulus of resilience
Explanation: The area under the elastic region represents elastic strain energy stored per unit volume.

Q37. A material that undergoes considerable plastic deformation before fracture is:
A. Ductile
B. Brittle
C. Perfectly rigid
D. Non-deformable
Answer: A. Ductile
Explanation: Ductility is the ability to undergo significant plastic deformation in tension before fracture.
Q38. A brittle material generally shows:

A. Large plastic deformation before fracture
B. Little plastic deformation before fracture
C. Unlimited elongation
D. No fracture
Answer: B. Little plastic deformation before fracture
Explanation: Brittle materials generally fracture with relatively little plastic deformation.

Q39. Compression testing is particularly useful for evaluating:
A. Compressive behavior
B. Electrical conductivity
C. Melting temperature
D. Magnetic permeability only
Answer: A. Compressive behavior
Explanation: Compression tests evaluate the response of a material to compressive loading.

Q40. Which material is commonly evaluated by compression testing because tensile testing may be less representative of its service behavior?
A. Concrete
B. Copper wire only
C. Spring wire only
D. Aluminium foil only
Answer: A. Concrete
Explanation: Concrete has high compressive strength but comparatively low tensile strength, making compression testing particularly important.

Q41. A specimen under compression generally experiences:
A. Reduction in length
B. Increase in length
C. Only twisting
D. No deformation
Answer: A. Reduction in length
Explanation: Compressive loading tends to shorten the specimen.

Q42. The primary purpose of a torsion test is to determine:
A. Behavior under twisting
B. Resistance to indentation
C. Impact energy
D. Thermal expansion
Answer: A. Behavior under twisting
Explanation: Torsion testing determines the response of a material to applied torque.

Q43. Torsion testing is particularly important for:
A. Shafts
B. Flat glass windows
C. Bricks only
D. Paint coatings only
Answer: A. Shafts
Explanation: Shafts transmit torque and therefore must have adequate torsional strength and stiffness.

Q44. The angle through which a torsion specimen rotates under applied torque is called:
A. Angle of twist
B. Angle of friction
C. Angle of impact
D. Angle of hardness
Answer: A. Angle of twist
Explanation: The angular deformation caused by torque is called the angle of twist.

Q45. The main objective of an impact test is to determine:
A. Energy absorption under sudden loading
B. Melting point
C. Thermal conductivity
D. Electrical resistance
Answer: A. Energy absorption under sudden loading
Explanation: Impact tests evaluate resistance to fracture under sudden loading.

Q46. Which of the following is an impact testing machine/test?
A. Charpy
B. Brinell
C. Rockwell
D. Vickers
Answer: A. Charpy
Explanation: Charpy is an impact test, whereas Brinell, Rockwell and Vickers are hardness tests.

Q47. Which pair consists entirely of impact tests?
A. Charpy and Izod
B. Brinell and Vickers
C. Rockwell and Brinell
D. Vickers and Izod
Answer: A. Charpy and Izod
Explanation: Both Charpy and Izod are pendulum impact tests.

Q48. In a Charpy test, the specimen is generally:
A. Simply supported
B. Held as a vertical cantilever
C. Clamped at both ends
D. Held without support
Answer: A. Simply supported
Explanation: A standard Charpy specimen rests horizontally on supports and is struck by the pendulum.
Q49. In an Izod test, the specimen is:

A. Held as a cantilever
B. Simply supported at both ends
C. Freely suspended
D. Placed horizontally without support
Answer: A. Held as a cantilever
Explanation: The Izod specimen is fixed vertically at one end.

Q50. The energy absorbed by an impact specimen is determined from:
A. Loss of pendulum energy
B. Change in colour
C. Increase in temperature only
D. Weight of the specimen alone
Answer: A. Loss of pendulum energy
Explanation: The difference between the pendulum’s energy before and after striking the specimen corresponds to the energy absorbed, accounting for machine losses as applicable.

Q51. Which hardness test uses the diameter of an indentation as an important measurement?
A. Brinell
B. Rockwell
C. Ultrasonic
D. Radiographic
Answer: A. Brinell
Explanation: Brinell hardness is determined from the load and the diameter of the indentation produced by the spherical indenter.

Q52. In the Rockwell test, the hardness value is mainly related to:
A. Depth of penetration
B. Pendulum height
C. Specimen elongation
D. Reduction in area
Answer: A. Depth of penetration
Explanation: Rockwell hardness is based on indentation depth under specified minor and major loads.

Q53. The Vickers hardness number is determined from:
A. Indentation diagonals and applied load
B. Tensile elongation only
C. Impact energy only
D. Pendulum velocity only
Answer: A. Indentation diagonals and applied load
Explanation: The Vickers test measures the diagonals of the diamond-pyramid indentation.

Q54. Which hardness test is particularly useful for very small areas when appropriate loads are selected?
A. Vickers
B. Charpy
C. Izod
D. Compression
Answer: A. Vickers
Explanation: Vickers testing can be performed with relatively small loads and is widely used in microhardness applications.

Q55. Which of the following is a major advantage of Rockwell hardness testing?
A. Rapid measurement
B. Requires complete fracture
C. Requires tensile specimen
D. Measures impact energy
Answer: A. Rapid measurement
Explanation: Rockwell testing is widely used for quick production inspection.

Q56. Fatigue testing involves:
A. Repeated or fluctuating loading
B. Only one static load
C. Only thermal loading
D. Only hydrostatic pressure
Answer: A. Repeated or fluctuating loading
Explanation: Fatigue damage develops under cyclic stress variations.

Q57. Fatigue failure can occur:
A. Only above UTS
B. At stress levels below static tensile strength
C. Only at melting temperature
D. Only under compression
Answer: B. At stress levels below static tensile strength
Explanation: Repeated loading can initiate and propagate cracks even when individual stress cycles are below the material’s static strength.

Q58. A fatigue crack usually begins at:
A. A region of stress concentration or surface defect
B. The centre of a perfectly uniform specimen only
C. A region of zero stress
D. The measuring scale
Answer: A. A region of stress concentration or surface defect

Explanation: Notches, scratches, holes and other discontinuities can promote fatigue crack initiation.
Q59. The S-N curve is also known as:
A. Wöhler curve
B. Brinell curve
C. Creep curve
D. Hardness curve
Answer: A. Wöhler curve
Explanation: The S-N relationship is historically associated with August Wöhler.

Q60. In an S-N curve, S generally represents:
A. Stress
B. Strain only
C. Surface area
D. Speed
Answer: A. Stress
Explanation: S represents the selected cyclic stress measure, commonly stress amplitude.

Q61. Which test is used to study time-dependent deformation?
A. Creep test
B. Brinell test
C. Charpy test
D. Tensile hardness test
Answer: A. Creep test
Explanation: Creep testing measures progressive deformation under sustained stress with time.

Q62. Creep is particularly important in:
A. High-temperature components
B. Components with no load
C. Room-temperature unloaded parts only
D. Measuring instruments only
Answer: A. High-temperature components
Explanation: Elevated temperature significantly accelerates creep in many engineering materials.

Q63. Which stage of creep has a decreasing creep rate?
A. Primary creep
B. Secondary creep
C. Tertiary creep
D. Fracture stage only
Answer: A. Primary creep
Explanation: During primary creep, the creep rate decreases with time.

Q64. Which stage of creep has approximately constant creep rate?
A. Primary
B. Secondary
C. Tertiary
D. Fracture
Answer: B. Secondary
Explanation: Secondary creep is characterized by an approximately steady-state creep rate.

Q65. Which stage of creep generally precedes rupture?
A. Tertiary creep
B. Primary creep
C. Elastic region
D. Proportional region
Answer: A. Tertiary creep
Explanation: Tertiary creep involves accelerating deformation and commonly ends in rupture.

Q66. Visual testing can detect:
A. Visible surface defects
B. Deep internal defects in every case
C. Atomic-level defects
D. All subsurface defects
Answer: A. Visible surface defects
Explanation: Visual inspection is mainly used for accessible surface conditions and visible discontinuities.

Q67. Liquid penetrant testing is primarily used to detect:
A. Surface-breaking discontinuities
B. Deep internal defects only
C. Bulk density
D. Young’s modulus
Answer: A. Surface-breaking discontinuities
Explanation: Penetrant enters surface-connected openings and is subsequently revealed by the developer.

Q68. The first important step in liquid penetrant testing is generally:
A. Surface cleaning
B. Applying developer immediately
C. Applying magnetic field
D. Fracturing the specimen
Answer: A. Surface cleaning
Explanation: The surface must be properly cleaned so the penetrant can enter relevant surface-breaking discontinuities.

Q69. In liquid penetrant testing, the developer is used to:
A. Draw penetrant out of discontinuities and make indications visible
B. Magnetize the component
C. Increase tensile strength
D. Produce a fracture
Answer: A. Draw penetrant out of discontinuities and make indications visible
Explanation: Developer creates a contrasting indication by drawing penetrant back to the surface.

Q70. Magnetic particle testing requires the test component to be:
A. Ferromagnetic
B. Transparent
C. Non-metallic only
D. Liquid
Answer: A. Ferromagnetic
Explanation: Magnetization and magnetic flux leakage are fundamental to this method.
Q71. A discontinuity in magnetic particle testing produces:

A. Magnetic flux leakage
B. Thermal expansion only
C. Sound absorption only
D. Electrical insulation only
Answer: A. Magnetic flux leakage
Explanation: A discontinuity disturbs the magnetic field, causing flux leakage where particles can accumulate.

Q72. Ultrasonic testing can be used to detect:
A. Internal discontinuities
B. Only colour variations
C. Only surface paint
D. Only electrical defects
Answer: A. Internal discontinuities
Explanation: Reflected ultrasonic waves can reveal internal defects and interfaces.

Q73. The device that sends and/or receives ultrasonic waves in UT is called:
A. Transducer
B. Pendulum
C. Indenter
D. Extensometer only
Answer: A. Transducer
Explanation: The transducer converts electrical energy to ultrasonic mechanical waves and receives returning signals.

Q74. Radiographic testing is particularly useful for:
A. Examining internal discontinuities
B. Measuring hardness directly
C. Measuring tensile strength directly
D. Measuring elongation directly
Answer: A. Examining internal discontinuities
Explanation: Radiography produces an image based on differential absorption of penetrating radiation.

Q75. Which radiation can be used in industrial radiographic testing?
A. X-rays
B. Visible light only
C. Sound waves
D. Radio waves only
Answer: A. X-rays
Explanation: Industrial radiography commonly uses X-rays and gamma radiation.

Q76. Which NDT method generally requires special radiation-safety precautions?
A. Radiographic testing
B. Visual testing
C. Liquid penetrant testing
D. Magnetic particle testing
Answer: A. Radiographic testing
Explanation: Ionizing radiation can be hazardous and requires controlled areas, shielding and appropriate safety procedures.

Q77. Which NDT method does NOT require the material to be ferromagnetic?
A. Liquid penetrant testing
B. Magnetic particle testing
C. Both require ferromagnetism
D. Neither can inspect metals
Answer: A. Liquid penetrant testing
Explanation: PT can be applied to many non-porous materials, whereas MT requires ferromagnetic material.

Q78. Which test is best associated with detecting surface cracks in a non-ferromagnetic, non-porous material?
A. Liquid penetrant test
B. Magnetic particle test
C. Brinell test
D. Compression test
Answer: A. Liquid penetrant test
Explanation: PT is suitable for surface-breaking defects in many non-porous materials, including non-ferromagnetic alloys.

Q79. Which method is especially useful for detecting subsurface defects in ferromagnetic components?
A. Magnetic particle testing
B. Visual testing only
C. Liquid penetrant only
D. Brinell testing
Answer: A. Magnetic particle testing
Explanation: MT can detect surface and certain near-surface discontinuities in ferromagnetic materials.

Q80. Which NDT method uses sound waves rather than electromagnetic radiation?
A. Ultrasonic testing
B. Radiography
C. Visual testing
D. Magnetic particle testing
Answer: A. Ultrasonic testing
Explanation: UT uses mechanical sound waves, generally at frequencies well above audible sound.

Q81. A steel specimen has an original gauge length of 100 mm and final gauge length of 120 mm. Percentage elongation is:
A. 10%
B. 20%
C. 25%
D. 30%
Answer: B. 20%
Explanation:
%EL=(120-100)/100×100=20%

Numerical
Q82. A specimen has an original area of 500 mm² and final area of 400 mm². Percentage reduction in area is:
A. 10%
B. 15%
C. 20%
D. 25%
Answer: C. 20%
Explanation:
%RA=(500-400)/500×100=20%

Numerical
Q83. A tensile specimen carries a load of 60 kN and has an original area of 300 mm². Engineering stress is:
A. 100 MPa
B. 150 MPa
C. 200 MPa
D. 300 MPa
Answer: C. 200 MPa
Explanation:
σ=(60,000)/300=200″ ” N/mm^2=200″ ” MPa

Numerical
Q84. A material has Young’s modulus of 200 GPa. If stress is 100 MPa, the elastic strain is:
A. 0.0005
B. 0.005
C. 0.05
D. 0.5
Answer: A. 0.0005
Explanation:
ϵ=σ/E=100/200000=0.0005

Numerical
Q85. If the maximum load during a tensile test is 50 kN and original area is 250 mm², UTS is:
A. 100 MPa
B. 150 MPa
C. 200 MPa
D. 250 MPa
Answer: C. 200 MPa
Explanation:
UTS=P_max/A_0
=(50,000)/250=200″ ” MPa

Numerical
Q86. A specimen’s original length is 250 mm and its final length is 275 mm. Percentage elongation is:
A. 5%
B. 10%
C. 15%
D. 20%
Answer: B. 10%
Explanation:
(275-250)/250×100=10%

Numerical
Q87. A specimen’s original area is 800 mm² and final area is 600 mm². Reduction in area is:
A. 10%
B. 20%
C. 25%
D. 30%
Answer: C. 25%
Explanation:
(800-600)/800×100=25%

Numerical
Q88. If the stress is 240 MPa and Young’s modulus is 120 GPa, the strain is:
A. 0.0002
B. 0.001
C. 0.002
D. 0.02
Answer: C. 0.002
Explanation:
120″ ” GPa=120000″ ” MPa
ϵ=240/120000=0.002

Numerical
Q89. A specimen has a final area of 90 mm² and an original area of 100 mm². Percentage reduction in area is:
A. 5%
B. 10%
C. 15%
D. 20%
Answer: B. 10%
Explanation:
(100-90)/100×100=10%

Numerical
Q90. A component has a failure strength of 500 MPa and allowable stress of 100 MPa. Factor of safety is:
A. 2
B. 3
C. 4
D. 5
Answer: D. 5
Explanation:
FOS=500/100=5

Numerical
Q91. Which testing method is most appropriate for determining ultimate tensile strength?
A. Tensile test
B. Brinell test
C. Radiographic test
D. Liquid penetrant test
Answer: A. Tensile test
Explanation: UTS is directly obtained from the maximum engineering stress in a tensile test.

Q92. Which test is primarily used to measure resistance to indentation?
A. Hardness test
B. Tensile test
C. Fatigue test
D. Creep test
Answer: A. Hardness test
Explanation: Hardness tests measure resistance to localized deformation, commonly through indentation.

Q93. Which combination is correctly matched?
A. Brinell — spherical indenter
B. Rockwell — pendulum
C. Charpy — diamond pyramid
D. Vickers — magnetic particles
Answer: A. Brinell — spherical indenter
Explanation: Brinell uses a spherical indenter; Rockwell uses depth measurement, Charpy is an impact test and Vickers uses a diamond pyramid.

Q94. Which combination is correctly matched?
A. Vickers — diamond pyramid
B. Charpy — hardness test
C. Izod — creep test
D. Rockwell — radiography
Answer: A. Vickers — diamond pyramid
Explanation: The Vickers test uses a diamond pyramid indenter.

Q95. Which combination is correctly matched?
A. S-N curve — fatigue
B. Creep curve — hardness
C. Brinell curve — tensile testing
D. Charpy curve — radiography
Answer: A. S-N curve — fatigue
Explanation: S-N curves describe the relationship between cyclic stress and number of cycles to failure.

Q96. Which combination is correctly matched?
A. PT — surface-breaking discontinuities
B. MT — all non-metallic materials
C. UT — indentation hardness
D. RT — tensile elongation
Answer: A. PT — surface-breaking discontinuities
Explanation: Liquid penetrant testing reveals surface-breaking discontinuities in suitable non-porous surfaces.

Q97. Which combination is correctly matched?
A. MT — ferromagnetic materials
B. UT — only transparent materials
C. RT — hardness measurement
D. PT — only ferromagnetic materials
Answer: A. MT — ferromagnetic materials
Explanation: Magnetic particle testing requires a material capable of being magnetized sufficiently for flux leakage to reveal discontinuities.

Q98. Which NDT technique can produce an image of internal discontinuities using penetrating radiation?
A. Radiographic testing
B. Visual testing
C. Magnetic particle testing
D. Liquid penetrant testing
Answer: A. Radiographic testing
Explanation: X-rays or gamma rays pass through the component and produce differential absorption that can reveal internal features.

Q99. Which NDT method uses reflected ultrasonic waves to locate discontinuities?
A. Ultrasonic testing
B. Brinell testing
C. Rockwell testing
D. Liquid penetrant testing
Answer: A. Ultrasonic testing
Explanation: UT evaluates reflected acoustic energy from interfaces and discontinuities.

Q100. Which statement is correct?
A. Destructive testing never damages the specimen
B. NDT is intended to inspect components without significant damage
C. Tensile testing is an NDT method
D. Charpy testing is a hardness test
Answer: B. NDT is intended to inspect components without significant damage
Explanation: NDT methods inspect materials/components while preserving their serviceability, subject to the particular method and inspection process.

CHAPTER 4 — QUICK REVISION

Test Main Purpose

Tensile Strength & ductility

Compression Compressive behavior

Shear Shear strength

Torsion Twisting behavior

Charpy Impact energy

Izod Impact energy

Brinell Hardness

Rockwell Hardness

Vickers Hardness

Fatigue Cyclic loading behavior

Creep Time-dependent deformation

VT Visible defects

PT Surface-breaking defects

MT Surface/near-surface defects in ferromagnetic materials

UT Internal discontinuities using sound waves

RT Internal discontinuities using X-rays/gamma rays

CHAPTER 5 — FOUNDRY TECHNOLOGY & CASTING PROCESSES

5.1 Introduction

Casting is one of the oldest and most important manufacturing processes. In casting, molten metal is poured into a prepared mould cavity having the desired shape. After solidification, the casting is removed from the mould and subjected to finishing operations.
Casting is particularly useful for producing:
Complex shapes
Large components
Components with internal cavities
Components that are difficult to manufacture by machining
Components from metals having relatively low machinability
Examples include:
Engine blocks
Cylinder heads
Pump housings
Machine beds
Pipes and pipe fittings
Flywheels
Gear blanks
Valve bodies

5.2 Definition of Casting

Casting is a manufacturing process in which molten material is introduced into a mould cavity of the required shape and allowed to solidify.
After solidification, the component is removed from the mould.
Basic Casting Sequence
Pattern → Mould → Melting → Pouring → Solidification → Shakeout → Fettling → Inspection

5.3 Basic Principle of Casting

The basic principle involves four major stages:

Step 1 — Preparation of mould

A cavity corresponding to the desired component is prepared.

Step 2 — Melting

The metal is heated above its melting temperature

Step 3 — Pouring

The molten metal is introduced into the mould cavity.

Step 4 — Solidification

The metal cools and solidifies, taking the shape of the mould cavity.

5.4 Advantages of Casting

Casting offers several important advantages.

Complex shape
Very complex geometries can be produced.
Large components
Very large components can be manufactured economically.
Internal cavities
Cores can be used to produce internal holes and passages.
Wide material range
Many ferrous and non-ferrous alloys can be cast.
Reduced machining
Near-net-shape castings can reduce subsequent machining.
Economical for suitable production quantities
Casting can be economical for both certain small-batch and mass-production applications depending on the process.
5.5 Limitations of Casting
Some limitations include:
Possible casting defects
Porosity
Shrinkage
Gas defects
Dimensional variations
Surface-finish limitations in some processes
Mould preparation requirements
Metallurgical problems if cooling is not properly controlled
5.6 Classification of Casting Processes
Casting processes can broadly be classified into:
A. Expendable Mould Processes
The mould is normally destroyed to remove the casting.
Examples:
Sand casting
Shell moulding
Investment casting
Lost-foam casting
B. Permanent Mould Processes
The mould is reused for many castings.
Examples:
Gravity die casting
Pressure die casting
Centrifugal casting
5.7 Pattern
A pattern is a replica or representation of the desired casting shape used to form the mould cavity.
The pattern is not necessarily an exact-size replica because allowances may be provided.
5.8 Functions of a Pattern
A pattern is used to:
Produce the mould cavity
Establish the basic shape of the casting
Provide allowances
Provide core prints where required
Facilitate moulding
Help maintain dimensional accuracy
5.9 Pattern Materials
Patterns may be made from:
Wood
Metals
Plastics
Plaster
Wax
Resins
Other suitable materials
5.10 Wooden Patterns
Wood is commonly used for patterns because it is:
Lightweight
Relatively inexpensive
Easy to shape
Easy to repair
Easy to modify
Limitations
Wooden patterns can:
Absorb moisture
Warp
Wear relatively quickly
Require proper seasoning and surface treatment
5.11 Metal Patterns
Metal patterns are generally more durable than wooden patterns.
Common pattern metals include:
Aluminium alloys
Cast iron
Brass
Bronze
Steel
They are useful when:
Large numbers of castings are required
Better durability is needed
Better dimensional stability is required
5.12 Types of Patterns
Important pattern types include:
Single-piece pattern
Split pattern
Match-plate pattern
Cope-and-drag pattern
Loose-piece pattern
Sweep pattern
Skeleton pattern
Segmental pattern
Gated pattern
Follow-board pattern
5.13 Single-Piece Pattern
A single-piece pattern is made as one integral piece.
It is generally used for:
Simple shapes
Small production quantities
Components that can be easily withdrawn from the mould
5.14 Split Pattern
A split pattern consists of two or more parts.
The common two-part pattern is divided along a parting line.
Advantage
It facilitates withdrawal of the pattern from the mould without damaging the mould cavity.
5.15 Match-Plate Pattern
A match-plate pattern has the pattern halves mounted on opposite sides of a plate.
It is commonly used for:
High-production work
Machine moulding
Accurate mould alignment
5.16 Cope and Drag Pattern
In a cope-and-drag arrangement, pattern sections are mounted on separate plates.
It is useful for:
Large castings
Machine moulding
High-production applications
5.17 Sweep Pattern
A sweep pattern consists of a shaped board or template that is rotated around an axis to generate the mould cavity.
It is useful for:
Large circular or symmetrical castings
Large components where a complete pattern would be expensive
5.18 Skeleton Pattern
A skeleton pattern is a framework representing the shape of the casting.
It is generally used for:
Large castings
Simple geometries
Small production quantities
5.19 Gated Pattern
In a gated pattern, several patterns are connected to a common gating system.
This arrangement allows multiple castings to be produced in one mould.
5.20 Pattern Allowances
Pattern allowances are dimensional modifications provided on the pattern to compensate for various effects during casting and moulding.
Major allowances include:
Shrinkage allowance
Machining allowance
Draft allowance
Distortion allowance
Rapping/shake allowance
5.21 Shrinkage Allowance
Most metals shrink during cooling and solidification.
Therefore, the pattern is generally made slightly larger than the desired casting dimensions to compensate for shrinkage.
Important
Pattern size > corresponding final casting size
5.22 Machining Allowance
Additional material is provided on surfaces that will later be machined.
Purpose
It allows removal of:
Surface irregularities
Oxidized material
Dimensional variations
Casting skin
5.23 Draft Allowance
Draft is a small taper provided on vertical surfaces of the pattern.
Purpose
To facilitate easy withdrawal of the pattern from the mould without damaging the mould cavity.
Important
Draft → Easy pattern withdrawal
5.24 Distortion Allowance
Some castings may distort during cooling because different portions contract differently.
The pattern may therefore be intentionally distorted in the opposite direction to compensate.
5.25 Shake Allowance
When a pattern is rapped before removal, the mould cavity can become slightly enlarged.
Therefore, a small negative allowance may be considered to compensate for this effect.
5.26 Moulding Sand
Moulding sand is used to create the mould around the pattern.
Important requirements include:
Refractoriness
Permeability
Strength
Plasticity
Flowability
Collapsibility
Adhesiveness
Cohesiveness
5.27 Refractoriness
Refractoriness is the ability of moulding sand to withstand the high temperature of molten metal without melting or losing its essential properties.
Remember:
Refractoriness → Resistance to high temperature
5.28 Permeability
Permeability is the ability of moulding sand to allow gases and air to pass through it.
Adequate permeability is important for avoiding:
Blowholes
Gas porosity
Other gas-related defects
5.29 Cohesiveness
Cohesiveness is the ability of sand grains to stick to each other.
Good cohesiveness helps the mould retain its shape.
5.30 Adhesiveness
Adhesiveness is the ability of moulding sand to adhere to the surface of the moulding box or other supporting surfaces.
5.31 Plasticity
Plasticity is the ability of moulding sand to deform and reproduce the pattern shape without cracking or breaking.
5.32 Collapsibility
Collapsibility is the ability of moulding sand to break down or yield after solidification of the casting.
Good collapsibility helps:
Casting removal
Reduction of hot tearing
Release of internal stresses
5.33 Green Sand
Green sand is moulding sand used in a moist condition, containing sufficient moisture and binder for moulding.
It does not necessarily mean that the sand is green in colour.
5.34 Dry Sand Mould
A dry sand mould is dried or baked before molten metal is poured.
Compared with ordinary green-sand moulding, drying can provide greater mould strength and dimensional stability for suitable applications.
5.35 Core
A core is a preformed body of material placed inside a mould to create an internal cavity or passage in the casting.
Examples:
Engine cylinder internal cavity
Pipe passage
Valve passage
Internal holes
5.36 Core Prints
Core prints are projections or recesses provided in the pattern and corresponding mould regions to locate and support the core.
Important:
Core print → Supports and locates the core
5.37 Gating System
The gating system is the network of passages through which molten metal flows from the pouring basin into the mould cavity.
Main components can include:
Pouring basin
Sprue
Sprue well
Runner
Ingate
5.38 Pouring Basin
The pouring basin receives molten metal from the ladle and directs it into the sprue.
It helps:
Reduce turbulence
Remove some impurities
Provide a convenient pouring location
5.39 Sprue
A sprue is the vertical passage through which molten metal flows downward from the pouring basin.
In a well-designed system, the sprue is generally tapered to reduce air aspiration and maintain proper flow.
5.40 Runner
The runner is the horizontal or substantially horizontal passage that carries molten metal from the sprue toward one or more ingates.
5.41 Ingate
The ingate is the opening through which molten metal enters the mould cavity from the runner.
5.42 Riser
A riser is a reservoir of molten metal connected to the casting that supplies additional metal during solidification to compensate for shrinkage.
Important:
Riser → Feeds molten metal during solidification
5.43 Functions of a Riser
A properly designed riser helps:
Compensate for solidification shrinkage
Promote directional solidification
Reduce shrinkage cavities
5.44 Chills
A chill is a metallic insert placed in or near a mould cavity to increase the local rate of heat extraction.
Purpose
To promote faster solidification in selected regions.
5.45 Cupola Furnace
The cupola furnace is widely used for melting cast iron in foundries.
It is a vertical cylindrical furnace in which:
Coke acts as fuel
Air is supplied through tuyeres
Metal charge is melted continuously during operation
5.46 Cupola Furnace — Main Components
Important parts include:
Steel shell
Refractory lining
Charging door
Tuyeres
Wind belt
Slag hole
Tap hole
Chimney/stack
Drop bottom
5.47 Tuyeres
Tuyeres are openings through which air is supplied into the cupola furnace.
The supplied air supports combustion.
Remember:
Tuyere → Air supply
5.48 Cupola Fuel
Traditionally, coke is the primary fuel used in a conventional cupola furnace.
5.49 Casting Defects
A casting defect is an undesirable irregularity or imperfection that reduces the quality or usefulness of a casting.
Common defects include:
Blowholes
Porosity
Shrinkage cavity
Misrun
Cold shut
Hot tear
Sand inclusion
Scab
Metal penetration
Mismatch
5.50 Blowholes
Blowholes are cavities caused by trapped gas.
Possible causes include:
Excess moisture
Poor permeability
Excessive gas generation
Inadequate venting
5.51 Shrinkage Cavity
Shrinkage cavity occurs when insufficient liquid metal is available to compensate for volumetric contraction during solidification.
Prevention
Proper riser design
Directional solidification
Proper feeding system
5.52 Misrun
A misrun occurs when molten metal fails to completely fill the mould cavity.
Possible causes:
Low pouring temperature
Slow pouring
Poor fluidity
Thin sections
Inadequate gating
5.53 Cold Shut
A cold shut occurs when two streams of molten metal meet but fail to fuse properly.
It appears as a seam or line on the casting.
5.54 Hot Tear
A hot tear is a crack formed during the late stages of solidification when the metal cannot accommodate contraction because of restraint.
Factors include:
Poor mould/core collapsibility
Restrained contraction
Improper casting design
Thermal stresses
5.55 Sand Inclusion
Sand inclusion occurs when moulding sand becomes incorporated into the casting.
Possible causes:
Weak mould surface
Poor mould handling
Excessive erosion
Turbulent metal flow
5.56 Metal Penetration
Metal penetration occurs when molten metal enters the spaces between sand grains, producing a rough surface.
It can be influenced by:
Mould characteristics
Metal temperature
Sand grain size
Mould strength

5.57 Fettling

Fettling refers to finishing operations performed on a casting after it has been removed from the mould.
Operations may include:
Removal of gates
Removal of risers
Removal of fins
Cleaning
Grinding
Surface finishing

5.58 Shakeout

Shakeout is the process of removing the solidified casting from the mould.
In sand casting, the mould is broken to retrieve the casting.

5.59 Special Casting Processes

Important special casting processes include:
Die casting
Investment casting
Centrifugal casting
Shell moulding
Continuous casting
Lost-foam casting
These processes are selected according to:
Required accuracy
Surface finish
Production volume
Component size
Material
Complexity

5.60 Die Casting

Die casting forces molten metal into a metallic die under pressure.
It is commonly used for high-volume production of relatively small and complex non-ferrous components.
Typical alloys include:
Aluminium alloys
Zinc alloys
Magnesium alloys

5.61 Investment Casting

Investment casting is also known as lost-wax casting.
A wax pattern is coated with refractory material to create the mould.
The wax is subsequently removed before pouring the metal.
Major Advantage
It can produce:
Complex shapes
Fine details
Good dimensional accuracy
Good surface finish

5.62 Centrifugal Casting

In centrifugal casting, molten metal is poured into a rotating mould.
Centrifugal force helps distribute the molten metal against the mould wall.
It is particularly suitable for:
Pipes
Tubes
Cylindrical components

5.63 Shell Moulding

Shell moulding uses a thin shell of resin-bonded sand formed around a heated pattern.
Advantages include:
Good surface finish
Good dimensional accuracy
Reduced machining
Suitable for relatively complex shapes

5.64 Continuous Casting

In continuous casting, molten metal is continuously poured into a mould and withdrawn as a continuously solidifying strand.
Products may include:
Slabs
Billets
Blooms
Continuous casting is widely used in modern metal production.

5.65 Key Revision Table

Term Main Point

Pattern Forms mould cavity

Shrinkage allowance Compensates for contraction

Machining allowance Material for later machining

Draft allowance Easy pattern withdrawal

Core Forms internal cavity

Core print Supports/locates core

Sprue Vertical metal passage

Runner Carries metal toward ingates

Ingate Entry into mould cavity

Riser Feeds metal during solidification

Chill Increases local cooling

Permeability Allows gases to escape

Refractoriness Withstands high temperature

Collapsibility Breaks down after solidification

Cupola Melts cast iron

Tuyere Supplies air

Misrun Incomplete filling

Cold shut Poor fusion of metal streams

Blowhole Gas cavity

Shrinkage cavity Feeding-related void

Fettling Casting finishing

Investment casting Lost-wax process

Die casting Pressure injection into die

Centrifugal casting Rotating mould

Continuous casting Continuous strand production

MCQ 1
Casting is a process in which molten metal is:
A. Rolled into sheets
B. Poured into a mould cavity and solidified
C. Forged under a hammer
D. Drawn through a die
Answer: B. Poured into a mould cavity and solidified
Explanation: Casting produces a component by filling a mould cavity with molten material and allowing it to solidify.

MCQ 2
The main function of a pattern is to:
A. Melt the metal
B. Form the mould cavity
C. Cool the casting
D. Measure hardness
Answer: B. Form the mould cavity
Explanation: The pattern is used to create the desired cavity in the mould.

MCQ 3
Which allowance is provided to compensate for metal contraction during cooling?
A. Draft allowance
B. Machining allowance
C. Shrinkage allowance
D. Distortion allowance
Answer: C. Shrinkage allowance
Explanation: Metals generally contract during solidification and cooling, so pattern dimensions are adjusted accordingly.

MCQ 4
Draft allowance is provided mainly to:
A. Increase hardness
B. Facilitate pattern withdrawal
C. Increase melting temperature
D. Reduce density
Answer: B. Facilitate pattern withdrawal
Explanation: Draft provides taper on surfaces parallel to the direction of pattern withdrawal.

MCQ 5
Which allowance provides extra metal for subsequent machining?
A. Machining allowance
B. Draft allowance
C. Shake allowance
D. Distortion allowance
Answer: A. Machining allowance
Explanation: Extra material is deliberately provided on surfaces that will be machined later.

MCQ 6
A core is mainly used to produce:
A. External colour
B. Internal cavities
C. Surface hardness
D. Metal melting
Answer: B. Internal cavities
Explanation: Cores occupy regions within the mould cavity to create internal holes, passages or cavities.

MCQ 7
Which property of moulding sand allows gases to escape?
A. Cohesiveness
B. Permeability
C. Adhesiveness
D. Plasticity
Answer: B. Permeability
Explanation: Permeability permits gases generated during pouring and solidification to pass through the mould.

MCQ 8
The ability of moulding sand to withstand high temperature is called:
A. Permeability
B. Refractoriness
C. Adhesiveness
D. Collapsibility
Answer: B. Refractoriness
Explanation: Refractoriness is resistance to the high temperature of molten metal.

MCQ 9
The ability of moulding sand to break down after casting solidification is called:
A. Collapsibility
B. Permeability
C. Adhesiveness
D. Fluidity
Answer: A. Collapsibility
Explanation: Good collapsibility helps casting removal and reduces restraint during contraction.

MCQ 10
Which component of the gating system is generally vertical?
A. Runner
B. Sprue
C. Ingate
D. Riser
Answer: B. Sprue
Explanation: The sprue is the vertical passage carrying molten metal downward from the pouring basin.

Q11. A pattern used for producing a simple casting in small quantity is generally:
A. Match-plate pattern
B. Single-piece pattern
C. Gated pattern
D. Cope-and-drag pattern
Answer: B. Single-piece pattern
Explanation: Single-piece patterns are economical and suitable for simple shapes and limited production.
Q12. A split pattern is divided into two or more parts mainly to:

A. Increase melting temperature
B. Facilitate pattern withdrawal
C. Increase hardness
D. Reduce metal density
Answer: B. Facilitate pattern withdrawal
Explanation: Splitting the pattern allows it to be removed from the mould without damaging the cavity.

Q13. A common split pattern is divided along the:
A. Centre line/parting line
B. Sprue
C. Riser
D. Runner
Answer: A. Centre line/parting line
Explanation: The two halves normally meet along the mould parting plane.

Q14. Match-plate patterns are particularly suitable for:
A. Very low production only
B. Machine moulding and mass production
C. Hand forging
D. Welding
Answer: B. Machine moulding and mass production
Explanation: Match-plate patterns provide accurate alignment and are highly suitable for repetitive machine moulding.

Q15. Which pattern consists of a template rotated around an axis?
A. Sweep pattern
B. Split pattern
C. Match-plate pattern
D. Gated pattern
Answer: A. Sweep pattern
Explanation: A sweep pattern generates a mould cavity by rotating a shaped template around a fixed axis.

Q16. Skeleton patterns are particularly useful for:
A. Very small precision components only
B. Large castings of simple shape
C. Mass-produced tiny castings
D. Wire drawing
Answer: B. Large castings of simple shape
Explanation: A skeleton pattern saves pattern material and labour for large, relatively simple shapes.

Q17. A pattern carrying several identical patterns connected to a common gating system is called:
A. Sweep pattern
B. Gated pattern
C. Skeleton pattern
D. Segmental pattern
Answer: B. Gated pattern
Explanation: A gated pattern permits several castings to be produced from one mould.

Q18. Which pattern material is generally lightweight and easy to work?
A. Wood
B. Tungsten
C. Ceramic only
D. Diamond
Answer: A. Wood
Explanation: Wood is widely used because it is inexpensive, lightweight and easy to shape.

Q19. One important disadvantage of wooden patterns is:
A. Excessive electrical conductivity
B. Moisture absorption and dimensional changes
C. Very high melting point
D. Excessive density
Answer: B. Moisture absorption and dimensional changes
Explanation: Wood can absorb moisture and may warp or change dimensions.

Q20. Metal patterns are generally preferred when:
A. Only one casting is required
B. High production quantity is required
C. No accuracy is required
D. The pattern must be disposable
Answer: B. High production quantity is required
Explanation: Metal patterns offer greater durability and dimensional stability.

Q21. Which allowance compensates for the contraction of the casting during cooling?
A. Draft
B. Shrinkage
C. Machining
D. Shake
Answer: B. Shrinkage
Explanation: The pattern is made larger to compensate for metal contraction.

Q22. The machining allowance is provided on:
A. All surfaces regardless of machining
B. Surfaces that will be machined
C. Only internal cavities
D. Only the sprue
Answer: B. Surfaces that will be machined
Explanation: Extra metal is provided where material will subsequently be removed.

Q23. Draft allowance is generally provided on:
A. Vertical surfaces
B. Horizontal surfaces only
C. Riser only
D. Runner only
Answer: A. Vertical surfaces
Explanation: Taper is provided on surfaces parallel to the direction of pattern withdrawal.

Q24. The purpose of draft allowance is to:
A. Increase casting weight
B. Facilitate withdrawal of the pattern
C. Increase metal temperature
D. Reduce permeability
Answer: B. Facilitate withdrawal of the pattern
Explanation: Without adequate draft, the pattern can damage the mould cavity during withdrawal.

Q25. Distortion allowance is mainly provided to compensate for:
A. Unequal contraction
B. Gas evolution
C. Sand permeability
D. Metal colour
Answer: A. Unequal contraction
Explanation: Different portions of a casting may cool and contract at different rates, causing distortion.
Q26. Shake allowance is generally associated with:

A. Rapping of the pattern
B. Metal melting
C. Core baking
D. Welding
Answer: A. Rapping of the pattern
Explanation: Rapping can enlarge the mould cavity slightly, so an allowance may be used to compensate.

Q27. Which of the following is NOT a common pattern allowance?
A. Shrinkage
B. Draft
C. Machining
D. Electrical resistance
Answer: D. Electrical resistance
Explanation: Electrical resistance is not a pattern allowance.

Q28. Pattern dimensions are generally larger than final casting dimensions mainly because of:
A. Shrinkage

B. Permeability
C. Refractoriness
D. Cohesiveness
Answer: A. Shrinkage
Explanation: Metal contracts during solidification and cooling.

Q29. A pattern should generally be designed so that it can be:
A. Easily withdrawn from the mould
B. Permanently locked inside the mould
C. Melted with the metal in every process
D. Used as a cutting tool
Answer: A. Easily withdrawn from the mould
Explanation: Proper pattern design and draft are essential for producing an undamaged mould cavity.

Q30. Which pattern is commonly mounted on a plate?
A. Match-plate pattern
B. Sweep pattern
C. Skeleton pattern
D. Single-piece pattern
Answer: A. Match-plate pattern
Explanation: Pattern halves and often the gating system are mounted on opposite sides of a match plate.

MCQ 31–50 — Moulding Sand & Cores

Q31. The most important property of moulding sand for escape of gases is:
A. Permeability
B. Hardness
C. Density
D. Thermal conductivity
Answer: A. Permeability
Explanation: Permeability allows gases to pass through the mould.

Q32. High refractoriness is particularly important because:
A. Sand must withstand molten-metal temperature
B. Sand must conduct electricity
C. Sand must become magnetic
D. Sand must melt quickly
Answer: A. Sand must withstand molten-metal temperature
Explanation: Moulding sand should not melt or deteriorate excessively when exposed to molten metal.

Q33. The ability of sand grains to hold together is:
A. Cohesiveness
B. Permeability
C. Refractoriness
D. Fluidity
Answer: A. Cohesiveness
Explanation: Cohesiveness is the bonding tendency between sand grains.

Q34. The ability of moulding sand to stick to the moulding box is:
A. Adhesiveness
B. Refractoriness
C. Permeability
D. Collapsibility
Answer: A. Adhesiveness
Explanation: Adhesiveness allows the sand to adhere to the moulding-box surface.

Q35. The ability of moulding sand to reproduce the pattern shape is related to:
A. Plasticity
B. Density only
C. Electrical conductivity
D. Magnetism
Answer: A. Plasticity
Explanation: Plasticity helps the sand deform around the pattern and retain the required mould shape.

Q36. Good collapsibility of moulding sand helps to:

A. Facilitate casting removal
B. Increase melting point
C. Prevent all gas escape
D. Increase pattern size
Answer: A. Facilitate casting removal
Explanation: After solidification, mould material should yield or break down sufficiently to allow casting contraction and removal.

Q37. Green sand moulding means that the mould is generally:
A. Used in a moist condition
B. Painted green
C. Made only from green-coloured sand
D. Completely molten
Answer: A. Used in a moist condition
Explanation: “Green” refers to the presence of moisture and the mould being used without complete drying.

Q38. Which of the following is NOT an essential property of good moulding sand?
A. Permeability
B. Refractoriness
C. Strength
D. Electrical insulation only
Answer: D. Electrical insulation only
Explanation: Electrical insulation is not a primary moulding-sand requirement.

Q39. A core is generally made from:
A. Core sand
B. Pure molten metal
C. Cutting fluid
D. Lubricating oil
Answer: A. Core sand
Explanation: Cores are commonly produced from specially prepared sand mixtures designed to withstand casting conditions and provide suitable collapsibility.

Q40. A core is used to produce:
A. Internal cavities
B. External draft
C. Surface colour
D. Metal hardness
Answer: A. Internal cavities
Explanation: The core occupies the space that must remain hollow in the finished casting.

Q41. Core prints are provided to:
A. Support and locate cores
B. Increase metal temperature
C. Measure hardness
D. Remove slag
Answer: A. Support and locate cores
Explanation: Core prints create supporting seats for positioning the core accurately.

Q42. Excessively low permeability may cause:
A. Gas-related defects
B. Better venting
C. Higher ductility
D. Lower melting temperature
Answer: A. Gas-related defects
Explanation: If gases cannot escape adequately, defects such as blowholes may develop.

Q43. Excessively high moisture in moulding sand may contribute to:
A. Gas defects
B. Increased tensile strength
C. Improved electrical conductivity
D. Higher metal hardness
Answer: A. Gas defects
Explanation: Moisture can generate steam and gases when molten metal enters the mould.

Q44. Which property helps moulding sand withstand molten metal without fusing?
A. Refractoriness
B. Adhesiveness
C. Plasticity
D. Permeability
Answer: A. Refractoriness
Explanation: Refractoriness is resistance to high temperatures.

Q45. Which property is especially important for releasing gases from a mould?
A. Permeability
B. Cohesiveness
C. Adhesiveness
D. Hardness
Answer: A. Permeability
Explanation: Gas escape through the mould is essential to prevent gas-related defects.

Q46. A moulding sand with inadequate strength may:
A. Break or erode during pouring
B. Always improve casting quality
C. Increase metal strength
D. Prevent all defects
Answer: A. Break or erode during pouring
Explanation: Insufficient mould strength can cause mould damage, sand inclusion and dimensional problems.

Q47. Which property is particularly important for easy removal of the casting?
A. Collapsibility
B. Electrical conductivity
C. Magnetism
D. Hardness only
Answer: A. Collapsibility
Explanation: A collapsible mould breaks down sufficiently to release the casting.

Q48. A core should generally have sufficient:
A. Strength and refractoriness
B. Electrical resistance only
C. Transparency
D. Magnetism only
Answer: A. Strength and refractoriness
Explanation: The core must retain its shape and withstand contact with molten metal.

Q49. The primary function of a core is:
A. To make an internal passage
B. To melt the casting
C. To harden the pattern
D. To feed molten metal
Answer: A. To make an internal passage
Explanation: Cores create internal cavities or passages that cannot normally be produced by the mould cavity alone.

Q50. Which of the following is correctly matched?
A. Permeability — gas escape
B. Refractoriness — pattern withdrawal
C. Draft — gas escape
D. Core print — melting
Answer: A. Permeability — gas escape
Explanation: Permeability permits gases to escape through the mould.

MCQ 51–70 — Gating System, Riser & Furnace

Q51. The gating system is used to:
A. Carry molten metal into the mould cavity
B. Remove machining chips
C. Test hardness
D. Measure elongation
Answer: A. Carry molten metal into the mould cavity
Explanation: The gating system provides controlled passages for molten metal from the pouring location to the cavity.

Q52. The vertical passage in a gating system is called:
A. Runner
B. Sprue
C. Ingate
D. Riser
Answer: B. Sprue
Explanation: The sprue carries molten metal downward from the pouring basin.

Q53. The horizontal passage connecting the sprue to the ingate is generally called:
A. Runner
B. Core
C. Riser
D. Chill
Answer: A. Runner
Explanation: The runner distributes molten metal from the sprue to one or more ingates.
Q54. The passage through which molten metal enters the mould cavity is:
A. Ingate
B. Sprue
C. Riser
D. Vent
Answer: A. Ingate
Explanation: The ingate is the final entry passage into the casting cavity.

Q55. The main purpose of a riser is to:
A. Feed molten metal during solidification
B. Increase mould permeability
C. Remove the pattern
D. Reduce metal temperature immediately
Answer: A. Feed molten metal during solidification
Explanation: A riser supplies additional liquid metal to compensate for solidification shrinkage.
Q56. A riser should generally remain molten:

A. Longer than the casting region it feeds
B. For no time
C. Only before pouring
D. Only during mould preparation
Answer: A. Longer than the casting region it feeds
Explanation: The riser must provide liquid metal while the casting is solidifying and contracting.
Q57. Directional solidification is promoted primarily to:

A. Guide solidification toward the riser
B. Prevent metal melting
C. Increase sand moisture
D. Remove the pattern
Answer: A. Guide solidification toward the riser
Explanation: Proper casting design and feeding promote solidification from remote regions toward the riser.

Q58. A chill is used to:
A. Increase local cooling rate
B. Increase pouring temperature
C. Reduce mould strength
D. Remove the core
Answer: A. Increase local cooling rate
Explanation: Chills extract heat rapidly from selected regions.

Q59. A pouring basin is located:
A. At the top of the gating system
B. Inside the riser only
C. Under the casting
D. Inside the core
Answer: A. At the top of the gating system
Explanation: The pouring basin receives metal from the ladle and directs it into the sprue.

Q60. The main function of a runner is to:
A. Distribute molten metal
B. Measure hardness
C. Support the core
D. Remove moisture
Answer: A. Distribute molten metal
Explanation: The runner carries metal from the sprue toward the ingates.

Q61. The cupola furnace is mainly used for melting:
A. Cast iron
B. Aluminium foil only
C. Copper wire only
D. Plastic
Answer: A. Cast iron
Explanation: Cupola furnaces are traditionally used in foundries for melting cast iron.

Q62. The usual fuel in a conventional cupola furnace is:
A. Coke
B. Wood only
C. Petrol
D. Natural rubber
Answer: A. Coke
Explanation: Coke serves as the primary fuel and also contributes to the metallurgical environment in the cupola.

Q63. Air is supplied to a cupola through:
A. Tuyeres
B. Risers
C. Runners
D. Cores
Answer: A. Tuyeres
Explanation: Tuyeres introduce air into the furnace to support combustion.

Q64. The cupola is essentially a:
A. Vertical cylindrical furnace
B. Horizontal milling machine
C. Lathe
D. Hydraulic press
Answer: A. Vertical cylindrical furnace
Explanation: A cupola is a vertical shaft-type furnace used for melting cast iron.

Q65. Slag is removed from a cupola through the:
A. Slag hole
B. Core print
C. Runner
D. Ingate
Answer: A. Slag hole
Explanation: A separate slag opening allows accumulated slag to be removed.

Q66. Molten metal is generally tapped from a cupola through the:
A. Tap hole
B. Vent
C. Core print
D. Riser
Answer: A. Tap hole
Explanation: The tap hole is used to withdraw molten metal from the furnace.

Q67. The function of the wind belt in a cupola is associated with:
A. Distribution of air to tuyeres
B. Removing patterns
C. Machining castings
D. Measuring temperature only
Answer: A. Distribution of air to tuyeres
Explanation: The wind belt/plenum distributes the supplied air to the tuyere openings.

Q68. Which furnace is traditionally associated with cast-iron melting in foundries?
A. Cupola
B. Blast furnace only
C. Electric kettle
D. Reverberatory laboratory oven only
Answer: A. Cupola
Explanation: The cupola has long been a common foundry furnace for cast iron.

Q69. Proper gating design primarily helps control:
A. Flow of molten metal
B. Electrical resistance
C. Tool hardness
D. Pattern colour
Answer: A. Flow of molten metal
Explanation: Gating determines how metal enters and fills the cavity and helps manage turbulence and inclusions.

Q70. A properly designed riser helps reduce:
A. Shrinkage defects
B. Tool wear
C. Electrical resistance
D. Pattern moisture
Answer: A. Shrinkage defects
Explanation: The riser feeds liquid metal to compensate for solidification contraction.

MCQ 71–90 — Casting Defects

Q71. A cavity caused by trapped gas in a casting is called:
A. Blowhole
B. Misrun
C. Cold shut
D. Hot tear
Answer: A. Blowhole

Explanation: Blowholes are gas cavities resulting from inadequate escape of gases.
Q72. A casting that fails to completely fill the mould cavity has:
A. Misrun
B. Blowhole
C. Scab
D. Penetration
Answer: A. Misrun
Explanation: Misrun occurs when molten metal solidifies before the cavity is completely filled.

Q73. A defect caused by improper fusion of two streams of molten metal is:
A. Cold shut
B. Blowhole
C. Shrinkage cavity
D. Sand inclusion
Answer: A. Cold shut
Explanation: A cold shut appears where two streams meet but do not properly fuse.

Q74. A shrinkage cavity is mainly associated with:
A. Inadequate feeding during solidification
B. Excessive pattern draft
C. High permeability alone
D. Good directional solidification
Answer: A. Inadequate feeding during solidification
Explanation: If liquid metal is not available to compensate for contraction, shrinkage cavities can form.

Q75. Which defect is associated with cracking during the late stage of solidification?
A. Hot tear
B. Blowhole
C. Misrun
D. Sand inclusion
Answer: A. Hot tear
Explanation: Hot tearing occurs when contraction is restrained while the metal has insufficient strength to accommodate the resulting stresses.

Q76. Excess moisture in moulding sand may contribute to:
A. Blowholes
B. Increased hardness
C. Better machining
D. Higher ductility
Answer: A. Blowholes
Explanation: Moisture can generate steam and other gases during pouring.

Q77. A defect resulting from sand particles becoming embedded in the casting is:
A. Sand inclusion
B. Cold shut
C. Misrun
D. Hot tear
Answer: A. Sand inclusion
Explanation: Erosion or breakdown of the mould can cause sand to enter the molten metal.

Q78. Metal penetrating into spaces between sand grains can produce:
A. Metal penetration
B. Misrun
C. Blowhole
D. Hot tear
Answer: A. Metal penetration
Explanation: Molten metal can enter the mould’s surface pores under certain conditions, producing a rough casting surface.

Q79. Which defect is most directly related to incomplete filling?
A. Misrun
B. Blowhole
C. Shrinkage cavity
D. Sand inclusion
Answer: A. Misrun
Explanation: Misrun means the mould cavity is not completely filled.

Q80. Which defect appears as a seam where two metal fronts meet?
A. Cold shut
B. Blowhole
C. Shrinkage
D. Scab
Answer: A. Cold shut
Explanation: Two metal streams that meet without proper fusion create a cold-shut indication.

Q81. Proper riser design mainly prevents:
A. Shrinkage cavity
B. Tool chatter
C. Electrical short circuit
D. Pattern wear
Answer: A. Shrinkage cavity
Explanation: Risers provide molten metal to compensate for solidification contraction.

Q82. Poor mould permeability is most likely to cause:
A. Gas-related defects
B. Increased ductility
C. Better surface finish always
D. Higher melting point
Answer: A. Gas-related defects
Explanation: Trapped gases can produce blowholes and other gas-related imperfections.

Q83. Excessive turbulence in the gating system may promote:
A. Mould erosion and inclusions
B. Perfect casting quality
C. Higher hardness only
D. Lower density of the mould
Answer: A. Mould erosion and inclusions
Explanation: Turbulent flow can erode mould surfaces and entrain oxides or sand.

Q84. A hot tear is associated with:
A. Restrained contraction
B. Excessive permeability only
C. Pattern colour
D. Low hardness of the pattern only
Answer: A. Restrained contraction
Explanation: During solidification, contraction can generate stresses that cause tearing when movement is restrained.

Q85. Which defect is caused primarily by insufficient molten metal feeding?
A. Shrinkage cavity
B. Cold shut
C. Sand inclusion
D. Scab
Answer: A. Shrinkage cavity
Explanation: Inadequate feeding leaves a void as the metal contracts during solidification.

Q86. A casting defect caused by two streams meeting without complete fusion is:
A. Cold shut
B. Blowhole
C. Metal penetration
D. Shrinkage cavity
Answer: A. Cold shut
Explanation: The streams meet at a temperature or condition insufficient for proper fusion.

Q87. Which defect is most likely associated with inadequate venting?
A. Blowhole
B. Hot tear
C. Misrun only
D. Mismatch only
Answer: A. Blowhole
Explanation: Inadequate venting can trap gases inside the mould and produce blowholes.

Q88. An irregular crack caused during solidification is most closely associated with:
A. Hot tear
B. Misrun
C. Sand inclusion
D. Blowhole
Answer: A. Hot tear
Explanation: Hot tears are cracks that develop during the final stages of solidification under restrained contraction.

Q89. Which casting defect is associated with erosion of mould material?
A. Sand inclusion
B. UTS
C. Yielding
D. Creep
Answer: A. Sand inclusion
Explanation: Mould erosion can release sand particles that become entrapped in the casting.

Q90. Which measure can help reduce shrinkage defects?
A. Proper riser design
B. Removing all risers
C. Increasing mould damage
D. Eliminating feeding
Answer: A. Proper riser design
Explanation: Properly located and sized risers provide liquid metal during solidification.

MCQ 91–100 — Special Casting Processes

Q91. Investment casting is also known as:
A. Lost-wax casting
B. Sand forging
C. Pressure welding
D. Cold rolling
Answer: A. Lost-wax casting
Explanation: A wax pattern is used and subsequently removed from the refractory mould before metal pouring.

Q92. Investment casting is particularly suitable for:
A. Complex and detailed shapes
B. Only simple flat plates
C. Only rolled sheets
D. Only welded joints
Answer: A. Complex and detailed shapes
Explanation: The process can reproduce intricate geometries with good dimensional accuracy and surface finish.

Q93. In die casting, molten metal is introduced into the die:
A. Under pressure
B. Only by gravity in all cases
C. By hammering
D. By rolling
Answer: A. Under pressure
Explanation: Pressure die casting forces molten metal into a reusable metallic die.

Q94. Die casting is particularly suitable for:
A. High-volume production
B. One-off wooden patterns only
C. Very large sand moulds only
D. Hand forging
Answer: A. High-volume production
Explanation: Reusable dies and rapid cycles make die casting suitable for high production rates.

Q95. Which material is commonly used in pressure die casting?
A. Aluminium alloy
B. Concrete
C. Wood
D. Rubber only
Answer: A. Aluminium alloy
Explanation: Aluminium, zinc and magnesium alloys are common die-casting materials.

Q96. Centrifugal casting uses:
A. A rotating mould
B. A fixed wooden pattern only
C. A hammer
D. A rolling mill
Answer: A. A rotating mould
Explanation: Rotation generates centrifugal force that distributes molten metal against the mould wall.

Q97. Centrifugal casting is particularly suitable for producing:
A. Pipes and cylindrical components
B. Flat sheets only
C. Bolts by forging only
D. Wooden components
Answer: A. Pipes and cylindrical components
Explanation: The process is especially effective for tubular and rotationally symmetric castings.

Q98. Shell moulding uses:
A. Resin-bonded sand shell
B. Pure water only
C. Forged steel mould only
D. Wax without refractory material
Answer: A. Resin-bonded sand shell
Explanation: A thin shell of resin-bonded sand is formed around a heated pattern.

Q99. Continuous casting produces:
A. A continuously withdrawn solidifying strand
B. Only individual sand castings
C. Forged gears only
D. Welded pipes only
Answer: A. A continuously withdrawn solidifying strand
Explanation: Molten metal is continuously supplied to a mould while the partially solidified product is continuously withdrawn.

Q100. Which casting process is most closely associated with a rotating mould?
A. Centrifugal casting
B. Investment casting
C. Sand casting
D. Shell moulding
Answer: A. Centrifugal casting
Explanation: Rotation of the mould is the defining feature of centrifugal casting.

CHAPTER 5 — ONE-PAGE REVISION

Pattern

Pattern → Mould cavity

Pattern Allowances

Shrinkage → Cooling contraction

.
Machining → Future machining

Draft → Easy withdrawal

Distortion → Unequal contraction

Shake → Rapping effect

Moulding Sand

Permeability → Gas escape

Refractoriness → High-temperature resistance

Cohesiveness → Sand grains stick together

Adhesiveness → Sand sticks to mould box

Plasticity → Reproduces pattern shape

Collapsibility → Easy casting removal

Gating

Pouring Basin → Receives molten metal

Sprue → Vertical passage

Runner → Distributes metal

Ingate → Entry into cavity

Riser → Feeds molten metal

Chill → Faster local cooling

Defects

Blowhole → Gas

Misrun → Incomplete filling

Cold Shut → Incomplete fusion

Shrinkage Cavity → Poor feeding

Hot Tear → Restrained contraction

Sand Inclusion → Mould sand enters casting

Metal Penetration → Metal enters sand pores

Special Processes

Investment → Lost wax

Die Casting → Pressure + permanent die

Centrifugal → Rotating mould

Shell Moulding → Resin-coated sand shell

Continuous Casting → Continuous strand

CHAPTER 6 — METAL FORMING PROCESSES

6.1 Introduction

Metal forming is a manufacturing process in which a metal workpiece is plastically deformed into the required shape by applying an external force.
Unlike machining, metal forming generally does not remove material in the form of chips.
Metal forming is widely used in:
Automobile components
Railway components
Aircraft structures
Machine parts
Pipes and tubes
Sheets and plates
Shafts
Gears
Connecting rods
Bolts and fasteners

6.2 Definition of Metal Forming

Metal forming is a manufacturing process in which the shape of a metal is changed permanently by plastic deformation under the action of externally applied forces.
Key Point
Metal forming → Plastic deformation → Required shape

6.3 Principle of Metal Forming

The basic principle is based on the plasticity of metals.
When a sufficiently large force is applied to a metal:
Elastic deformation occurs initially.
The applied stress reaches the yield strength.
Plastic deformation begins.
After removal of the load, the material retains its newly formed shape.
Therefore:
Elastic deformation → Yielding → Plastic deformation → Permanent shape

6.4 Classification of Metal Forming
Metal forming processes can broadly be classified into:
A. Bulk Deformation Processes
These involve relatively large changes in cross-section.
Important processes:
Rolling
Forging
Extrusion
Drawing
B. Sheet Metal Forming Processes
These are generally performed on sheet or strip materials.
Important processes:
Bending
Deep drawing
Blanking
Punching
Bending
Shearing
Embossing
Coining

6.5 Hot Working

Hot working is metal deformation carried out at a temperature sufficiently high that significant recrystallization occurs during deformation.
Examples:
Hot rolling
Hot forging
Hot extrusion
Advantages
Lower forming force
Large deformation possible
Improved workability
Grain refinement can occur
Internal defects may be reduced or closed under suitable conditions
Disadvantages
Oxidation/scaling
Poorer surface finish
Less dimensional accuracy than many cold-working operations
Heating equipment required

6.6 Cold Working

Cold working is plastic deformation performed below the recrystallization temperature, commonly near room temperature.
Examples:
Cold rolling
Wire drawing
Cold extrusion
Cold forging
Advantages
Better surface finish
Better dimensional accuracy
Increased strength and hardness due to strain hardening
No heating scale from hot working
Disadvantages
Higher forming force
Lower ductility
Residual stresses may develop
Greater tool wear can occur

6.7 Warm Working

Warm working is carried out at a temperature between typical cold-working and hot-working conditions.
It can provide a compromise between:
Lower forming force than cold working
Better surface and dimensional control than many hot-working operations

6.8 Recrystallization

Recrystallization is the formation of new, relatively strain-free grains in a plastically deformed metal during appropriate heat treatment.
The recrystallization temperature is important in distinguishing hot and cold working.
Remember
Above suitable recrystallization conditions → Hot working
Below recrystallization temperature → Cold working

6.9 Strain Hardening

Strain hardening, also called work hardening, is the increase in strength and hardness of a metal due to plastic deformation.
It is particularly important in cold working.
Effect of Cold Working
Generally:
Strength ↑
Hardness ↑
Ductility ↓

6.10 Rolling

Rolling is a metal-forming process in which metal is passed between rotating rolls to reduce thickness or change its cross-sectional shape.
Basic principle
Metal → Rotating rolls → Plastic deformation → Reduced thickness/changed shape

6.11 Products of Rolling

Rolling can produce:
Sheets
Plates
Strips
Bars
Rails
Structural sections
Rods

6.12 Types of Rolling Mills

Important rolling-mill arrangements include:
Two-high rolling mill
Three-high rolling mill
Four-high rolling mill
Cluster rolling mill
Tandem rolling mill

6.13 Two-High Rolling Mill

A two-high rolling mill has:
Two rolls
The rolls may rotate in opposite directions at the point of contact with the workpiece.

6.14 Three-High Rolling Mill

A three-high mill consists of:
Three rolls arranged vertically.
The workpiece can pass alternately between the upper and middle rolls and between the middle and lower rolls.

6.15 Four-High Rolling Mill

A four-high rolling mill consists of:
Two small work rolls
Two larger backup rolls
Main purpose of backup rolls
They support the smaller work rolls and reduce bending.

6.16 Cluster Rolling Mill

A cluster mill uses multiple backup rolls to support relatively small work rolls.
It is useful for rolling thin material.

6.17 Tandem Rolling Mill

A tandem rolling mill contains several rolling stands arranged in succession.
The strip passes continuously through multiple stands.
Advantage
High production rate.

6.18 Roll Bite

The roll bite is the region where the workpiece is in contact with the rolls.
For rolling to occur, friction between the rolls and workpiece must be sufficient to draw the material into the roll gap.

6.19 Neutral Point

The neutral point is the point along the arc of contact where the velocity of the strip equals the peripheral velocity of the roll.

6.20 Forward Slip

In rolling, the exit velocity of the strip is generally greater than the peripheral velocity of the roll.
This difference is associated with forward slip.

6.21 Forging

Forging is a metal-forming process in which a workpiece is plastically deformed under compressive forces.
Forces may be applied using:
Hammer
Press
Die
Forging is widely used for producing:
Crankshafts
Connecting rods
Spanners
Axles
Shafts
Bolts
Aircraft components

6.22 Advantages of Forging

Important advantages include:
High strength
Good toughness
Improved grain flow
Reduced internal defects under suitable processing
Excellent mechanical properties for many applications

6.23 Open-Die Forging

In open-die forging, the workpiece is compressed between dies that do not completely enclose it.
It is commonly used for:
Large components
Low-to-medium production
Large shafts
Heavy forgings

6.24 Closed-Die Forging

In closed-die forging, the workpiece is deformed within impressions in the dies.
It is suitable for:
Complex shapes
High production
Better dimensional consistency
Excess material may form flash at the die parting line.

6.25 Flash

Flash is excess metal squeezed out between the die halves during closed-die forging.
The flash is generally removed after forging.

6.26 Drop Forging
Drop forging uses repeated blows from a hammer to deform the workpiece in dies.
The energy of the falling hammer produces the deformation.

6.27 Press Forging

In press forging, deformation is produced primarily by continuous squeezing pressure rather than repeated impact blows.
Comparison
Hammer forging → Impact
Press forging → Continuous pressure

6.28 Extrusion

Extrusion is a metal-forming process in which a billet is forced through a die opening to produce a long product of constant cross-section.
Examples:
Rods
Tubes
Channels
Aluminium sections
Window frames

6.29 Direct Extrusion

In direct extrusion, the billet and ram move in the same direction relative to the die opening.
The ram pushes the billet through the die.

6.30 Indirect Extrusion

In indirect extrusion, the die moves toward or into the billet, and the extruded material flows opposite to the direction of ram movement.
Important
Direct extrusion → Billet flow generally same direction as ram movement
Indirect extrusion → Metal flow opposite to ram movement

6.31 Extrusion Ratio

The extrusion ratio is generally defined as:
Where:
= initial cross-sectional area
= final extruded cross-sectional area
A larger extrusion ratio indicates a greater reduction in cross-sectional area.

6.32 Drawing

Drawing is a metal-forming process in which a wire, rod or tube is pulled through a die to reduce its cross-sectional area and/or change its shape.
Important
Extrusion → Material is pushed through die
Drawing → Material is pulled through die

6.33 Wire Drawing

Wire drawing is commonly used to produce:
Electrical wires
Fine wires
Cables
Springs
Small-diameter rods

6.34 Tube Drawing

Tube drawing is used to reduce the diameter or wall dimensions of tubes.
A mandrel may be used when control of internal dimensions is required.

6.35 Sheet Metal Working

Sheet metal processes transform thin metal sheets into useful components.
Common operations include:
Shearing
Blanking
Punching
Bending
Deep drawing
Embossing
Coining

6.36 Shearing

Shearing is a cutting operation in which a sheet is separated by applying shear forces.
It is performed using tools such as:
Shears
Punch and die

6.37 Blanking

In blanking, the portion cut out from the sheet is the desired product.
Golden Rule
Blanking → Blank is the product

6.38 Punching

In punching, the hole produced in the sheet is the desired feature, while the removed slug is generally scrap.
Golden Rule
Punching → Hole is the desired feature

6.39 Bending

Bending changes the shape of a sheet or strip by applying force without intentionally removing material.
Examples:
V-bending
U-bending
Angle bending

6.40 Springback

Springback is the elastic recovery of a sheet after the bending load is removed.
Because of springback, the final angle may differ from the angle imposed by the tooling.
Reduction of Springback
It can be controlled by:
Over-bending
Coining
Appropriate tooling
Process optimization

6.41 Deep Drawing

Deep drawing is a sheet-metal forming process in which a flat blank is drawn into a die to produce a cup-like or hollow component.
Examples:
Cups
Cans
Kitchen utensils
Automotive components

6.42 Blank Holder

A blank holder is used in deep drawing to control the movement of the sheet and help prevent wrinkling.

6.43 Punch and Die

In sheet-metal operations:
Punch → Moves into/through the sheet
Die → Supports and provides the required opening
The clearance between punch and die is important for cutting quality and tool life.

6.44 Embossing

Embossing produces raised or recessed designs on sheet metal.
It is commonly used for:
Identification marks
Decorative patterns
Stiffening features

6.45 Coining

Coining is a severe sheet-metal forming operation in which the material is subjected to high compressive pressure between dies.
It can produce:
Fine details
Accurate impressions
Raised or recessed features

6.46 Advantages of Metal Forming

Major advantages:
High production rate
Good material utilization
Improved mechanical properties in many processes
Good surface finish in cold working
Reduced machining requirements
Suitable for mass production

6.47 Limitations

Limitations include:
High initial tooling cost
High forming forces
Springback in sheet-metal forming
Work hardening
Residual stresses
Defects such as laps, cracks and wrinkles

6.48 Common Forming Defects

Important defects include:
Cracks
Laps
Wrinkles
Surface defects
Internal defects
Alligatoring
Excessive springback

6.49 Quick Revision Table

Process Main Principle
Rolling Metal passes between rolls
Forging Compressive deformation
Extrusion Pushing metal through die
Drawing Pulling metal through die
Blanking Cut-out piece is product
Punching Hole is desired feature
Bending Change in sheet angle/shape
Deep drawing Sheet converted into cup/hollow form
Embossing Raised/recessed design
Coining High-pressure impression
Hot working Above suitable recrystallization conditions
Cold working Below recrystallization temperature
Warm working Intermediate temperature range
Springback Elastic recovery
Strain hardening Strength increase due to plastic deformation

Q1. Metal forming is primarily based on:

A. Elastic deformation
B. Plastic deformation
C. Brittle fracture
D. Melting
Answer: B. Plastic deformation
Explanation: Metal forming permanently changes the shape of a material through plastic deformation.

Q2. Which of the following is a bulk metal-forming process?
A. Rolling
B. Painting
C. Welding
D. Grinding
Answer: A. Rolling
Explanation: Rolling is one of the major bulk deformation processes.

Q3. Which process uses rotating rolls to reduce the thickness of metal?
A. Forging
B. Rolling
C. Drawing
D. Casting
Answer: B. Rolling
Explanation: Rolling passes the workpiece through the gap between rotating rolls.

Q4. Forging primarily involves:
A. Tensile forces
B. Compressive forces
C. Electrical forces
D. Thermal radiation only
Answer: B. Compressive forces
Explanation: Forging plastically deforms the workpiece mainly through compressive loading.

Q5. In extrusion, the billet is:
A. Pulled through the die
B. Pushed through the die
C. Melted completely
D. Rolled into a sheet
Answer: B. Pushed through the die
Explanation: A ram applies compressive force to force the billet through the die opening.

Q6. In drawing, the workpiece is:
A. Pushed through the die
B. Pulled through the die
C. Melted
D. Cast
Answer: B. Pulled through the die
Explanation: Drawing reduces the cross-section by pulling the material through a die.

Q7. Which process generally increases hardness due to strain hardening?
A. Cold working
B. Annealing
C. Casting only
D. Melting
Answer: A. Cold working
Explanation: Plastic deformation at low temperature increases dislocation density, generally increasing strength and hardness.

Q8. One common disadvantage of cold working is:
A. Increased ductility
B. Work hardening
C. Complete elimination of residual stress
D. Loss of all strength
Answer: B. Work hardening
Explanation: Cold deformation increases strength and hardness but reduces ductility.

Q9. Which process is generally performed at a temperature where recrystallization can occur during deformation?
A. Hot working
B. Cold working
C. Room-temperature machining
D. Grinding
Answer: A. Hot working
Explanation: Hot working occurs at sufficiently elevated temperatures to permit significant recrystallization during deformation.

Q10. Which of the following is a sheet-metal operation?
A. Deep drawing
B. Blast furnace melting
C. Sand moulding
D. Arc welding
Answer: A. Deep drawing
Explanation: Deep drawing forms sheet metal into cup-like or hollow shapes.

Q11. In blanking:
A. The hole is the product
B. The blank is the product
C. Both are always scrap
D. No material is removed
Answer: B. The blank is the product
Explanation: The cut-out portion of the sheet is the desired component in blanking.

Q12. In punching:
A. The hole is the desired feature
B. The slug is always the final product
C. No cutting occurs
D. The sheet is melted
Answer: A. The hole is the desired feature
Explanation: Punching produces a hole in the sheet; the removed slug is generally scrap.

Q13. Springback in sheet metal is caused by:
A. Elastic recovery
B. Melting
C. Plastic flow only
D. Oxidation
Answer: A. Elastic recovery
Explanation: After the forming load is removed, the elastically deformed material partially returns toward its original shape.

Q14. Which operation produces a cup-like component from a flat sheet?
A. Deep drawing
B. Rolling
C. Wire drawing
D. Forging
Answer: A. Deep drawing
Explanation: Deep drawing transforms a flat blank into a hollow component.

Q15. A four-high rolling mill uses:
A. Four work rolls
B. Two work rolls and two backup rolls
C. One work roll and three dies
D. Four dies
Answer: B. Two work rolls and two backup rolls
Explanation: The smaller work rolls are supported by larger backup rolls.

Q16. A tandem rolling mill consists of:
A. Several rolling stands in succession
B. One die only
C. One hammer only
D. A furnace and a mould
Answer: A. Several rolling stands in succession
Explanation: Multiple stands permit successive reductions and high production rates.

Q17. Excess metal squeezed out between closed forging dies is called:
A. Flash
B. Burr only
C. Slag
D. Riser
Answer: A. Flash
Explanation: Flash forms at the die parting line during closed-die forging and is subsequently trimmed.

Q18. Open-die forging is especially suitable for:
A. Large components
B. Only tiny electronic parts
C. Thin plastic films
D. Glass bottles
Answer: A. Large components
Explanation: Open-die forging is commonly used for large shafts, rings and other heavy components.

Q19. The extrusion ratio is generally:
A.
B.
C.
D.
Answer: B.
Explanation:
where is the initial billet area and is the final extruded area.

Q20. In indirect extrusion, metal flow is generally:
A. In the same direction as ram movement
B. Opposite to ram movement
C. Perpendicular to the die
D. Circular only
Answer: B. Opposite to ram movement
Explanation: In indirect extrusion, the die moves into the billet and material flows through the die in the opposite direction to the ram.

Q21. The main purpose of rolling is to:
A. Increase the thickness of a plate
B. Reduce thickness or change cross-section
C. Join two metals
D. Remove chips
Answer: B. Reduce thickness or change cross-section
Explanation: Rolling plastically deforms metal between rotating rolls to reduce thickness or produce a required section.

Q22. In rolling, the workpiece is subjected mainly to:
A. Tensile stress
B. Compressive stress
C. Torsional stress only
D. Bending stress only
Answer: B. Compressive stress
Explanation: The rolls apply compressive forces to reduce the thickness of the workpiece.

Q23. Which product can commonly be manufactured by rolling?
A. Sheet
B. Sand mould
C. Welding electrode only
D. Cutting fluid
Answer: A. Sheet
Explanation: Sheets, plates, strips, rails and structural sections are common rolling products.

Q24. The distance between the surfaces of two rolls at the point of minimum separation is called:
A. Roll gap
B. Draft angle
C. Die clearance
D. Pitch
Answer: A. Roll gap
Explanation: Roll gap is the minimum separation between the two rolls through which the material passes.

Q25. Draft in rolling refers to:
A. Increase in thickness
B. Reduction in thickness
C. Increase in width only
D. Reduction in length only
Answer: B. Reduction in thickness
Explanation:
where is the initial thickness and is the final thickness.

Q26. If the initial thickness is 20 mm and final thickness is 15 mm, the draft is:
A. 3 mm
B. 5 mm
C. 15 mm
D. 35 mm
Answer: B. 5 mm
Explanation:

Q27. The percentage reduction in thickness is calculated by:
A.
B.
C.
D.
Answer: B.
Explanation: Percentage reduction represents the decrease in thickness relative to the initial thickness.

Q28. The roll bite is the region where:
A. Metal is heated
B. Metal contacts the rolls
C. Metal is melted
D. Metal is welded
Answer: B. Metal contacts the rolls
Explanation: The arc or region of contact between the workpiece and rolls is associated with the roll bite.

Q29. Friction between the rolls and workpiece is necessary primarily to:
A. Prevent deformation
B. Draw the workpiece into the rolls
C. Melt the workpiece
D. Increase electrical resistance
Answer: B. Draw the workpiece into the rolls
Explanation: Adequate friction enables the rolls to grip and pull the workpiece into the roll gap.

Q30. Excessive friction in rolling can lead to:
A. Reduced roll wear
B. Increased power requirement and defects
C. Zero deformation
D. Elimination of all stresses
Answer: B. Increased power requirement and defects
Explanation: Although friction is required for biting, excessive friction increases power consumption and may promote undesirable deformation.

Q31. A two-high rolling mill consists of:
A. Two rolls
B. Three rolls
C. Four rolls
D. Six rolls
Answer: A. Two rolls
Explanation: The simplest rolling mill arrangement has two rolls.

Q32. In a three-high rolling mill, the rolls are generally arranged:
A. Horizontally in one plane
B. Vertically one above another
C. In a triangular pattern
D. Randomly
Answer: B. Vertically one above another
Explanation: Three-high mills use three rolls positioned one above another.

Q33. The major advantage of a three-high rolling mill is:
A. Reversal of workpiece movement without reversing roll rotation
B. No need for friction
C. No deformation
D. Elimination of all roll wear
Answer: A. Reversal of workpiece movement without reversing roll rotation
Explanation: The workpiece can pass alternately through the upper and lower roll gaps while the rolls continue rotating in their respective directions.

Q34. In a four-high rolling mill, backup rolls are used mainly to:
A. Heat the metal
B. Support work rolls
C. Cut the metal
D. Lubricate the workpiece
Answer: B. Support work rolls
Explanation: Backup rolls reduce bending of the smaller work rolls.

Q35. A cluster rolling mill is particularly suitable for:
A. Very thin sheets
B. Sand casting
C. Forging dies only
D. Welding rods only
Answer: A. Very thin sheets
Explanation: Multiple backup rolls permit the use of small work rolls and help produce thin material.

Q36. A tandem rolling mill is used mainly for:
A. Low-speed single-piece production
B. High production rate
C. Hand forging
D. Sand mould preparation
Answer: B. High production rate
Explanation: Multiple stands arranged sequentially permit continuous high-speed rolling.

Q37. In rolling, the neutral point is where:
A. Metal melts
B. Strip velocity equals roll surface velocity
C. Thickness becomes zero
D. Friction becomes zero
Answer: B. Strip velocity equals roll surface velocity
Explanation: The neutral point separates regions of backward and forward slip.

Q38. Forward slip occurs because:
A. Exit strip velocity is greater than roll peripheral velocity
B. Exit strip velocity is zero
C. Roll velocity is always greater than strip velocity
D. The strip melts
Answer: A. Exit strip velocity is greater than roll peripheral velocity
Explanation: The strip accelerates as it moves through the roll bite, resulting in forward slip at exit.

Q39. Roll flattening is caused mainly by:
A. High rolling force
B. Low temperature of air
C. Pattern draft
D. Core expansion
Answer: A. High rolling force
Explanation: Large rolling forces elastically deform the rolls, affecting the effective roll gap.

Q40. Which defect is associated with excessive non-uniform deformation during rolling?
A. Wavy edges
B. Blowhole
C. Cold shut
D. Hot tear
Answer: A. Wavy edges
Explanation: Unequal elongation across the strip width can produce wavy edges.

MCQ 41–60: Forging
Q41. Forging is primarily a:
A. Casting process
B. Metal-forming process
C. Machining process
D. Welding process
Answer: B. Metal-forming process
Explanation: Forging changes the shape of a workpiece through plastic deformation under compressive loading.

Q42. The major force in forging is:
A. Compression
B. Tension
C. Pure torsion
D. Electrical force
Answer: A. Compression
Explanation: Forging dies apply compressive forces to deform the workpiece.

Q43. Open-die forging is generally preferred for:
A. Very large components
B. Tiny electronic components
C. Plastic sheets
D. Glass products
Answer: A. Very large components
Explanation: Open dies can accommodate large workpieces and are widely used for heavy forgings.

Q44. Closed-die forging is particularly suitable for:
A. Complex shapes and high production
B. Only rough large blocks
C. Sand moulds
D. Thin wires only
Answer: A. Complex shapes and high production
Explanation: Die impressions provide controlled shaping and repeatability.

Q45. Flash in closed-die forging is:
A. Molten slag
B. Excess metal squeezed out at the die parting line
C. Lubricant
D. A crack in the forging
Answer: B. Excess metal squeezed out at the die parting line
Explanation: Excess material flows into the flash region between the die halves.

Q46. Flash is generally removed by:
A. Trimming
B. Rolling
C. Casting
D. Annealing only
Answer: A. Trimming
Explanation: A trimming operation removes unwanted flash from the forged component.

Q47. Drop forging uses:
A. Repeated hammer blows
B. Continuous rolling
C. Wire drawing
D. A rotating mould
Answer: A. Repeated hammer blows
Explanation: A hammer delivers impact energy to deform the workpiece within the dies.

Q48. Press forging differs from drop forging because press forging uses mainly:
A. Continuous squeezing action
B. No force
C. Melting
D. Tensile fracture
Answer: A. Continuous squeezing action
Explanation: A forging press applies force progressively rather than mainly through repeated impact blows.

Q49. Which is a major advantage of forged components?
A. Improved grain flow
B. Guaranteed zero machining
C. No tooling required
D. Very low strength
Answer: A. Improved grain flow
Explanation: Proper forging can produce favorable grain flow and excellent mechanical properties.

Q50. Forging is widely used for manufacturing:
A. Connecting rods
B. Glass bottles
C. Sand moulds
D. Plastic films
Answer: A. Connecting rods
Explanation: Connecting rods are commonly produced by forging because of the required strength and toughness.

Q51. A forging defect in which the material folds over itself is called:
A. Lap
B. Blowhole
C. Misrun
D. Porosity
Answer: A. Lap
Explanation: A lap is a surface defect caused by folding of metal during deformation.

Q52. Proper die design is important mainly to:
A. Ensure controlled metal flow
B. Eliminate all friction
C. Melt the workpiece
D. Produce sand
Answer: A. Ensure controlled metal flow
Explanation: Proper die geometry helps material flow correctly and reduces forging defects.

Q53. In impression-die forging, the workpiece is deformed:
A. Within die impressions
B. Between rolling rolls
C. Through a wire-drawing die
D. Inside a sand mould
Answer: A. Within die impressions
Explanation: Die cavities define the desired forging geometry.

Q54. The grain flow produced by forging can improve:
A. Mechanical performance
B. Electrical insulation only
C. Casting permeability
D. Melting temperature only
Answer: A. Mechanical performance
Explanation: Favorable grain flow can improve fatigue strength, toughness and directional mechanical properties.

Q55. Hot forging generally requires:
A. Lower deformation force than cold forging
B. No deformation force
C. Only tensile force
D. No dies
Answer: A. Lower deformation force than cold forging
Explanation: Elevated temperature lowers the flow stress of the material.

Q56. Cold forging generally provides:
A. Good dimensional accuracy and surface finish
B. Heavy oxidation scale
C. Very low strength
D. No work hardening
Answer: A. Good dimensional accuracy and surface finish
Explanation: Cold forging can produce accurate parts and also increases strength through work hardening.

Q57. Which process is commonly used to manufacture bolts in large quantities?
A. Cold heading/cold forging
B. Sand casting only
C. Centrifugal casting
D. Investment casting only
Answer: A. Cold heading/cold forging
Explanation: Cold heading is widely used for high-volume production of fasteners.

Q58. Upsetting in forging generally:
A. Increases cross-sectional area and reduces length
B. Reduces diameter and increases length
C. Produces a hole
D. Cuts the material
Answer: A. Increases cross-sectional area and reduces length
Explanation: In upsetting, the workpiece is compressed along its length.

Q59. Drawing out in forging generally:
A. Increases length and reduces cross-section
B. Decreases length
C. Produces a hole
D. Produces sheet by rolling
Answer: A. Increases length and reduces cross-section
Explanation: Drawing out elongates the workpiece while reducing its cross-sectional dimensions.

Q60. A forging hammer applies:
A. Impact load
B. Pure hydrostatic pressure only
C. Tensile load only
D. Electrical current
Answer: A. Impact load
Explanation: Hammers deform the workpiece using high-energy impact blows.

MCQ 61–80: Extrusion & Drawing

Q61. Extrusion produces:
A. Long products of constant cross-section
B. Only spherical products
C. Only flat sheets
D. Sand moulds
Answer: A. Long products of constant cross-section
Explanation: Material is forced through a die to obtain the required continuous cross-sectional shape.

Q62. In direct extrusion, metal flow is generally:
A. In the direction of ram movement
B. Opposite to ram movement
C. Perpendicular to ram movement
D. Circular
Answer: A. In the direction of ram movement
Explanation: The ram pushes the billet toward and through the die.

Q63. The major advantage of indirect extrusion is:
A. Lower friction between billet and container
B. No deformation
C. No die required
D. No pressure required
Answer: A. Lower friction between billet and container
Explanation: In indirect extrusion, there is less relative movement between the billet and container wall.

Q64. Extrusion is especially suitable for producing:
A. Complex cross-sections
B. Only cast iron blocks
C. Sand cores
D. Weld beads
Answer: A. Complex cross-sections
Explanation: Extrusion can produce intricate and constant cross-sectional profiles.

Q65. Aluminium is widely extruded because of its:
A. Good extrudability
B. Extremely high brittleness
C. Very low plasticity
D. Inability to deform
Answer: A. Good extrudability
Explanation: Aluminium alloys are widely used for extruded sections because many grades have good workability.

Q66. In extrusion, the die determines:
A. Final cross-sectional shape
B. Furnace fuel
C. Metal colour
D. Workpiece temperature only
Answer: A. Final cross-sectional shape
Explanation: The opening in the extrusion die defines the cross-sectional profile of the product.

Q67. The extrusion ratio is the ratio of:
A. Final area to initial area
B. Initial area to final area
C. Initial length to final length
D. Final length to initial length
Answer: B. Initial area to final area
Explanation:

Q68. In wire drawing, the material is:
A. Pulled through a die
B. Pushed through a die
C. Cast into a mould
D. Rolled between four rolls
Answer: A. Pulled through a die
Explanation: Tensile force pulls the wire through the die, reducing its cross-section.

Q69. Wire drawing is commonly used to manufacture:
A. Fine wires
B. Large castings
C. Engine blocks
D. Sand moulds
Answer: A. Fine wires
Explanation: Drawing is an important process for reducing wire diameter.

Q70. The material property most important for successful wire drawing is:
A. Ductility
B. Brittleness
C. Porosity
D. Very low strength
Answer: A. Ductility
Explanation: The material must withstand substantial plastic deformation without cracking.

Q71. A drawing die is used to:
A. Reduce cross-sectional area
B. Increase melting temperature
C. Produce a mould cavity
D. Join two wires
Answer: A. Reduce cross-sectional area
Explanation: The die opening is smaller than the incoming material cross-section.

Q72. Lubrication in drawing is used mainly to:
A. Reduce friction and die wear
B. Increase friction
C. Melt the material
D. Increase oxidation
Answer: A. Reduce friction and die wear
Explanation: Proper lubrication lowers frictional resistance and improves tool life and surface quality.

Q73. Tube drawing may use a mandrel to control:
A. Internal dimensions
B. Furnace temperature
C. External colour
D. Sheet thickness only
Answer: A. Internal dimensions
Explanation: A mandrel supports and controls the internal surface during tube drawing.

Q74. In extrusion, the material is subjected mainly to:
A. Compressive stress
B. Tensile stress only
C. Pure bending
D. Impact only
Answer: A. Compressive stress
Explanation: The ram applies compressive force to push the billet through the die.

Q75. In drawing, the material is subjected significantly to:
A. Tensile stress
B. Pure compression only
C. Bending only
D. Impact only
Answer: A. Tensile stress
Explanation: The drawing force pulls the workpiece through the die.

Q76. Which process can produce an aluminium window-frame profile?
A. Extrusion
B. Punching only
C. Deep drawing only
D. Open-die forging only
Answer: A. Extrusion
Explanation: Extrusion is widely used for long aluminium profiles with complex constant cross-sections.

Q77. In indirect extrusion, friction between billet and container is generally:
A. Lower than in direct extrusion
B. Higher than in direct extrusion
C. Always zero
D. Unrelated to the process
Answer: A. Lower than in direct extrusion
Explanation: The billet does not slide relative to the container in the same manner as in direct extrusion.

Q78. Which process is more appropriate for reducing the diameter of a wire?
A. Wire drawing
B. Forging
C. Casting
D. Deep drawing
Answer: A. Wire drawing
Explanation: Wire drawing is specifically designed for producing smaller wire diameters.

Q79. Which process is generally associated with pushing a billet through a die?
A. Extrusion
B. Drawing
C. Bending
D. Shearing
Answer: A. Extrusion
Explanation: Extrusion uses compressive force to push material through the die.

Q80. Which process is generally associated with pulling a workpiece through a die?
A. Drawing
B. Extrusion
C. Rolling
D. Forging
Answer: A. Drawing
Explanation: Drawing uses tensile pulling force to pass the material through a die.

MCQ 81–100: Sheet Metal Processes

Q81. Sheet metal working is generally performed on:
A. Thin sheets and strips
B. Molten metal only
C. Sand
D. Wooden blocks
Answer: A. Thin sheets and strips
Explanation: Sheet-metal processes shape and cut relatively thin metal stock.

Q82. Which operation separates sheet metal by shear?
A. Shearing
B. Forging
C. Extrusion
D. Rolling only
Answer: A. Shearing
Explanation: Shearing separates sheet material through localized shear deformation.

Q83. In blanking, the cut-out portion is:
A. The desired component
B. Always scrap
C. The punch
D. The die
Answer: A. The desired component
Explanation: The blank is the required product in blanking.

Q84. In punching, the removed portion is generally:
A. Scrap
B. The final sheet
C. The die
D. The punch
Answer: A. Scrap
Explanation: The hole is the desired feature, while the removed slug is generally discarded.

Q85. The tool that enters the sheet during punching is:
A. Punch
B. Riser
C. Core
D. Runner
Answer: A. Punch
Explanation: The punch moves relative to the die and cuts the sheet.

Q86. Clearance in a punching operation is provided between:
A. Punch and die
B. Riser and runner
C. Core and mould box
D. Hammer and anvil only
Answer: A. Punch and die
Explanation: Proper punch-die clearance is essential for good cutting quality and tool life.

Q87. Excessive clearance in blanking may produce:
A. Poor edge quality
B. Perfect edge quality always
C. No cutting
D. No deformation
Answer: A. Poor edge quality
Explanation: Incorrect clearance can increase burr formation and reduce cut quality.

Q88. Bending is primarily used to:
A. Change the shape/angle of sheet metal
B. Remove large amounts of material
C. Melt sheet metal
D. Cast a component
Answer: A. Change the shape/angle of sheet metal
Explanation: Bending plastically deforms the sheet around an axis.

Q89. Springback is particularly important in:
A. Sheet-metal bending
B. Sand casting
C. Cupola operation
D. Welding electrode coating
Answer: A. Sheet-metal bending
Explanation: Elastic recovery after bending changes the final angle and shape.

Q90. One method used to compensate for springback is:
A. Over-bending
B. Removing all tooling
C. Reducing all forces to zero
D. Increasing sheet thickness indefinitely
Answer: A. Over-bending
Explanation: The material can be bent slightly beyond the required angle so that elastic recovery brings it closer to the desired final angle.

Q91. Deep drawing uses:
A. Punch and die
B. Only rolling rolls
C. Only a hammer
D. A cupola
Answer: A. Punch and die
Explanation: The punch pushes the sheet blank into the die cavity to form the desired hollow shape.

Q92. A blank holder in deep drawing is used mainly to:
A. Control material flow and reduce wrinkling
B. Melt the blank
C. Increase casting shrinkage
D. Cut the blank completely
Answer: A. Control material flow and reduce wrinkling
Explanation: The blank holder controls the flange region during drawing.

Q93. Wrinkling in deep drawing is associated mainly with:
A. Compressive stresses in the flange
B. Tensile stress only
C. Melting
D. Welding
Answer: A. Compressive stresses in the flange
Explanation: Compressive circumferential stresses can cause the flange to buckle and form wrinkles.

Q94. Excessive tensile stress in deep drawing can cause:
A. Tearing
B. Wrinkling only
C. Embossing
D. Coining
Answer: A. Tearing
Explanation: Excessive drawing force can exceed the material’s forming capability and cause tearing.

Q95. Embossing is used to produce:
A. Raised or recessed patterns
B. Deep holes only
C. Cast cavities
D. Forging flash
Answer: A. Raised or recessed patterns
Explanation: Embossing forms localized raised or recessed features in sheet metal.

Q96. Coining involves:
A. High compressive pressure
B. Only tensile loading
C. Melting
D. Sand moulding
Answer: A. High compressive pressure
Explanation: Coining uses high pressure between dies to produce detailed impressions.

Q97. Which operation is used to produce a hollow cylindrical component from sheet metal?
A. Deep drawing
B. Rolling
C. Wire drawing
D. Open-die forging
Answer: A. Deep drawing
Explanation: Deep drawing converts a flat blank into a hollow shape.

Q98. Which of the following is NOT normally classified as a sheet-metal cutting operation?
A. Punching
B. Blanking
C. Shearing
D. Deep drawing
Answer: D. Deep drawing
Explanation: Deep drawing is a forming operation rather than a cutting operation.

Q99. Which operation produces the required blank by cutting it from a sheet?
A. Blanking
B. Drawing
C. Forging
D. Extrusion
Answer: A. Blanking
Explanation: The separated blank becomes the desired product.

Q100. Which operation produces a hole as the desired result?
A. Punching
B. Blanking
C. Rolling
D. Extrusion
Answer: A. Punching
Explanation: In punching, the hole is the required feature and the removed slug is generally scrap.

CHAPTER 6 — EXAM REVISION CAPSULE

Remember these pairs:

Rolling → Rolls

Forging → Compression

Extrusion → Push through die

Drawing → Pull through die

Blanking → Blank is product

Punching → Hole is product

Deep Drawing → Cup/hollow component

Bending → Sheet angle changes

Embossing → Raised/recessed design

Coining → High-pressure impression

Hot Working → Recrystallization during deformation

Cold Working → Work hardening

Springback → Elastic recovery

Important Numerical Formulae

Draft in Rolling

Percentage Reduction

Extrusion Ratio

WHERE:
= Initial cross-sectional area
= Final cross-sectional area

CHAPTER 7 — WELDING TECHNOLOGY

7.1 Introduction

Welding is one of the most important permanent joining processes used in manufacturing and workshop technology.
It is extensively used in:
Automobile manufacturing
Railway equipment
Bridges
Pressure vessels
Pipelines
Shipbuilding
Structural fabrication
Machine frames
Boilers
Storage tanks
Aerospace components
Unlike temporary fastening methods such as nuts and bolts, welding generally produces a permanent joint.

7.2 Definition of Welding

Welding is a permanent joining process in which two or mo

re materials are joined by applying heat, pressure, or a combination of heat and pressure, with or without the use of filler material.
Key Concept
Welding → Permanent joining → Heat/Pressure → Joint

7.3 Objectives of Welding

The main objectives are:
To permanently join two or more components.
To produce a strong joint.
To fabricate complex structures.
To repair damaged components.
To manufacture large structures economically.
To join similar or, with suitable processes, dissimilar materials.

7.4 Welding vs Brazing vs Soldering

These three processes are frequently asked in competitive examinations.

Process Basic Principle Filler Metal

Welding Base metals are joined by heat/pressure May or may not be used

Brazing Filler metal melts above 450°C Used

Soldering Filler metal melts below 450°C Used

Important

Brazing: Filler metal melting temperature is above 450°C but below the melting temperature of the base metals.

Soldering: Filler metal melting temperature is below 450°C.

7.5 Classification of Welding Processes

Welding processes can broadly be classified as:

A. Fusion Welding

The base metal is melted during joining.

Examples:

Gas welding

Arc welding

Thermit welding

Laser beam welding

Electron beam welding

B. Solid-State Welding

The base metals are joined without melting the base material.

Examples:

Forge welding

Friction welding

Diffusion welding

Ultrasonic welding

Explosive welding

7.6 Arc Welding

Arc welding uses an electric arc to generate heat for melting the workpiece and, where applicable, the electrode/filler.
The temperature of an electric arc is extremely high and is sufficient to melt many engineering metals.

7.7 Electric Arc

An electric arc is established between:
Electrode and workpiece, or
Two electrodes
The electrical energy is converted into heat energy.
Basic Principle
Electrical energy → Arc → Heat → Melting → Weld joint

7.8 Shielded Metal Arc Welding (SMAW)

SMAW is commonly known as:
Manual Metal Arc Welding (MMA/MMAW)
It uses a flux-coated consumable electrode.
Main Features
Electrode is consumable.
Electrode coating provides shielding.
Slag is formed.
Suitable for many fabrication applications.
Relatively portable.

7.9 Electrode

An electrode is the component through which electric current is supplied to establish the arc.
Electrodes may be:
Consumable
Non-consumable
Consumable Electrode
The electrode melts and becomes part of the weld metal.
Example:
SMAW electrode
Non-Consumable Electrode
The electrode does not normally become part of the weld.
Example:
TIG tungsten electrode

7.10 Flux

Flux is a material used during welding to assist in removing/preventing oxides and to help protect the molten weld pool.
Functions include:
Preventing atmospheric contamination
Removing oxides
Forming protective slag in relevant processes
Improving weld quality

7.11 Slag

Slag is a non-metallic layer formed over the weld during processes such as shielded metal arc welding.
It protects the molten/solidifying weld metal from atmospheric contamination.
After welding, slag may need to be removed.

7.12 Gas Welding

Gas welding uses heat generated by combustion of a fuel gas with oxygen or another oxidizer.
The most common traditional gas-welding process is:
Oxy-acetylene welding

7.13 Oxy-Acetylene Welding

Oxy-acetylene welding uses:
Oxygen
Acetylene
The gases are mixed and burned at the welding torch.
Applications
Sheet-metal work
Repair work
Pipe work
Cutting
Maintenance operations

7.14 Welding Flame

In oxy-acetylene welding, three important flame types are:
Neutral flame
Carburizing/reducing flame
Oxidizing flame

7.15 Neutral Flame

A neutral flame has approximately balanced oxygen and acetylene proportions.
It has:
Inner cone
Outer envelope
It is widely used for welding many steels and other metals.
Remember
Neutral flame → General-purpose flame

7.16 Carburizing Flame

A carburizing flame is also called a:
Reducing flame
It contains excess acetylene relative to oxygen.
It can introduce carbon-rich/reducing conditions and is useful for selected materials and applications.

7.17 Oxidizing Flame

An oxidizing flame contains excess oxygen.
It is used for specific materials such as certain copper alloys and is generally unsuitable for ordinary welding of steels because excessive oxidation can be harmful.
7.18 TIG Welding
TIG = Tungsten Inert Gas Welding

The modern process designation is:

Gas Tungsten Arc Welding (GTAW)

It uses a non-consumable tungsten electrode and an inert shielding gas.

Common shielding gases include:

Argon

Helium

Important

TIG → Tungsten electrode → Non-consumable

7.19 Advantages of TIG Welding

High-quality welds

Excellent control

Clean welds

No slag from flux-coated electrode

Suitable for thin materials

Suitable for many non-ferrous metals

7.20 MIG Welding

MIG = Metal Inert Gas Welding

It is commonly associated with:

Gas Metal Arc Welding (GMAW)

A continuously fed consumable wire electrode is used.

The shielding gas protects the weld pool from atmospheric contamination.

Important

MIG → Consumable wire electrode

7.21 MIG vs TIG

Feature	MIG	TIG
Electrode	Consumable wire	Non-consumable tungsten
Wire feed	Continuous	Separate filler may be used
Productivity	Generally high	Generally lower
Control	Good	Excellent
Typical use	Production	High-quality precision welding

7.22 Resistance Welding

Resistance welding generates heat due to the electrical resistance of the workpiece.

The heat generated is related to:

Where:

= heat

= current

= electrical resistance

= time

Principle

Electrical resistance → Heat → Pressure → Weld

7.23 Spot Welding

Spot welding is a resistance-welding process in which overlapping sheets are joined at discrete spots.

It is extensively used in:

Automobile bodies

Sheet-metal assemblies

Appliances

7.24 Seam Welding

Seam welding produces a series of overlapping weld nuggets, often forming a continuous or leak-tight seam.

It uses wheel-shaped electrodes.

7.25 Projection Welding

In projection welding, localized projections on one or both components concentrate current and pressure.

It is useful for:

Nuts

Fasteners

Sheet assemblies

7.26 Butt Welding

Butt welding joins components placed approximately end-to-end.

Resistance butt welding is one important form.

7.27 Thermit Welding

Thermit welding uses the heat generated by an exothermic chemical reaction.

A thermit mixture commonly involves:

Aluminium + Metal oxide

The reaction produces intense heat and molten metal.

Application

A famous application is:

Rail joining

7.28 Friction Welding

Friction welding is a solid-state welding process.

Heat is generated by friction between surfaces in relative motion.

After sufficient heating, pressure is applied to form the joint.

Important

Friction welding → Solid-state process

7.29 Ultrasonic Welding

Ultrasonic welding uses:

High-frequency mechanical vibrations

Pressure

It is a solid-state joining process.

It is commonly used for:

Thin sheets

Electrical/electronic components

Certain plastics and metals

7.30 Diffusion Welding

Diffusion welding is a solid-state process in which surfaces are joined under:

Pressure

Elevated temperature

Controlled conditions

Bonding occurs through atomic diffusion across the interface.

7.31 Welding Joints

Common welding joint types include:

Butt joint
Lap joint
T-joint
Corner joint
Edge joint

7.32 Butt Joint

In a butt joint, two components are placed approximately:

In the same plane, edge to edge.

7.33 Lap Joint

In a lap joint, two sheets:

Overlap each other.

7.34 T-Joint

A T-joint is formed when one component is positioned approximately perpendicular to another, producing a T-shaped configuration.

7.35 Corner Joint

A corner joint joins two components at a corner.

7.36 Edge Joint

In an edge joint, adjacent edges of two sheets are joined.

7.37 Welding Positions

Common welding positions are:

Flat

Horizontal

Vertical

Overhead

Most difficult among common positions

Overhead welding generally requires greater skill and control.

7.38 Weld Defects

Important welding defects include:

Porosity

Cracks

Undercut

Slag inclusion

Lack of fusion

Lack of penetration

Spatter

Distortion

Burn-through

7.39 Porosity

Porosity consists of cavities or gas pores trapped in the weld metal.

Possible causes include:

Moisture

Contamination

Inadequate shielding

Improper welding parameters

7.40 Undercut

Undercut is a groove formed along the edge/toe of a weld that is not properly filled with weld metal.

Possible causes:

Excessive current

Excessive travel speed

Incorrect electrode angle

7.41 Slag Inclusion

Slag inclusion occurs when non-metallic slag becomes trapped within the weld metal.

It may result from:

Inadequate cleaning between passes

Improper welding technique

Incorrect electrode manipulation

7.42 Lack of Fusion

Lack of fusion occurs when weld metal fails to properly fuse with:

Base metal, or

Previous weld bead

7.43 Lack of Penetration

Lack of penetration means that the weld does not extend sufficiently into the joint root.

7.44 Welding Distortion

Distortion occurs because of:

Uneven heating and cooling

Different regions expand and contract differently, producing dimensional changes.

7.45 Welding Safety

Important safety precautions include:

Use proper welding helmet.

Protect eyes from arc radiation.

Wear suitable gloves.

Use protective clothing.

Ensure proper ventilation.

Keep flammable materials away.

Inspect cables and equipment.

Handle gas cylinders correctly.

7.46 Quick Revision Table

Topic	Key Point
Welding	Permanent joining
SMAW	Consumable flux-coated electrode
TIG/GTAW	Non-consumable tungsten
MIG/GMAW	Consumable wire
Gas welding	Combustion of fuel gas
Neutral flame	Balanced oxygen-acetylene condition
Resistance welding
Spot welding	Individual weld spots
Seam welding	Continuous/overlapping seam
Thermit welding	Exothermic reaction
Friction welding	Solid-state
Ultrasonic welding	High-frequency vibration
Butt joint	Edge-to-edge
Lap joint	Overlapping sheets
T-joint	T-shaped arrangement
Porosity	Gas cavities
Undercut	Groove at weld toe
Slag inclusion	Slag trapped in weld
Distortion	Uneven heating/cooling

Q1. Welding is generally classified as a:

A. Temporary joining process
B. Permanent joining process
C. Measuring process
D. Surface finishing process

Answer: B. Permanent joining process

Explanation: Welding normally produces a permanent joint between components.

Q2. Which of the following is a fusion welding process?

A. Arc welding
B. Friction welding
C. Diffusion welding
D. Ultrasonic welding

Answer: A. Arc welding

Explanation: In arc welding, the base material is melted to form the joint.

Q3. Which of the following is a solid-state welding process?

A. Gas welding
B. Arc welding
C. Friction welding
D. Thermit welding

Answer: C. Friction welding

Explanation: Friction welding produces a joint without melting the base materials.

Q4. TIG welding uses:

A. Consumable tungsten electrode
B. Non-consumable tungsten electrode
C. Carbon dioxide electrode only
D. Copper electrode only

Answer: B. Non-consumable tungsten electrode

Explanation: TIG/GTAW uses a tungsten electrode that normally does not melt into the weld.

Q5. MIG welding generally uses:

A. Consumable wire electrode
B. Non-consumable tungsten electrode
C. No electrode
D. Carbon rod only

Answer: A. Consumable wire electrode

Explanation: GMAW/MIG uses a continuously fed consumable wire electrode.

Q6. The shielding gas commonly used in TIG welding is:

A. Argon
B. Oxygen only
C. Hydrogen only
D. Chlorine

Answer: A. Argon

Explanation: Argon is widely used as an inert shielding gas in TIG welding.

Q7. SMAW uses:

A. Flux-coated consumable electrode
B. Non-consumable tungsten only
C. Laser beam
D. Friction wheel

Answer: A. Flux-coated consumable electrode

Explanation: Shielded Metal Arc Welding uses a flux-coated consumable electrode.

Q8. The primary function of shielding gas is to:

A. Protect the molten weld pool from atmospheric contamination
B. Increase rusting
C. Cool the electrode completely
D. Produce mechanical chips

Answer: A. Protect the molten weld pool from atmospheric contamination

Explanation: Shielding prevents harmful reactions between the molten metal and atmospheric gases.

Q9. The heat generated in resistance welding is proportional to:

A.
B.
C.
D.

Answer: A.

Explanation:

This is the fundamental Joule-heating relationship used in resistance welding.

Q10. Spot welding is a type of:

A. Resistance welding
B. Gas welding
C. Thermit welding
D. Friction welding

Answer: A. Resistance welding

Explanation: Spot welding generates heat from electrical resistance and uses electrode pressure to make localized welds.

Q11. Seam welding commonly uses:

A. Wheel-shaped electrodes
B. Tungsten rods only
C. Gas nozzles only
D. Hammer dies

Answer: A. Wheel-shaped electrodes

Explanation: Rotating wheel electrodes are characteristic of resistance seam welding.

Q12. Thermit welding is based on:

A. Exothermic chemical reaction
B. Ultrasonic vibration
C. Friction only
D. Resistance heating only

Answer: A. Exothermic chemical reaction

Explanation: Thermit welding uses heat released by a highly exothermic chemical reaction.

Q13. Thermit welding is commonly associated with joining:

A. Railway rails
B. Thin plastic films
C. Wooden sheets
D. Glass fibres

Answer: A. Railway rails

Explanation: Thermit welding is traditionally used for field joining and repair of railway rails.

Q14. Friction welding is classified as:

A. Solid-state welding
B. Fusion welding
C. Gas welding
D. Arc cutting

Answer: A. Solid-state welding

Explanation: The materials are joined without melting the base metals.

Q15. In brazing, the filler metal melts at a temperature:

A. Below 450°C
B. Above 450°C but below the melting temperature of the base metals
C. Above the melting temperature of the base metals
D. Exactly 0°C

Answer: B. Above 450°C but below the melting temperature of the base metals

Explanation: This temperature criterion distinguishes conventional brazing from soldering.

Q16. Soldering generally uses a filler metal melting below:

A. 100°C
B. 250°C
C. 450°C
D. 1000°C

Answer: C. 450°C

Explanation: Conventional classification defines soldering as using filler metal with a melting temperature below 450°C.

Q17. A joint in which two sheets overlap each other is called:

A. Butt joint
B. Lap joint
C. T-joint
D. Edge joint

Answer: B. Lap joint

Explanation: In a lap joint, one component overlaps the other.

Q18. Which welding position is generally considered most difficult among the standard basic positions?

A. Flat
B. Horizontal
C. Vertical
D. Overhead

Answer: D. Overhead

Explanation: Overhead welding requires greater control because molten metal tends to fall under gravity.

Q19. Gas cavities in a weld are known as:

A. Porosity
B. Undercut
C. Overlap
D. Distortion

Answer: A. Porosity

Explanation: Porosity results from gas becoming trapped in the solidifying weld metal.

Q20. A groove formed at the toe of a weld is called:

A. Porosity
B. Undercut
C. Slag inclusion
D. Crack

Answer: B. Undercut

Explanation: Undercut is a groove along the weld toe that reduces the effective section of the joint.

MCQ 21–40: Arc Welding & Electrodes

Q21. In arc welding, the heat required for welding is generated by:

A. Chemical reaction only
B. Electric arc
C. Mechanical friction only
D. Steam pressure

Answer: B. Electric arc

Explanation: An electric arc produces intense heat that melts the base metal and/or electrode.

Q22. Which of the following is a consumable electrode process?

A. TIG
B. SMAW
C. Carbon arc welding
D. Plasma arc welding with non-consumable electrode

Answer: B. SMAW

Explanation: Shielded Metal Arc Welding uses a flux-coated consumable electrode that melts during welding.

Practice

Q23. The coating on a shielded metal arc welding electrode primarily helps to:

A. Increase electrical resistance of the workpiece
B. Provide shielding and form slag
C. Prevent melting of the electrode
D. Remove the base metal

Answer: B. Provide shielding and form slag

Explanation: Electrode coating produces gases and slag that protect the molten weld pool.

Q24. The core wire of a coated electrode mainly acts as:

A. Insulator
B. Filler metal and current carrier
C. Coolant
D. Shielding gas

Answer: B. Filler metal and current carrier

Explanation: The metal core conducts welding current and melts to contribute to the weld.

Q25. The arc length in arc welding is the distance between:

A. Electrode and workpiece
B. Two workpieces
C. Welding machine and electrode
D. Ground and machine

Answer: A. Electrode and workpiece

Explanation: Arc length refers to the distance across the electrical arc between the electrode tip and workpiece.

Q26. Excessively long arc length may result in:

A. Increased spatter and poor weld quality
B. Perfect penetration in all cases
C. No arc formation
D. Zero heat input

Answer: A. Increased spatter and poor weld quality

Explanation: Excessive arc length can make the arc unstable and increase spatter and atmospheric contamination.

Q27. If the welding current is excessively high, it may cause:

A. Excessive penetration and undercut
B. No melting
C. Zero heat generation
D. Complete elimination of distortion

Answer: A. Excessive penetration and undercut

Explanation: Excessive current increases heat input and can cause excessive melting, undercut and burn-through.

Q28. Welding current is measured in:

A. Volt
B. Ampere
C. Ohm
D. Watt-hour

Answer: B. Ampere

Explanation: Welding current is expressed in amperes (A).

Q29. Welding voltage is measured in:

A. Ampere
B. Volt
C. Ohm
D. Coulomb

Answer: B. Volt

Explanation: Arc voltage is measured in volts.

Q30. The electrode holder in manual arc welding is used to:

A. Hold the electrode and conduct current
B. Supply shielding gas only
C. Cool the weld pool
D. Cut the workpiece

Answer: A. Hold the electrode and conduct current

Explanation: The electrode holder mechanically holds the electrode and provides electrical connection.

Q31. The welding cable carries:

A. Welding current
B. Cooling water only
C. Acetylene only
D. Slag

Answer: A. Welding current

Explanation: Welding cables connect the power source to the electrode holder and workpiece.

Q32. The return cable in arc welding connects the:

A. Workpiece to the welding power source
B. Electrode to gas cylinder
C. Torch to regulator only
D. Die to punch

Answer: A. Workpiece to the welding power source

Explanation: The return circuit completes the electrical path required for arc welding.

Q33. Arc welding power sources may provide:

A. AC or DC
B. Only hydraulic pressure
C. Only compressed air
D. Only steam

Answer: A. AC or DC

Explanation: Depending on the welding process and application, alternating or direct current can be used.

Q34. DC welding allows control of:

A. Polarity
B. Atmospheric pressure
C. Room temperature
D. Metal density

Answer: A. Polarity

Explanation: With DC, the electrode can be connected as positive or negative depending on the required welding characteristics.

Q35. DCEP means:

A. Direct Current Electrode Positive
B. Direct Current Electrode Pressure
C. Direct Current Energy Process
D. Direct Current External Power

Answer: A. Direct Current Electrode Positive

Explanation: In DCEP, the electrode is connected to the positive terminal of the DC power source.

Q36. DCEN means:

A. Direct Current Electrode Negative
B. Direct Current Energy Neutral
C. Direct Current Electrode Normal
D. Direct Current External Negative

Answer: A. Direct Current Electrode Negative

Explanation: In DCEN, the electrode is connected to the negative terminal.

Q37. Which electrode is used in TIG welding?

A. Tungsten
B. Mild steel wire only
C. Copper wire only
D. Aluminium strip only

Answer: A. Tungsten

Explanation: TIG uses a non-consumable tungsten electrode.

Q38. The main function of shielding in arc welding is to protect the molten metal from:

A. Atmospheric gases
B. Mechanical vibration
C. Cutting forces
D. Rolling forces

Answer: A. Atmospheric gases

Explanation: Oxygen and nitrogen from the atmosphere can adversely affect weld quality.

Q39. Which of the following is NOT normally a function of electrode coating?

A. Shielding
B. Slag formation
C. Arc stabilization
D. Increasing workpiece weight

Answer: D. Increasing workpiece weight

Explanation: Electrode coating can provide shielding, slag and arc-stabilizing compounds, but it does not serve to increase workpiece weight.

Q40. Slag formed during SMAW should generally be:

A. Removed after welding/pass completion as appropriate
B. Permanently left on every weld
C. Melted into the workpiece manually
D. Used as cutting fluid

Answer: A. Removed after welding/pass completion as appropriate

Explanation: Slag must be removed where required, particularly between passes, to avoid slag inclusion.

MCQ 41–60: TIG, MIG & Gas Welding

Q41. TIG welding is also known as:

A. GTAW
B. GMAW
C. SMAW
D. SAW

Answer: A. GTAW

Explanation: TIG corresponds to Gas Tungsten Arc Welding (GTAW).

Q42. MIG welding is commonly classified as:

A. GMAW
B. GTAW
C. SAW
D. PAW only

Answer: A. GMAW

Explanation: MIG is commonly used to describe Gas Metal Arc Welding.

Q43. In MIG welding, the electrode is:

A. Continuously fed consumable wire
B. Non-consumable tungsten
C. Carbon block only
D. Ceramic rod

Answer: A. Continuously fed consumable wire

Explanation: A continuous wire electrode serves as both electrode and filler metal.

Q44. One major advantage of MIG welding is:

A. High deposition rate
B. No need for shielding
C. No electrical power required
D. No electrode consumption

Answer: A. High deposition rate

Explanation: Continuous wire feeding enables high productivity.

Q45. TIG welding is especially suitable where:

A. High-quality and precise weld control is required
B. Maximum slag production is required
C. No shielding is required
D. Only impact loading is used

Answer: A. High-quality and precise weld control is required

Explanation: TIG offers excellent control of the arc and weld pool.

Q46. The most common shielding gases for TIG include:

A. Argon and helium
B. Oxygen and hydrogen
C. Chlorine and fluorine
D. Nitrogen only

Answer: A. Argon and helium

Explanation: Argon and helium are inert gases widely used for GTAW/TIG.

Q47. In MIG welding, shielding gas is supplied through the:

A. Welding gun/torch
B. Hammer
C. Die
D. Electrode coating only

Answer: A. Welding gun/torch

Explanation: Shielding gas flows through the welding gun nozzle around the arc and weld pool.

Q48. A major disadvantage of TIG compared with MIG is generally:

A. Lower productivity
B. No arc control
C. No shielding gas
D. No usable electrode

Answer: A. Lower productivity

Explanation: TIG is highly controllable but generally has a lower deposition rate than continuous-wire MIG.

Q49. Oxy-acetylene welding uses:

A. Oxygen and acetylene
B. Nitrogen and oxygen
C. Hydrogen and nitrogen
D. Argon and helium

Answer: A. Oxygen and acetylene

Explanation: The mixture of oxygen and acetylene produces the welding flame.

Q50. The main components of a conventional oxy-acetylene welding setup include:

A. Gas cylinders, regulators, hoses and torch
B. Rolling mill and furnace only
C. Punch and die only
D. Hammer and anvil only

Answer: A. Gas cylinders, regulators, hoses and torch

Explanation: These components control and deliver oxygen and fuel gas to the welding torch.

Q51. The regulator in gas welding is used to:

A. Control gas pressure
B. Produce an electric arc
C. Remove slag
D. Cut threads

Answer: A. Control gas pressure

Explanation: Regulators reduce cylinder pressure to the required working pressure.

Q52. The purpose of a welding torch is to:

A. Mix and control gases to produce the flame
B. Measure weld hardness
C. Roll sheet metal
D. Produce forging flash

Answer: A. Mix and control gases to produce the flame

Explanation: The torch controls the flow and mixing of oxygen and fuel gas.

Q53. A neutral oxy-acetylene flame has:

A. Approximately balanced oxygen and acetylene
B. Large excess oxygen
C. Large excess acetylene only
D. No oxygen

Answer: A. Approximately balanced oxygen and acetylene

Explanation: A neutral flame has approximately balanced proportions and is widely used for general welding.

Q54. An oxidizing flame contains:

A. Excess oxygen
B. Excess acetylene
C. No oxygen
D. Only nitrogen

Answer: A. Excess oxygen

Explanation: Increasing oxygen relative to acetylene produces an oxidizing flame.

Q55. A carburizing flame is also called:

A. Reducing flame
B. Oxidizing flame
C. Neutral flame
D. Plasma flame

Answer: A. Reducing flame

Explanation: A carburizing flame contains excess fuel and has a reducing/carburizing character.

Q56. The most commonly used general-purpose flame for oxy-acetylene welding is:

A. Neutral flame
B. Oxidizing flame
C. Strongly carburizing flame
D. Plasma flame

Answer: A. Neutral flame

Explanation: Neutral flame is suitable for welding many common engineering materials.

Q57. Oxygen cylinders should generally be kept away from:

A. Oil and grease contamination
B. Clean metal surfaces
C. Welding helmets
D. Steel plates

Answer: A. Oil and grease contamination

Explanation: Oxygen supports combustion strongly, so contact with oil/grease can create a serious fire hazard.

Q58. Acetylene cylinders should be:

A. Handled and stored according to approved safety procedures
B. Exposed to uncontrolled heat
C. Placed beside open flames
D. Used without regulators

Answer: A. Handled and stored according to approved safety procedures

Explanation: Fuel-gas cylinders require controlled storage, handling and pressure regulation.

Q59. In gas welding, the flame provides:

A. Heat for melting the joint region
B. Mechanical pressure only
C. Electrical current only
D. Cutting chips

Answer: A. Heat for melting the joint region

Explanation: Combustion of the gases generates the heat required for fusion welding.

Q60. Gas welding is particularly useful for:

A. Repair and relatively thin-material applications
B. Only very large forgings
C. High-speed rolling
D. Powder metallurgy

Answer: A. Repair and relatively thin-material applications

Explanation: Gas welding provides relatively controllable heat and is widely used for maintenance and repair work.

MCQ 61–80: Resistance Welding & Welding Joints

Q61. Resistance welding generates heat mainly because of:

A. Electrical resistance
B. Chemical combustion
C. Mechanical cutting
D. Laser reflection only

Answer: A. Electrical resistance

Explanation: Electrical current passing through resistance generates heat according to .

Q62. The basic heat equation for resistance welding is:

A.
B.
C.
D.

Answer: A.

Explanation: This is Joule’s law of heating.

Q63. Spot welding is most commonly used for:

A. Overlapping sheet metals
B. Large solid shafts
C. Sand casting
D. Thread cutting

Answer: A. Overlapping sheet metals

Explanation: Spot welding produces localized weld nuggets between overlapping sheets.

Q64. The electrodes used in resistance spot welding are generally:

A. Copper-alloy electrodes
B. Wooden electrodes
C. Tungsten cutting tools only
D. Ceramic electrodes only

Answer: A. Copper-alloy electrodes

Explanation: Copper alloys provide good electrical and thermal conductivity along with suitable strength.

Q65. In resistance spot welding, pressure is applied by:

A. Electrodes
B. Gas cylinder
C. Welding helmet
D. Slag hammer

Answer: A. Electrodes

Explanation: The electrodes press the sheets together while current passes through the joint.

Q66. Seam welding uses:

A. Wheel electrodes
B. Flat dies only
C. Hammer blows
D. Gas nozzles only

Answer: A. Wheel electrodes

Explanation: Rotating wheel electrodes create a sequence of overlapping weld spots.

Q67. Projection welding differs from spot welding because:

A. Projections concentrate current and pressure
B. No current is used
C. No pressure is used
D. It requires a gas flame

Answer: A. Projections concentrate current and pressure

Explanation: Designed projections localize the welding action.

Q68. Resistance welding generally requires:

A. Electrical current and electrode pressure
B. Only a gas flame
C. Only a hammer
D. Only filler rod

Answer: A. Electrical current and electrode pressure

Explanation: Heat is generated electrically and pressure ensures proper contact and forging of the weld region.

Q69. Which joint has two plates approximately in the same plane?

A. Butt joint
B. Lap joint
C. T-joint
D. Corner joint

Answer: A. Butt joint

Explanation: Butt joints join members edge-to-edge.

Q70. Which joint has overlapping plates?

A. Lap joint
B. Butt joint
C. Edge joint
D. T-joint

Answer: A. Lap joint

Explanation: One sheet overlaps another in a lap joint.

Q71. A T-joint has approximately:

A. 90° intersection between members
B. 0° intersection
C. 180° overlap only
D. Circular intersection

Answer: A. 90° intersection between members

Explanation: One component is generally positioned perpendicular to another, creating a T configuration.

Q72. A corner joint is formed:

A. At the corner of two members
B. Only at the centre of a sheet
C. Between two wires only
D. Inside a casting mould

Answer: A. At the corner of two members

Explanation: The members meet at a corner configuration.

Q73. Which joint is commonly used when two plates are to be joined edge-to-edge?

A. Butt joint
B. Lap joint
C. Projection joint
D. Spot joint only

Answer: A. Butt joint

Explanation: Butt joints are specifically intended for edge-to-edge joining.

Q74. Which of the following is NOT a standard basic welding position?

A. Flat
B. Horizontal
C. Vertical
D. Circular

Answer: D. Circular

Explanation: Flat, horizontal, vertical and overhead are standard basic welding positions.

Q75. Overhead welding means welding:

A. From below a joint
B. Only on a horizontal plate
C. Under water only
D. Inside a furnace

Answer: A. From below a joint

Explanation: In overhead welding, the weld is made on the underside of the workpiece.

Q76. Welding position affects:

A. Welder technique and molten-metal control
B. Atomic number
C. Material density
D. Melting point permanently

Answer: A. Welder technique and molten-metal control

Explanation: Gravity affects the molten pool differently in different positions.

Q77. Which resistance welding process uses individual localized welds?

A. Spot welding
B. Seam welding
C. Butt welding only
D. Flash welding only

Answer: A. Spot welding

Explanation: Spot welding creates discrete weld nuggets at selected locations.

Q78. Which resistance process can produce a continuous leak-tight joint?

A. Seam welding
B. Spot welding only
C. Projection welding only
D. Upset forging

Answer: A. Seam welding

Explanation: Overlapping weld nuggets can form a continuous seam suitable for leak-resistant applications.

Q79. Projection welding is commonly used for joining:

A. Nuts to sheet metal
B. Railway rails by thermit only
C. Plastic films only
D. Wooden blocks

Answer: A. Nuts to sheet metal

Explanation: Projections on nuts or components concentrate the current and pressure during welding.

Q80. Resistance welding is particularly suitable for:

A. High-volume sheet-metal production
B. Only one-off heavy forgings
C. Sand mould preparation
D. Gear cutting

Answer: A. High-volume sheet-metal production

Explanation: Resistance welding is fast and readily automated, making it suitable for mass production.

MCQ 81–100: Welding Defects, Inspection & Safety

Q81. Gas cavities trapped inside weld metal are called:

A. Porosity
B. Undercut
C. Overlap
D. Distortion

Answer: A. Porosity

Explanation: Porosity consists of voids caused by trapped gas.

Q82. Slag trapped inside the weld is called:

A. Slag inclusion
B. Porosity
C. Undercut
D. Burn-through

Answer: A. Slag inclusion

Explanation: Non-metallic slag becomes trapped within the weld metal.

Q83. Failure of weld metal to properly fuse with the base metal is:

A. Lack of fusion
B. Porosity
C. Spatter
D. Distortion

Answer: A. Lack of fusion

Explanation: Lack of fusion occurs when the weld metal does not properly bond with the parent material.

Q84. Insufficient depth of fusion at the root is known as:

A. Lack of penetration
B. Undercut
C. Porosity
D. Cratering

Answer: A. Lack of penetration

Explanation: The weld does not extend sufficiently into the root of the joint.

Q85. A groove along the weld toe is called:

A. Undercut
B. Porosity
C. Slag inclusion
D. Crack

Answer: A. Undercut

Explanation: Undercut removes base metal at the weld toe without adequate filling.

Q86. Uneven heating and cooling during welding may cause:

A. Distortion
B. Increased density
C. Perfect dimensional accuracy
D. No residual stress

Answer: A. Distortion

Explanation: Local thermal expansion and contraction produce distortion and residual stresses.

Q87. Excessive welding current may contribute to:

A. Undercut and excessive penetration
B. No melting
C. Zero heat input
D. No weld formation

Answer: A. Undercut and excessive penetration

Explanation: Excessive current produces excessive heat and can damage the joint edges.

Q88. Moisture in welding electrodes can contribute to:

A. Hydrogen-related weld problems
B. Improved weld quality in every case
C. Zero porosity
D. Lower atmospheric contamination

Answer: A. Hydrogen-related weld problems

Explanation: Moisture can introduce hydrogen into the weld, increasing the risk of cracking in susceptible materials.

Q89. Weld cracks are considered:

A. Serious welding defects
B. Normal decorative features
C. Useful shielding layers
D. Types of flux

Answer: A. Serious welding defects

Explanation: Cracks can severely reduce the integrity and service life of a welded component.

Q90. Weld inspection is performed mainly to:

A. Detect defects and verify weld quality
B. Increase fuel consumption
C. Melt the weld again
D. Remove all base metal

Answer: A. Detect defects and verify weld quality

Explanation: Inspection determines whether welds satisfy specified quality requirements.

Q91. Which is a non-destructive testing method?

A. Radiographic testing
B. Tensile testing to fracture
C. Bend testing to failure
D. Machining test

Answer: A. Radiographic testing

Explanation: Radiography can inspect internal discontinuities without destroying the component.

Q92. Ultrasonic testing uses:

A. High-frequency sound waves
B. Electric sparks only
C. Chemical flames
D. Cutting tools

Answer: A. High-frequency sound waves

Explanation: Ultrasonic testing detects internal discontinuities through reflected sound waves.

Q93. Dye penetrant testing is mainly used to detect:

A. Surface-breaking defects
B. Deep internal defects only
C. Material density
D. Melting temperature

Answer: A. Surface-breaking defects

Explanation: Penetrant enters open-to-surface cracks and discontinuities.

Q94. Magnetic particle testing is suitable for detecting surface and near-surface defects in:

A. Ferromagnetic materials
B. All plastics
C. Glass only
D. Wood only

Answer: A. Ferromagnetic materials

Explanation: The method relies on magnetic flux leakage and is therefore suited to ferromagnetic materials.

Q95. A welding helmet primarily protects the:

A. Eyes and face
B. Feet only
C. Welding machine
D. Gas cylinder

Answer: A. Eyes and face

Explanation: The helmet protects against intense arc radiation, sparks and molten metal.

Q96. Welding fumes should be controlled by:

A. Adequate ventilation/fume extraction
B. Closing all ventilation openings
C. Increasing smoke concentration
D. Removing the helmet

Answer: A. Adequate ventilation/fume extraction

Explanation: Proper ventilation reduces exposure to harmful welding fumes and gases.

Q97. One important electrical safety precaution is to:

A. Inspect cables and connections
B. Use damaged cables
C. Touch live conductors
D. Weld in standing water

Answer: A. Inspect cables and connections

Explanation: Damaged insulation or connections can create electric-shock and fire hazards.

Q98. Welding near flammable materials should be:

A. Avoided or controlled using appropriate precautions
B. Encouraged
C. Performed without a fire watch
D. Performed beside fuel containers

Answer: A. Avoided or controlled using appropriate precautions

Explanation: Sparks and hot metal can ignite combustible materials.

Q99. The main purpose of welding symbols on engineering drawings is to:

A. Communicate weld type, location and requirements
B. Show material density
C. Indicate machine weight
D. Specify workshop temperature only

Answer: A. Communicate weld type, location and requirements

Explanation: Standard welding symbols provide manufacturing information to the fabricator.

Q100. Which statement is correct?

A. Welding safety is optional
B. Proper PPE and ventilation are essential
C. Welding helmets are unnecessary
D. Gas cylinders can be handled carelessly

Answer: B. Proper PPE and ventilation are essential

Explanation: Welding involves electrical, thermal, radiation, fumes and fire hazards, so proper safety practices are essential.

CHAPTER 7 — ONE-PAGE EXAM REVISION

Welding Process → Key Feature

SMAW → Flux-coated consumable electrode

TIG/GTAW → Non-consumable tungsten electrode

MIG/GMAW → Continuously fed consumable wire

Gas welding → Combustion flame

Spot welding → Individual weld nuggets

Seam welding → Wheel electrodes

Projection welding → Projections concentrate current

Thermit welding → Exothermic chemical reaction

Friction welding → Solid-state + friction

Ultrasonic welding → High-frequency vibration

Resistance welding →

Flame → Identification

Neutral → Approximately balanced

Oxidizing → Excess oxygen

Carburizing → Excess fuel / reducing character

Defect → Meaning

Porosity → Gas cavities

Slag inclusion → Trapped slag

Undercut → Groove at weld toe

Lack of fusion → Inadequate fusion

Lack of penetration → Inadequate root penetration

Crack → Fracture/discontinuity

Distortion → Dimensional change due to thermal effects

Top of Form

Bottom of Form

CHAPTER 8 — FOUNDRY & CASTING TECHNOLOGY

8.1 Introduction

Casting is one of the oldest and most important manufacturing processes. It is widely used for producing components having complex shapes, internal cavities, large dimensions, and intricate geometries.

Casting is extensively used in:

Automobile industries

Machine-tool industries

Railway equipment

Agricultural machinery

Pumps and valves

Engines

Turbines

Industrial machinery

Aerospace components

Defence equipment

The basic idea is simple:

Melt the metal → Pour into mould → Allow it to solidify → Remove casting

8.2 Definition of Casting

Casting is a manufacturing process in which molten material is poured into a mould cavity of the desired shape and allowed to solidify.

After solidification, the solidified product is removed from the mould and subjected to finishing operations if required.

Key Concept

Casting = Melting + Pouring + Solidification + Removal

8.3 What is a Foundry?

A foundry is a manufacturing facility where metal castings are produced.

Typical foundry operations include:

Pattern making
Mould preparation
Core making
Melting
Pouring
Solidification
Shakeout
Fettling
Inspection

8.4 Basic Steps of Casting

The general sequence is:

Step 1 — Pattern Making

A pattern representing the desired casting is prepared.

Step 2 — Mould Making

The pattern is used to create the mould cavity.

Step 3 — Core Making

Cores are inserted when internal holes or cavities are required.

Step 4 — Melting

The metal is heated above its required melting temperature.

Step 5 — Pouring

Molten metal is poured into the mould cavity.

Step 6 — Solidification

The molten metal cools and becomes solid.

Step 7 — Shakeout

The casting is removed from the mould.

Step 8 — Fettling

Extra material such as gates, runners and risers is removed and the casting is cleaned.

Step 9 — Inspection

The finished casting is inspected for defects and dimensional accuracy.

8.5 Pattern

A pattern is a replica or representation of the desired casting used to form the mould cavity.

The pattern is not necessarily identical in dimensions to the final casting because allowances are generally provided.

8.6 Functions of a Pattern

The main functions of a pattern are:

To create the mould cavity

To reproduce the required shape

To provide necessary allowances

To facilitate moulding

To provide provisions for cores where required

8.7 Pattern Materials

Patterns may be made from:

Wood

Metal

Plastic

Plaster

Wax

Other suitable materials

Wooden Patterns

Advantages:

Cheap

Easy to manufacture

Lightweight

Easy to modify

Disadvantages:

Wear relatively quickly

Absorb moisture

Less durable than metal patterns

8.8 Metal Patterns

Common pattern metals include:

Aluminium alloys

Cast iron

Brass

Bronze

Steel

Metal patterns are generally:

Stronger

More durable

More dimensionally stable

They are suitable for larger production quantities.

8.9 Pattern Allowances

A pattern is generally modified from the exact final casting dimensions because of various manufacturing considerations.

Important pattern allowances include:

Shrinkage allowance
Machining allowance
Draft allowance
Distortion allowance
Rapping/shake allowance

8.10 Shrinkage Allowance

Most metals shrink during solidification and cooling.

Therefore, the pattern is generally made larger than the required final casting dimensions to compensate for shrinkage.

Important

Shrinkage allowance → Positive allowance

8.11 Machining Allowance

Additional material is provided on surfaces that will later be machined.

Purpose

To allow removal of:

Surface irregularities

Oxidized material

Dimensional inaccuracies

Casting skin

Important

Machining allowance → Extra metal for machining

8.12 Draft Allowance

A slight taper is provided on pattern surfaces to facilitate easy removal of the pattern from the mould.

Without adequate draft, the mould cavity may be damaged during pattern withdrawal.

Important

Draft → Easy pattern withdrawal

8.13 Distortion Allowance

Some castings may distort during cooling because of uneven contraction.

In such cases, the pattern can be intentionally distorted in the opposite direction to compensate for expected distortion.

8.14 Shake or Rapping Allowance

When a pattern is loosened by rapping before removal, the mould cavity can become slightly larger.

Therefore, the pattern may require a negative allowance to compensate for this effect.

Important

Rapping allowance → Negative allowance

8.15 Types of Patterns

Important types include:

Single-piece pattern

Split pattern

Match-plate pattern

Cope-and-drag pattern

Loose-piece pattern

Sweep pattern

Skeleton pattern

Segmental pattern

Gated pattern

Follow-board pattern

8.16 Single-Piece Pattern

A single-piece pattern consists of one solid piece.

It is generally suitable for:

Simple shapes

Small production quantities

Simple moulding operations

8.17 Split Pattern

A split pattern is divided into two or more parts.

The division is generally made along the parting line.

Advantage

It facilitates removal of the pattern from the mould.

8.18 Match-Plate Pattern

A match-plate pattern has pattern halves mounted on opposite sides of a plate.

The plate provides the parting surface.

Application

It is particularly useful for:

Mass production of small and medium castings.

8.19 Loose-Piece Pattern

A loose-piece pattern contains detachable portions that allow difficult projections or undercuts to be moulded and the pattern to be removed.

8.20 Sweep Pattern

A sweep pattern consists of a specially shaped board that is rotated around an axis to generate a mould cavity.

It is useful for:

Large axisymmetric castings

Large simple shapes

8.21 Skeleton Pattern

A skeleton pattern consists of a framework representing the shape of the casting.

It is economical for:

Large castings produced in small quantities.

8.22 Mould

A mould is a cavity or form into which molten metal is poured to produce the desired casting.

Moulds may be:

Expendable

Permanent

8.23 Expendable Mould

An expendable mould is normally destroyed during removal of the casting.

Examples:

Sand mould

Plaster mould

Ceramic mould

Main advantage

Complex shapes can be produced relatively easily.

8.24 Permanent Mould

A permanent mould can be reused for producing many castings.

It is generally made from:

Cast iron

Steel

Other heat-resistant materials

Examples:

Permanent mould casting

Die casting

8.25 Moulding Sand

Moulding sand is used to produce the mould cavity in sand casting.

Important properties include:

Refractoriness
Permeability
Strength
Flowability
Plasticity
Adhesiveness
Cohesiveness
Collapsibility

8.26 Refractoriness

Refractoriness is the ability of moulding sand to withstand high temperature without melting or losing its essential properties.

Remember:

Refractoriness → Resistance to high temperature

8.27 Permeability

Permeability is the ability of moulding sand to allow gases and vapours to pass through it.

Why important?

During pouring and solidification, gases are generated. If they cannot escape, they can cause defects such as blowholes and gas porosity.

8.28 Strength

Moulding sand must have sufficient strength to:

Maintain mould shape

Resist erosion

Withstand handling

Resist pressure during pouring

8.29 Cohesiveness

Cohesiveness is the ability of sand particles to stick to one another.

It helps the mould maintain its shape.

8.30 Adhesiveness

Adhesiveness is the ability of moulding sand to stick to the surface of the moulding box or other surfaces.

8.31 Collapsibility

Collapsibility is the ability of moulding sand to break down or yield after solidification of the casting.

It helps prevent excessive resistance to contraction and reduces the risk of hot tearing.

8.32 Green Sand

Green sand is a commonly used moulding sand containing:

Sand

Clay/binder

Water

Other additives as required

The term green refers to the fact that the mould contains moisture and is generally used in the moist condition.

8.33 Dry Sand Mould

A dry sand mould is dried or baked before pouring.

Compared with green sand moulds, dry sand moulds generally have:

Higher strength

Better dimensional stability

Higher cost

8.34 Core

A core is used to produce internal cavities or holes in a casting.

Example

If a casting requires an internal passage, a core can be placed inside the mould cavity before pouring.

Key Concept

Core → Internal cavity

8.35 Core Print

A core print is a projection or recess provided on the pattern/moulding arrangement to locate and support the core.

8.36 Gating System

The gating system is the passage system through which molten metal flows from the pouring basin to the mould cavity.

Typical components include:

Pouring basin

Sprue

Runner

Gate

Riser

8.37 Pouring Basin

The pouring basin receives molten metal from the ladle and directs it toward the sprue.

It helps provide controlled entry of molten metal.

8.38 Sprue

The sprue is the vertical passage through which molten metal flows downward from the pouring basin.

In many conventional systems, it also helps provide a smooth flow path and may be tapered to reduce aspiration.

8.39 Runner

The runner is a horizontal or approximately horizontal passage that carries molten metal from the sprue toward the gates.

8.40 Gate

A gate is the passage through which molten metal enters the mould cavity from the runner.

8.41 Riser

A riser, also called a feeder, is a reservoir of molten metal that supplies additional metal to the casting during solidification.

Main function

Compensate for solidification shrinkage.

8.42 Casting Defects

Important casting defects include:

Blowholes

Porosity

Shrinkage cavity

Misrun

Cold shut

Hot tears

Sand inclusion

Metal penetration

Mould shift

Core shift

Fins

Scabs

8.43 Misrun

A misrun occurs when molten metal fails to completely fill the mould cavity before solidifying.

Possible causes:

Low pouring temperature

Insufficient fluidity

Slow pouring

Thin sections

Poor gating design

8.44 Cold Shut

A cold shut occurs when two streams of molten metal meet but fail to fuse properly.

It appears as a seam or line on the casting.

8.45 Shrinkage Cavity

Shrinkage cavity results from insufficient feeding of molten metal during solidification.

A properly designed riser helps reduce this defect.

8.46 Blowholes

Blowholes are relatively large cavities caused by gases trapped within the casting.

Possible causes include:

Poor mould permeability

Excess moisture

Improper venting

8.47 Hot Tears

Hot tears are cracks formed during the final stages of solidification when the metal is unable to contract freely.

Poor collapsibility of the mould/core can contribute to hot tearing.

8.48 Fettling

Fettling includes cleaning and finishing operations performed after casting removal.

Typical operations include:

Removing gates

Removing risers

Removing fins

Cleaning sand

Grinding rough surfaces

8.49 Cupola Furnace

The cupola furnace is traditionally used for melting:

Cast iron

It is a vertical shaft furnace used extensively in foundries.

8.50 Important Casting Revision

Term	Key Point
Pattern	Forms mould cavity
Shrinkage allowance	Compensates for shrinkage
Machining allowance	Extra metal for machining
Draft allowance	Easy pattern withdrawal
Rapping allowance	Usually negative
Core	Internal cavity
Core print	Supports/locates core
Refractoriness	Withstands high temperature
Permeability	Allows gases to escape
Collapsibility	Allows mould to yield after solidification
Sprue	Vertical passage
Runner	Carries metal toward gates
Gate	Entry into cavity
Riser	Feeds metal during solidification
Misrun	Incomplete filling
Cold shut	Streams fail to fuse
Blowhole	Gas cavity
Hot tear	Crack during solidification
Fettling	Cleaning/finishing
Cupola	Traditionally melts cast iron

Q1. Casting is a process in which molten metal is:

A. Rolled into sheets
B. Poured into a mould and solidified
C. Forged between dies
D. Cut by a tool

Answer: B. Poured into a mould and solidified

Explanation: Casting produces a component by pouring molten material into a mould cavity and allowing it to solidify.

Q2. A foundry is primarily concerned with:

A. Casting production
B. Thread cutting
C. Gear hobbing only
D. Sheet rolling only

Answer: A. Casting production

Explanation: A foundry is a facility where metal melting, moulding, pouring and casting operations are performed.

Q3. The replica used to form the mould cavity is called:

A. Core
B. Pattern
C. Riser
D. Runner

Answer: B. Pattern

Explanation: The pattern represents the shape of the desired casting and is used to form the mould cavity.

Q4. Which allowance compensates for metal contraction during cooling?

A. Draft allowance
B. Shrinkage allowance
C. Machining allowance
D. Rapping allowance

Answer: B. Shrinkage allowance

Explanation: The pattern is enlarged to compensate for contraction of the metal during solidification and cooling.

Q5. Draft allowance is provided mainly to:

A. Facilitate pattern removal
B. Increase metal hardness
C. Reduce melting temperature
D. Increase mould moisture

Answer: A. Facilitate pattern removal

Explanation: A slight taper allows the pattern to be withdrawn without damaging the mould cavity.

Q6. Machining allowance provides:

A. Extra material for subsequent machining
B. Extra gas for the mould
C. Extra water for sand
D. Extra core support

Answer: A. Extra material for subsequent machining

Explanation: Additional metal is intentionally provided on surfaces that will be machined after casting.

Q7. Rapping allowance is generally:

A. Positive
B. Negative
C. Zero in every case
D. Equal to machining allowance

Answer: B. Negative

Explanation: Rapping can enlarge the mould cavity, so a negative allowance can compensate for the effect.

Q8. A split pattern is generally divided along the:

A. Parting line
B. Sprue
C. Runner
D. Riser

Answer: A. Parting line

Explanation: The split permits easier pattern withdrawal from the mould.

Q9. Match-plate patterns are especially suitable for:

A. Mass production
B. One-off giant castings only
C. Hand forging
D. Welding

Answer: A. Mass production

Explanation: Match-plate patterns facilitate rapid and consistent mould production.

Q10. A skeleton pattern is generally economical for:

A. Large castings in small quantities
B. Mass-produced tiny castings
C. Wire drawing
D. Sheet rolling

Answer: A. Large castings in small quantities

Explanation: Only a framework is provided, reducing pattern material and manufacturing cost.

Q11. A sweep pattern is useful for producing:

A. Large axisymmetric moulds
B. Small gears only
C. Bolts only
D. Welding electrodes

Answer: A. Large axisymmetric moulds

Explanation: A shaped board is swept around an axis to generate the mould surface.

Q12. A core is primarily used to produce:

A. External surface finish
B. Internal cavity
C. Pattern draft
D. Riser height

Answer: B. Internal cavity

Explanation: Cores occupy space in the mould and create internal holes or passages.

Q13. Which property of moulding sand allows gases to escape?

A. Permeability
B. Hardness
C. Density
D. Elasticity

Answer: A. Permeability

Explanation: Permeability allows gases generated during pouring and solidification to pass through the mould.

Q14. Refractoriness of moulding sand refers to its ability to:

A. Resist high temperature
B. Absorb oil
C. Increase casting weight
D. Melt rapidly

Answer: A. Resist high temperature

Explanation: Refractory sand must withstand molten-metal temperatures without melting or deteriorating excessively.

Q15. Collapsibility of moulding sand is important because it:

A. Allows the mould to yield during casting contraction
B. Increases melting temperature
C. Prevents all gas escape
D. Makes the metal harder

Answer: A. Allows the mould to yield during casting contraction

Explanation: Good collapsibility reduces resistance to contraction and helps reduce hot tearing.

Q16. Green sand normally contains:

A. Sand, clay/binder and water
B. Only pure metal
C. Only cement
D. Only oil

Answer: A. Sand, clay/binder and water

Explanation: Green sand is commonly a moist sand mixture containing clay/binder and other additives.

Q17. The vertical passage in a conventional gating system is called:

A. Runner
B. Sprue
C. Gate
D. Riser

Answer: B. Sprue

Explanation: The sprue carries molten metal downward from the pouring basin.

Q18. The horizontal passage carrying metal from sprue to gate is called:

A. Runner
B. Core
C. Riser
D. Pattern

Answer: A. Runner

Explanation: The runner distributes molten metal from the sprue toward one or more gates.

Q19. The passage through which molten metal enters the mould cavity is the:

A. Gate
B. Core print
C. Pattern
D. Vent only

Answer: A. Gate

Explanation: The gate connects the runner to the mould cavity.

Q20. The main function of a riser is to:

A. Feed molten metal during solidification
B. Create the pattern
C. Remove the core
D. Increase permeability

Answer: A. Feed molten metal during solidification

Explanation: The riser acts as a reservoir and compensates for solidification shrinkage.

Q21. A casting defect caused by incomplete filling of the mould is:

A. Misrun
B. Blowhole
C. Hot tear
D. Scab

Answer: A. Misrun

Explanation: A misrun occurs when metal solidifies before completely filling the mould cavity.

Q22. A defect caused when two streams of molten metal fail to fuse is:

A. Cold shut
B. Shrinkage cavity
C. Blowhole
D. Sand inclusion

Answer: A. Cold shut

Explanation: A cold shut appears where separate streams meet but do not properly fuse.

Q23. A gas cavity in a casting is called:

A. Blowhole
B. Cold shut
C. Misrun
D. Hot tear

Answer: A. Blowhole

Explanation: Blowholes result from trapped gases in the casting.

Q24. A shrinkage cavity is mainly associated with:

A. Insufficient feeding during solidification
B. Excessive pattern draft only
C. Excessive mould permeability only
D. Pattern colour

Answer: A. Insufficient feeding during solidification

Explanation: As metal contracts during solidification, a sufficient supply of molten metal is needed to prevent internal voids.

Q25. Cupola furnaces are traditionally used mainly for melting:

A. Cast iron
B. Aluminium only
C. Copper only
D. Plastic

Answer: A. Cast iron

Explanation: The cupola is a vertical shaft furnace traditionally used extensively for melting cast iron in foundries.

MCQ 26–40 — Moulding Sand & Patterns

Q26. The property of moulding sand that enables it to withstand molten-metal temperature is:

A. Permeability
B. Refractoriness
C. Plasticity
D. Adhesiveness

Answer: B. Refractoriness

Explanation: Refractoriness is the ability of moulding material to withstand high temperatures without fusing or deteriorating excessively.

Q27. Which property of moulding sand is essential for the escape of gases?

A. Permeability
B. Toughness
C. Hardness
D. Elasticity

Answer: A. Permeability

Explanation: Gases generated during pouring and solidification must escape through the mould.

Q28. The ability of moulding sand to retain its shape during handling is mainly related to:

A. Strength
B. Melting point
C. Density
D. Thermal conductivity

Answer: A. Strength

Explanation: Adequate mould strength prevents the cavity from collapsing or eroding during mould handling and pouring.

Q29. Which property allows moulding sand to stick to another surface?

A. Adhesiveness
B. Permeability
C. Refractoriness
D. Collapsibility

Answer: A. Adhesiveness

Explanation: Adhesiveness is the tendency of moulding sand to adhere to the surface of the moulding box or other materials.

Q30. The ability of sand particles to stick to one another is called:

A. Cohesiveness
B. Adhesiveness
C. Permeability
D. Fluidity

Answer: A. Cohesiveness

Explanation: Cohesiveness helps individual sand grains bind together and maintain the mould shape.

Q31. Which property is desirable to allow easy breakdown of the mould after casting?

A. Collapsibility
B. Excessive hardness
C. Low refractoriness
D. Low strength

Answer: A. Collapsibility

Explanation: The mould should collapse sufficiently after solidification to allow casting removal and accommodate contraction.

Q32. Excessive moisture in moulding sand may lead to:

A. Gas-related defects
B. Increased metal strength in every case
C. Zero porosity
D. Elimination of shrinkage

Answer: A. Gas-related defects

Explanation: Excess moisture can generate steam and gases during pouring, potentially causing blowholes and other defects.

Q33. Which type of sand mould is used in a moist condition?

A. Green sand mould
B. Dry sand mould
C. Ceramic mould
D. Permanent mould

Answer: A. Green sand mould

Explanation: Green sand contains moisture and is generally used without complete drying.

Q34. The major binder traditionally used in green sand is:

A. Clay
B. Copper
C. Aluminium
D. Steel

Answer: A. Clay

Explanation: Clay provides bonding between sand grains and helps maintain mould strength.

Q35. The primary purpose of a pattern is to:

A. Produce the mould cavity
B. Melt the metal
C. Feed the casting
D. Remove slag

Answer: A. Produce the mould cavity

Explanation: The pattern represents the casting geometry and is used to create the cavity into which molten metal is poured.

Q36. A pattern is generally made larger than the required casting because of:

A. Allowances
B. Welding defects
C. Cutting forces
D. Rolling pressure

Answer: A. Allowances

Explanation: Shrinkage, machining and other allowances are incorporated into the pattern as required.

Q37. Which allowance is provided to facilitate pattern withdrawal?

A. Draft allowance
B. Shrinkage allowance
C. Machining allowance
D. Rapping allowance

Answer: A. Draft allowance

Explanation: Draft provides taper on vertical pattern surfaces, making removal easier.

Q38. The amount of draft required depends on:

A. Pattern material and moulding method
B. Colour of the pattern
C. Foundry floor area only
D. Metal electrical conductivity only

Answer: A. Pattern material and moulding method

Explanation: Pattern surface condition, moulding method, depth and material influence the required draft.

Q39. Machining allowance is generally greater for:

A. Surfaces requiring extensive machining
B. Surfaces requiring no finishing
C. Wax patterns only
D. Core prints only

Answer: A. Surfaces requiring extensive machining

Explanation: More material must be provided where greater metal removal will be required during machining.

Q40. Which pattern is divided into two parts?

A. Split pattern
B. Sweep pattern
C. Skeleton pattern
D. Single-piece pattern

Answer: A. Split pattern

Explanation: Split patterns consist of separate portions, generally corresponding to the two sides of the parting line.

MCQ 41–55 — Pattern Types & Cores

Q41. A pattern consisting of two halves mounted on opposite sides of a plate is:

A. Match-plate pattern
B. Skeleton pattern
C. Sweep pattern
D. Segmental pattern

Answer: A. Match-plate pattern

Explanation: Match-plate patterns have the pattern halves attached to a common plate and are useful for production moulding.

Q42. A skeleton pattern is particularly suitable for:

A. Large castings in small quantities
B. High-volume tiny castings
C. Wire production
D. Sheet rolling

Answer: A. Large castings in small quantities

Explanation: A framework is used instead of a solid pattern, reducing pattern cost for large, low-volume castings.

Q43. A sweep pattern generates a mould surface by:

A. Rotating a shaped board around an axis
B. Welding two plates
C. Rolling a metal sheet
D. Hammering the mould

Answer: A. Rotating a shaped board around an axis

Explanation: The sweep board produces the required mould profile as it is rotated.

Q44. A loose-piece pattern is useful when:

A. The pattern contains difficult projections or undercuts
B. No mould is required
C. Only flat surfaces are involved
D. No pattern withdrawal is needed

Answer: A. The pattern contains difficult projections or undercuts

Explanation: Detachable portions allow the pattern to be removed without damaging the mould.

Q45. A core is used primarily to produce:

A. Internal cavities
B. External dimensions
C. Pattern colour
D. Riser volume

Answer: A. Internal cavities

Explanation: Cores occupy space within the mould and create internal holes, passages and cavities.

Q46. A core is generally made from:

A. Core sand
B. Pure molten metal
C. Cutting fluid
D. Lubricating oil

Answer: A. Core sand

Explanation: Specially prepared core sand is used to produce cores with adequate strength and collapsibility.

Q47. The core is supported in the mould by:

A. Core prints
B. Runners only
C. Risers only
D. Gates only

Answer: A. Core prints

Explanation: Core prints provide locating and supporting surfaces for the core.

Q48. Core prints are generally provided on:

A. The pattern
B. The ladle
C. The furnace wall
D. The runner only

Answer: A. The pattern

Explanation: Core prints are incorporated into the pattern to create supporting recesses in the mould.

Q49. Which casting component creates an internal cylindrical hole?

A. Core
B. Riser
C. Runner
D. Sprue

Answer: A. Core

Explanation: A cylindrical core placed in the mould creates the corresponding internal hole.

Q50. The main requirement of a core is:

A. Adequate strength and collapsibility
B. Complete non-porosity under all conditions
C. Maximum hardness only
D. Zero gas permeability

Answer: A. Adequate strength and collapsibility

Explanation: The core must survive handling and pouring but should also collapse sufficiently after solidification.

Q51. Core prints are primarily used to:

A. Locate the core
B. Increase metal temperature
C. Reduce melting time
D. Remove slag

Answer: A. Locate the core

Explanation: They establish the correct position of the core inside the mould.

Q52. Which component is NOT normally part of a conventional core?

A. Core sand
B. Binder
C. Reinforcement where required
D. Molten casting metal

Answer: D. Molten casting metal

Explanation: A core is made before pouring and consists of prepared core material rather than molten casting metal.

Q53. A core should have sufficient permeability because:

A. Gases must escape
B. It must prevent all gas flow
C. It must increase casting shrinkage
D. It must act as a riser

Answer: A. Gases must escape

Explanation: Gas generated within or around the core must be vented to prevent casting defects.

Q54. Excessively strong cores may cause:

A. Difficulty in collapse after casting solidification
B. Zero casting weight
C. Increased fluidity
D. Reduced metal temperature

Answer: A. Difficulty in collapse after casting solidification

Explanation: Poor core collapsibility can restrict contraction and contribute to hot tears or difficulties during shakeout.

Q55. Which component creates an opening but does NOT normally form part of the final metal casting?

A. Core
B. Casting wall
C. Metal insert
D. Permanent feature

Answer: A. Core

Explanation: The core is removed after casting, leaving the cavity or passage.

MCQ 56–70 — Gating System & Riser

Q56. The complete passage system carrying molten metal to the mould cavity is called:

A. Gating system
B. Core system
C. Pattern system
D. Cooling system

Answer: A. Gating system

Explanation: The gating system controls the delivery of molten metal into the mould cavity.

Q57. The first receiving portion of a conventional gating system is:

A. Pouring basin
B. Riser
C. Core
D. Gate

Answer: A. Pouring basin

Explanation: The pouring basin receives molten metal from the ladle and directs it into the sprue.

Q58. The sprue is generally:

A. Vertical
B. Horizontal only
C. Circular only
D. Inclined at 90° only

Answer: A. Vertical

Explanation: In conventional gravity casting systems, the sprue is a vertical passage.

Q59. The runner is used to:

A. Distribute molten metal toward gates
B. Create internal holes
C. Remove the pattern
D. Support the core

Answer: A. Distribute molten metal toward gates

Explanation: The runner connects the sprue to one or more gates.

Q60. The gate connects the:

A. Runner and mould cavity
B. Core and riser
C. Pattern and furnace
D. Ladle and furnace

Answer: A. Runner and mould cavity

Explanation: Molten metal enters the mould cavity through the gate.

Q61. The principal function of a riser is to:

A. Supply molten metal during solidification
B. Create the mould cavity
C. Remove gases only
D. Hold the pattern

Answer: A. Supply molten metal during solidification

Explanation: The riser compensates for shrinkage as the casting solidifies.

Q62. A riser is also called a:

A. Feeder
B. Core
C. Pattern
D. Sprue

Answer: A. Feeder

Explanation: A riser feeds additional molten metal to the casting.

Q63. The riser should generally remain molten:

A. Longer than the casting section it feeds
B. Shorter than the casting in every case
C. Before pouring begins
D. Only after complete solidification

Answer: A. Longer than the casting section it feeds

Explanation: The riser must remain liquid sufficiently long to supply metal during solidification.

Q64. Which component is designed primarily to reduce shrinkage defects?

A. Riser
B. Pattern
C. Core print
D. Moulding box

Answer: A. Riser

Explanation: A properly designed feeder/riser provides molten metal to compensate for solidification contraction.

Q65. A properly designed gating system should:

A. Deliver metal smoothly and minimize turbulence
B. Maximize air entrapment
C. Prevent all metal flow
D. Increase slag formation deliberately

Answer: A. Deliver metal smoothly and minimize turbulence

Explanation: Controlled flow reduces mould erosion, air entrainment and other defects.

Q66. Excessive turbulence during pouring can increase:

A. Oxidation and air entrapment
B. Dimensional accuracy
C. Metal purity in every case
D. Core strength

Answer: A. Oxidation and air entrapment

Explanation: Turbulent flow can entrain air and oxide films and may erode mould surfaces.

Q67. A sprue may be tapered to:

A. Reduce aspiration and improve flow
B. Increase air entry
C. Stop metal flow
D. Increase casting porosity

Answer: A. Reduce aspiration and improve flow

Explanation: A properly tapered sprue helps maintain a full-flowing stream and reduces air aspiration.

Q68. The molten metal enters the mould cavity through the:

A. Gate
B. Riser only
C. Core print
D. Pattern

Answer: A. Gate

Explanation: The gate is the final passage between the runner and mould cavity.

Q69. Which sequence is correct for a conventional gravity gating system?

A. Pouring basin → Sprue → Runner → Gate → Cavity
B. Gate → Runner → Sprue → Basin → Cavity
C. Cavity → Gate → Basin → Sprue
D. Riser → Core → Runner → Basin

Answer: A. Pouring basin → Sprue → Runner → Gate → Cavity

Explanation: This represents the normal direction of molten-metal flow.

Q70. A riser is normally located:

A. At a suitable location connected to the casting
B. Inside the furnace only
C. Inside the ladle only
D. On the pattern storage rack

Answer: A. At a suitable location connected to the casting

Explanation: Its location is selected to feed regions most susceptible to shrinkage.

MCQ 71–85 — Furnaces & Casting Processes

Q71. A cupola furnace is primarily used for melting:

A. Cast iron
B. Wood
C. Plastic
D. Glass only

Answer: A. Cast iron

Explanation: Cupola furnaces have traditionally been widely used for melting cast iron in foundries.

Q72. A cupola is a:

A. Vertical shaft furnace
B. Horizontal rolling machine
C. Forging press
D. Welding machine

Answer: A. Vertical shaft furnace

Explanation: The cupola has a vertical cylindrical shaft through which charge materials descend.

Q73. Which fuel is traditionally used in a cupola furnace?

A. Coke
B. Wood only
C. Petrol only
D. Water

Answer: A. Coke

Explanation: Coke acts as a fuel and provides heat for melting in traditional cupola operation.

Q74. The charge in a cupola may include:

A. Metal, coke and flux
B. Only sand
C. Only water
D. Only clay

Answer: A. Metal, coke and flux

Explanation: The metallic charge, fuel and flux are important components of cupola operation.

Q75. The purpose of flux in a melting furnace is generally to:

A. Help form and remove slag
B. Increase pattern dimensions
C. Produce cores
D. Measure temperature only

Answer: A. Help form and remove slag

Explanation: Flux combines with impurities to form slag that can be separated from the molten metal.

Q76. Which casting process uses a reusable metal mould?

A. Permanent mould casting
B. Green sand casting only
C. Shell sand casting only
D. Plaster mould casting only

Answer: A. Permanent mould casting

Explanation: Permanent moulds are designed for repeated use.

Q77. Die casting generally uses:

A. A permanent metal die
B. A disposable wooden pattern only
C. A sand core as the entire mould
D. A paper mould

Answer: A. A permanent metal die

Explanation: Die casting uses reusable dies and is suited to high-volume production.

Q78. Die casting is particularly suitable for:

A. High-volume production of relatively small complex parts
B. One-off huge sand castings
C. Hand forging
D. Wood products

Answer: A. High-volume production of relatively small complex parts

Explanation: High production rates and good dimensional consistency are major advantages of die casting.

Q79. In pressure die casting, molten metal is introduced into the die:

A. Under pressure
B. Only by gravity
C. By hand hammering
D. Through a sand shovel

Answer: A. Under pressure

Explanation: Pressure assists rapid filling of the permanent die cavity.

Q80. Investment casting is also commonly called:

A. Lost-wax casting
B. Sand forging
C. Cold rolling
D. Drop forging

Answer: A. Lost-wax casting

Explanation: A wax pattern is surrounded by investment material and later removed before metal is cast.

Q81. Investment casting is suitable for producing:

A. Complex and accurate components
B. Only very simple plates
C. Only wooden components
D. Only rolled sheets

Answer: A. Complex and accurate components

Explanation: The process can reproduce intricate geometries and fine details.

Q82. In investment casting, the wax pattern is:

A. Removed before metal casting
B. Retained as the final metal component
C. Used as the riser
D. Used as the furnace lining

Answer: A. Removed before metal casting

Explanation: The wax is melted or otherwise removed to create the cavity into which metal is poured.

Q83. Centrifugal casting uses:

A. Centrifugal force
B. Only compressed air
C. Only chemical reaction
D. Manual hammering

Answer: A. Centrifugal force

Explanation: Rotation forces molten metal against the mould wall.

Q84. Centrifugal casting is particularly suitable for:

A. Hollow cylindrical components
B. Flat wooden plates
C. Small bolts only
D. Welding rods

Answer: A. Hollow cylindrical components

Explanation: Pipes, tubes and similar rotationally symmetric hollow components are common applications.

Q85. Shell moulding uses:

A. A thin shell of resin-bonded sand
B. Only molten metal
C. A wooden shell
D. A rubber tube

Answer: A. A thin shell of resin-bonded sand

Explanation: A heated pattern is coated with resin-bonded sand to form a relatively thin mould shell.

MCQ 86–100 — Casting Defects, Finishing & Inspection

Q86. A casting that does not completely fill the mould cavity has:

A. Misrun
B. Cold shut
C. Hot tear
D. Scab

Answer: A. Misrun

Explanation: A misrun results from premature solidification before complete cavity filling.

Q87. A cold shut is associated with:

A. Failure of two molten streams to fuse
B. Excessive riser feeding
C. Pattern removal
D. Complete mould filling

Answer: A. Failure of two molten streams to fuse

Explanation: Separate streams meet but do not form a continuous homogeneous metal connection.

Q88. Shrinkage cavities are most directly related to:

A. Solidification contraction
B. Pattern colour
C. Sand grain colour
D. Tool geometry

Answer: A. Solidification contraction

Explanation: Metal contracts during solidification, and inadequate feeding can leave internal cavities.

Q89. A blowhole is mainly caused by:

A. Trapped gas
B. Excessive machining
C. Pattern draft
D. Rapping

Answer: A. Trapped gas

Explanation: Gases that cannot escape can form cavities within the casting.

Q90. Sand inclusion means:

A. Sand particles become embedded in the casting
B. Gas becomes trapped
C. Metal fails to melt
D. Pattern expands

Answer: A. Sand particles become embedded in the casting

Explanation: Mould erosion or poor mould strength can cause sand to become incorporated into the metal.

Q91. Hot tears occur mainly because of:

A. Restrained contraction during solidification
B. Excessive machining allowance only
C. Pattern colour
D. High permeability alone

Answer: A. Restrained contraction during solidification

Explanation: If the casting cannot contract freely during late solidification, tensile stresses can cause hot tearing.

Q92. A mould shift can result in:

A. Dimensional mismatch between casting halves
B. Better dimensional accuracy
C. Increased melting point
D. Zero defects

Answer: A. Dimensional mismatch between casting halves

Explanation: Improper alignment of cope and drag can produce a mismatch at the parting line.

Q93. Core shift may cause:

A. Incorrect position of internal cavities
B. Increased metal purity
C. Reduced casting weight in every case
D. Improved dimensional accuracy

Answer: A. Incorrect position of internal cavities

Explanation: If the core moves from its intended position, internal holes or passages will be misplaced.

Q94. Fins on castings are generally caused by:

A. Metal entering unwanted gaps at mould joints
B. Low gas pressure only
C. Insufficient pattern size
D. Core permeability

Answer: A. Metal entering unwanted gaps at mould joints

Explanation: Thin projections can form when molten metal penetrates cracks or gaps in the mould.

Q95. Fettling is carried out:

A. After casting removal
B. Before pattern manufacture only
C. Before melting
D. Before mould preparation

Answer: A. After casting removal

Explanation: Fettling includes removal of gates, risers, fins, adhering sand and other unwanted material.

Q96. One operation in fettling is:

A. Removal of gates and risers
B. Pattern design
C. Core printing
D. Furnace charging only

Answer: A. Removal of gates and risers

Explanation: Gates and risers are unwanted portions attached to the casting and are removed during finishing.

Q97. Radiographic testing of castings is used mainly to detect:

A. Internal defects
B. Pattern colour
C. Surface roughness only
D. Casting weight only

Answer: A. Internal defects

Explanation: X-rays or gamma rays can reveal internal discontinuities such as porosity and inclusions.

Q98. Dye penetrant inspection is particularly useful for:

A. Surface-breaking cracks
B. Deep internal shrinkage only
C. Melting-point measurement
D. Chemical composition measurement

Answer: A. Surface-breaking cracks

Explanation: Penetrant enters open surface discontinuities and makes them visible during inspection.

Q99. Dimensional inspection of a casting is performed to:

A. Verify required dimensions and tolerances
B. Increase metal temperature
C. Remove all internal cavities
D. Change the chemical composition

Answer: A. Verify required dimensions and tolerances

Explanation: Measuring instruments are used to determine whether the casting conforms to its specified dimensions.

Q100. Which sequence correctly represents the basic casting process?

A. Pattern → Mould → Melting → Pouring → Solidification → Shakeout
B. Melting → Pattern → Welding → Rolling
C. Welding → Pattern → Forging → Casting
D. Rolling → Melting → Pattern → Grinding

Answer: A. Pattern → Mould → Melting → Pouring → Solidification → Shakeout

Explanation: This is the basic sequence from pattern preparation through removal of the solidified casting.

CHAPTER 8 — QUICK REVISION

Pattern

Pattern → Produces mould cavity

Allowances

Shrinkage → Compensates metal contraction

Machining → Extra material for machining

Draft → Easy pattern withdrawal

Distortion → Compensates expected distortion

Rapping → Generally negative

Moulding Sand

Refractoriness → Withstands heat

Permeability → Allows gas escape

Strength → Maintains mould shape

Cohesiveness → Sand grains stick together

Adhesiveness → Sand sticks to mould box

Collapsibility → Breaks down after solidification

Gating System

Pouring Basin → Sprue → Runner → Gate → Mould Cavity

Feeding

Riser → Feeds molten metal during solidification

Core

Core → Internal cavity

Important Processes

Sand casting → Expendable mould

Die casting → Permanent die + pressure

Investment casting → Lost-wax process

Centrifugal casting → Rotation/centrifugal force

Shell moulding → Resin-bonded sand shell

Cupola → Traditionally used for cast iron

Important Defects

Misrun → Incomplete filling

Cold shut → Streams fail to fuse

Blowhole → Gas cavity

Shrinkage cavity → Inadequate feeding

Hot tear → Restrained contraction

Sand inclusion → Sand trapped in casting

Mould shift → Misalignment of mould halves

Core shift → Incorrect internal cavity position

CHAPTER 9 — FORGING TECHNOLOGY

9.1 Introduction

Forging is one of the oldest metal-forming processes and is extremely important in manufacturing engineering. It is widely used when components require high strength, toughness, reliability and directional grain flow.

Forging is commonly used to manufacture:

Crankshafts

Connecting rods

Gear blanks

Spanners

Bolts

Shafts

Axles

Hooks

Wrenches

Aircraft components

Automobile components

Hand tools

9.2 Definition of Forging

Forging is a manufacturing process in which a metal workpiece is plastically deformed into the desired shape by the application of compressive forces.

The compressive force may be applied using:

Hammer

Press

Die

Mechanical equipment

Hydraulic equipment

Key Concept

Forging = Plastic deformation + Compressive force

9.3 Principle of Forging

The basic principle of forging is to bring the workpiece into a condition where it can undergo plastic deformation and then apply sufficient compressive force to obtain the desired shape.

Depending on the process, the metal may be heated before deformation.

9.4 Why Is Metal Heated Before Forging?

In hot forging, the workpiece is heated to an appropriate temperature to:

Reduce flow stress

Increase ductility

Reduce required forging force

Permit greater deformation

Refine the grain structure under suitable conditions

However, overheating must be avoided because it can cause:

Excessive grain growth

Oxidation

Burning

Loss of material properties

9.5 Types of Forging Based on Temperature

Forging can broadly be classified as:

Hot forging
Warm forging
Cold forging

9.6 Hot Forging

Hot forging is carried out at a temperature sufficiently high to allow substantial plastic deformation with relatively low resistance.

Advantages

Lower forging force

Large deformation possible

Better workability

Suitable for large components

Disadvantages

Oxidation/scale formation

Lower dimensional accuracy than cold forging

Surface finish may be poorer

Heating cost

9.7 Cold Forging

Cold forging is performed at or near room temperature.

Advantages

Good dimensional accuracy

Good surface finish

No heating scale

Improved strength due to work hardening

Disadvantages

High deformation force

Limited deformation

Greater possibility of cracking in less ductile materials

Tool loads are high

9.8 Warm Forging

Warm forging is performed between conventional cold-forging and hot-forging temperature ranges.

It attempts to obtain a balance between:

Lower forming force

Better dimensional accuracy

Reduced oxidation

Improved material formability

9.9 Classification Based on Equipment

Forging can also be classified according to the equipment used:

1. Hammer Forging

The deformation is produced mainly by impact.

2. Press Forging

The deformation is produced mainly by gradual application of compressive force.

9.10 Hammer Forging

In hammer forging, the workpiece is deformed by repeated blows.

Examples of equipment include:

Drop hammer

Power hammer

Main characteristic

Impact loading

9.11 Press Forging

In press forging, deformation is produced by applying pressure gradually.

Presses may be:

Mechanical

Hydraulic

Main characteristic

Gradual compressive loading

9.12 Hammer vs Press Forging

Hammer Forging	Press Forging
Impact load	Gradual load
Repeated blows	Continuous pressure
Deformation may be concentrated near surface	Deformation can penetrate deeper
High strain rate	Lower strain rate
Suitable for many die-forging operations	Suitable for large/deep deformation

9.13 Open-Die Forging

In open-die forging, the workpiece is compressed between dies that do not completely enclose the material.

The metal is allowed to flow laterally.

Applications

Large shafts

Large rings

Heavy forgings

Large blocks

9.14 Closed-Die Forging

In closed-die forging, the workpiece is placed within shaped die cavities.

The dies approach each other and force the material to flow into the cavity.

Advantages

Complex shapes possible

Good dimensional accuracy

High production rate

Good mechanical properties

9.15 Impression-Die Forging

In impression-die forging, the dies contain impressions corresponding to the desired component geometry.

The material flows into these impressions under compressive force.

Excess material may form flash around the die parting line.

9.16 Flash

Flash is the thin excess metal that flows out between the die faces during impression-die forging.

Flash is subsequently removed by a trimming operation.

Important

Flash → Excess metal at die parting line

9.17 Flashless Forging

In flashless forging, the amount of material is carefully controlled so that the workpiece fills the die cavity without producing significant flash.

Advantages

Better material utilization

Reduced waste

Requirement

Accurate control of billet volume is important.

9.18 Upset Forging

Upset forging increases the cross-sectional area of a portion of the workpiece by reducing its length.

Example

Production of:

Bolt heads

Rivet heads

Fastener heads

Key Concept

Upsetting → Length decreases, cross-sectional area increases

9.19 Drawing Out

Drawing out is a forging operation in which:

Length increases and cross-sectional area decreases.

It is essentially the opposite of upsetting.

Key Concept

Drawing out → Length ↑, area ↓

9.20 Fullering

Fullering is used to distribute metal along the length of a workpiece.

Fullers have rounded or specially shaped surfaces.

It is often used before drawing-out operations.

9.21 Edging

Edging is used to gather or redistribute material at a particular location.

It is commonly used in die forging to prepare the required amount of material for subsequent impressions.

9.22 Bending

Bending is a forging operation in which the workpiece is given a curved or angular shape.

It is commonly used in producing:

Hooks

Links

Brackets

Certain hand tools

9.23 Punching

Punching is the operation of producing a hole by forcing a punch through a hot workpiece.

The removed material may form a slug.

9.24 Piercing

Piercing is related to producing a hole or cavity by forcing a tool into the workpiece.

The exact terminology can vary with the forging process and application.

9.25 Trimming

Trimming removes unwanted flash from a forged component.

Sequence

Forging → Flash formation → Trimming

9.26 Swaging

Swaging is a forging operation used to reduce or modify the cross-section of a workpiece by dies.

It can be performed using:

Rotary swaging

Die-based equipment

9.27 Heading

Heading is a form of upsetting used extensively in fastener manufacturing.

It is used for producing:

Bolt heads

Screw heads

Rivet heads

9.28 Coining

Coining is a precision forging operation in which very high pressure is used to produce fine surface details and accurate dimensions.

It is commonly associated with:

Coins

Medallions

Precision components

Important

Coining → High-pressure precision forging

9.29 Sizing

Sizing is a finishing forging operation used to obtain:

Better dimensional accuracy

Improved surface conformity

Only a relatively small amount of deformation is generally involved.

9.30 Roll Forging

In roll forging, the workpiece passes between rotating rolls containing shaped grooves.

The rolls progressively deform the workpiece.

Applications

Tapered components

Shafts

Axle components

Blanks

9.31 Rotary Forging

Rotary forging uses a die that applies deformation progressively over the workpiece rather than deforming the entire area simultaneously.

It can reduce required force compared with some conventional forging arrangements.

9.32 Forging Dies

Forging dies provide the surfaces against which the workpiece is deformed.

They can broadly be:

Open dies

Impression dies

Closed dies

9.33 Die Materials

Forging dies require materials having:

High strength

High toughness

Good wear resistance

Resistance to thermal fatigue

Adequate hardness at operating temperature

Common die materials include suitable tool steels and other specialized die materials.

9.34 Forging Machines

Important forging equipment includes:

Smith’s hammer

Power hammer

Drop hammer

Mechanical press

Hydraulic press

Screw press

Upset forging machine

9.35 Drop Forging

In drop forging, the upper die is raised and allowed to fall onto the workpiece, producing deformation through impact.

Important

Drop forging → Impact

9.36 Mechanical Press Forging

Mechanical presses use mechanical mechanisms such as:

Eccentric drives

Crank mechanisms

to convert rotary motion into controlled linear movement.

9.37 Hydraulic Press Forging

Hydraulic presses use hydraulic pressure to apply a controlled compressive force.

Advantages

Large force capacity

Smooth force application

Good control

Suitable for large forgings

9.38 Screw Press

A screw press uses rotational motion of a screw to generate forging force.

It can be used for:

Impression forging

Heading

Coining

Other forging operations

9.39 Advantages of Forging

Major advantages include:

High strength
Improved toughness
Good fatigue resistance
Refined grain structure under appropriate conditions
Reduced internal defects compared with some cast products
Favorable grain flow
High reliability

9.40 Grain Flow in Forging

One of the major advantages of forging is the development of favorable grain flow that follows the shape of the component.

This can improve:

Strength

Fatigue resistance

Toughness

Important

Forging → Directional grain flow

9.41 Disadvantages of Forging

Limitations include:

High equipment cost

High die cost

High initial investment

Shape limitations compared with some casting processes

Material waste in some die-forging operations due to flash

High forces required for cold forging

9.42 Forging Defects

Important forging defects include:

Cracks

Laps

Cold shuts

Flakes

Internal bursts

Underfilling

Die shift

Scale pits

Improper grain flow

9.43 Forging Laps

A lap is a surface defect caused by folding of metal over itself during forging.

It can result from:

Improper metal flow

Incorrect die design

Excessive deformation in a particular region

9.44 Internal Burst

An internal burst is an internal crack that can develop because of unfavorable stress conditions during deformation.

It may occur particularly when deformation conditions and material temperature are unsuitable.

9.45 Flakes

Flakes are internal cracks associated particularly with hydrogen and delayed cracking phenomena in certain steels.

They may be detected by appropriate inspection methods.

9.46 Scale

Scale forms on the surface of hot-forged material due to oxidation at elevated temperatures.

Excessive scale can affect:

Surface quality

Dimensional accuracy

Tool life

9.47 Underfilling

Underfilling occurs when the metal does not completely fill the die impression.

Possible causes include:

Insufficient material

Improper die design

Incorrect forging temperature

Inadequate forging force

9.48 Die Shift

Die shift occurs when the two die halves are not properly aligned.

It can produce:

Mismatch

Dimensional errors

Uneven geometry

9.49 Forging Temperature

The correct forging temperature depends on:

Material

Alloy composition

Forging operation

Required deformation

Equipment

There is no single forging temperature applicable to all metals.

9.50 Important Forging Revision

Term	Key Point
Forging	Plastic deformation by compressive force
Hot forging	High-temperature deformation
Warm forging	Intermediate temperature
Cold forging	Near-room-temperature deformation
Hammer forging	Impact
Press forging	Gradual pressure
Open-die	Dies do not completely enclose workpiece
Closed-die	Workpiece deforms within die cavity
Flash	Excess metal at die parting line
Upsetting	Length ↓, area ↑
Drawing out	Length ↑, area ↓
Fullering	Distributes metal
Edging	Gathers/redistributes metal
Bending	Produces angular/curved shape
Punching	Produces hole
Trimming	Removes flash
Heading	Produces fastener heads
Coining	High-pressure precision forging
Sizing	Improves dimensional accuracy
Roll forging	Deformation between rotating rolls
Drop forging	Impact
Hydraulic press	Controlled large compressive force
Lap	Folded-over metal defect
Flake	Internal crack associated with hydrogen
Underfill	Incomplete die filling
Die shift	Die misalignment

Q1. Forging is primarily a:

A. Casting process
B. Metal forming process
C. Machining process
D. Joining process

Answer: B. Metal forming process

Explanation: Forging changes the shape of metal through plastic deformation rather than removing material.

Practice

Q2. The principal force in forging is:

A. Tensile force
B. Compressive force
C. Shear force only
D. Bending force only

Answer: B. Compressive force

Explanation: Forging primarily involves plastic deformation under compressive loading.

Q3. A major advantage of forging is:

A. Favorable grain flow
B. High internal porosity
C. No deformation
D. Very low strength

Answer: A. Favorable grain flow

Explanation: Proper forging can produce grain flow that follows the component geometry, improving mechanical performance.

Q4. Hot forging is performed at:

A. Elevated temperature
B. Only absolute zero
C. Below the freezing point of the metal
D. Room temperature only

Answer: A. Elevated temperature

Explanation: The workpiece is heated sufficiently to facilitate plastic deformation.

Q5. Cold forging is generally carried out:

A. Near room temperature
B. Above the melting point
C. Inside a furnace only
D. At boiling temperature

Answer: A. Near room temperature

Explanation: Cold forging occurs without heating the workpiece to conventional hot-forging temperatures.

Q6. The major advantage of hot forging over cold forging is:

A. Lower deformation force
B. No oxidation
C. Higher dimensional accuracy in every case
D. Zero heating requirement

Answer: A. Lower deformation force

Explanation: Heating reduces the flow stress of many metals and makes large deformation easier.

Q7. Cold forging can improve strength mainly through:

A. Work hardening
B. Melting
C. Casting
D. Annealing

Answer: A. Work hardening

Explanation: Plastic deformation at low temperature can increase strength through strain/work hardening.

Q8. Hammer forging primarily applies:

A. Impact loading
B. Hydrostatic loading only
C. Tensile loading
D. Thermal loading only

Answer: A. Impact loading

Explanation: Hammer forging deforms the workpiece through repeated or single high-energy blows.

Q9. Press forging applies force:

A. Gradually
B. Only through explosion
C. Only through cutting
D. Without contact

Answer: A. Gradually

Explanation: A press applies compressive force over a relatively controlled stroke.

Q10. Open-die forging uses dies that:

A. Do not completely enclose the workpiece
B. Completely surround the workpiece in every case
C. Are made only of sand
D. Never contact the workpiece

Answer: A. Do not completely enclose the workpiece

Explanation: Material is allowed to flow laterally between relatively simple die surfaces.

Q11. Closed-die forging is also associated with:

A. Impression forging
B. Sand casting
C. Rolling only
D. Welding

Answer: A. Impression forging

Explanation: Shaped die impressions force the workpiece into a desired geometry.

Q12. Excess metal formed between impression-die faces is called:

A. Flash
B. Scale
C. Slag
D. Core

Answer: A. Flash

Explanation: Flash is excess material squeezed out around the die parting line.

Q13. Flash is generally removed by:

A. Trimming
B. Annealing only
C. Casting
D. Rolling

Answer: A. Trimming

Explanation: Trimming removes unwanted flash from the forged component.

Q14. In upsetting, the length of the workpiece generally:

A. Decreases
B. Increases
C. Remains unchanged in every case
D. Becomes zero

Answer: A. Decreases

Explanation: Upsetting increases cross-sectional area by reducing the axial length.

Q15. In drawing out, the cross-sectional area generally:

A. Decreases
B. Increases
C. Becomes infinite
D. Always remains constant

Answer: A. Decreases

Explanation: Drawing out increases length while reducing cross-sectional area.

Q16. Bolt heads are commonly produced by:

A. Upset forging/heading
B. Sand casting only
C. Rolling only
D. Extrusion only

Answer: A. Upset forging/heading

Explanation: Heading increases material at one end to form the head of a bolt, screw or rivet.

Q17. Fullering is primarily used to:

A. Distribute metal along the workpiece
B. Remove flash
C. Produce a casting cavity
D. Measure hardness

Answer: A. Distribute metal along the workpiece

Explanation: Fullers help spread and redistribute metal before subsequent forging operations.

Q18. Edging is mainly used to:

A. Gather material in a desired region
B. Remove scale
C. Produce holes only
D. Melt the workpiece

Answer: A. Gather material in a desired region

Explanation: Edging prepares the billet by concentrating material where required for subsequent die impressions.

Q19. Coining is characterized by:

A. Very high pressure and fine detail reproduction
B. Very low pressure
C. Sand moulding
D. Gas welding

Answer: A. Very high pressure and fine detail reproduction

Explanation: Coining is a precision forging operation used to reproduce fine surface details.

Q20. Sizing is primarily used to improve:

A. Dimensional accuracy
B. Melting temperature
C. Chemical composition
D. Gas content

Answer: A. Dimensional accuracy

Explanation: Sizing provides a small final deformation to improve dimensional conformity.

Q21. Roll forging uses:

A. Rotating rolls
B. Sand moulds
C. Welding electrodes
D. Cutting tools only

Answer: A. Rotating rolls

Explanation: The workpiece passes between shaped rotating rolls and is progressively deformed.

Q22. A hydraulic forging press applies force using:

A. Hydraulic pressure
B. Centrifugal force only
C. Gravity only
D. Magnetic force only

Answer: A. Hydraulic pressure

Explanation: Hydraulic systems generate controlled compressive forces suitable for large forgings.

Q23. A major disadvantage of cold forging is:

A. High forming force
B. Poor surface finish in every case
C. High oxidation
D. No work hardening

Answer: A. High forming force

Explanation: Materials have higher flow stress at lower temperatures, requiring greater forming loads.

Q24. A forging defect caused by folding of metal over itself is:

A. Lap
B. Blowhole
C. Shrinkage cavity
D. Sand inclusion

Answer: A. Lap

Explanation: A lap is produced when flowing metal folds and the fold is not properly welded together.

Q25. Flakes in steel forgings are associated particularly with:

A. Hydrogen
B. Nitrogen only
C. Carbon dioxide only
D. Water vapour in moulding sand only

Answer: A. Hydrogen

Explanation: Flakes are internal cracks associated with hydrogen-related delayed cracking in susceptible steels.

A. Forging Fundamentals — MCQs 26–40

Q26. Which process produces a component by plastic deformation under compressive force?

A. Casting
B. Forging
C. Welding
D. Grinding

Answer: B. Forging

Explanation: Forging changes the shape of a workpiece by plastic deformation using compressive forces.

Practice

Q27. Which of the following is generally NOT a characteristic advantage of forging?

A. Improved mechanical properties
B. Favorable grain flow
C. High internal porosity
D. Good fatigue strength

Answer: C. High internal porosity

Explanation: Forging generally reduces or closes certain internal discontinuities rather than intentionally producing porosity.

Q28. Forged components are commonly preferred for critical applications because of:

A. High reliability
B. High porosity
C. Very low strength
D. Poor fatigue resistance

Answer: A. High reliability

Explanation: Properly forged components can provide excellent strength, toughness and fatigue performance.

Q29. Which of the following is a typical forged component?

A. Crankshaft
B. Glass bottle
C. Plastic film
D. Ceramic tile

Answer: A. Crankshaft

Explanation: Crankshafts are commonly manufactured by forging because of the strength and fatigue resistance required.

Q30. The deformation in forging is mainly:

A. Elastic
B. Plastic
C. Thermal only
D. Chemical only

Answer: B. Plastic

Explanation: Permanent shape change occurs when the material is plastically deformed.

Q31. The flow stress of a metal generally decreases when the metal is:

A. Heated for hot forging
B. Cooled to extremely low temperature
C. Hardened completely
D. Made brittle

Answer: A. Heated for hot forging

Explanation: Increasing temperature generally reduces resistance to plastic deformation, within the appropriate forging range.

Q32. Excessive heating of a forging billet may cause:

A. Grain growth and burning
B. Improved properties in every case
C. Zero oxidation
D. Complete elimination of defects

Answer: A. Grain growth and burning

Explanation: Excessive temperature can cause undesirable metallurgical changes and oxidation.

Q33. The oxide layer formed during hot forging is called:

A. Scale
B. Flash
C. Slag
D. Burr

Answer: A. Scale

Explanation: Scale forms because the hot metal reacts with oxygen in the atmosphere.

Q34. Hot forging is particularly useful when:

A. Large deformation is required
B. No deformation is required
C. Only surface coating is required
D. Only cutting is required

Answer: A. Large deformation is required

Explanation: Heating reduces resistance to deformation and allows substantial plastic deformation.

Q35. Which forging method generally provides better dimensional accuracy?

A. Cold forging
B. Very high-temperature forging
C. Rough open-die forging only
D. Manual hammering only

Answer: A. Cold forging

Explanation: Cold forging can produce excellent dimensional accuracy and surface finish, although tooling and forming forces are higher.

Q36. One important effect of cold working is:

A. Work hardening
B. Grain melting
C. Complete removal of residual stress
D. Reduction of strength in every case

Answer: A. Work hardening

Explanation: Plastic deformation below the recrystallization temperature generally increases strength and hardness.

Q37. A limitation of cold forging is:

A. High forming load
B. Low dimensional accuracy
C. High oxidation
D. Need for melting

Answer: A. High forming load

Explanation: Higher flow stress at low temperature increases the required forging force.

Q38. Warm forging is positioned approximately between:

A. Hot and cold forging
B. Casting and welding
C. Rolling and machining
D. Grinding and turning

Answer: A. Hot and cold forging

Explanation: Warm forging provides an intermediate-temperature forming condition.

Q39. The main purpose of heating a billet before hot forging is to:

A. Reduce deformation resistance
B. Increase brittleness
C. Prevent all grain movement
D. Eliminate plastic deformation

Answer: A. Reduce deformation resistance

Explanation: Heating makes plastic deformation easier and reduces the required forging force.

Q40. Forging is generally classified as a:

A. Bulk deformation process
B. Joining process
C. Surface coating process
D. Material removal process

Answer: A. Bulk deformation process

Explanation: Forging is one of the major bulk metal-forming processes, along with rolling and extrusion.

B. Hammer and Press Forging — MCQs 41–55

Q41. The main characteristic of hammer forging is:

A. Impact
B. Continuous melting
C. Tensile loading
D. Chemical reaction

Answer: A. Impact

Explanation: Hammer forging uses repeated or single blows to deform the workpiece.

Q42. The main characteristic of press forging is:

A. Gradual application of force
B. Impact only
C. No die contact
D. Tensile loading

Answer: A. Gradual application of force

Explanation: Presses apply force progressively through a controlled stroke.

Q43. Which machine is commonly associated with drop forging?

A. Drop hammer
B. Lathe
C. Milling machine
D. Shaper

Answer: A. Drop hammer

Explanation: A drop hammer uses the potential energy of a raised ram to produce an impact blow.

Q44. In a drop hammer, the ram is:

A. Raised and dropped onto the workpiece
B. Rotated continuously
C. Used as a cutting tool
D. Cooled below room temperature

Answer: A. Raised and dropped onto the workpiece

Explanation: The falling ram provides impact energy to deform the workpiece.

Q45. Hydraulic presses are especially suitable for:

A. Large forgings
B. Only very small screws
C. Cutting thin sheets
D. Grinding surfaces

Answer: A. Large forgings

Explanation: Hydraulic presses can generate very large, controlled forces.

Q46. A mechanical forging press commonly converts rotary motion into:

A. Linear motion
B. Chemical energy
C. Thermal energy only
D. Electrical energy only

Answer: A. Linear motion

Explanation: Crank and eccentric mechanisms convert rotary motion into reciprocating ram movement.

Q47. A screw press generates forging force through:

A. Screw motion
B. Centrifugal force only
C. Gas pressure only
D. Magnetic force

Answer: A. Screw motion

Explanation: Rotational movement of the screw produces controlled axial movement and forging force.

Q48. Compared with a hammer, a press generally applies force:

A. More gradually
B. Only instantaneously
C. Without contacting the workpiece
D. Through tension

Answer: A. More gradually

Explanation: Press forging involves controlled squeezing rather than repeated impact blows.

Q49. Press forging can provide:

A. Better control of deformation
B. No deformation
C. Only surface hardening
D. Only cutting

Answer: A. Better control of deformation

Explanation: The press stroke and force can be controlled more precisely than repeated hammer blows.

Q50. Which equipment is most closely associated with impact forging?

A. Power hammer
B. Hydraulic press
C. Screw jack only
D. Lathe

Answer: A. Power hammer

Explanation: Power hammers deliver repeated impact blows to deform the workpiece.

Q51. A major advantage of hydraulic presses is:

A. High force capacity
B. No force generation
C. Only intermittent operation
D. Inability to control force

Answer: A. High force capacity

Explanation: Hydraulic systems can generate and control very large compressive loads.

Q52. Hammer forging is particularly associated with:

A. High strain rate
B. Zero strain rate
C. Tensile deformation only
D. No contact pressure

Answer: A. High strain rate

Explanation: The rapid impact produces a relatively high deformation rate.

Q53. Press forging generally has a:

A. Lower deformation rate than hammer forging
B. Higher impact rate than hammer forging
C. Zero deformation rate
D. Purely thermal deformation

Answer: A. Lower deformation rate than hammer forging

Explanation: Presses apply deformation more gradually.

Q54. The energy of a drop hammer is mainly associated with:

A. Falling ram
B. Cutting speed
C. Coolant pressure
D. Electric resistance

Answer: A. Falling ram

Explanation: The elevated ram possesses potential energy that is converted into impact energy during the drop.

Q55. Which machine is suitable for controlled high-force forging?

A. Hydraulic press
B. Hand file
C. Drill press only
D. Grinding wheel

Answer: A. Hydraulic press

Explanation: Hydraulic presses provide large and controllable compressive forces.

C. Open-Die and Closed-Die Forging — MCQs 56–70

Q56. In open-die forging, the workpiece is:

A. Compressed between relatively simple dies
B. Completely enclosed in a die cavity
C. Melted inside the die
D. Cut by a milling cutter

Answer: A. Compressed between relatively simple dies

Explanation: The dies do not completely surround the workpiece.

Q57. Open-die forging is particularly suitable for:

A. Large components
B. Mass production of tiny precision screws only
C. Plastic bottles
D. Thin wires only

Answer: A. Large components

Explanation: Large shafts, rings and heavy components are commonly produced using open-die forging.

Q58. Which of the following is a typical open-die forging application?

A. Large shaft
B. Plastic cup
C. Glass lens
D. Paper clip

Answer: A. Large shaft

Explanation: Open-die forging is widely used for large shafts and other heavy components.

Q59. In closed-die forging, the workpiece is:

A. Forced into shaped die impressions
B. Allowed to remain molten
C. Machined by a drill
D. Rolled into a sheet

Answer: A. Forced into shaped die impressions

Explanation: Die cavities determine the final geometry.

Q60. Impression-die forging is another term closely associated with:

A. Closed-die forging
B. Sand casting
C. Wire drawing
D. Arc welding

Answer: A. Closed-die forging

Explanation: Impression dies contain shaped cavities into which the metal flows.

Q61. Flash in impression-die forging forms mainly at the:

A. Die parting line
B. Furnace bottom
C. Core print
D. Billet centre only

Answer: A. Die parting line

Explanation: Excess material is squeezed between the die faces at the parting region.

Q62. The principal disadvantage of flash formation is:

A. Material wastage
B. Zero deformation
C. Complete absence of strength
D. Elimination of grain flow

Answer: A. Material wastage

Explanation: The flash must subsequently be removed, resulting in some material loss.

Q63. Flashless forging requires accurate control of:

A. Billet volume
B. Furnace colour
C. Die paint only
D. Coolant colour

Answer: A. Billet volume

Explanation: The billet must contain approximately the correct amount of material to fill the die without producing significant flash.

Q64. Closed-die forging is generally more suitable than open-die forging for:

A. Complex shapes in production quantities
B. Extremely large simple blocks only
C. Rough preliminary shaping only
D. Melting operations

Answer: A. Complex shapes in production quantities

Explanation: Shaped die cavities can produce relatively complex geometries repeatedly.

Q65. Open-die forging provides:

A. Greater freedom of metal flow
B. Complete confinement of material
C. No deformation
D. Only tensile stress

Answer: A. Greater freedom of metal flow

Explanation: The material can flow laterally beyond the die surfaces.

Q66. A forging operation that increases cross-section while reducing length is:

A. Upsetting
B. Drawing out
C. Rolling
D. Trimming

Answer: A. Upsetting

Explanation: Axial compression causes the material to spread laterally.

Q67. A forging operation that increases length while reducing cross-section is:

A. Drawing out
B. Upsetting
C. Heading
D. Coining

Answer: A. Drawing out

Explanation: The material is elongated while its cross-sectional area decreases.

Q68. Which operation is commonly used to prepare material distribution before impression forging?

A. Fullering
B. Grinding
C. Drilling
D. Lapping

Answer: A. Fullering

Explanation: Fullering helps spread material to appropriate locations before subsequent die operations.

Q69. Edging is primarily used to:

A. Gather material
B. Remove flash
C. Produce surface cracks
D. Melt the billet

Answer: A. Gather material

Explanation: Edging concentrates material in selected regions of the billet.

Q70. Which operation removes flash after impression-die forging?

A. Trimming
B. Fullering
C. Edging
D. Upsetting

Answer: A. Trimming

Explanation: Trimming cuts away the unwanted flash surrounding the forged component.

D. Forging Operations — MCQs 71–85

Q71. Heading is essentially a form of:

A. Upsetting
B. Drawing
C. Rolling
D. Bending only

Answer: A. Upsetting

Explanation: Heading increases the cross-sectional area at one end of a workpiece.

Q72. Which component is commonly produced by heading?

A. Bolt head
B. Large casting mould
C. Sheet-metal die
D. Cutting fluid

Answer: A. Bolt head

Explanation: Heading is widely used for bolts, screws and rivets.

Q73. Coining involves:

A. High-pressure deformation for fine detail
B. Low-pressure casting
C. Gas welding
D. Sand moulding

Answer: A. High-pressure deformation for fine detail

Explanation: Coining reproduces detailed impressions on the surface of the workpiece.

Q74. Which process is commonly associated with manufacturing coins?

A. Coining
B. Fullering
C. Drawing out
D. Edging

Answer: A. Coining

Explanation: Coining is a precision forging process used to reproduce detailed designs.

Q75. Sizing is generally a:

A. Finishing operation
B. Melting operation
C. Casting operation
D. Joining operation

Answer: A. Finishing operation

Explanation: Sizing provides small final deformation to achieve dimensional accuracy.

Q76. Swaging is used primarily to:

A. Modify or reduce cross-section using dies
B. Melt the metal
C. Remove internal gases
D. Produce a mould cavity

Answer: A. Modify or reduce cross-section using dies

Explanation: Swaging shapes the workpiece by die action, often reducing or changing its cross-section.

Q77. Roll forging uses:

A. Rotating grooved rolls
B. Stationary sand moulds
C. Cutting tools
D. Welding electrodes

Answer: A. Rotating grooved rolls

Explanation: The rolls contain grooves that progressively deform the workpiece.

Q78. Roll forging is particularly useful for:

A. Producing tapered sections
B. Producing glass products
C. Cutting threads only
D. Casting hollow sand moulds

Answer: A. Producing tapered sections

Explanation: Roll forging can efficiently produce tapered shafts and similar components.

Q79. Bending in forging is used to produce:

A. Curved or angular shapes
B. Internal porosity
C. Molten metal
D. Sand cores only

Answer: A. Curved or angular shapes

Explanation: Controlled plastic deformation changes the axis or shape of the workpiece.

Q80. Punching in forging is used to:

A. Produce a hole
B. Remove scale only
C. Increase billet length only
D. Produce a riser

Answer: A. Produce a hole

Explanation: A punch is driven into or through the workpiece to create an opening.

Q81. Fullering tools generally have:

A. Rounded or specially shaped surfaces
B. Only flat cutting edges
C. Grinding wheels
D. Drill points

Answer: A. Rounded or specially shaped surfaces

Explanation: Their shape facilitates redistribution of material.

Q82. Drawing out is commonly performed to:

A. Increase length
B. Reduce length
C. Produce flash
D. Create a mould cavity

Answer: A. Increase length

Explanation: Drawing out elongates the workpiece and reduces its cross-sectional area.

Q83. Upsetting is commonly used to produce:

A. Enlarged ends
B. Long thin sheets
C. Internal casting cavities
D. Sand moulds

Answer: A. Enlarged ends

Explanation: Axial compression produces a larger cross-section, making it useful for bolt and rivet heads.

Q84. Which operation is associated with removing unwanted metal from the edge of a forging?

A. Trimming
B. Fullering
C. Edging
D. Drawing

Answer: A. Trimming

Explanation: Trimming removes flash and other unwanted excess material.

Q85. Which operation is used to improve the final dimensional accuracy of a forging with relatively small deformation?

A. Sizing
B. Fullering
C. Bending
D. Drawing out

Answer: A. Sizing

Explanation: Sizing is a finishing operation used to bring a forged part closer to the required dimensions.

E. Forging Defects, Dies & Quality — MCQs 86–100

Q86. A forging lap is caused by:

A. Folding of metal over itself
B. Gas trapped in a mould
C. Shrinkage of molten metal
D. Sand inclusion

Answer: A. Folding of metal over itself

Explanation: A lap occurs when material folds during metal flow and the fold is not properly consolidated.

Q87. Which defect is associated with internal cracking in certain steels due to hydrogen?

A. Flakes
B. Flash
C. Misrun
D. Scab

Answer: A. Flakes

Explanation: Flakes are internal cracks associated with hydrogen and delayed cracking mechanisms in susceptible steels.

Q88. Underfilling means:

A. The die cavity is not completely filled
B. Excess flash is produced
C. The forging is completely machined
D. The billet is melted

Answer: A. The die cavity is not completely filled

Explanation: Underfilling leaves portions of the die impression unfilled.

Q89. One possible cause of underfilling is:

A. Insufficient billet material
B. Excessive correct material volume
C. Perfect die design
D. Proper forging temperature

Answer: A. Insufficient billet material

Explanation: If there is inadequate material, the die cavity cannot be completely filled.

Q90. Die shift is primarily caused by:

A. Misalignment of die halves
B. Excessive permeability
C. Gas in moulding sand
D. Riser failure

Answer: A. Misalignment of die halves

Explanation: Incorrect die alignment produces mismatch between the two sides of the forging.

Q91. Scale formation during hot forging is mainly due to:

A. Oxidation
B. Hydrogen absorption only
C. Plastic deformation alone
D. Machining

Answer: A. Oxidation

Explanation: The hot metal reacts with oxygen and forms oxide scale.

Q92. Excessive scale can adversely affect:

A. Surface quality
B. Only electrical conductivity
C. Only colour
D. Nothing

Answer: A. Surface quality

Explanation: Scale can produce rough surfaces and may become embedded or cause dimensional issues.

Q93. A good forging die should have:

A. High wear resistance
B. Very low strength
C. Very low toughness
D. Poor thermal stability

Answer: A. High wear resistance

Explanation: Dies experience repeated mechanical and thermal loading and therefore require good wear resistance.

Q94. Forging dies are commonly made from:

A. Suitable tool steels
B. Wood only
C. Pure rubber
D. Glass

Answer: A. Suitable tool steels

Explanation: Tool steels and specialized die materials provide the required strength, toughness and wear resistance.

Q95. The grain flow in a properly forged component generally:

A. Follows the component geometry
B. Disappears completely
C. Becomes random in every region
D. Is unrelated to deformation

Answer: A. Follows the component geometry

Explanation: Controlled metal flow can produce favorable directional grain structure.

Q96. Favorable grain flow can improve:

A. Fatigue resistance
B. Porosity
C. Casting shrinkage
D. Mould permeability

Answer: A. Fatigue resistance

Explanation: Appropriate grain flow can enhance mechanical performance, especially under cyclic loading.

Q97. Which forging process generally produces no flash by design?

A. Flashless forging
B. Conventional impression forging
C. Open-die forging
D. Drop forging with uncontrolled billet volume

Answer: A. Flashless forging

Explanation: Flashless forging uses accurately controlled material volume to fill the die without significant flash formation.

Q98. A major economic advantage of flashless forging is:

A. Better material utilization
B. Increased scrap
C. Lower dimensional accuracy
D. Increased oxidation

Answer: A. Better material utilization

Explanation: Since little or no flash is generated, less material is wasted.

Q99. Which of the following is generally a disadvantage of forging?

A. High die cost
B. High strength
C. Favorable grain flow
D. Good fatigue resistance

Answer: A. High die cost

Explanation: Forging dies can be expensive, particularly for complex closed-die components.

Q100. Which statement best describes forging?

A. Metal is plastically shaped primarily by compressive forces
B. Metal is always melted and poured into a mould
C. Material is removed entirely by cutting
D. Two pieces are joined by an adhesive

Answer: A. Metal is plastically shaped primarily by compressive forces

Explanation: This is the fundamental principle of forging.

CHAPTER 9 — EXAM REVISION SHEET

Remember these relationships:

Forging → Compressive force

Hot forging → Lower flow stress + large deformation

Cold forging → Better accuracy + work hardening

Hammer → Impact

Press → Gradual force

Open die → Large/simple/heavy components

Closed die → Complex production components

Flash → Excess metal

Trimming → Flash removal

Upsetting → Length ↓, Area ↑

Drawing out → Length ↑, Area ↓

Fullering → Distribute metal

Edging → Gather metal

Heading → Bolt/rivet/screw heads

Coining → Fine details + high pressure

Sizing → Final dimensional improvement

Roll forging → Rotating rolls

Lap → Folded metal

Flake → Hydrogen-related internal crack

Underfill → Incomplete die filling

Die shift → Die misalignment

Grain flow → Important forging advantage

CHAPTER 10 — SHEET METAL WORKING

10.1 Introduction

Sheet metal working is a manufacturing process in which thin metal sheets are cut, bent, formed, or otherwise shaped into useful components.

It is extensively used in:

Automobile bodies

Aircraft structures

Railway coaches

Electrical panels

Kitchen equipment

Metal containers

Computer cabinets

Refrigerators

Air-conditioner bodies

Automobile fuel tanks

Roofing products

Sheet-metal operations are generally characterized by high production rate, relatively low material wastage in suitable processes, and good dimensional repeatability.

10.2 Definition of Sheet Metal Working

Sheet metal working is a manufacturing process in which sheet or strip metal is subjected to operations such as cutting, bending and forming to produce the required shape.

The material is generally processed without removing large quantities of material in the form of chips.

Key Concept

Sheet Metal Working = Cutting + Bending + Forming

10.3 Important Terms in Sheet Metal Working

Before studying individual operations, the following terms are essential.

1. Sheet

A relatively thin, flat piece of metal.

2. Strip

A long, narrow metal sheet supplied in continuous or coil form.

3. Blank

A piece of sheet metal cut to the required shape for a subsequent forming operation.

4. Punch

The tool that moves relative to the die and performs cutting or forming.

5. Die

The stationary or supporting tool containing the required opening or forming surface.

6. Clearance

The difference or gap between the punch and die dimensions.

7. Burr

A sharp, unwanted projection produced along a cut edge.

8. Slug

The piece of material removed during a punching operation.

10.4 Classification of Sheet-Metal Operations

Sheet-metal operations can broadly be divided into:

A. Cutting Operations

Shearing

Blanking

Punching

Perforating

Notching

Slitting

Trimming

B. Bending Operations

V-bending

U-bending

Angle bending

Flanging

Hemming

Curling

C. Drawing/Forming Operations

Deep drawing

Stretch forming

Spinning

Embossing

Bulging

10.5 Shearing

Shearing is the process of cutting sheet metal by applying shear forces using cutting edges.

The material is separated without producing a conventional saw-cut.

Basic Principle

Punch/upper blade + lower blade/die + sheet → separation

10.6 Blanking

In blanking, the piece that is cut out is the required product.

The remaining sheet is scrap, subject to layout and process conditions.

Most Important Rule

Blanking → Blank is the product

10.7 Punching

In punching, the hole produced in the sheet is the required feature, while the removed piece is generally considered scrap.

Most Important Rule

Punching → Hole is the product

The removed portion is called the slug.

10.8 Blanking vs Punching

Blanking	Punching
Cut-out piece is useful	Hole is useful
Blank is the product	Sheet with hole is the product
Cut-out is called blank	Removed piece is called slug
Remaining sheet is generally scrap	Slug is generally scrap

Easy Memory Trick

Blanking → Blank = useful

Punching → Hole = useful

10.9 Perforating

Perforating produces a number of holes in a sheet by punching.

Examples:

Perforated screens
Ventilation panels
Filters
Decorative sheets

10.10 Notching

Notching removes material from the edge of a sheet.

It may be used to prepare the sheet for:

Bending

Joining

Forming

10.11 Slitting

Slitting separates sheet or strip material along a line, usually using rotary cutters or knives.

It is widely used to produce narrower strips from wider coils.

10.12 Trimming

Trimming removes unwanted material from a previously formed or drawn component.

Example

Removing excess flange from a deep-drawn cup.

10.13 Bending

Bending is a sheet-metal operation in which the sheet is plastically deformed around an axis.

The thickness generally remains approximately constant, although some thinning can occur depending on the operation and severity.

10.14 V-Bending

In V-bending, the sheet is bent using a V-shaped die.

It is one of the most common sheet-metal bending operations.

10.15 U-Bending

In U-bending, the sheet is formed into a U-shaped cross-section.

10.16 Flanging

Flanging produces a flange or rim along the edge of a sheet or component.

Applications include:

Joining

Stiffening

Assembly

Structural reinforcement

10.17 Hemming

Hemming folds the edge of a sheet over itself.

It is commonly used to:

Remove sharp edges

Improve stiffness

Improve appearance

Provide safe edges

Automobile body panels commonly use hemming.

10.18 Curling

Curling rolls the edge of a sheet into a curved or tubular form.

It can be used to:

Strengthen edges

Provide rounded edges

Prepare components for assembly

10.19 Springback

Springback is the elastic recovery that occurs after the bending force is removed.

As a result, the final angle may differ slightly from the die angle.

Important

Springback → Elastic recovery after unloading

10.20 Why Does Springback Occur?

During bending, the sheet experiences both:

Plastic deformation

Elastic deformation

When the load is removed, the elastic portion recovers, causing the sheet to partially return toward its original shape.

10.21 Methods of Reducing Springback

Springback can be reduced by techniques such as:

Over-bending

Bottoming

Coining

Proper tool design

Appropriate process parameters

10.22 Neutral Axis

During bending, a region exists within the sheet where the longitudinal strain is approximately zero.

This is called the neutral axis.

Important

Material outside the neutral axis on the bending side experiences tension, while material on the opposite side experiences compression.

10.23 Bend Allowance

Bend allowance represents the length of material required along the neutral region for a bend.

It is used when calculating the flat length of a sheet-metal component before bending.

10.24 Deep Drawing

Deep drawing is a sheet-metal forming process in which a flat blank is drawn into a die cavity using a punch to produce a cup-shaped or hollow component.

Typical products:

Cups

Cans

Utensils

Automobile components

Fuel tanks

Cylindrical containers

10.25 Main Components of Deep Drawing

Important components include:

Punch
Die
Blank holder
Blank
Die cavity

10.26 Function of Blank Holder

The blank holder helps prevent unwanted wrinkling of the flange during deep drawing.

Important

Blank holder → Controls wrinkling

However, excessive blank-holder force can restrict material flow and increase the possibility of tearing.

10.27 Drawing Ratio

The drawing ratio is commonly expressed as:

where:

= blank diameter

= punch diameter

A larger drawing ratio generally indicates a more severe drawing operation.

10.28 Deep Drawing Defects

Important defects include:

Wrinkling

Tearing

Earing

Surface scratches

Excessive thinning

10.29 Wrinkling

Wrinkling is the formation of unwanted folds or wrinkles, commonly in the flange region.

A suitable blank-holder force helps control it.

10.30 Tearing

Tearing occurs when the tensile stress becomes too high and the sheet fails.

It may occur near the punch radius or other highly stressed regions.

Possible causes:

Excessive drawing ratio

Excessive blank-holder force

Small punch radius

Inadequate lubrication

Material limitations

10.31 Earing

Earing refers to the formation of ears or uneven peaks around the rim of a deep-drawn cup.

It is primarily related to anisotropy of the sheet material.

Important

Earing → Plastic anisotropy

10.32 Lubrication in Deep Drawing

Lubrication helps:

Reduce friction

Reduce drawing force

Reduce tool wear

Improve surface finish

Facilitate material flow

10.33 Stretch Forming

In stretch forming, a sheet is clamped at its edges and stretched over a form block or die.

The sheet undergoes tensile deformation.

It is widely used in:

Aircraft structures

Large curved panels

Aerospace components

10.34 Spinning

Metal spinning forms a circular sheet blank over a rotating mandrel using a tool.

It is suitable for:

Conical components

Cylindrical components

Hemispherical components

Reflectors

Utensils

10.35 Embossing

Embossing produces raised or recessed patterns on sheet metal.

Applications include:

Decorative panels

Name plates

Identification markings

Stiffening patterns

10.36 Coining in Sheet Metal

In sheet-metal forming, coining involves localized high-pressure deformation to produce accurate details or impressions.

It can also be used to improve dimensional control in certain operations.

10.37 Punch and Die Clearance

Clearance is the difference between the dimensions of the punch and die, considering the appropriate cutting relationship.

Correct clearance is extremely important.

Too little clearance may cause:

Excessive force

Increased tool wear

Poor cutting conditions

Too much clearance may cause:

Large burr

Poor edge quality

Excessive deformation

10.38 Burr

A burr is a sharp projection left on the edge after a cutting operation.

Burr formation is influenced by:

Tool sharpness

Clearance

Material properties

Tool alignment

Sheet thickness

10.39 Press Tools

Sheet-metal operations are often performed using press tools.

A typical press tool consists of:

Punch

Die

Punch plate

Die block

Guide elements

Stripper

Back plate

Other supporting components

10.40 Stripper

A stripper helps remove the sheet or strip from the punch after the cutting operation.

It can also help hold the material in position.

10.41 Progressive Die

A progressive die performs multiple operations at different stations as the strip moves through the die.

Advantages:

High production rate

Automation

Good repeatability

10.42 Compound Die

A compound die performs multiple cutting operations in a single stroke at one station.

This is an important distinction.

Remember:

Progressive die → Multiple stations

Compound die → Multiple operations, one station

10.43 Combination Die

A combination die performs both:

Cutting

Forming

operations in the same die during the manufacturing sequence.

10.44 Single-Operation Die

A single-operation die performs one principal operation at a time.

It is simpler than progressive or compound tooling.

10.45 Sheet-Metal Materials

Common sheet-metal materials include:

Mild steel

Stainless steel

Aluminium

Copper

Brass

Zinc

Titanium alloys

Material selection depends on:

Formability

Strength

Corrosion resistance

Weight

Cost

Surface requirements

10.46 Formability

Formability is the ability of a sheet material to undergo the required deformation without failure.

Good formability is particularly important for:

Deep drawing

Stretch forming

Bending

10.47 Ductility and Sheet Forming

Ductile materials generally undergo larger plastic deformation before fracture.

Therefore, ductility is an important consideration in sheet-metal forming.

10.48 Advantages of Sheet-Metal Working

Major advantages include:

High production rate

Good repeatability

Low material wastage in suitable operations

Good surface finish

Suitable for automation

Suitable for mass production

Lightweight components can be produced

10.49 Limitations

Limitations include:

Tooling cost

Springback

Wrinkling

Tearing

Burr formation

Material limitations

Requirement for accurate tooling

10.50 QUICK REVISION TABLE

Term	Key Point
Sheet	Thin flat metal
Blank	Cut piece used as product/forming starting piece
Punch	Moving forming/cutting tool
Die	Supporting/forming tool
Clearance	Gap between punch and die
Blanking	Blank is useful
Punching	Hole is useful
Slug	Removed piece in punching
Perforating	Multiple holes
Notching	Removes material from edge
Slitting	Separates strip/sheet longitudinally
Trimming	Removes unwanted material
Bending	Plastic deformation around an axis
Springback	Elastic recovery
Hemming	Folding sheet edge
Flanging	Producing a flange
Deep drawing	Flat blank → hollow component
Blank holder	Controls wrinkling
Earing	Due to anisotropy
Stretch forming	Sheet stretched over form
Spinning	Sheet formed over rotating mandrel
Embossing	Raised/recessed pattern
Burr	Sharp projection on cut edge
Progressive die	Multiple stations
Compound die	Multiple operations, one station

Q1. Sheet-metal working primarily involves:

A. Cutting, bending and forming
B. Melting only
C. Welding only
D. Grinding only

Answer: A. Cutting, bending and forming

Explanation: Sheet-metal manufacturing uses various cutting and forming operations to produce components from sheets and strips.

Practice

Q2. In blanking, the:

A. Cut-out piece is the product
B. Hole is the product
C. Slug is always the product
D. Die is the product

Answer: A. Cut-out piece is the product

Explanation: The blank separated from the sheet is the required component.

Q3. In punching, the useful product is generally:

A. The hole in the sheet
B. The slug
C. The punch
D. The die

Answer: A. The hole in the sheet

Explanation: Punching creates a hole; the removed slug is generally scrap.

Q4. The removed piece in punching is called:

A. Slug
B. Blank
C. Riser
D. Flash

Answer: A. Slug

Explanation: The material removed during punching is called a slug.

Q5. Which operation produces multiple holes in a sheet?

A. Perforating
B. Drawing
C. Bending
D. Hemming

Answer: A. Perforating

Explanation: Perforating involves producing a series of holes in sheet material.

Q6. Notching removes material from:

A. The edge of a sheet
B. The centre of a billet only
C. A forging die
D. A casting riser

Answer: A. The edge of a sheet

Explanation: Notching is commonly used to remove material from the edge before subsequent forming or joining.

Q7. Slitting is used to:

A. Separate sheet or strip along a line
B. Produce deep cups
C. Produce raised patterns
D. Produce bolt heads

Answer: A. Separate sheet or strip along a line

Explanation: Slitting divides wide sheet or strip into narrower sections.

Q8. Which operation removes excess material from a formed sheet-metal component?

A. Trimming
B. Drawing
C. Stretching
D. Embossing

Answer: A. Trimming

Explanation: Trimming removes unwanted portions from a previously formed component.

Q9. Bending primarily produces:

A. Plastic deformation around an axis
B. Melting
C. Casting
D. Welding

Answer: A. Plastic deformation around an axis

Explanation: Bending changes the shape of the sheet without intentionally removing material.

Q10. Springback is caused by:

A. Elastic recovery
B. Melting
C. Plastic flow only
D. Oxidation

Answer: A. Elastic recovery

Explanation: After the bending load is removed, the elastically deformed portion recovers.

Q11. Springback can be compensated by:

A. Over-bending
B. Increasing burrs
C. Reducing all tooling accuracy
D. Removing the die

Answer: A. Over-bending

Explanation: The sheet can be intentionally bent beyond the desired final angle to compensate for elastic recovery.

Q12. During bending, the neutral axis has approximately:

A. Zero longitudinal strain
B. Maximum tensile strain
C. Maximum compressive strain
D. Zero thickness

Answer: A. Zero longitudinal strain

Explanation: The neutral region separates tensile and compressive deformation zones.

Q13. The outer region of a bent sheet generally experiences:

A. Tension
B. Compression only
C. No deformation
D. Melting

Answer: A. Tension

Explanation: The outer fibres are stretched during bending.

Q14. The inner region of a bent sheet generally experiences:

A. Compression
B. Tension only
C. No stress
D. Melting

Answer: A. Compression

Explanation: The inner fibres are compressed during bending.

Q15. Deep drawing converts a flat blank into:

A. A cup-like or hollow component
B. A weld joint
C. A gear tooth
D. A forged shaft only

Answer: A. A cup-like or hollow component

Explanation: A punch draws the blank into a die cavity.

Q16. The main function of a blank holder in deep drawing is to:

A. Control wrinkling
B. Produce a riser
C. Melt the blank
D. Cut threads

Answer: A. Control wrinkling

Explanation: The blank holder controls the flange and helps prevent excessive wrinkling.

Q17. Excessive blank-holder force can:

A. Restrict material flow and promote tearing
B. Always eliminate tearing
C. Eliminate friction completely
D. Produce casting porosity

Answer: A. Restrict material flow and promote tearing

Explanation: Excessive restraint prevents the sheet from flowing properly into the die cavity.

Q18. Earing in deep drawing is primarily caused by:

A. Anisotropy
B. Casting shrinkage
C. Gas porosity
D. Welding current

Answer: A. Anisotropy

Explanation: Directional differences in plastic properties can produce uneven ear formation.

Q19. The drawing ratio is commonly defined as:

A. Blank diameter / Punch diameter
B. Punch diameter / Blank thickness
C. Sheet thickness / Blank diameter
D. Die diameter / Sheet thickness

Answer: A. Blank diameter / Punch diameter

Explanation: A common drawing ratio is .

Q20. Lubrication during deep drawing helps to:

A. Reduce friction
B. Increase tool wear
C. Increase tearing intentionally
D. Eliminate material flow

Answer: A. Reduce friction

Explanation: Proper lubrication facilitates material flow and reduces friction and tool wear.

Q21. Stretch forming involves:

A. Stretching sheet over a form
B. Punching holes only
C. Cutting strips only
D. Forging a billet

Answer: A. Stretching sheet over a form

Explanation: The sheet is clamped and stretched over a die or form block.

Q22. Metal spinning generally uses:

A. A rotating mandrel
B. A stationary sand mould
C. A casting riser
D. A forging hammer only

Answer: A. A rotating mandrel

Explanation: A circular sheet blank is formed against a rotating mandrel.

Q23. Embossing produces:

A. Raised or recessed patterns
B. Internal casting cavities
C. Forging flash
D. Welding beads

Answer: A. Raised or recessed patterns

Explanation: Embossing is used to create surface details and can also improve stiffness.

Q24. A burr is:

A. A sharp projection on a cut edge
B. A deep drawing ratio
C. A type of die
D. A sheet-metal blank

Answer: A. A sharp projection on a cut edge

Explanation: Burrs are unwanted projections produced during cutting operations.

Q25. Excessive punch-die clearance can result in:

A. Larger burr and poorer edge quality
B. Zero burr
C. Perfect edge quality in every case
D. No cutting force

Answer: A. Larger burr and poorer edge quality

Explanation: Incorrectly large clearance can produce excessive deformation and a rougher cut edge.

A. Cutting Operations — MCQs 26–40

Q26. In a shearing operation, the sheet is separated primarily by:

A. Tensile stress
B. Shear stress
C. Bending stress only
D. Thermal stress

Answer: B. Shear stress

Explanation: Cutting of sheet metal occurs mainly through shearing deformation followed by fracture.

Q27. Which operation produces a useful cut-out piece called a blank?

A. Punching
B. Blanking
C. Slitting
D. Notching

Answer: B. Blanking

Explanation: In blanking, the separated portion is the desired product.

Q28. In punching, the removed portion is called:

A. Blank
B. Slug
C. Flash
D. Burr

Answer: B. Slug

Explanation: The slug is the piece removed from the sheet during punching.

Q29. In blanking, the die opening generally determines the:

A. Blank size
B. Punch colour
C. Sheet hardness
D. Lubricant viscosity

Answer: A. Blank size

Explanation: In conventional blanking, the die opening determines the external dimensions of the blank.

Q30. In punching, the punch generally determines the:

A. Hole size
B. Sheet thickness
C. Die hardness
D. Blank material

Answer: A. Hole size

Explanation: The punch size corresponds closely to the desired hole dimensions, with allowance for cutting clearance.

Q31. The gap between punch and die is called:

A. Draft
B. Clearance
C. Rake
D. Allowance only

Answer: B. Clearance

Explanation: Clearance is provided between the cutting edges of the punch and die.

Q32. Proper punch-die clearance is important for:

A. Cutting force and edge quality
B. Colour of sheet
C. Melting point only
D. Electrical resistance only

Answer: A. Cutting force and edge quality

Explanation: Clearance strongly affects cutting force, burr formation, tool life and cut-edge quality.

Q33. If punch-die clearance is too small, it may result in:

A. Excessive cutting force and tool wear
B. No deformation
C. Zero tool load
D. Perfect operation in every case

Answer: A. Excessive cutting force and tool wear

Explanation: Insufficient clearance increases the resistance to shearing and may accelerate tool damage.

Q34. If punch-die clearance is excessively large, it may cause:

A. Large burr and poor edge quality
B. Zero burr
C. No fracture
D. No cutting action

Answer: A. Large burr and poor edge quality

Explanation: Excessive clearance causes more deformation before fracture and generally produces a rougher edge with a larger burr.

Q35. The sharp projection left after sheet-metal cutting is called:

A. Burr
B. Slug
C. Blank
D. Flash

Answer: A. Burr

Explanation: Burr is unwanted material projecting from the cut edge.

Q36. Burr formation is influenced by:

A. Clearance
B. Tool sharpness
C. Material properties
D. All of the above

Answer: D. All of the above

Explanation: Clearance, tool condition and workpiece properties all influence burr formation.

Q37. A large number of holes produced simultaneously or sequentially in sheet metal is known as:

A. Perforating
B. Forging
C. Drawing
D. Rolling

Answer: A. Perforating

Explanation: Perforating creates multiple holes in sheet material.

Q38. Notching is primarily used to:

A. Remove material from the sheet edge
B. Produce a deep cup
C. Stretch the sheet
D. Produce a forged shaft

Answer: A. Remove material from the sheet edge

Explanation: Notching removes portions from the edge of a sheet or strip.

Q39. Slitting is generally performed to:

A. Divide sheet or strip into narrower sections
B. Produce deep-drawn cups
C. Produce raised patterns
D. Produce bolt heads

Answer: A. Divide sheet or strip into narrower sections

Explanation: Slitting separates sheet or strip along a predetermined line.

Q40. Which operation removes unwanted material from a previously formed component?

A. Trimming
B. Stretch forming
C. Bending
D. Spinning

Answer: A. Trimming

Explanation: Trimming removes excess material from the edges of formed or drawn parts.

B. Bending Operations — MCQs 41–55

Q41. During sheet-metal bending, the outer fibres are generally subjected to:

A. Tension
B. Compression
C. No strain
D. Shear only

Answer: A. Tension

Explanation: The outer region of a bent sheet is stretched.

Q42. During bending, the inner fibres are generally subjected to:

A. Compression
B. Tension
C. No stress
D. Thermal expansion only

Answer: A. Compression

Explanation: The inner region is compressed during bending.

Q43. The neutral axis during bending is the region where longitudinal strain is approximately:

A. Zero
B. Maximum
C. Infinite
D. Equal to tensile strain

Answer: A. Zero

Explanation: The neutral axis separates the tensile and compressive regions.

Q44. Springback is:

A. Elastic recovery after unloading
B. Plastic deformation during loading
C. Melting after heating
D. Fracture during cutting

Answer: A. Elastic recovery after unloading

Explanation: The elastic portion of deformation recovers when the bending force is removed.

Q45. Springback generally causes the final bend angle to:

A. Differ from the tooling angle
B. Become exactly zero
C. Become infinite
D. Remain unchanged in all cases

Answer: A. Differ from the tooling angle

Explanation: Elastic recovery changes the final geometry after unloading.

Q46. One method of compensating for springback is:

A. Over-bending
B. Increasing sheet thickness indefinitely
C. Eliminating all tooling
D. Reducing all deformation

Answer: A. Over-bending

Explanation: The workpiece is bent beyond the desired angle so that elastic recovery brings it closer to the target.

Q47. V-bending uses:

A. V-shaped die
B. Circular saw
C. Flat grinding wheel
D. Sand mould

Answer: A. V-shaped die

Explanation: A punch presses the sheet into a V-shaped die.

Q48. U-bending produces:

A. U-shaped cross-section
B. Circular hole
C. Flat blank only
D. Threaded shaft

Answer: A. U-shaped cross-section

Explanation: The sheet is bent around a U-shaped forming geometry.

Q49. Flanging is used to produce:

A. A flange or rim
B. A hole only
C. A casting cavity
D. A forging flash

Answer: A. A flange or rim

Explanation: Flanging forms a projecting edge or rim on the sheet.

Q50. Hemming involves:

A. Folding the sheet edge over
B. Punching a circular hole
C. Stretching a sheet over a die only
D. Cutting a strip longitudinally

Answer: A. Folding the sheet edge over

Explanation: Hemming folds an edge to improve safety, stiffness and appearance.

Q51. Automobile body panels commonly use:

A. Hemming
B. Sand casting
C. Forging only
D. Thread rolling only

Answer: A. Hemming

Explanation: Hemming is widely used to create safe and stiff edges on sheet-metal body panels.

Q52. Curling is used to:

A. Roll the edge into a curved form
B. Punch holes
C. Remove a slug
D. Produce a forging die

Answer: A. Roll the edge into a curved form

Explanation: Curling produces a rounded or tubular edge.

Q53. Bend allowance is related to:

A. Length of material required for a bend
B. Punch hardness
C. Sheet colour
D. Tool temperature only

Answer: A. Length of material required for a bend

Explanation: Bend allowance helps determine the flat pattern length needed to produce the required bent geometry.

Q54. Which property is particularly desirable for severe sheet forming?

A. Good ductility
B. Extreme brittleness
C. Very low formability
D. Zero plasticity

Answer: A. Good ductility

Explanation: Ductility allows significant plastic deformation before fracture.

Q55. Which factor can influence springback?

A. Material properties
B. Sheet thickness
C. Bend geometry
D. All of the above

Answer: D. All of the above

Explanation: Springback depends on material strength, elastic modulus, thickness, bend radius and process conditions.

C. Deep Drawing — MCQs 56–75

Q56. Deep drawing is used to produce:

A. Hollow cup-like components
B. Gear teeth by cutting
C. Welded joints
D. Forging dies

Answer: A. Hollow cup-like components

Explanation: A flat sheet blank is drawn into a die cavity by a punch.

Q57. The main tools in deep drawing are:

A. Punch, die and blank holder
B. Drill, reamer and tap
C. Hammer and anvil only
D. Grinding wheel and dresser

Answer: A. Punch, die and blank holder

Explanation: These components control the deformation and material flow during drawing.

Q58. The blank holder primarily prevents:

A. Wrinkling
B. All friction
C. Elastic recovery
D. Punch movement

Answer: A. Wrinkling

Explanation: The blank holder restrains the flange and reduces buckling/wrinkling.

Q59. Excessive blank-holder pressure can increase the possibility of:

A. Tearing
B. Wrinkling only
C. No deformation
D. Casting porosity

Answer: A. Tearing

Explanation: Excessive restraint makes it difficult for the blank to flow into the die.

Q60. The drawing ratio is generally expressed as:

A. Blank diameter / Punch diameter
B. Punch diameter / Blank diameter
C. Sheet thickness / Blank diameter
D. Die radius / Punch radius

Answer: A. Blank diameter / Punch diameter

Explanation: A common drawing ratio is .

Q61. A higher drawing ratio generally means:

A. More severe drawing
B. No deformation
C. Less material movement
D. Only cutting

Answer: A. More severe drawing

Explanation: A larger ratio means the blank must undergo greater reduction to reach the required cup diameter.

Q62. A common defect in deep drawing is:

A. Wrinkling
B. Flash only
C. Sand inclusion
D. Welding porosity

Answer: A. Wrinkling

Explanation: Compressive stresses in the flange can cause wrinkles.

Q63. Tearing in deep drawing occurs mainly due to:

A. Excessive tensile stress
B. Zero tensile stress
C. Excessive compressive stress only
D. No deformation

Answer: A. Excessive tensile stress

Explanation: If the material cannot withstand the tensile stresses generated during drawing, it may tear.

Q64. Earing is associated with:

A. Anisotropy of sheet metal
B. Casting temperature
C. Welding current
D. Forging flash

Answer: A. Anisotropy of sheet metal

Explanation: Directional variation in plastic properties causes uneven deformation around the rim.

Q65. Ears are generally observed around the:

A. Rim of a drawn cup
B. Centre of the punch only
C. Bottom of the die only
D. Tool shank

Answer: A. Rim of a drawn cup

Explanation: Anisotropic deformation creates peaks or ears around the cup circumference.

Q66. Lubrication in deep drawing primarily reduces:

A. Friction
B. Ductility
C. Sheet thickness
D. Blank diameter

Answer: A. Friction

Explanation: Lubrication facilitates sliding between the sheet and tooling.

Q67. Proper lubrication can also reduce:

A. Tool wear
B. Material flow
C. Formability
D. Blank holding

Answer: A. Tool wear

Explanation: Lower friction reduces heat and mechanical wear at the tool-workpiece interface.

Q68. A very small punch radius may increase the tendency for:

A. Tearing
B. Earing elimination
C. Zero deformation
D. Slitting

Answer: A. Tearing

Explanation: A sharp punch radius can produce severe localized deformation and stress concentration.

Q69. A deep-drawn cylindrical cup is produced using:

A. Punch and die
B. Welding electrode
C. Lathe tool
D. Milling cutter

Answer: A. Punch and die

Explanation: The punch pushes the blank into the die cavity.

Q70. The flange region of a deep-drawn blank mainly undergoes:

A. Compressive circumferential stress
B. Pure tension only
C. No deformation
D. Melting

Answer: A. Compressive circumferential stress

Explanation: The flange is subjected to circumferential compression, which can cause wrinkling.

Q71. The wall of a deep-drawn cup is mainly subjected to:

A. Tensile stress in the drawing direction
B. Pure compression only
C. No stress
D. Shear only

Answer: A. Tensile stress in the drawing direction

Explanation: Material is pulled into the die cavity, producing tensile stresses along the wall/drawing direction.

Q72. The blank holder force should be:

A. Properly controlled
B. Always maximum possible
C. Always zero
D. Independent of material and process

Answer: A. Properly controlled

Explanation: Too little force promotes wrinkling, while too much force can restrict flow and promote tearing.

Q73. One important application of deep drawing is manufacturing:

A. Metal cups and cans
B. Forging hammers
C. Cutting inserts only
D. Grinding wheels

Answer: A. Metal cups and cans

Explanation: Deep drawing is widely used for hollow sheet-metal containers.

Q74. If a deep drawing operation exceeds the material’s forming capability, the likely result is:

A. Failure/tearing
B. Perfect forming
C. No deformation
D. Automatic annealing

Answer: A. Failure/tearing

Explanation: Excessive deformation can exceed the forming limit of the sheet.

Q75. Intermediate annealing may be required in:

A. Multi-stage severe drawing
B. Simple punching only
C. Slitting only
D. Single light bending only

Answer: A. Multi-stage severe drawing

Explanation: Annealing can restore ductility between drawing stages when significant work hardening has accumulated.

D. Press Tools and Dies — MCQs 76–90

Q76. A progressive die performs operations:

A. At multiple stations
B. Only outside the press
C. Without a strip
D. Only during casting

Answer: A. At multiple stations

Explanation: The strip advances from one station to the next, with different operations performed at successive positions.

Q77. A compound die performs multiple operations:

A. At one station in one stroke
B. At many independent machines only
C. Without a punch
D. Only during forging

Answer: A. At one station in one stroke

Explanation: Multiple cutting operations can be completed simultaneously at a single die station.

Q78. A combination die performs:

A. Cutting and forming operations
B. Only grinding
C. Only welding
D. Only rolling

Answer: A. Cutting and forming operations

Explanation: Combination dies combine cutting and forming functions.

Q79. A stripper in a press tool is used mainly to:

A. Remove material from the punch
B. Heat the sheet
C. Melt the die
D. Increase sheet thickness

Answer: A. Remove material from the punch

Explanation: The stripper separates the sheet/strip from the punch after the stroke.

Q80. A major advantage of progressive dies is:

A. High production rate
B. No tooling requirement
C. No material movement
D. Very low repeatability

Answer: A. High production rate

Explanation: Progressive dies are highly suitable for automated mass production.

Q81. Progressive dies are particularly suitable for:

A. Mass production
B. One-off handmade components only
C. Casting sand preparation
D. Welding repair only

Answer: A. Mass production

Explanation: Multiple operations can be integrated into a continuous strip-processing sequence.

Q82. The part that performs cutting or forming movement in a press tool is the:

A. Punch
B. Die shoe only
C. Guide post
D. Back plate

Answer: A. Punch

Explanation: The punch moves relative to the die and performs the intended operation.

Q83. The stationary component receiving the punch during cutting is generally the:

A. Die
B. Punch
C. Stripper
D. Guide pin

Answer: A. Die

Explanation: The die provides the opening or forming surface against which the sheet is deformed/cut.

Q84. Guide elements in a press tool help to:

A. Maintain alignment
B. Increase sheet thickness
C. Melt the punch
D. Produce lubricants

Answer: A. Maintain alignment

Explanation: Guide posts and bushings help maintain proper alignment between punch and die.

Q85. Poor punch-die alignment can cause:

A. Uneven clearance and tool damage
B. Perfect cutting
C. Zero wear
D. No force requirement

Answer: A. Uneven clearance and tool damage

Explanation: Misalignment changes the clearance around the cutting edges and can accelerate wear.

Q86. The die block primarily:

A. Provides the die opening/forming cavity
B. Supplies hydraulic pressure
C. Measures sheet hardness
D. Acts as lubricant

Answer: A. Provides the die opening/forming cavity

Explanation: The die block contains the working die geometry.

Q87. A press tool is generally mounted on a:

A. Press machine
B. Lathe only
C. Furnace only
D. Welding table only

Answer: A. Press machine

Explanation: Press tools are designed to perform sheet-metal cutting and forming operations in presses.

Q88. The selection of punch-die clearance depends significantly on:

A. Sheet material and thickness
B. Paint colour
C. Operator height
D. Machine room size

Answer: A. Sheet material and thickness

Explanation: Different materials and thicknesses require appropriate clearances for efficient cutting.

Q89. Excessive tool wear can result in:

A. Poor dimensional and edge quality
B. Perfect burr-free cutting indefinitely
C. Zero force
D. Increased ductility of the sheet

Answer: A. Poor dimensional and edge quality

Explanation: Worn cutting edges degrade the quality and dimensional accuracy of the cut.

Q90. A major advantage of press-tool production is:

A. Repeatability
B. Extremely low production rate
C. No need for tooling
D. No dimensional control

Answer: A. Repeatability

Explanation: Properly designed press tools can produce large numbers of consistent components.

E. Forming, Defects and Applications — MCQs 91–100

Q91. Stretch forming is widely used in:

A. Aerospace components
B. Sand casting
C. Brick making
D. Welding electrodes

Answer: A. Aerospace components

Explanation: Stretch forming is suitable for producing large curved sheet structures used in aircraft and aerospace applications.

Q92. In stretch forming, the sheet is:

A. Stretched over a form
B. Poured into a mould
C. Forged between hammers
D. Machined by a cutter

Answer: A. Stretched over a form

Explanation: The sheet is held under tension while being wrapped around the forming surface.

Q93. Metal spinning generally produces:

A. Axisymmetric components
B. Random irregular castings
C. Flat bars only
D. Welded joints

Answer: A. Axisymmetric components

Explanation: Spinning is particularly suitable for circular and rotationally symmetric components.

Q94. A common product made by metal spinning is:

A. Reflector
B. Gear tooth
C. Connecting rod
D. Welding electrode

Answer: A. Reflector

Explanation: Reflectors and other conical, cylindrical and hemispherical components can be produced by spinning.

Q95. Embossing is mainly used to:

A. Produce raised or recessed details
B. Produce deep holes only
C. Remove all sheet material
D. Produce casting cores

Answer: A. Produce raised or recessed details

Explanation: Embossing creates surface patterns, markings or stiffening features.

Q96. Wrinkling in deep drawing is primarily associated with:

A. Compressive stresses in the flange
B. Pure tensile stress only
C. Melting
D. Welding

Answer: A. Compressive stresses in the flange

Explanation: Circumferential compression can make the flange unstable and cause wrinkles.

Q97. Tearing in deep drawing is primarily associated with:

A. Excessive tensile stress
B. Zero stress
C. Only compressive stress
D. Sand inclusion

Answer: A. Excessive tensile stress

Explanation: If the tensile stress exceeds the material’s forming capability, fracture can occur.

Q98. Which defect is strongly related to sheet-metal anisotropy?

A. Earing
B. Burr
C. Flash
D. Die shift

Answer: A. Earing

Explanation: Directional plastic properties cause uneven height around the rim of a drawn cup.

Q99. Which of the following is an important advantage of sheet-metal working?

A. High production rate
B. High chip generation in every operation
C. Extremely poor repeatability
D. No possibility of automation

Answer: A. High production rate

Explanation: Press-based sheet-metal processes are highly suitable for mass production and automation.

Q100. Which statement is correct?

A. Blanking produces a useful blank, while punching produces a useful hole
B. Blanking and punching always have identical products
C. Punching produces only forged components
D. Blanking is a welding operation

Answer: A. Blanking produces a useful blank, while punching produces a useful hole

Explanation: This distinction is one of the most important concepts in sheet-metal cutting operations.

CHAPTER 10 — ONE-PAGE EXAM REVISION

Cutting

Shearing → Separation by shear

Blanking → Blank is product

Punching → Hole is product

Slug → Removed piece during punching

Perforating → Multiple holes

Notching → Edge material removal

Slitting → Dividing strip/sheet

Trimming → Excess material removal

Bending

Bending → Plastic deformation

Outer surface → Tension

Inner surface → Compression

Neutral axis → Approximately zero longitudinal strain

Springback → Elastic recovery

Hemming → Edge folded over

Flanging → Flange formation

Deep Drawing

Blank → Flat starting sheet

Punch → Pushes blank into die

Blank holder → Controls wrinkling

Drawing ratio → Blank diameter / Punch diameter

Wrinkling → Compressive flange stress

Tearing → Excessive tensile stress

Earing → Anisotropy

Lubrication → Reduces friction

Dies

Progressive die → Multiple stations

Compound die → Multiple operations at one station

Combination die → Cutting + forming

Stripper → Removes sheet from punch

CHAPTER 11 — METAL CUTTING & MACHINE TOOLS

11.1 Introduction

Metal cutting is one of the most important manufacturing processes in workshop technology. It is a material-removal process in which unwanted material is removed from a workpiece in the form of chips to obtain the required:

Shape

Size

Accuracy

Surface finish

Metal cutting is performed using cutting tools mounted on machine tools such as:

Lathe

Drilling machine

Shaper

Planer

Slotter

Milling machine

Grinding machine

11.2 Definition of Metal Cutting

Metal cutting is a manufacturing process in which a cutting tool removes unwanted material from a workpiece in the form of chips to produce the required geometry and surface finish.

Key Concept

Metal Cutting = Workpiece + Cutting Tool + Relative Motion + Material Removal

11.3 Definition of Machine Tool

A machine tool is a power-driven machine used to hold and move a cutting tool and/or workpiece to perform machining operations accurately.

Examples:

Lathe

Milling machine

Drilling machine

Shaper

Planer

Slotter

Grinding machine

11.4 Machining

Machining is the controlled removal of material from a workpiece using a cutting tool.

Examples:

Turning

Drilling

Milling

Shaping

Planning

Boring

Reaming

11.5 Cutting Tool

A cutting tool is a device having one or more cutting edges designed to remove material from a workpiece.

Cutting tools may be:

Single-point

Double-point

Multi-point

11.6 Single-Point Cutting Tool

A single-point cutting tool has essentially one principal cutting edge responsible for material removal.

Examples:

Lathe turning tool

Shaper tool

Planer tool

11.7 Multi-Point Cutting Tool

A multi-point cutting tool has more than one cutting edge.

Examples:

Milling cutter

Broach

Grinding wheel

Drill

Important

A drill is generally considered a multi-point cutting tool.

11.8 Basic Requirements of a Cutting Tool

A good cutting tool should possess:

High hardness

High hot hardness

Good wear resistance

Adequate toughness

Resistance to thermal shock

Chemical stability

Ability to retain its cutting edge

11.9 Tool Hardness

A cutting tool must generally be harder than the workpiece under cutting conditions.

Hardness helps the tool:

Penetrate the workpiece

Resist deformation

Maintain the cutting edge

11.10 Hot Hardness

Hot hardness is the ability of a tool material to retain its hardness at elevated temperatures.

This property is particularly important in high-speed machining.

Important

Hot hardness → Hardness retained at high temperature

11.11 Tool Toughness

Toughness is the ability to absorb energy before fracture.

A cutting tool requires adequate toughness to resist:

Chipping

Impact

Interrupted cutting

Sudden loads

11.12 Tool Wear Resistance

Wear resistance allows a tool to maintain its geometry and cutting performance for a longer period.

11.13 Cutting Tool Materials

Common cutting tool materials include:

High-speed steel (HSS)

Cemented carbide

Ceramics

Cermets

Cubic boron nitride (CBN)

Diamond

11.14 High-Speed Steel

HSS is an alloy tool steel capable of retaining useful hardness at elevated temperatures.

Advantages:

Good toughness

Relatively easy to grind

Suitable for many cutting operations

Can withstand interrupted cutting better than many brittle tool materials

Applications include:

Drills

Taps

Reamers

Milling cutters

Turning tools

11.15 Cemented Carbide

Cemented carbide tools have very high:

Hardness

Wear resistance

Hot hardness

They permit higher cutting speeds than conventional HSS in many applications.

A common carbide system is based on tungsten carbide particles bonded with cobalt, although other carbide systems are also used.

11.16 Ceramic Cutting Tools

Ceramic tools possess:

High hot hardness

Good wear resistance

High-temperature capability

However, many ceramics are relatively brittle and can be sensitive to shock and vibration.

11.17 CBN

Cubic Boron Nitride (CBN) is an extremely hard cutting-tool material.

It is particularly useful for machining:

Hardened steels

Hard alloys

Difficult-to-machine materials

11.18 Diamond Cutting Tools

Diamond has extremely high hardness and excellent wear resistance.

It is used particularly for:

Non-ferrous materials

Abrasive materials

Precision machining

Diamond is generally not preferred for machining ordinary ferrous steels at high temperatures because of chemical interaction/diffusion issues.

11.19 Cutting Parameters

Three fundamental machining parameters are:

Cutting speed

Feed

Depth of cut

11.20 Cutting Speed

Cutting speed is the relative speed between the cutting edge and the workpiece at the cutting zone.

For turning:

where:

= cutting speed in m/min

= workpiece diameter in mm

= spindle speed in rpm

11.21 Feed

Feed is the distance advanced by the cutting tool relative to the workpiece during one revolution or one stroke, depending on the machine/process.

For turning, feed is commonly expressed in:

mm/revolution

11.22 Feed Rate

Feed rate is the speed at which the tool advances through the workpiece.

For turning:

where:

= feed rate in mm/min

= feed in mm/rev

= spindle speed in rpm

11.23 Depth of Cut

Depth of cut is the thickness of material removed in one machining pass measured approximately perpendicular to the machined surface.

For external turning:

where:

= initial diameter

= final diameter

11.24 Cutting Tool Geometry

Important tool angles include:

Rake angle

Clearance angle

Cutting-edge angle

Side cutting-edge angle

End cutting-edge angle

Nose radius

11.25 Rake Angle

The rake angle influences:

Chip flow

Cutting force

Cutting temperature

Tool strength

It is an important parameter in cutting-tool geometry.

11.26 Positive Rake Angle

A positive rake angle generally:

Reduces cutting forces

Facilitates chip flow

Can reduce power requirement

However, excessive positive rake can weaken the cutting edge.

11.27 Negative Rake Angle

Negative rake angles generally provide:

Stronger cutting edge

Greater wedge strength

But they can increase cutting forces and power requirements.

11.28 Clearance Angle

The clearance angle prevents excessive rubbing between the tool flank and the newly machined surface.

Important

Clearance angle → Prevents rubbing

11.29 Nose Radius

The nose radius is the rounded portion at the tool tip.

Increasing nose radius can generally improve surface finish under suitable conditions, but excessively large nose radius can increase cutting forces and vibration.

11.30 Chip

A chip is the unwanted material removed from the workpiece during machining.

Chip formation is an important indicator of:

Cutting conditions

Material behaviour

Tool geometry

11.31 Types of Chips

Common classifications include:

Continuous chip

Discontinuous chip

Continuous chip with built-up edge

11.32 Continuous Chip

Continuous chips are generally produced when machining:

Ductile materials

At relatively suitable/high cutting speeds

With appropriate positive rake conditions

They form a relatively continuous ribbon.

11.33 Discontinuous Chip

Discontinuous chips are commonly associated with:

Brittle materials

Lower cutting speeds under certain conditions

Less favourable cutting conditions

The chip breaks into separate segments.

11.34 Built-Up Edge

A built-up edge (BUE) is a layer of workpiece material that adheres to the cutting edge during machining.

It can affect:

Surface finish

Tool geometry

Cutting forces

Dimensional accuracy

11.35 Factors Affecting Built-Up Edge

BUE is influenced by:

Cutting speed

Workpiece material

Tool material

Rake angle

Cutting temperature

Friction

11.36 Machining Forces

The major force components in machining are commonly resolved into:

Cutting force

Feed force

Radial/thrust force

The exact terminology depends on the machining operation and force system used.

11.37 Cutting Power

Machining power can be approximately expressed as:

where:

= cutting power

= cutting force

= cutting velocity

Appropriate unit conversion must be used.

11.38 Cutting Fluids

Cutting fluids are used to:

Cool the cutting zone

Lubricate

Reduce friction

Flush chips

Improve tool life

Improve surface finish

11.39 Types of Cutting Fluids

Common categories include:

Straight cutting oils

Soluble oils

Synthetic fluids

Semi-synthetic fluids

11.40 Functions of Cutting Fluid

A cutting fluid may provide:

Cooling

Removes heat from the cutting zone.

Lubrication

Reduces friction between tool, chip and workpiece.

Chip removal

Helps carry chips away from the cutting region.

11.41 Tool Wear

Tool wear is the gradual loss of tool material during machining.

Major types include:

Flank wear

Crater wear

Nose wear

Notch wear

11.42 Flank Wear

Flank wear occurs on the flank face of the cutting tool.

It is caused mainly by rubbing and abrasive/adhesive interactions with the newly machined surface.

11.43 Crater Wear

Crater wear occurs on the rake face of the tool where the chip flows.

It is strongly associated with:

High temperature

Diffusion

Adhesion

Chemical interaction

11.44 Tool Life

Tool life is the useful cutting time or machining quantity obtained before the tool reaches a specified wear criterion or becomes unsuitable for machining.

11.45 Taylor’s Tool Life Equation

A commonly used empirical relationship is:

where:

= cutting speed

= tool life

= tool-life exponent

= constant for specified conditions

Important Relationship

As cutting speed increases, tool life generally decreases.

11.46 Machining Economics

The selection of cutting speed is a compromise between:

Production rate

Tool life

Tool-changing cost

Machining cost

Higher speed can increase productivity but may reduce tool life.

11.47 Orthogonal Cutting

In orthogonal cutting, the cutting edge is perpendicular to the direction of cutting velocity.

The chip flows approximately normal to the cutting edge.

11.48 Oblique Cutting

In oblique cutting, the cutting edge is inclined to the direction of cutting velocity.

Chip flow occurs sideways relative to the cutting edge.

11.49 Orthogonal vs Oblique Cutting

Orthogonal Cutting	Oblique Cutting
Cutting edge perpendicular to cutting velocity	Cutting edge inclined
Simplified 2D analysis	More realistic 3D cutting
Chip flows approximately normal to cutting edge	Chip flows sideways
Simpler force analysis	More complex force analysis

11.50 Important Revision Points

Metal cutting → Material removal as chips

Machine tool → Power-driven machining machine

Single-point → Lathe/shaper/planer tools

Multi-point → Drill/mill/broach

HSS → Good toughness + hot hardness

Carbide → High cutting speed

CBN → Hardened steels

Diamond → Many non-ferrous/abrasive materials

Cutting speed → m/min

Feed → mm/rev in turning

Depth of cut → Material removed radially in turning

Positive rake → Lower cutting force

Clearance angle → Prevents rubbing

Continuous chip → Usually ductile material

Discontinuous chip → Often brittle material

BUE → Material adhered to cutting edge

Flank wear → Flank face

Crater wear → Rake face

Taylor equation →

Orthogonal cutting → Cutting edge perpendicular to cutting velocity

Oblique cutting → Cutting edge inclined

Q1. Metal cutting is primarily a:

A. Material-removal process
B. Joining process
C. Casting process
D. Heat-treatment process

Answer: A. Material-removal process

Explanation: Machining removes unwanted material from a workpiece, generally in the form of chips.

Practice

Q2. Which of the following is a machine tool?

A. Lathe
B. Furnace
C. Welding electrode
D. Hammer only

Answer: A. Lathe

Explanation: A lathe is a power-driven machine used to perform various machining operations.

Q3. A conventional lathe turning tool is generally:

A. Single-point
B. Double-point
C. Multi-point
D. Zero-point

Answer: A. Single-point

Explanation: A standard turning tool primarily uses one main cutting edge.

Q4. Which is a multi-point cutting tool?

A. Drill
B. Single-point turning tool
C. Shaper tool
D. Planer tool

Answer: A. Drill

Explanation: A drill has multiple cutting edges, usually two main lips in a conventional twist drill.

Q5. Which property is essential for a cutting tool?

A. High hardness
B. Very low hardness
C. High brittleness only
D. Low wear resistance

Answer: A. High hardness

Explanation: Tool hardness helps the cutting edge penetrate and remove material without excessive deformation.

Q6. Hot hardness means the ability of a tool to:

A. Retain hardness at elevated temperature
B. Melt at low temperature
C. Absorb water
D. Reduce workpiece hardness

Answer: A. Retain hardness at elevated temperature

Explanation: Cutting generates heat, so the tool must retain adequate hardness at operating temperature.

Q7. Which cutting-tool material generally has good toughness and is widely used for drills and taps?

A. High-speed steel
B. Glass
C. Rubber
D. Wood

Answer: A. High-speed steel

Explanation: HSS combines useful hardness with relatively good toughness and is widely used for cutting tools.

Q8. Cemented carbide tools generally permit:

A. Higher cutting speeds than HSS
B. No cutting speed
C. Only hand machining
D. No heat generation

Answer: A. Higher cutting speeds than HSS

Explanation: Carbides retain high hardness at elevated temperatures and can support high-speed machining.

Q9. CBN tools are particularly suitable for machining:

A. Hardened steels
B. Soft wood
C. Rubber
D. Paper

Answer: A. Hardened steels

Explanation: CBN has excellent hardness and thermal stability for machining hard ferrous materials.

Q10. Diamond cutting tools are especially useful for:

A. Many non-ferrous and abrasive materials
B. Ordinary high-temperature ferrous machining in every case
C. Wooden components only
D. Sand moulding

Answer: A. Many non-ferrous and abrasive materials

Explanation: Diamond offers exceptional hardness and wear resistance but has limitations when machining ferrous materials at elevated temperatures.

Q11. Which of the following is NOT a fundamental cutting parameter?

A. Cutting speed
B. Feed
C. Depth of cut
D. Colour of workpiece

Answer: D. Colour of workpiece

Explanation: Cutting speed, feed and depth of cut are fundamental machining parameters.

Q12. In turning, cutting speed is commonly expressed in:

A. m/min
B. mm/rev
C. kg
D. N/mm² only

Answer: A. m/min

Explanation: Cutting speed is conventionally expressed in metres per minute.

Q13. In turning, feed is commonly expressed in:

A. mm/rev
B. m/s only
C. kg/min
D. N

Answer: A. mm/rev

Explanation: Feed indicates tool travel per revolution of the workpiece.

Q14. For turning, cutting speed is given by:

A.
B.
C.
D.

Answer: A.

Explanation: When is in mm and in rpm, the equation gives cutting speed in m/min.

Q15. If workpiece diameter increases while spindle speed remains constant, cutting speed:

A. Increases
B. Decreases
C. Becomes zero
D. Remains exactly unchanged

Answer: A. Increases

Explanation: From , cutting speed is directly proportional to diameter at constant speed.

Q16. In external turning, depth of cut is:

A.
B.
C.
D.

Answer: A.

Explanation: The diameter reduction occurs on both sides of the workpiece.

Q17. The main purpose of a clearance angle is to:

A. Prevent rubbing of the tool flank
B. Increase rubbing
C. Eliminate the cutting edge
D. Produce chips without deformation

Answer: A. Prevent rubbing of the tool flank

Explanation: Clearance separates the flank from the newly machined surface.

Q18. A positive rake angle generally:

A. Reduces cutting force
B. Always increases cutting force
C. Prevents chip formation
D. Eliminates tool wear completely

Answer: A. Reduces cutting force

Explanation: Positive rake facilitates shearing and chip flow, generally reducing cutting resistance.

Q19. Excessively positive rake can:

A. Weaken the cutting edge
B. Increase edge strength indefinitely
C. Prevent all wear
D. Eliminate heat

Answer: A. Weaken the cutting edge

Explanation: Increasing positive rake reduces the wedge angle and can make the cutting edge less robust.

Q20. A continuous chip is commonly associated with:

A. Ductile materials
B. Very brittle materials only
C. Wood only
D. Ceramic moulding sand

Answer: A. Ductile materials

Explanation: Ductile materials can undergo substantial plastic deformation and form continuous chips under suitable conditions.

Q21. Discontinuous chips are commonly associated with:

A. Brittle materials
B. Highly ductile materials under every condition
C. Rubber
D. Glass fibre only

Answer: A. Brittle materials

Explanation: Brittle materials tend to fracture during chip formation, producing segmented chips.

Q22. Built-up edge is:

A. Workpiece material adhered to the cutting edge
B. A type of machine tool
C. A cutting fluid
D. A grinding wheel

Answer: A. Workpiece material adhered to the cutting edge

Explanation: BUE develops when work material adheres to the tool near the cutting edge.

Q23. Flank wear occurs mainly on the:

A. Flank face
B. Rake face only
C. Shank only
D. Tool holder only

Answer: A. Flank face

Explanation: Flank wear develops on the clearance/flank face in contact with the newly machined surface.

Q24. Crater wear occurs mainly on the:

A. Rake face
B. Flank face only
C. Tool shank
D. Machine bed

Answer: A. Rake face

Explanation: The chip flows over the rake face and high temperature can cause crater formation there.

Q25. Taylor’s tool-life equation is:

A.
B.
C.
D.

Answer: A.

Explanation: Taylor’s empirical relationship connects cutting speed and tool life for specified machining conditions.

A. CUTTING SPEED, FEED & DEPTH OF CUT — MCQs 26–40

Q26. In turning, if the spindle speed is doubled while diameter remains constant, cutting speed will:

A. Become half
B. Become double
C. Remain unchanged
D. Become four times

Answer: B. Become double

Explanation:

At constant , cutting speed is directly proportional to spindle speed .

Practice

Q27. A workpiece of diameter 100 mm rotates at 500 rpm. The cutting speed is approximately:

A. 78.5 m/min
B. 157 m/min
C. 314 m/min
D. 500 m/min

Answer: A. 157 m/min

Explanation:

Therefore, B is the correct option.

Q28. In a turning operation, the diameter changes from 60 mm to 50 mm. The depth of cut is:

A. 2 mm
B. 5 mm
C. 10 mm
D. 55 mm

Answer: B. 5 mm

Explanation:

Q29. If feed is 0.2 mm/rev and spindle speed is 600 rpm, feed rate is:

A. 60 mm/min
B. 100 mm/min
C. 120 mm/min
D. 300 mm/min

Answer: C. 120 mm/min

Explanation:

Q30. Increasing feed in turning generally increases:

A. Material removal rate
B. Tool life indefinitely
C. Workpiece hardness only
D. Machine accuracy automatically

Answer: A. Material removal rate

Explanation: Increasing feed increases the amount of material removed per revolution, subject to machine and tool limitations.

Q31. Increasing depth of cut generally increases:

A. Material removal rate
B. Tool clearance angle automatically
C. Workpiece diameter
D. Tool hardness

Answer: A. Material removal rate

Explanation: A larger depth of cut removes more material in each pass.

Q32. The unit of feed in turning is commonly:

A. mm/rev
B. m/min
C. N
D. kW

Answer: A. mm/rev

Q33. The unit of cutting speed is commonly:

A. m/min
B. mm/rev
C. kg
D. N

Answer: A. m/min

Q34. If diameter is reduced by machining while rpm remains constant, cutting speed:

A. Decreases
B. Increases
C. Remains constant
D. Becomes infinite

Answer: A. Decreases

Explanation: Cutting speed is proportional to diameter at constant spindle speed.

Q35. Which parameter is normally measured in mm/revolution in turning?

A. Feed
B. Cutting speed
C. Cutting power
D. Cutting force

Answer: A. Feed

Q36. Material removal rate in turning is influenced by:

A. Feed
B. Depth of cut
C. Cutting speed
D. All of the above

Answer: D. All of the above

Explanation: These parameters jointly determine the volume of material removed per unit time.

Q37. If feed is increased while all other conditions remain unchanged, the chip cross-section generally:

A. Increases
B. Becomes zero
C. Remains exactly unchanged
D. Disappears

Answer: A. Increases

Explanation: Higher feed generally increases uncut chip thickness.

Q38. A higher cutting speed generally causes:

A. Higher cutting-zone temperature
B. Zero heat generation
C. No tool wear
D. No chip formation

Answer: A. Higher cutting-zone temperature

Explanation: Increasing cutting speed generally increases the rate of energy conversion into heat and can increase tool temperature.

Q39. A machining operation requires 2 mm depth of cut. If the original diameter is 40 mm, the final diameter will be:

A. 36 mm
B. 38 mm
C. 40 mm
D. 42 mm

Answer: A. 36 mm

Explanation:

Q40. The feed rate in turning is calculated as:

A.
B.
C.
D.

Answer: A.

Explanation:

where is feed in mm/rev and is rpm.

B. CHIP FORMATION & ORTHOGONAL CUTTING — MCQs 41–55

Q41. During metal cutting, the material removed from the workpiece is called:

A. Chip
B. Flash
C. Riser
D. Slug only

Answer: A. Chip

Explanation: Chips are produced when the cutting tool shears material away from the workpiece.

Q42. The primary deformation zone in machining is associated with:

A. Shearing of work material
B. Cooling only
C. Tool holding
D. Machine-bed vibration

Answer: A. Shearing of work material

Explanation: Plastic deformation primarily occurs along the shear zone during chip formation.

Q43. In orthogonal cutting, the cutting edge is:

A. Perpendicular to cutting velocity
B. Parallel to cutting velocity
C. At any random angle
D. Curved around the workpiece

Answer: A. Perpendicular to cutting velocity

Explanation: This is the defining geometric simplification of orthogonal cutting.

Q44. In oblique cutting, the cutting edge is:

A. Inclined to the cutting velocity
B. Always perpendicular
C. Always parallel
D. Absent

Answer: A. Inclined to the cutting velocity

Q45. Orthogonal cutting is generally treated as:

A. Two-dimensional cutting
B. Purely thermal cutting
C. Casting
D. Welding

Answer: A. Two-dimensional cutting

Explanation: Orthogonal cutting is a simplified 2D model useful for analysing chip formation and cutting forces.

Q46. Oblique cutting is generally:

A. Three-dimensional
B. One-dimensional
C. Zero-dimensional
D. Purely thermal

Answer: A. Three-dimensional

Explanation: The inclination of the cutting edge causes sideways chip flow and a more complex 3D force system.

Q47. The angle between the rake face and a reference plane is related to:

A. Rake angle
B. Clearance angle only
C. Helix angle only
D. Lead angle only

Answer: A. Rake angle

Explanation: Rake angle describes the inclination of the rake face and strongly affects chip flow and cutting forces.

Q48. The main function of the rake face is to:

A. Allow chip flow
B. Hold the machine bed
C. Support the workpiece only
D. Cool the spindle

Answer: A. Allow chip flow

Explanation: The chip slides over the rake face after being sheared from the workpiece.

Q49. The chip thickness after cutting is generally:

A. Greater than the uncut chip thickness
B. Always equal to zero
C. Less than the uncut thickness in all cases
D. Independent of deformation

Answer: A. Greater than the uncut chip thickness

Explanation: Plastic deformation compresses the material, causing the chip to become thicker.

Q50. Chip thickness ratio is commonly defined as:

A. Uncut chip thickness / cut chip thickness
B. Cut chip thickness / uncut chip thickness
C. Cutting speed / feed
D. Feed / cutting speed

Answer: A. Uncut chip thickness / cut chip thickness

Explanation:

where is uncut chip thickness and is chip thickness after cutting.

Q51. The chip thickness ratio is generally:

A. Less than 1
B. Always greater than 10
C. Equal to infinity
D. Zero in normal cutting

Answer: A. Less than 1

Explanation: Since chip thickness increases due to plastic deformation, , making .

Q52. The shear plane is the region where:

A. Severe plastic deformation occurs
B. The machine bed moves
C. Cutting fluid is stored
D. The tool is mounted

Answer: A. Severe plastic deformation occurs

Explanation: The work material undergoes intense shearing along the primary shear zone.

Q53. Increasing positive rake angle generally causes the shear angle to:

A. Increase
B. Become zero
C. Always decrease
D. Remain mathematically fixed under all conditions

Answer: A. Increase

Explanation: In simplified cutting theory, increasing rake angle generally increases shear angle and reduces deformation/work.

Q54. A larger shear angle generally indicates:

A. Reduced chip thickness and lower deformation
B. Infinite chip thickness
C. No cutting
D. Increased tool mass

Answer: A. Reduced chip thickness and lower deformation

Explanation: A larger shear angle shortens the shear plane and generally reduces the amount of plastic deformation.

Q55. Merchant’s analysis is primarily associated with:

A. Metal-cutting force and shear-angle relationships
B. Welding design
C. Casting defects
D. Heat-treatment furnaces

Answer: A. Metal-cutting force and shear-angle relationships

Explanation: Merchant’s cutting model provides an important analytical framework for orthogonal cutting.

C. CUTTING FORCES & POWER — MCQs 56–65

Q56. The force acting in the direction of cutting velocity is commonly called:

A. Cutting force
B. Feed force
C. Radial force
D. Holding force

Answer: A. Cutting force

Q57. Cutting power is approximately given by:

A.
B.
C.
D.

Answer: A.

Explanation: Power is force multiplied by velocity, with suitable unit conversion.

Q58. If cutting force remains constant and cutting speed doubles, cutting power:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Explanation: Since , power is directly proportional to cutting speed at constant force.

Q59. The feed force acts generally:

A. In the feed direction
B. Only vertically upward
C. Opposite gravity
D. Along the machine bed only

Answer: A. In the feed direction

Explanation: Force components are commonly resolved according to the cutting and feed directions.

Q60. Cutting force is affected by:

A. Feed
B. Depth of cut
C. Work material
D. All of the above

Answer: D. All of the above

Explanation: Cutting force depends on machining parameters, material properties, tool geometry and cutting conditions.

Q61. Increasing depth of cut generally:

A. Increases cutting force
B. Eliminates cutting force
C. Makes the workpiece disappear
D. Has no effect under all conditions

Answer: A. Increases cutting force

Explanation: A larger material cross-section is being sheared.

Q62. Increasing feed generally:

A. Increases cutting force
B. Always reduces cutting force
C. Eliminates chip formation
D. Has no effect

Answer: A. Increases cutting force

Explanation: Higher feed generally increases uncut chip thickness and therefore cutting load.

Q63. Cutting power is normally expressed in:

A. kW
B. mm/rev
C. m/min only
D. rpm only

Answer: A. kW

Explanation: Machining power is commonly expressed in watts or kilowatts.

Q64. The efficiency of a machine tool is related to:

A. Useful cutting power versus input power
B. Workpiece colour
C. Tool length only
D. Chip shape only

Answer: A. Useful cutting power versus input power

Q65. If cutting speed is expressed in m/min and force in newtons, power calculation requires:

A. Appropriate unit conversion
B. No conversion ever
C. Conversion to kilograms only
D. Multiplication by diameter only

Answer: A. Appropriate unit conversion

Explanation: SI power requires velocity in m/s when force is in newtons.

D. CUTTING FLUIDS — MCQs 66–75

Q66. A major function of cutting fluid is:

A. Cooling
B. Increasing friction
C. Increasing tool wear
D. Preventing chip formation

Answer: A. Cooling

Q67. Cutting fluid also provides:

A. Lubrication
B. Hardening of every workpiece
C. Casting
D. Welding

Answer: A. Lubrication

Q68. Cutting fluid can help improve:

A. Tool life
B. Tool wear rate
C. Friction
D. Heat generation

Answer: A. Tool life

Explanation: Cooling and lubrication can reduce thermal and mechanical stresses on the cutting tool.

Q69. Cutting fluids may assist in:

A. Chip removal
B. Increasing chip adhesion intentionally
C. Increasing tool temperature
D. Eliminating machine motion

Answer: A. Chip removal

Q70. Soluble oils are generally:

A. Oil-water emulsions used for cooling and lubrication
B. Pure gases
C. Solid cutting tools
D. Abrasive wheels

Answer: A. Oil-water emulsions used for cooling and lubrication

Q71. Straight cutting oils are primarily:

A. Oil-based fluids
B. Pure water only
C. Solid lubricants only
D. Gases

Answer: A. Oil-based fluids

Q72. Which cutting-fluid function helps reduce friction between tool and chip?

A. Lubrication
B. Casting
C. Forging
D. Annealing

Answer: A. Lubrication

Q73. Excessive cutting temperature can cause:

A. Increased tool wear
B. Infinite tool life
C. Zero thermal effects
D. No change in tool properties

Answer: A. Increased tool wear

Q74. Cutting fluid selection depends on:

A. Work material
B. Cutting operation
C. Tool material
D. All of the above

Answer: D. All of the above

Explanation: Fluid selection must consider the machining operation, material, tooling and required finish.

Q75. One important purpose of coolant is to:

A. Remove heat from the cutting zone
B. Increase cutting temperature
C. Increase friction
D. Reduce tool hardness

Answer: A. Remove heat from the cutting zone

E. TOOL WEAR & TOOL LIFE — MCQs 76–90

Q76. Tool wear means:

A. Gradual loss of tool material
B. Increase in tool dimensions
C. Heat treatment of the tool
D. Sharpening of the tool

Answer: A. Gradual loss of tool material

Q77. Flank wear occurs on the:

A. Flank face
B. Rake face only
C. Tool shank only
D. Machine table

Answer: A. Flank face

Q78. Crater wear occurs mainly on:

A. Rake face
B. Flank face
C. Tool holder
D. Machine bed

Answer: A. Rake face

Q79. Crater wear is strongly associated with:

A. High temperature and chip flow
B. Workpiece storage
C. Machine painting
D. Tool packaging

Answer: A. High temperature and chip flow

Q80. Flank wear is strongly related to:

A. Rubbing between tool flank and machined surface
B. Casting shrinkage
C. Welding current
D. Furnace atmosphere only

Answer: A. Rubbing between tool flank and machined surface

Q81. Tool life is generally defined with respect to:

A. A specified wear criterion
B. Tool colour
C. Machine weight
D. Workpiece length only

Answer: A. A specified wear criterion

Explanation: Tool life ends when the tool reaches a specified wear limit or no longer produces acceptable machining.

Q82. Taylor’s tool-life equation is:

A.
B.
C.
D.

Answer: A.

Q83. According to Taylor’s equation, increasing cutting speed generally:

A. Decreases tool life
B. Increases tool life indefinitely
C. Has no effect
D. Makes tool life infinite

Answer: A. Decreases tool life

Q84. If and are constants, doubling cutting speed will generally:

A. Reduce tool life
B. Double tool life
C. Have no effect
D. Eliminate tool wear

Answer: A. Reduce tool life

Explanation: From , higher requires lower .

Q85. Tool wear is generally accelerated by:

A. Excessive cutting temperature
B. Appropriate lubrication only
C. Proper cutting conditions only
D. Correct tool geometry only

Answer: A. Excessive cutting temperature

Q86. Which mechanism can contribute to tool wear at high temperatures?

A. Diffusion
B. Painting
C. Welding of machine bed
D. Casting

Answer: A. Diffusion

Explanation: At elevated temperatures, diffusion between tool and work/chip materials can contribute to wear.

Q87. Adhesive wear occurs when:

A. Material transfers between contacting surfaces
B. The tool melts completely
C. The workpiece is cast
D. The machine is switched off

Answer: A. Material transfers between contacting surfaces

Q88. Abrasive wear is associated with:

A. Hard particles or hard constituents rubbing against the tool
B. Only coolant flow
C. Machine vibration alone
D. Tool painting

Answer: A. Hard particles or hard constituents rubbing against the tool

Q89. A worn cutting tool may produce:

A. Poor surface finish
B. Improved finish indefinitely
C. Zero cutting force
D. No heat

Answer: A. Poor surface finish

Q90. Excessive tool wear may also cause:

A. Dimensional inaccuracy
B. Perfect dimensional accuracy
C. Zero vibration
D. Elimination of cutting forces

Answer: A. Dimensional inaccuracy

F. MACHINABILITY & TOOL MATERIALS — MCQs 91–100

Q91. Machinability refers to:

A. Ease with which a material can be machined satisfactorily
B. Ability to be painted
C. Ability to be welded only
D. Ability to be cast only

Answer: A. Ease with which a material can be machined satisfactorily

Q92. A material with good machinability generally allows:

A. Good tool life and acceptable surface finish under suitable conditions
B. Extremely rapid tool failure
C. No chip formation
D. No material removal

Answer: A. Good tool life and acceptable surface finish under suitable conditions

Q93. Which tool material has very high hardness and good hot hardness?

A. Cemented carbide
B. Mild steel
C. Copper
D. Aluminium

Answer: A. Cemented carbide

Q94. Which material is commonly used for drills, taps and reamers?

A. High-speed steel
B. Rubber
C. Wood
D. Glass

Answer: A. High-speed steel

Q95. CBN stands for:

A. Cubic Boron Nitride
B. Carbon Based Nickel
C. Cubic Beryllium Nitride
D. Carbon Boron Nickel

Answer: A. Cubic Boron Nitride

Q96. CBN is particularly useful for machining:

A. Hardened ferrous materials
B. Soft wood
C. Paper
D. Plastic sheets only

Answer: A. Hardened ferrous materials

Q97. Diamond is characterized by:

A. Extremely high hardness
B. Very low hardness
C. Very low wear resistance
D. Complete chemical inertness with every material

Answer: A. Extremely high hardness

Q98. Ceramic cutting tools generally have:

A. High hot hardness but relatively low toughness
B. Very low hardness and very high ductility
C. No thermal resistance
D. No cutting capability

Answer: A. High hot hardness but relatively low toughness

Explanation: Many ceramic tools are hard and temperature-resistant but relatively brittle.

Q99. Which property is especially important for interrupted cutting?

A. Toughness
B. Colour
C. Electrical conductivity only
D. Density only

Answer: A. Toughness

Explanation: Interrupted cuts subject the tool to impact and mechanical shock, making toughness important.

Q100. The most suitable general statement about cutting-tool selection is:

A. Tool material must be selected according to work material and cutting conditions
B. One tool material is best for every operation
C. Tool hardness is never important
D. Cutting speed has no relation to tool selection

Answer: A. Tool material must be selected according to work material and cutting conditions

Explanation: Tool selection depends on workpiece material, cutting speed, feed, depth of cut, required surface finish, machine rigidity and economic considerations.

CHAPTER 11 — EXAM QUICK REVISION

Topic	Key Fact
Metal cutting	Material removal in chip form
Machine tool	Power-driven machining machine
Single-point tool	Turning/shaper/planer
Multi-point tool	Drill/mill/broach
Cutting speed	m/min
Turning feed	mm/rev
Depth of cut
Positive rake	Generally reduces cutting force
Clearance angle	Prevents rubbing
Continuous chip	Common with ductile materials
Discontinuous chip	Common with brittle materials
BUE	Work material adhered to tool edge
Flank wear	Flank face
Crater wear	Rake face
Cutting fluid	Cooling + lubrication + chip removal
Taylor equation
Orthogonal cutting	Cutting edge perpendicular to velocity
Oblique cutting	Cutting edge inclined
HSS	Good toughness
Carbide	High-speed machining
CBN	Hardened steels
Diamond	Very hard, useful for many non-ferrous/abrasive materials
Machinability	Ease of satisfactory machining

CHAPTER 12 — LATHE & TURNING OPERATIONS

12.1 Definition of Lathe

A lathe is a machine tool in which the workpiece is rotated about its axis while a cutting tool is fed against it to remove material and produce the required shape and dimensions.

Basic Principle

Workpiece → Rotates

Cutting tool → Moves/fed against workpiece

Material → Removed as chips

12.2 Why is Lathe Called the Mother of Machine Tools?

The lathe is called the mother of machine tools because it can perform a large variety of machining operations and has historically played a fundamental role in the development of machine tools.

12.3 Main Functions of a Lathe

A lathe can perform:

Turning
Facing
Taper turning
Thread cutting
Knurling
Drilling
Boring
Reaming
Parting-off
Grooving
Chamfering
Form turning

12.4 Main Parts of a Lathe

The principal parts are:

Bed

Headstock

Tailstock

Carriage

Lead screw

Feed rod

Spindle

Chuck

Tool post

Apron

Cross-slide

Compound rest

12.5 Lathe Bed

The bed is the main supporting structure of the lathe.

It:

Supports the headstock

Supports the tailstock

Supports the carriage

Maintains alignment

Provides guideways for carriage movement

Important

Bed = Foundation/supporting structure of lathe

12.6 Headstock

The headstock is mounted at one end of the lathe bed.

It contains:

Main spindle

Speed-changing mechanism

Gears/pulleys

Bearings

Spindle drive arrangement

Main Function

It provides rotary motion to the workpiece.

12.7 Spindle

The spindle is the rotating shaft of the lathe.

The work-holding device such as a chuck may be mounted on the spindle.

Important

Spindle → Rotates the workpiece

12.8 Tailstock

The tailstock is mounted on the bed opposite the headstock.

It is used for:

Supporting long workpieces

Holding drills

Holding reamers

Holding centres

Supporting work during machining

12.9 Carriage

The carriage carries and moves the cutting tool.

Major parts include:

Saddle

Cross-slide

Compound rest

Tool post

Apron

12.10 Saddle

The saddle is mounted on the lathe bed and supports the cross-slide and other carriage components.

It permits longitudinal movement along the bed.

12.11 Cross-Slide

The cross-slide provides movement of the tool:

Perpendicular to the axis of the workpiece.

It is primarily used for:

Facing

Controlling depth of cut

12.12 Compound Rest

The compound rest is mounted above the cross-slide.

It can be swivelled to set an angle.

It is particularly useful for:

Taper turning

Angular cuts

Short tapers

Fine tool positioning

12.13 Tool Post

The tool post holds the cutting tool.

It allows:

Tool positioning

Tool adjustment

Secure tool clamping

Common types include:

Single tool post

Four-way tool post

uick-change tool post

12.14 Apron

The apron is attached to the front of the carriage.

It contains mechanisms for:

Feed control

Carriage movement

Automatic longitudinal feed

Cross feed

12.15 Lead Screw

The lead screw is used mainly for:

Thread cutting.

It provides controlled movement of the carriage in synchronization with spindle rotation.

Important Exam Point

Lead screw → Thread cutting

12.16 Feed Rod

The feed rod is generally used to transmit power for:

Automatic longitudinal feed

Automatic cross feed

Important

Feed rod → Normal automatic feed

Lead screw → Thread cutting

12.17 Lathe Chuck

A chuck is a work-holding device mounted on the spindle.

Common types:

Three-jaw chuck
Four-jaw independent chuck
Collet chuck
Magnetic chuck
Combination chuck

12.18 Three-Jaw Chuck

The three-jaw chuck is also called a:

Self-centering chuck

The three jaws move simultaneously.

Advantages

Quick work holding

Automatic centering

Suitable for circular and hexagonal work

Limitation

It is less suitable when highly accurate independent adjustment of an irregular workpiece is required.

12.19 Four-Jaw Independent Chuck

In a four-jaw independent chuck:

Each jaw can be adjusted independently.

It is suitable for:

Square work

Rectangular work

Irregular work

Accurate setting of eccentric work

12.20 Three-Jaw vs Four-Jaw Chuck

Three-Jaw	Four-Jaw Independent
Self-centering	Independent jaws
Quick setting	More time required
Circular/hexagonal work	Square/irregular/eccentric work
Convenient	Greater setting flexibility

12.21 Lathe Centres

Centres support the workpiece between headstock and tailstock.

Types include:

Dead centre

Live centre

A centre generally has a standard point angle of approximately:

60°

12.22 Steady Rest

A steady rest provides additional support to a long, slender workpiece.

It is mounted on the:

Lathe bed

It helps reduce:

Deflection

Vibration

Chatter

12.23 Follower Rest

A follower rest is attached to the:

Carriage

It moves with the cutting tool and provides support close to the cutting zone.

12.24 Turning

Turning is the operation of reducing the diameter of a cylindrical workpiece by feeding a cutting tool parallel to the axis of rotation.

Purpose

To produce:

Cylindrical surfaces

Required diameter

Dimensional accuracy

12.25 Facing

Facing is the operation of producing a flat surface at the end of a workpiece by feeding the cutting tool approximately perpendicular to the axis of rotation.

Important

Turning → Tool feed parallel to axis

Facing → Tool feed perpendicular to axis

12.26 Taper Turning

A taper is a gradual reduction or increase in diameter along the length of a cylindrical workpiece.

Taper turning produces:

Conical surfaces.

Methods include:

Compound rest method
Tailstock offset method
Taper turning attachment
Form tool method

12.27 Thread Cutting

Thread cutting produces:

Helical grooves on a cylindrical or conical surface.

During thread cutting, the tool movement must remain synchronized with spindle rotation.

This is achieved using the:

Lead screw and change gears/gear train as appropriate.

12.28 Knurling

Knurling is a forming operation in which a patterned surface is produced on a workpiece by pressing hardened knurling wheels against it.

Important:

Knurling is not primarily a metal-cutting operation.

It produces:

Diamond pattern

Straight pattern

Improved grip

12.29 Drilling on a Lathe

A drill can be held in the:

Tailstock

The workpiece rotates while the drill is fed into it.

12.30 Boring

Boring is the operation of enlarging or correcting an existing hole using a single-point cutting tool.

Important distinction

Drilling → Produces a hole

Boring → Enlarges/improves an existing hole

12.31 Reaming

Reaming is a finishing operation used to improve the dimensional accuracy and surface finish of an existing hole.

A reamer removes a relatively small amount of material.

12.32 Parting-Off

Parting-off, also called cutting-off, separates a portion of the workpiece from the main stock.

A narrow cutting tool is fed:

Radially toward the centre of the workpiece.

12.33 Grooving

Grooving produces:

A narrow recess or groove on the workpiece.

12.34 Chamfering

Chamfering produces:

A bevelled edge on a workpiece.

It is commonly performed to remove sharp edges.

12.35 Form Turning

In form turning, a specially shaped tool produces:

A predetermined profile in one or a limited number of tool movements.

12.36 Lathe Speed

Spindle speed is normally measured in:

rpm — revolutions per minute

12.37 Cutting Speed in Turning

where:

= cutting speed in m/min

= workpiece diameter in mm

= spindle speed in rpm

Therefore:

12.38 Machining Time in Turning

For simple longitudinal turning:

where:

= machining time in minutes

= length of cut in mm

= feed in mm/rev

= rpm

12.39 Important Lathe Revision Table

Part	Main Function
Bed	Supports machine components
Headstock	Drives spindle
Spindle	Rotates work
Tailstock	Supports work/holds drills
Carriage	Supports and moves tool
Cross-slide	Cross movement
Compound rest	Angular tool movement
Tool post	Holds tool
Apron	Feed mechanism
Lead screw	Thread cutting
Feed rod	Automatic feed
Chuck	Holds work
Steady rest	Supports long work
Follower rest	Supports work near cutting zone

Q1. A lathe is primarily used for:

A. Producing surfaces of revolution
B. Welding plates
C. Casting components
D. Heat treatment

Answer: A. Producing surfaces of revolution

Explanation: The workpiece rotates about its axis while the tool removes material.

Q2. A lathe is commonly called the:

A. Mother of machine tools
B. Father of welding
C. Mother of furnaces
D. King of casting

Answer: A. Mother of machine tools

Explanation: Its versatility and historical importance have led to this traditional designation.

Q3. In a conventional lathe, the workpiece generally:

A. Rotates
B. Remains completely stationary
C. Moves only vertically
D. Reciprocates like a shaper

Answer: A. Rotates

Q4. In turning, the cutting tool generally moves:

A. Parallel to the workpiece axis
B. Only vertically
C. Circumferentially with the work
D. Randomly

Answer: A. Parallel to the workpiece axis

Q5. The main supporting structure of a lathe is the:

A. Bed
B. Chuck
C. Tool post
D. Apron

Answer: A. Bed

Q6. Which lathe component houses the main spindle?

A. Headstock
B. Tailstock
C. Saddle
D. Cross-slide

Answer: A. Headstock

Q7. The spindle of a lathe provides:

A. Rotary motion to the workpiece
B. Cooling water
C. Linear motion to the tailstock only
D. Hydraulic pressure only

Answer: A. Rotary motion to the workpiece

Q8. The tailstock is normally located:

A. Opposite the headstock
B. Inside the chuck
C. Below the bed
D. Inside the apron

Answer: A. Opposite the headstock

Q9. Which part is used to support a long workpiece?

A. Tailstock
B. Tool post
C. Cross-slide
D. Apron

Answer: A. Tailstock

Explanation: A centre mounted in the tailstock can support the free end of a long workpiece.

Q10. Which lathe part carries the cutting tool?

A. Carriage
B. Headstock only
C. Tailstock only
D. Spindle bearing

Answer: A. Carriage

Q11. The tool post is used to:

A. Hold the cutting tool
B. Rotate the workpiece
C. Support the lathe bed
D. Supply coolant only

Answer: A. Hold the cutting tool

Q12. The cross-slide provides tool movement:

A. Perpendicular to the workpiece axis
B. Only parallel to the axis
C. Circularly around the spindle
D. Vertically only

Answer: A. Perpendicular to the workpiece axis

Q13. The compound rest is especially useful for:

A. Taper turning
B. Cooling
C. Workpiece casting
D. Welding

Answer: A. Taper turning

Q14. The apron contains mechanisms associated with:

A. Carriage feed
B. Workpiece melting
C. Grinding-wheel balancing
D. Casting

Answer: A. Carriage feed

Q15. The lead screw is mainly used for:

A. Thread cutting
B. Cooling
C. Workpiece heating
D. Grinding

Answer: A. Thread cutting

Q16. The feed rod is mainly used for:

A. Powering normal automatic feeds
B. Holding the workpiece
C. Cutting threads only
D. Supporting the bed

Answer: A. Powering normal automatic feeds

Q17. A three-jaw chuck is generally:

A. Self-centering
B. Independent-jaw only
C. Used only for square work
D. Used only for grinding

Answer: A. Self-centering

Q18. In a four-jaw independent chuck:

A. Each jaw can be adjusted independently
B. All jaws always move simultaneously
C. There are no jaws
D. The chuck cannot hold irregular work

Answer: A. Each jaw can be adjusted independently

Q19. A three-jaw chuck is particularly suitable for:

A. Circular work
B. Highly irregular work only
C. Square work only
D. Eccentric work requiring independent adjustment

Answer: A. Circular work

Q20. Which chuck is particularly suitable for irregular or eccentric work?

A. Four-jaw independent chuck
B. Three-jaw self-centering chuck only
C. Collet only
D. Magnetic chuck only

Answer: A. Four-jaw independent chuck

Q21. Facing produces:

A. A flat end surface
B. A helical thread
C. A knurled surface only
D. A deep hole only

Answer: A. A flat end surface

Q22. In facing, the tool generally moves:

A. Radially across the end face
B. Only parallel to the work axis
C. Around the spindle without feed
D. Along the tailstock quill only

Answer: A. Radially across the end face

Q23. Boring is used to:

A. Enlarge an existing hole
B. Produce a hole from solid material only
C. Produce external threads only
D. Produce knurling

Answer: A. Enlarge an existing hole

Q24. Knurling is primarily:

A. A forming operation
B. A drilling operation
C. A grinding operation
D. A welding operation

Answer: A. A forming operation

Explanation: Knurling forms a patterned surface by pressing hardened rollers against the workpiece.

Q25. Parting-off is used to:

A. Separate a portion of the workpiece
B. Produce a taper only
C. Produce a thread only
D. Increase workpiece diameter

Answer: A. Separate a portion of the workpiece

A. TYPES OF LATHES — MCQs 26–40

Q26. Which lathe is most commonly used for general-purpose machining?

A. Centre lathe
B. Special-purpose lathe
C. Automatic screw machine only
D. Wheel lathe

Answer: A. Centre lathe

Explanation: A centre lathe is a versatile machine suitable for a wide range of general machining operations.

Q27. A centre lathe is also commonly known as:

A. Engine lathe
B. Turret lathe only
C. Automatic lathe
D. Vertical boring machine

Answer: A. Engine lathe

Explanation: The conventional centre lathe is commonly referred to as an engine lathe.

Q28. Which lathe is particularly suitable for repetitive production work?

A. Capstan and turret lathe
B. Centre lathe only
C. Bench vice
D. Surface plate

Answer: A. Capstan and turret lathe

Explanation: Capstan and turret lathes are designed for repetitive machining operations and multiple-tool setups.

Q29. In a turret lathe, the turret generally carries:

A. Multiple tools
B. Only one centre
C. Coolant only
D. Workpiece only

Answer: A. Multiple tools

Explanation: Multiple tools can be mounted on the turret for sequential machining operations.

Q30. A major advantage of a turret lathe is:

A. Reduced tool-changing time
B. No cutting tool required
C. No spindle rotation
D. No work-holding device

Answer: A. Reduced tool-changing time

Explanation: Multiple tools are preset on the turret and brought into operation as required.

Q31. An automatic lathe is designed primarily for:

A. Automatic/repetitive production
B. Manual filing
C. Heat treatment
D. Casting

Answer: A. Automatic/repetitive production

Q32. A special-purpose lathe is designed for:

A. Specific machining applications
B. Every possible manufacturing operation
C. Welding only
D. Forging only

Answer: A. Specific machining applications

Q33. A vertical lathe is especially useful for:

A. Large-diameter, heavy workpieces
B. Very small drills only
C. Hand filing
D. Sheet-metal cutting only

Answer: A. Large-diameter, heavy workpieces

Explanation: Vertical orientation can make loading and supporting large heavy components easier.

Q34. In a vertical turning machine, the workpiece spindle axis is generally:

A. Vertical
B. Horizontal
C. Inclined at 45° always
D. Random

Answer: A. Vertical

Q35. A tool room lathe is primarily associated with:

A. Precision and tool-room work
B. Mass casting
C. Welding pipelines
D. Heat treatment

Answer: A. Precision and tool-room work

Q36. A bench lathe is generally:

A. Small and mounted on a bench
B. Designed only for very large castings
C. Used only for forging
D. A vertical boring machine

Answer: A. Small and mounted on a bench

Q37. A CNC lathe is controlled by:

A. Computer numerical control
B. Manual handwheel only
C. Gravity
D. Steam pressure

Answer: A. Computer numerical control

Q38. CNC lathes generally provide:

A. High repeatability and automated control
B. No dimensional control
C. Only manual tool movement
D. No programming capability

Answer: A. High repeatability and automated control

Q39. A turret lathe is particularly useful when:

A. Several operations must be performed sequentially
B. Only one manual cut is required
C. No tooling is available
D. The workpiece cannot rotate

Answer: A. Several operations must be performed sequentially

Q40. Which machine is best suited to high-volume repetitive production with automatic operation?

A. Automatic lathe
B. Bench vice
C. Hand drill
D. Surface plate

Answer: A. Automatic lathe

B. WORK-HOLDING DEVICES — MCQs 41–55

Q41. A chuck is used primarily to:

A. Hold the workpiece
B. Hold cutting fluid
C. Support the machine bed
D. Measure diameter

Answer: A. Hold the workpiece

Q42. A collet chuck is particularly suitable for:

A. Small-diameter work requiring accurate holding
B. Very large castings only
C. Welding plates
D. Sand moulds

Answer: A. Small-diameter work requiring accurate holding

Q43. A faceplate is commonly used for:

A. Irregularly shaped work
B. Only small drills
C. Thread measurement
D. Grinding wheels

Answer: A. Irregularly shaped work

Explanation: Work that cannot conveniently be held in a conventional chuck can be secured to a faceplate using suitable clamps.

Q44. Work held between centres is supported by:

A. Headstock and tailstock centres
B. Two chucks only
C. Two tool posts
D. Two aprons

Answer: A. Headstock and tailstock centres

Q45. A lathe dog is used when work is:

A. Held between centres
B. Held only in a three-jaw chuck
C. Being drilled on a radial drill
D. Being cast

Answer: A. Held between centres

Explanation: A lathe dog transmits rotary motion from the driving plate/faceplate to the workpiece.

Q46. A driving plate is associated with:

A. Work held between centres
B. Milling cutters only
C. Grinding wheels only
D. Welding machines

Answer: A. Work held between centres

Q47. A steady rest is used to:

A. Support long slender work
B. Hold the cutting tool
C. Drive the spindle
D. Cut threads

Answer: A. Support long slender work

Q48. A steady rest is normally mounted on the:

A. Lathe bed
B. Tool post
C. Chuck jaws
D. Tailstock quill only

Answer: A. Lathe bed

Q49. A follower rest generally moves with:

A. The carriage
B. The headstock
C. The machine bed
D. The spindle only

Answer: A. The carriage

Q50. A follower rest supports the work:

A. Close to the cutting tool
B. Only at the tailstock
C. Inside the headstock
D. At the chuck jaws only

Answer: A. Close to the cutting tool

Q51. The primary purpose of a centre is to:

A. Support the workpiece
B. Cut threads
C. Increase spindle speed
D. Measure surface roughness

Answer: A. Support the workpiece

Q52. A live centre generally:

A. Rotates with the work
B. Always remains stationary relative to the work
C. Is used only for grinding
D. Is a cutting tool

Answer: A. Rotates with the work

Q53. A dead centre generally:

A. Does not rotate with the work
B. Rotates at spindle speed
C. Cuts the workpiece
D. Drives the spindle

Answer: A. Does not rotate with the work

Explanation: A traditional dead centre remains stationary relative to the machine while the work rotates around it; lubrication may be required at the contact.

Q54. The standard included angle of a conventional lathe centre is approximately:

A. 30°
B. 45°
C. 60°
D. 90°

Answer: C. 60°

Q55. A four-jaw independent chuck is advantageous for:

A. Eccentric work
B. Only automatic centering
C. Only circular bar stock
D. Grinding operations only

Answer: A. Eccentric work

Explanation: Independent jaw adjustment allows the work axis to be deliberately offset.

C. TURNING OPERATIONS — MCQs 56–70

Q56. Turning is used primarily to produce:

A. Cylindrical surfaces
B. Flat plates only
C. Gear teeth only
D. Welding joints

Answer: A. Cylindrical surfaces

Q57. Straight turning generally involves tool movement:

A. Parallel to the work axis
B. Perpendicular to the work axis only
C. Radially inward only
D. Vertically upward only

Answer: A. Parallel to the work axis

Q58. Facing is performed to produce:

A. A flat end surface
B. A helical groove
C. A knurled pattern only
D. An internal thread only

Answer: A. A flat end surface

Q59. In facing, the cutting tool generally moves:

A. Across the end face toward or away from the axis
B. Only parallel to the work axis
C. Around the work without contact
D. Along the lead screw only

Answer: A. Across the end face toward or away from the axis

Q60. Taper turning produces:

A. Conical surfaces
B. Flat surfaces only
C. Spherical surfaces only
D. Gear teeth

Answer: A. Conical surfaces

Q61. Which is NOT a common method of taper turning?

A. Compound rest method
B. Tailstock offset method
C. Taper attachment
D. Sand casting method

Answer: D. Sand casting method

Q62. The compound-rest method is particularly suitable for:

A. Short tapers
B. Extremely long shafts only
C. Large castings only
D. Welding

Answer: A. Short tapers

Q63. Tailstock offset is generally suitable for:

A. Long, slight tapers
B. Very short steep tapers only
C. Thread cutting only
D. Knurling only

Answer: A. Long, slight tapers

Q64. Taper turning attachment is useful for:

A. Accurate taper production
B. Increasing workpiece hardness
C. Casting
D. Welding

Answer: A. Accurate taper production

Q65. Thread cutting on a lathe produces:

A. Helical grooves
B. Flat surfaces only
C. Random grooves
D. Knurled surfaces only

Answer: A. Helical grooves

Q66. During thread cutting, the carriage must move:

A. In synchronism with spindle rotation
B. Independently of spindle rotation
C. Only manually without synchronization
D. Randomly

Answer: A. In synchronism with spindle rotation

Q67. The lead screw is especially important during:

A. Thread cutting
B. Simple grinding
C. Casting
D. Heat treatment

Answer: A. Thread cutting

Q68. Parting-off is performed using:

A. A narrow parting tool
B. A drill
C. A reamer
D. A milling cutter

Answer: A. A narrow parting tool

Q69. In parting-off, the tool is fed:

A. Radially toward the work axis
B. Parallel to the axis only
C. Tangentially without penetration
D. Vertically upward only

Answer: A. Radially toward the work axis

Q70. Grooving produces:

A. A narrow recess
B. A complete hole
C. A taper only
D. A flat end only

Answer: A. A narrow recess

D. DRILLING, BORING, REAMING & KNURLING — MCQs 71–82

Q71. Drilling on a lathe is generally performed by mounting the drill in the:

A. Tailstock
B. Tool post only
C. Apron
D. Bed

Answer: A. Tailstock

Q72. In drilling on a conventional lathe:

A. Workpiece rotates and drill is fed
B. Drill rotates while workpiece always remains stationary
C. Neither rotates
D. Only the tailstock rotates

Answer: A. Workpiece rotates and drill is fed

Q73. Boring is used to:

A. Enlarge an existing hole
B. Produce an external thread only
C. Produce a flat end only
D. Produce a knurled surface

Answer: A. Enlarge an existing hole

Q74. A boring tool is generally:

A. Single-point cutting tool
B. Multi-point milling cutter
C. Grinding wheel
D. Welding electrode

Answer: A. Single-point cutting tool

Q75. Reaming is primarily a:

A. Finishing operation for holes
B. Rough forging operation
C. Welding operation
D. Casting operation

Answer: A. Finishing operation for holes

Q76. Compared with drilling, reaming generally removes:

A. A small amount of material
B. The entire workpiece
C. No material under any condition
D. A very large amount of material

Answer: A. A small amount of material

Q77. Knurling produces:

A. A patterned surface
B. A drilled hole
C. A conical hole only
D. A flat end face

Answer: A. A patterned surface

Q78. Knurling is primarily a:

A. Metal-forming operation
B. Cutting-only operation
C. Welding operation
D. Heat-treatment operation

Answer: A. Metal-forming operation

Q79. Knurling is commonly used to:

A. Improve grip
B. Produce deep holes
C. Cut threads
D. Reduce length

Answer: A. Improve grip

Q80. A common knurl pattern is:

A. Diamond
B. Square hole
C. Spiral drill
D. Hexagonal bore

Answer: A. Diamond

Q81. Chamfering is performed to:

A. Produce a bevelled edge
B. Produce a deep hole
C. Increase diameter uniformly
D. Produce a casting cavity

Answer: A. Produce a bevelled edge

Q82. Form turning is used to:

A. Produce a predetermined profile
B. Produce only flat surfaces
C. Drill holes only
D. Cut gears only

Answer: A. Produce a predetermined profile

E. LATHE CALCULATIONS — MCQs 83–100

Q83. The turning cutting-speed equation is:

A.
B.
C.
D.

Answer: A.

Q84. A 50 mm diameter workpiece rotates at 1000 rpm. The cutting speed is approximately:

A. 78.5 m/min
B. 157 m/min
C. 314 m/min
D. 500 m/min

Answer: B. 157 m/min

Q85. If cutting speed is 100 m/min and workpiece diameter is 50 mm, spindle speed is approximately:

A. 318 rpm
B. 637 rpm
C. 1000 rpm
D. 2000 rpm

Answer: B. 637 rpm

Q86. A workpiece diameter is reduced from 80 mm to 70 mm. Depth of cut is:

A. 2.5 mm
B. 5 mm
C. 10 mm
D. 15 mm

Answer: B. 5 mm

Q87. If feed is 0.25 mm/rev and spindle speed is 800 rpm, feed rate is:

A. 100 mm/min
B. 150 mm/min
C. 200 mm/min
D. 320 mm/min

Answer: C. 200 mm/min

Q88. If the length of cut is 100 mm, feed is 0.2 mm/rev and spindle speed is 500 rpm, machining time is:

A. 0.5 min
B. 1 min
C. 2 min
D. 5 min

Answer: B. 1 min

Q89. If feed is doubled while speed remains constant, machining time for the same length generally:

A. Decreases
B. Doubles
C. Remains unchanged
D. Becomes infinite

Answer: A. Decreases

Explanation: Higher feed means greater tool travel per revolution.

Q90. If spindle speed doubles and feed remains constant, feed rate:

A. Doubles
B. Halves
C. Remains constant
D. Becomes zero

Answer: A. Doubles

Q91. The pitch of a single-start thread is equal to its:

A. Lead
B. Diameter
C. Radius
D. Depth of cut

Answer: A. Lead

Explanation: For a single-start thread:

Q92. For a double-start thread:

A. Lead = 2 × pitch
B. Lead = pitch/2
C. Lead = pitch
D. Lead = 0

Answer: A. Lead = 2 × pitch

Q93. For a three-start thread, the relationship is:

A. Lead = 3 × pitch
B. Lead = pitch/3
C. Lead = pitch
D. Lead = 2 × pitch

Answer: A. Lead = 3 × pitch

Q94. If a single-start thread has a pitch of 2 mm, its lead is:

A. 1 mm
B. 2 mm
C. 4 mm
D. 6 mm

Answer: B. 2 mm

Q95. If a double-start thread has a pitch of 2 mm, its lead is:

A. 1 mm
B. 2 mm
C. 4 mm
D. 6 mm

Answer: C. 4 mm

Q96. During thread cutting, if the required thread pitch is , the carriage must advance:

A. mm per spindle revolution for a single-start thread
B. mm for every single-start thread
C. Zero mm per revolution
D. Randomly

Answer: A. mm per spindle revolution for a single-start thread

Q97. A workpiece rotates at 500 rpm and the feed is 0.4 mm/rev. The feed rate is:

A. 100 mm/min
B. 200 mm/min
C. 400 mm/min
D. 900 mm/min

Answer: B. 200 mm/min

Q98. A workpiece of diameter 100 mm rotates at 318 rpm. Cutting speed is approximately:

A. 50 m/min
B. 100 m/min
C. 150 m/min
D. 318 m/min

Answer: B. 100 m/min

Q99. If a workpiece of initial diameter 60 mm is reduced to 52 mm in one turning pass, depth of cut is:

A. 2 mm
B. 4 mm
C. 8 mm
D. 10 mm

Answer: B. 4 mm

Q100. Which combination is correct?

A. Lead screw — thread cutting
B. Cross-slide — spindle rotation
C. Chuck — coolant storage
D. Tailstock — cutting speed measurement

Answer: A. Lead screw — thread cutting

Explanation: The lead screw synchronizes carriage movement with spindle rotation during thread cutting.

CHAPTER 12 — IMPORTANT EXAM REVISION

Remember these pairs:

Bed → Supports machine

Headstock → Drives spindle

Spindle → Rotates work

Tailstock → Supports work / holds drill

Carriage → Carries cutting tool

Cross-slide → Cross movement

Compound rest → Taper turning

Tool post → Holds tool

Apron → Feed mechanism

Lead screw → Thread cutting

Feed rod → Automatic feed

3-jaw chuck → Self-centering

4-jaw independent chuck → Eccentric/irregular work

Steady rest → Fixed support on bed

Follower rest → Moves with carriage

Turning → Cylindrical surface

Facing → Flat end surface

Taper turning → Conical surface

Boring → Enlarges existing hole

Reaming → Finishes existing hole

Knurling → Pattern/grip

Parting-off → Separates work

Grooving → Narrow recess

Chamfering → Bevelled edge

Single-start thread → Lead = pitch

Double-start thread → Lead = 2 × pitch

CHAPTER 13 — DRILLING MACHINES & DRILLING OPERATIONS

13.1 Definition of Drilling

Drilling is a machining operation used to produce a circular hole in a solid material by means of a rotating multi-point cutting tool called a drill.

The most commonly used drill is the:

Twist Drill

13.2 Principle of Drilling

In conventional drilling:

The drill rotates.

The drill is fed axially into the workpiece.

Cutting edges remove material.

Material is removed in the form of chips.

Basic principle:

Rotating drill + axial feed → Hole formation

13.3 Main Characteristics of Drilling

Drilling is generally:

A hole-making operation

A multi-point cutting operation

A rotary cutting operation

Usually performed with a twist drill

13.4 What is a Twist Drill?

A twist drill is a multi-point cutting tool having helical flutes that provide cutting edges and passages for chip removal.

It generally consists of:

Shank
Body
Flutes
Lands
Margins
Web
Point
Cutting lips

13.5 Main Parts of a Twist Drill

1. Shank

The shank is the portion by which the drill is held in the machine.

Two common types are:

Straight shank

Taper shank

2. Body

The body is the portion between the shank and the point.

It contains:

Flutes

Lands

Margins

Web

3. Flutes

Flutes are helical grooves running along the body of the drill.

Functions of flutes:

Provide chip space

Help remove chips

Allow cutting fluid to reach the cutting zone

Form the cutting edges

4. Lands

The raised portions between adjacent flutes are called:

Lands

5. Margin

The narrow raised portion along the leading edge of the land is called the:

Margin

The margin helps guide the drill inside the hole.

6. Web

The central portion of the drill between the flutes is called the:

Web

The web provides strength to the drill.

7. Point

The conical cutting portion at the end of the drill is called the:

Point

8. Cutting Lips

The two principal cutting edges of a conventional twist drill are called:

Cutting lips

13.6 Standard Twist Drill

A standard twist drill commonly has:

Two main cutting lips

Two flutes

A chisel edge

A point angle of approximately 118°

Important Exam Fact

Standard drill point angle ≈ 118°

13.7 Chisel Edge

The chisel edge is located at the centre of the drill point.

It does not cut in the same efficient shearing manner as the main cutting lips.

It tends to:

Extrude material

Increase thrust force

Require substantial axial force

13.8 Drill Point Angle

The included angle between the two cutting lips is called the:

Point angle

For a conventional general-purpose twist drill:

is a commonly used value.

13.9 Helix Angle

The angle made by the helical flute with the drill axis is called the:

Helix angle

A commonly used standard twist drill has a helix angle of approximately:

13.10 Rake Angle of Drill

The rake angle in a twist drill varies along the cutting edge.

It is generally:

Smaller near the centre

Larger toward the outer circumference

13.11 Clearance Angle

The clearance angle prevents excessive rubbing between the drill and the newly machined hole surface.

If clearance is insufficient:

Friction increases

Heat increases

Tool wear increases

13.12 Drill Materials

Common drill materials include:

Carbon Tool Steel

Used for relatively low-speed applications.

High-Speed Steel — HSS

Widely used because of:

Good hardness

Good toughness

Good hot hardness

Good wear resistance

Carbide

Used where:

High cutting speed is required

High productivity is required

Suitable machine rigidity is available

13.13 Types of Drilling Machines

Important types include:

Portable drilling machine
Sensitive drilling machine
Bench drilling machine
Pillar drilling machine
Upright drilling machine
Radial drilling machine
Gang drilling machine
Multi-spindle drilling machine
Automatic drilling machine
CNC drilling machine

13.14 Portable Drilling Machine

A portable drilling machine is:

Small

Easily movable

Suitable for drilling holes at different locations

It is useful where moving the workpiece to a stationary drilling machine is difficult.

13.15 Sensitive Drilling Machine

A sensitive drilling machine is designed for:

Small holes

Light drilling

Accurate control of feed by the operator

The operator can sense the cutting pressure through the hand feed mechanism.

13.16 Bench Drilling Machine

A bench drilling machine is mounted on a:

Bench or table

It is commonly used for:

Small workpieces

Small and medium-sized holes

Light-duty drilling

13.17 Pillar Drilling Machine

A pillar drilling machine has a vertical supporting column or pillar.

It is suitable for:

General-purpose drilling

Larger workpieces than typical bench drills

13.18 Upright Drilling Machine

An upright drilling machine is a relatively heavy stationary drilling machine used for:

Medium and large work

Larger hole sizes

Production applications

13.19 Radial Drilling Machine

A radial drilling machine has a:

Radial arm

The drill head can move along the radial arm.

Major advantage

It can drill holes at different positions without repeatedly moving a large workpiece.

It is particularly useful for:

Large and heavy workpieces.

13.20 Gang Drilling Machine

A gang drilling machine has several drilling heads arranged in a row.

Different operations can be performed sequentially, such as:

Drilling

Counterboring

Reaming

Tapping

This reduces handling time.

13.21 Multi-Spindle Drilling Machine

A multi-spindle machine has:

Several spindles

It is useful when:

Multiple holes must be produced

High production rate is required

13.22 Main Parts of a Drilling Machine

Typical parts include:

Base

Column

Table

Spindle

Drill head

Motor

Feed mechanism

Chuck

Quill

Belt/gear drive

13.23 Base

The base:

Supports the machine

Provides stability

May support the column

May accommodate large workpieces

13.24 Column

The column is the vertical supporting member.

It supports:

Drill head

Table

Other machine components

13.25 Table

The table supports the workpiece.

It may be:

Fixed

Adjustable vertically

Swivelled depending on machine design

13.26 Spindle

The spindle:

Rotates the drill

Transmits power to the drill

13.27 Drill Chuck

A drill chuck is used to hold drills having suitable shanks.

13.28 Quill

The quill carries the spindle assembly and permits axial movement of the drill in many drilling machines.

13.29 Drilling Operations

Drilling-related operations include:

Drilling
Reaming
Boring
Counterboring
Countersinking
Spot facing
Tapping
Trepanning

13.30 Reaming

Reaming is a finishing operation used to improve the size accuracy and surface finish of an existing hole.

A reamer removes a relatively small amount of material.

Remember:

Drilling → Makes hole

Reaming → Finishes hole

13.31 Boring

Boring is the process of enlarging an existing hole using a cutting tool.

It can also improve:

Hole accuracy

Alignment

Surface finish

13.32 Counterboring

Counterboring produces:

A cylindrical enlargement at the mouth of an existing hole.

It is commonly used to provide seating for:

Socket-head screws

Bolt heads

Similar fasteners

13.33 Countersinking

Countersinking produces:

A conical enlargement at the mouth of a hole.

It is used to accommodate:

Countersunk screw heads.

13.34 Spot Facing

Spot facing produces:

A flat circular seating surface around an existing hole.

It is often used where a bolt head or nut requires a flat bearing surface.

13.35 Tapping

Tapping is the operation of producing:

Internal threads inside a hole.

The tool used is called a:

Tap

13.36 Die

A die is generally used to produce:

External threads

Therefore:

Tap → Internal thread

Die → External thread

13.37 Trepanning

Trepanning produces a:

Large-diameter hole by removing material in the form of a ring rather than removing the complete circular core.

It can save material compared with conventional solid drilling for large holes.

13.38 Drilling Cutting Speed

The cutting speed of a drill is:

where:

= cutting speed in m/min

= drill diameter in mm

= spindle speed in rpm

Therefore:

13.39 Feed in Drilling

Feed is commonly expressed as:

mm/rev

Feed rate:

where:

= feed in mm/rev

= rpm

= feed rate in mm/min

13.40 Drilling Time

For simple drilling, machining time can be approximated by:

where is the effective drilling length.

In practical calculations, approach and breakthrough allowances may need to be included depending on the question.

13.41 Important Drilling Revision Table

Item	Key Fact
Drilling	Produces a hole
Drill	Multi-point cutting tool
Twist drill	Most common drill
Standard point angle	About 118°
Flute	Chip removal
Web	Provides drill strength
Margin	Guides drill
Chisel edge	At centre of point
HSS	Common drill material
Radial drill	Large/heavy work
Gang drill	Sequential operations
Reaming	Hole finishing
Boring	Enlarges existing hole
Counterboring	Cylindrical enlargement
Countersinking	Conical enlargement
Spot facing	Flat seating surface
Tapping	Internal thread
Die	External thread
Trepanning	Large hole with annular cutting

Q1. Drilling is primarily used to:

A. Produce holes
B. Produce external threads only
C. Produce flat surfaces only
D. Produce gear teeth

Answer: A. Produce holes

Explanation: Drilling is fundamentally a hole-making machining operation.

Q2. A twist drill is a:

A. Multi-point cutting tool
B. Single-point tool
C. Grinding wheel
D. Forming die

Answer: A. Multi-point cutting tool

Q3. In conventional drilling, the drill generally:

A. Rotates and is fed axially
B. Only moves laterally
C. Remains completely stationary
D. Reciprocates without rotation

Answer: A. Rotates and is fed axially

Q4. The most commonly used drill for general-purpose drilling is:

A. Twist drill
B. Slab cutter
C. Form cutter
D. Side cutter

Answer: A. Twist drill

Q5. The helical grooves on a twist drill are called:

A. Flutes
B. Lands
C. Margins
D. Webs

Answer: A. Flutes

Q6. One important function of drill flutes is:

A. Chip removal
B. Workpiece heating
C. Increasing workpiece diameter
D. Holding the machine table

Answer: A. Chip removal

Q7. The central portion of a twist drill between the flutes is called:

A. Web
B. Margin
C. Shank
D. Land

Answer: A. Web

Q8. The web primarily provides:

A. Strength to the drill
B. Coolant storage
C. Workpiece rotation
D. Machine-bed support

Answer: A. Strength to the drill

Q9. The narrow raised portion that helps guide the drill in the hole is called:

A. Margin
B. Web
C. Point
D. Shank

Answer: A. Margin

Q10. The standard point angle of a general-purpose twist drill is approximately:

A. 60°
B. 90°
C. 118°
D. 180°

Answer: C. 118°

Q11. The chisel edge of a twist drill is located:

A. At the centre of the drill point
B. At the shank end
C. On the outer margin only
D. Inside the machine spindle

Answer: A. At the centre of the drill point

Q12. The chisel edge mainly contributes to:

A. Thrust force
B. Spindle lubrication
C. Machine cooling
D. Workpiece rotation

Answer: A. Thrust force

Explanation: The chisel edge does not cut efficiently by pure shearing and therefore requires significant axial force.

Q13. A common material for twist drills is:

A. High-speed steel
B. Rubber
C. Wood
D. Mild plastic

Answer: A. High-speed steel

Q14. HSS stands for:

A. High-Speed Steel
B. High-Surface Steel
C. Heat-Sensitive Steel
D. Hard-Shaped Steel

Answer: A. High-Speed Steel

Q15. A portable drilling machine is useful because:

A. It can be moved to the work
B. It can only machine stationary work
C. It cannot rotate a drill
D. It is used only for grinding

Answer: A. It can be moved to the work

Q16. A sensitive drilling machine is particularly suitable for:

A. Small holes and light work
B. Huge castings only
C. Heavy forging only
D. Large-diameter boring only

Answer: A. Small holes and light work

Q17. A bench drilling machine is generally mounted on a:

A. Bench or table
B. Crane
C. Furnace
D. Lathe spindle

Answer: A. Bench or table

Q18. A radial drilling machine is particularly suitable for:

A. Large and heavy workpieces
B. Only tiny watch components
C. Hand filing
D. Heat treatment

Answer: A. Large and heavy workpieces

Q19. The main special feature of a radial drilling machine is its:

A. Radial arm
B. Lathe chuck
C. Grinding wheel
D. Tailstock

Answer: A. Radial arm

Q20. A gang drilling machine contains:

A. Several drilling units arranged together
B. Only one hand drill
C. No spindle
D. Only a grinding wheel

Answer: A. Several drilling units arranged together

Q21. Reaming is primarily used to:

A. Finish an existing hole
B. Produce a rough hole from solid material
C. Cut external threads
D. Produce a knurled surface

Answer: A. Finish an existing hole

Q22. Boring is primarily used to:

A. Enlarge an existing hole
B. Produce external threads
C. Produce a flat face only
D. Produce a knurled pattern

Answer: A. Enlarge an existing hole

Q23. Tapping is used to produce:

A. Internal threads
B. External threads
C. Flat surfaces
D. Conical external surfaces only

Answer: A. Internal threads

Q24. Countersinking produces:

A. A conical enlargement at the mouth of a hole
B. A cylindrical enlargement only
C. A flat circular seating surface only
D. An external thread

Answer: A. A conical enlargement at the mouth of a hole

Q25. Counterboring produces:

A. A cylindrical enlargement at the mouth of a hole
B. A conical enlargement
C. An external thread
D. A knurled surface

Answer: A. A cylindrical enlargement at the mouth of a hole

A. TWIST DRILL GEOMETRY — MCQs 26–40

Q26. The angle included between the two main cutting lips of a standard twist drill is approximately:

A. 60°
B. 90°
C. 118°
D. 180°

Answer: C. 118°

Explanation: A standard general-purpose twist drill commonly uses a point angle of approximately 118°.

Q27. The angle of a twist-drill helix is measured between the:

A. Helix and drill axis
B. Cutting edge and work surface
C. Drill point and shank
D. Web and margin

Answer: A. Helix and drill axis

Q28. The main cutting edges of a twist drill are called:

A. Cutting lips
B. Margins
C. Lands
D. Webs

Answer: A. Cutting lips

Q29. The flutes of a twist drill are primarily provided for:

A. Chip removal
B. Increasing drill diameter
C. Holding the workpiece
D. Measuring hole depth

Answer: A. Chip removal

Q30. The land of a twist drill is:

A. The portion between adjacent flutes
B. The central web
C. The shank
D. The cutting point only

Answer: A. The portion between adjacent flutes

Q31. The margin of a twist drill helps to:

A. Guide the drill in the hole
B. Drive the spindle
C. Hold the workpiece
D. Measure cutting speed

Answer: A. Guide the drill in the hole

Q32. The web of a twist drill is generally:

A. Thicker toward the shank
B. Completely absent
C. Used as a cutting insert
D. A coolant passage only

Answer: A. Thicker toward the shank

Explanation: The web provides strength and its thickness commonly increases toward the shank.

Q33. The shank of a drill is used to:

A. Hold the drill in the machine
B. Remove chips
C. Cut the workpiece directly
D. Guide the drill inside the hole

Answer: A. Hold the drill in the machine

Q34. A straight-shank drill is commonly held by:

A. Drill chuck
B. Faceplate
C. Lathe dog
D. Steady rest

Answer: A. Drill chuck

Q35. A taper-shank drill is commonly mounted directly in:

A. A suitable tapered spindle/socket
B. A three-jaw lathe chuck only
C. A milling vice only
D. A faceplate

Answer: A. A suitable tapered spindle/socket

Q36. The point angle of a drill affects:

A. Cutting performance and thrust
B. Machine colour
C. Workpiece weight only
D. Coolant capacity

Answer: A. Cutting performance and thrust

Q37. A smaller point angle generally produces:

A. A sharper included point
B. A completely flat drill point
C. No cutting edge
D. Zero rake

Answer: A. A sharper included point

Q38. The clearance angle in drilling is provided mainly to:

A. Prevent rubbing behind the cutting edge
B. Increase friction
C. Stop chip formation
D. Increase drill weight

Answer: A. Prevent rubbing behind the cutting edge

Q39. Insufficient drill clearance can result in:

A. Increased rubbing and heat
B. Zero friction
C. Infinite tool life
D. No thrust force

Answer: A. Increased rubbing and heat

Q40. The drill point is the:

A. Cutting portion at the end of the drill
B. Holding portion at the shank
C. Machine spindle
D. Drill chuck

Answer: A. Cutting portion at the end of the drill

B. DRILLING MACHINE PARTS — MCQs 41–50

Q41. The base of a drilling machine primarily provides:

A. Support and stability
B. Cutting action
C. Thread cutting
D. Chip formation

Answer: A. Support and stability

Q42. The vertical structural member of many drilling machines is the:

A. Column
B. Chuck
C. Spindle
D. Quill only

Answer: A. Column

Q43. The drilling-machine table is used primarily to:

A. Support the workpiece
B. Rotate the drill
C. Store chips
D. Drive the motor

Answer: A. Support the workpiece

Q44. The spindle of a drilling machine:

A. Rotates the drill
B. Supports the floor
C. Holds coolant only
D. Measures hole diameter

Answer: A. Rotates the drill

Q45. The drill head generally contains:

A. Spindle and drive mechanism
B. Only the workpiece
C. Only the machine table
D. Only the coolant tank

Answer: A. Spindle and drive mechanism

Q46. The quill provides:

A. Axial movement of the spindle/drill assembly
B. Horizontal workpiece rotation
C. Coolant filtration only
D. Table lubrication only

Answer: A. Axial movement of the spindle/drill assembly

Q47. A drill chuck is used to:

A. Hold the drill
B. Hold the machine table
C. Support the column
D. Measure drill angle

Answer: A. Hold the drill

Q48. The feed mechanism of a drilling machine controls:

A. Axial movement of the drill
B. Workpiece colour
C. Coolant composition
D. Machine foundation

Answer: A. Axial movement of the drill

Q49. The motor of a drilling machine provides:

A. Power for spindle rotation
B. Workpiece measurement
C. Cutting-fluid filtration only
D. Manual feed only

Answer: A. Power for spindle rotation

Q50. The machine table may be adjustable to:

A. Position the workpiece correctly
B. Increase drill hardness
C. Change workpiece material
D. Remove the spindle

Answer: A. Position the workpiece correctly

C. DRILLING MACHINE TYPES — MCQs 51–60

Q51. Which drilling machine is suitable for large and heavy workpieces?

A. Radial drilling machine
B. Sensitive drilling machine
C. Small bench drill only
D. Hand drill only

Answer: A. Radial drilling machine

Q52. A sensitive drilling machine is mainly intended for:

A. Small holes and light work
B. Very large holes in heavy castings
C. Large gear cutting
D. Heavy forging

Answer: A. Small holes and light work

Q53. A gang drilling machine is useful because:

A. Several operations can be performed sequentially
B. It has no drill
C. It cannot perform production work
D. It eliminates all cutting tools

Answer: A. Several operations can be performed sequentially

Q54. A multi-spindle drilling machine is particularly useful for:

A. Producing multiple holes efficiently
B. Single manual filing
C. Heat treatment
D. Welding

Answer: A. Producing multiple holes efficiently

Q55. A portable drilling machine is especially useful when:

A. The machine must be taken to the work
B. The workpiece is too small for any machine
C. Only grinding is required
D. No hole is required

Answer: A. The machine must be taken to the work

Q56. An upright drilling machine is generally used for:

A. Medium and heavy drilling work
B. Only hand drilling
C. Surface grinding
D. Casting

Answer: A. Medium and heavy drilling work

Q57. A bench drilling machine is generally:

A. Smaller than an upright drilling machine
B. Larger than every radial drill
C. Used only for tapping
D. A grinding machine

Answer: A. Smaller than an upright drilling machine

Q58. The major advantage of a radial drilling machine is:

A. Drill head can be positioned over different locations of a large workpiece
B. It cannot move
C. It is limited to tiny holes
D. It does not have a spindle

Answer: A. Drill head can be positioned over different locations of a large workpiece

Q59. In a gang drilling machine, different machines/heads may be arranged:

A. In a row
B. Underground only
C. Inside the spindle
D. Around a lathe chuck

Answer: A. In a row

Q60. CNC drilling machines provide:

A. Programmable automated machining
B. Only manual operation
C. No repeatability
D. No spindle control

Answer: A. Programmable automated machining

D. DRILLING OPERATIONS — MCQs 61–75

Q61. The operation of enlarging an existing hole using a single-point tool is:

A. Boring
B. Drilling
C. Knurling
D. Facing

Answer: A. Boring

Q62. The operation used to improve the accuracy and finish of an existing hole is:

A. Reaming
B. Knurling
C. Facing
D. Parting

Answer: A. Reaming

Q63. The tool used for internal threading is:

A. Tap
B. Die
C. Reamer
D. Drill

Answer: A. Tap

Q64. The tool generally used for external threading is:

A. Die
B. Tap
C. Reamer
D. Countersink

Answer: A. Die

Q65. Counterboring produces:

A. Cylindrical enlargement
B. Conical enlargement
C. External thread
D. Flat face over the whole workpiece

Answer: A. Cylindrical enlargement

Q66. Countersinking produces:

A. Conical enlargement
B. Cylindrical enlargement
C. External groove only
D. Internal thread only

Answer: A. Conical enlargement

Q67. Spot facing produces:

A. A flat seating surface around a hole
B. A conical hole
C. An external thread
D. A large through-hole only

Answer: A. A flat seating surface around a hole

Q68. Trepanning is particularly useful for:

A. Large-diameter holes
B. Very small pilot holes only
C. External threads
D. Surface grinding

Answer: A. Large-diameter holes

Q69. A reamer normally removes:

A. A small amount of material
B. The complete workpiece
C. A very large amount of material
D. No material at all

Answer: A. A small amount of material

Q70. Which operation is generally performed before reaming?

A. Drilling
B. Knurling
C. Facing only
D. Threading only

Answer: A. Drilling

Q71. A pilot hole is useful when:

A. Starting a large hole
B. Producing a flat face
C. Cutting an external thread
D. Performing heat treatment

Answer: A. Starting a large hole

Q72. Peck drilling is used primarily to:

A. Help break and evacuate chips during deep-hole drilling
B. Increase workpiece hardness
C. Produce external threads
D. Produce a flat face

Answer: A. Help break and evacuate chips during deep-hole drilling

Q73. Deep-hole drilling requires special attention to:

A. Chip evacuation and cooling
B. Workpiece colour
C. Machine painting
D. Surface decoration

Answer: A. Chip evacuation and cooling

Q74. Tapping requires:

A. Correct synchronization/controlled feed according to thread pitch
B. Random feed
C. No rotation
D. No cutting fluid under any conditions

Answer: A. Correct synchronization/controlled feed according to thread pitch

Q75. The main purpose of a tap drill is to:

A. Produce the hole before internal tapping
B. Produce an external thread
C. Produce a flat face
D. Perform knurling

Answer: A. Produce the hole before internal tapping

E. DRILLING DEFECTS & PROBLEMS — MCQs 76–85

Q76. An oversized drilled hole may result from:

A. Drill runout or improper drill geometry
B. Perfect alignment only
C. Zero spindle rotation
D. Proper tool condition alone

Answer: A. Drill runout or improper drill geometry

Q77. Excessive drill runout can cause:

A. Poor hole accuracy
B. Perfect concentricity
C. Zero vibration
D. No cutting

Answer: A. Poor hole accuracy

Q78. Drill wandering at the start of a hole can be reduced by:

A. Providing a suitable starting surface/pilot or centre mark
B. Increasing random feed
C. Removing all support
D. Using a blunt drill intentionally

Answer: A. Providing a suitable starting surface/pilot or centre mark

Q79. Excessive feed may cause:

A. High thrust and possible drill breakage
B. Zero cutting force
C. Infinite tool life
D. No chip formation

Answer: A. High thrust and possible drill breakage

Q80. Excessive cutting speed can lead to:

A. Increased drill temperature and wear
B. Infinite tool life
C. Zero heat
D. Zero friction

Answer: A. Increased drill temperature and wear

Q81. A blunt drill generally causes:

A. Increased thrust force
B. Zero thrust
C. Zero heat
D. Infinite tool life

Answer: A. Increased thrust force

Q82. Poor chip evacuation in deep drilling can cause:

A. Chip packing and increased heat
B. Better cooling automatically
C. Lower cutting resistance always
D. Perfect surface finish automatically

Answer: A. Chip packing and increased heat

Q83. Lack of coolant during demanding drilling may cause:

A. Excessive temperature
B. Zero temperature
C. Infinite tool life
D. No tool wear

Answer: A. Excessive temperature

Q84. Unequal cutting lips of a twist drill may produce:

A. An oversized or inaccurate hole
B. Perfect hole geometry
C. Zero cutting force
D. No chip

Answer: A. An oversized or inaccurate hole

Q85. Chatter during drilling may result in:

A. Poor surface finish and vibration
B. Perfect finish
C. Zero noise
D. Increased accuracy automatically

Answer: A. Poor surface finish and vibration

F. DRILLING CALCULATIONS — MCQs 86–100

Q86. The cutting-speed formula for drilling is:

A.
B.
C.
D.

Answer: A.

Q87. A drill of diameter 20 mm rotates at 1000 rpm. Cutting speed is approximately:

A. 31.4 m/min
B. 62.8 m/min
C. 100 m/min
D. 200 m/min

Answer: B. 62.8 m/min

Calculation:

Q88. A 10 mm drill rotates at 1000 rpm. Cutting speed is approximately:

A. 15.7 m/min
B. 31.4 m/min
C. 62.8 m/min
D. 100 m/min

Answer: B. 31.4 m/min

Q89. If cutting speed is 30 m/min and drill diameter is 10 mm, spindle speed is approximately:

A. 318 rpm
B. 637 rpm
C. 955 rpm
D. 1500 rpm

Answer: C. 955 rpm

Calculation:

Q90. A drill rotates at 500 rpm with a feed of 0.2 mm/rev. Feed rate is:

A. 50 mm/min
B. 100 mm/min
C. 150 mm/min
D. 250 mm/min

Answer: B. 100 mm/min

Q91. If feed is 0.1 mm/rev and speed is 1000 rpm, feed rate is:

A. 10 mm/min
B. 50 mm/min
C. 100 mm/min
D. 1000 mm/min

Answer: C. 100 mm/min

Q92. A hole is drilled to an effective depth of 50 mm at a feed rate of 100 mm/min. Approximate drilling time is:

A. 0.25 min
B. 0.5 min
C. 1 min
D. 2 min

Answer: B. 0.5 min

Q93. A 25 mm drill runs at 400 rpm. Its cutting speed is approximately:

A. 15.7 m/min
B. 31.4 m/min
C. 62.8 m/min
D. 100 m/min

Answer: B. 31.4 m/min

Q94. If drill diameter is doubled at constant rpm, cutting speed:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q95. If spindle speed is doubled while drill diameter remains constant, cutting speed:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q96. If feed per revolution is doubled while rpm remains constant, feed rate:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q97. A 20 mm drill operates at 800 rpm and feed is 0.25 mm/rev. Feed rate is:

A. 100 mm/min
B. 150 mm/min
C. 200 mm/min
D. 250 mm/min

Answer: C. 200 mm/min

Q98. A drill travels 60 mm at a feed rate of 120 mm/min. Approximate machining time is:

A. 0.25 min
B. 0.5 min
C. 1 min
D. 2 min

Answer: B. 0.5 min

Q99. A 12 mm drill rotates at approximately 795 rpm. Its cutting speed is approximately:

A. 15 m/min
B. 30 m/min
C. 60 m/min
D. 120 m/min

Answer: B. 30 m/min

Q100. Which combination is correct?

A. Drill → Hole making
B. Reamer → External threading
C. Tap → External threading
D. Die → Internal threading

Answer: A. Drill → Hole making

Explanation: A drill produces the initial hole; a reamer finishes a hole, a tap produces internal threads and a die produces external threads.

CHAPTER 13 — 100-MCQ QUICK REVISION

Topic	Key Point
Drilling	Hole-making operation
Twist drill	Multi-point cutting tool
Standard drill point	≈ 118°
Flutes	Chip removal
Web	Drill strength
Margin	Drill guidance
Chisel edge	Produces substantial thrust
HSS	Common drill material
Sensitive drill	Small/light work
Radial drill	Large/heavy work
Gang drill	Sequential operations
Multi-spindle	Multiple holes/high production
Reaming	Hole finishing
Boring	Enlarging existing hole
Counterboring	Cylindrical enlargement
Countersinking	Conical enlargement
Spot facing	Flat seating surface
Tapping	Internal threads
Die	External threads
Trepanning	Large annular hole
Cutting speed
Feed rate
Drilling time

Bottom of Form

CHAPTER 14 — SHAPER, PLANER & SLOTTING MACHINES

14.1 Definition of Shaper

A shaper is a reciprocating machine tool in which a single-point cutting tool mounted on a ram removes material from the workpiece during the forward cutting stroke.

Basic principle:

Reciprocating tool + stationary workpiece → Machined surface

The tool performs the reciprocating motion while the workpiece generally remains stationary.

14.2 Principle of Shaper

In a conventional shaper:

The ram moves forward.
The cutting tool removes material during the forward stroke.
The ram returns during the return stroke.
The work is given a small feed after each stroke.
The process repeats until the required surface is obtained.

Important:

Forward stroke = Cutting stroke

Return stroke = Idle stroke

14.3 What is a Planer?

A planer is a machine tool in which the workpiece reciprocates under one or more stationary cutting tools.

This is the major difference from a shaper.

Shaper:

Tool reciprocates

Planer:

Workpiece reciprocates

14.4 What is a Slotter?

A slotting machine is essentially a vertical shaper in which the ram and cutting tool reciprocate vertically.

It is particularly useful for:

Internal slots

Keyways

Internal grooves

Internal profiles

14.5 Comparison of Shaper, Planer and Slotter

Feature	Shaper	Planer	Slotter
Cutting tool	Reciprocates	Generally stationary relative to machine	Reciprocates vertically
Workpiece	Generally stationary	Reciprocates	Generally stationary
Direction	Usually horizontal	Horizontal	Vertical
Typical work	Small/medium	Large/heavy	Internal slots/keyways
Tool	Single-point	Single/multiple	Single-point

14.6 Main Parts of a Shaper

Important parts include:

Base
Column
Cross rail
Ram
Tool head
Clapper box
Apron
Table
Saddle
Cross-slide
Feed mechanism
Quick-return mechanism

14.7 Base

The base:

Supports the machine

Provides rigidity

Carries the column

It is generally made of cast iron or a suitable machine-tool material.

14.8 Column

The column is the main vertical body of the shaper.

It houses or supports:

Drive mechanism

Quick-return mechanism

Feed mechanism

14.9 Ram

The ram is one of the most important parts of the shaper.

It:

Carries the tool head

Provides reciprocating motion

Moves forward and backward

14.10 Tool Head

The tool head holds the cutting tool.

It generally provides:

Vertical tool movement

Adjustment for depth of cut

Angular positioning for inclined surfaces

14.11 Clapper Box

The clapper box is mounted on the tool head.

Its important function is:

To allow the cutting tool to lift slightly during the return stroke.

This prevents the tool from rubbing against the freshly machined surface.

Exam point:

Clapper box → Prevents tool rubbing during return stroke

14.12 Table

The table supports the workpiece.

It can generally be adjusted:

Vertically

Horizontally/crosswise depending on design

14.13 Saddle

The saddle supports the table and permits its movement.

14.14 Cross-Slide

The cross-slide allows movement of the table across the machine.

This movement is important for:

Feed

14.15 Feed Mechanism

The feed mechanism provides controlled movement of the work relative to the cutting tool.

Feed is generally given after each cutting stroke.

14.16 Quick-Return Mechanism

The quick-return mechanism is one of the most important features of a shaper.

Its purpose is to:

Make the return stroke faster than the cutting stroke.

Therefore:

This reduces idle time and increases productivity.

14.17 Common Quick-Return Mechanisms

Important mechanisms include:

1. Whitworth quick-return mechanism

2. Crank and slotted link mechanism

3. Hydraulic quick-return mechanism

14.18 Whitworth Quick-Return Mechanism

The Whitworth mechanism is a mechanical quick-return mechanism commonly associated with shaper machines.

It converts:

Rotary motion → Reciprocating motion

and provides:

Quick return

14.19 Crank and Slotted Link Mechanism

The crank and slotted link mechanism is another common mechanical arrangement for producing reciprocating motion with a quick-return characteristic.

14.20 Hydraulic Shaper

A hydraulic shaper uses hydraulic power to produce ram movement.

Advantages include:

Smooth operation

Better control

Reduced mechanical impact

Convenient speed variation

14.21 Cutting Stroke

During the cutting stroke:

Tool moves relative to work

Material is removed

Cutting force is generated

Chips are produced

14.22 Return Stroke

During the return stroke:

Tool travels back

Normally no cutting occurs

Tool may lift through the clapper mechanism

The return stroke is ideally faster.

14.23 Feed in Shaper

Feed is the movement of the workpiece relative to the tool after each stroke.

Feed may be expressed in:

mm/stroke

14.24 Depth of Cut

Depth of cut represents the thickness of material removed in one pass.

It is generally adjusted using the:

Tool head/feed mechanism

14.25 Shaper Operations

A shaper can perform:

Horizontal surface machining
Vertical surface machining
Inclined surface machining
Angular surface machining
Slots
Grooves
Keyways
Steps
Dovetail surfaces

14.26 Horizontal Surface Machining

The shaper can produce flat horizontal surfaces by appropriately positioning the tool and work.

14.27 Vertical Surface Machining

Vertical surfaces can be produced by setting the tool head appropriately.

14.28 Inclined Surface Machining

Inclined surfaces can be produced by swivelling the tool head to the required angle.

14.29 Dovetail Machining

A shaper can produce:

Dovetail grooves and surfaces

by using a suitable tool and setting.

14.30 Slotting

Slots and grooves can be produced using appropriate shaper tools.

For internal slots, however, a slotting machine is generally more suitable.

14.31 Shaper Cutting Tool

The cutting tool used on a conventional shaper is generally:

Single-point cutting tool

The tool is similar in principle to a lathe cutting tool but is designed for reciprocating cutting.

14.32 Tool Material

Common cutting-tool materials include:

High-speed steel

Carbides

Other modern cutting-tool materials

14.33 Why a Single-Point Tool?

A single-point tool is suitable because cutting occurs during the forward stroke and the tool can be shaped to produce the required profile.

14.34 Planer Machine

A planer is designed mainly for machining:

Large and heavy workpieces.

In a planer:

Workpiece reciprocates

while:

Cutting tools are mounted on tool heads and remain stationary relative to the machine structure during the cutting movement.

14.35 Main Parts of Planer

Important parts include:

Bed

Table

Columns

Cross rail

Tool heads

Side tool heads

Drive mechanism

14.36 Planer Bed

The planer bed:

Supports the table

Guides table movement

Provides rigidity

14.37 Planer Table

The table carries the workpiece.

The table reciprocates:

Forward and backward

14.38 Planer Columns

Columns support the:

Cross rail and tool heads

14.39 Planer Cross Rail

The cross rail supports tool heads and can generally be adjusted vertically.

14.40 Planer Tool Heads

Planers may have multiple tool heads.

This allows:

Simultaneous machining of multiple surfaces.

14.41 Advantages of Planer

Planer is particularly advantageous for:

Large workpieces

Heavy workpieces

Long flat surfaces

Multiple cutting tools

Heavy cuts

14.42 Shaper vs Planer

Shaper

Tool reciprocates

Work remains generally stationary

Suitable for small/medium work

Usually one main cutting tool

Planer

Work reciprocates

Tools are mounted on stationary structures

Suitable for large/heavy work

Multiple tool heads possible

14.43 Slotting Machine

A slotting machine is essentially:

A vertical shaper.

The ram moves:

Vertically

14.44 Uses of Slotting Machine

Slotters are particularly useful for:

Internal keyways

Internal slots

Internal grooves

Internal splines

Internal profiles

14.45 Slotter Tool

The cutting tool is generally:

Single-point cutting tool

14.46 Slotter Applications

A slotter can be used for machining:

Keyways inside hubs

Internal slots

Small internal surfaces

Internal gear profiles in suitable applications

14.47 Cutting Speed in Shaper

Cutting speed can be expressed approximately as:

where:

= cutting speed in m/min

= cutting stroke length in metres

= number of cutting strokes per minute

If stroke length is expressed in mm:

14.48 Average Cutting Speed

Because the return stroke is generally faster than the cutting stroke, average ram speed is related to both stroke times.

If:

= stroke length

= cutting-stroke time

= return-stroke time

then:

and:

14.49 Quick-Return Ratio

The quick-return ratio is commonly expressed as:

Since return stroke is faster:

Therefore:

14.50 Important Exam Facts

Shaper

Tool reciprocates

Planer

Workpiece reciprocates

Slotter

Vertical shaper

Cutting tool

Single-point

Quick-return mechanism

Reduces return-stroke time

Clapper box

Prevents rubbing during return stroke

Planer

Large and heavy workpieces

Slotter

Internal keyways and slots

Q1. A shaper is primarily used for producing:

A. Flat surfaces
B. Round holes only
C. Gear teeth only
D. Cylindrical shafts only

Answer: A. Flat surfaces

Explanation: Shapers are particularly suitable for producing flat, inclined, stepped, grooved and similar surfaces.

Practice

Q2. In a conventional shaper, the reciprocating motion is given to the:

A. Tool
B. Workpiece
C. Table only
D. Chuck

Answer: A. Tool

Q3. In a planer, the reciprocating motion is given to the:

A. Workpiece/table
B. Cutting tool only
C. Drill
D. Tool post only

Answer: A. Workpiece/table

Q4. A slotting machine is essentially a:

A. Vertical shaper
B. Horizontal lathe
C. Milling machine
D. Grinding machine

Answer: A. Vertical shaper

Q5. The cutting tool used in a conventional shaper is generally:

A. Single-point tool
B. Multi-point drill
C. Grinding wheel
D. Reamer

Answer: A. Single-point tool

Q6. The ram of a shaper carries the:

A. Tool head
B. Motor only
C. Workpiece only
D. Coolant pump

Answer: A. Tool head

Q7. The main purpose of the quick-return mechanism is to:

A. Reduce return-stroke time
B. Increase idle time
C. Stop the cutting stroke
D. Eliminate feed

Answer: A. Reduce return-stroke time

Q8. During the forward stroke of a conventional shaper:

A. Cutting generally takes place
B. No movement occurs
C. Only coolant flows
D. The machine is switched off

Answer: A. Cutting generally takes place

Q9. The return stroke of a shaper is normally:

A. Faster than the cutting stroke
B. Slower than the cutting stroke
C. Equal in time under all mechanisms
D. The main cutting stroke

Answer: A. Faster than the cutting stroke

Q10. The clapper box is used mainly to:

A. Allow the tool to lift during return stroke
B. Drive the spindle
C. Hold the workpiece
D. Increase feed automatically

Answer: A. Allow the tool to lift during return stroke

Q11. The clapper box helps to prevent:

A. Tool rubbing during return stroke
B. Workpiece rotation
C. Coolant flow
D. Machine vibration completely

Answer: A. Tool rubbing during return stroke

Q12. The main body of a shaper that houses the driving mechanism is the:

A. Column
B. Table
C. Tool post
D. Chuck

Answer: A. Column

Q13. The workpiece in a shaper is normally mounted on the:

A. Table
B. Ram
C. Tool head
D. Clapper box

Answer: A. Table

Q14. Feed in a shaper is generally given:

A. After each cutting stroke
B. Only once during machine operation
C. During every return stroke only
D. Before mounting the work

Answer: A. After each cutting stroke

Q15. Feed in a shaper is commonly expressed in:

A. mm/stroke
B. kg/min
C. rpm only
D. m²/min

Answer: A. mm/stroke

Q16. Which mechanism is associated with quick return in a shaper?

A. Whitworth mechanism
B. Geneva mechanism only
C. Worm gear only
D. Differential screw only

Answer: A. Whitworth mechanism

Q17. A hydraulic shaper uses:

A. Hydraulic power for ram movement
B. Steam power only
C. Manual power only
D. Pneumatic cutting tools only

Answer: A. Hydraulic power for ram movement

Q18. A planer is particularly suitable for:

A. Large and heavy workpieces
B. Tiny holes only
C. Small hand tools only
D. Internal threading only

Answer: A. Large and heavy workpieces

Q19. In a planer, multiple tool heads can allow:

A. Simultaneous machining of different surfaces
B. Elimination of all cutting tools
C. Only one cut per day
D. Only drilling

Answer: A. Simultaneous machining of different surfaces

Q20. The table of a planer:

A. Reciprocates
B. Remains permanently fixed
C. Rotates continuously
D. Acts as a cutting tool

Answer: A. Reciprocates

Q21. A slotting machine is especially useful for producing:

A. Internal keyways
B. External cylindrical shafts only
C. Large external threads only
D. Flat plates only

Answer: A. Internal keyways

Q22. The ram of a slotting machine moves:

A. Vertically
B. Horizontally only
C. Circularly
D. Helically

Answer: A. Vertically

Q23. Which machine is generally preferred for very large flat surfaces?

A. Planer
B. Bench drill
C. Sensitive drill
D. Lathe

Answer: A. Planer

Q24. The quick-return mechanism converts:

A. Rotary motion into reciprocating motion
B. Reciprocating motion into heat only
C. Linear motion into welding current
D. Hydraulic pressure into casting

Answer: A. Rotary motion into reciprocating motion

Q25. Which statement is correct?

A. Shaper — tool reciprocates
B. Planer — tool always reciprocates
C. Slotter — workpiece rotates continuously
D. Shaper — drill rotates

Answer: A. Shaper — tool reciprocates

CHAPTER 14 — NEXT SECTION

MCQs 26–100 will cover the Whitworth and crank-and-slotted-link mechanisms, shaper parts, tool head, clapper box, feed mechanisms, shaper operations, planer construction, slotter applications, quick-return calculations, machining-time calculations and comparative questions.

A. SHAPER MECHANISM & PARTS — MCQs 26–45

Q26. The main function of the ram in a shaper is to:

A. Hold the workpiece
B. Provide reciprocating motion to the tool
C. Rotate the workpiece
D. Supply coolant

Answer: B. Provide reciprocating motion to the tool

Explanation: The ram carries the tool head and moves it forward and backward.

Q27. The ram of a shaper moves over the:

A. Column
B. Chuck
C. Tailstock
D. Spindle

Answer: A. Column

Q28. The table of a shaper is used to:

A. Support the workpiece
B. Rotate the tool
C. Drive the ram
D. Store cutting oil

Answer: A. Support the workpiece

Q29. The tool head of a shaper is mounted on the:

A. Ram
B. Base
C. Table
D. Cross rail

Answer: A. Ram

Q30. The tool head can generally be swivelled to machine:

A. Inclined surfaces
B. Only circular holes
C. Threads only
D. Cylindrical shafts only

Answer: A. Inclined surfaces

Q31. The clapper box is located between the:

A. Tool head and cutting tool
B. Table and base
C. Ram and column
D. Motor and belt

Answer: A. Tool head and cutting tool

Q32. The primary function of the clapper mechanism during return stroke is to:

A. Lift the tool slightly
B. Increase cutting depth
C. Increase feed
D. Rotate the tool

Answer: A. Lift the tool slightly

Q33. The cross-slide of a shaper provides:

A. Crosswise movement of the table
B. Ram rotation
C. Spindle rotation
D. Coolant movement

Answer: A. Crosswise movement of the table

Q34. The saddle of a shaper supports the:

A. Table
B. Cutting tool
C. Motor
D. Ram only

Answer: A. Table

Q35. The base of a shaper provides:

A. Foundation and support
B. Cutting action
C. Tool rotation
D. Workpiece rotation

Answer: A. Foundation and support

Q36. The feed mechanism of a shaper controls:

A. Movement of work relative to tool
B. Cutting-tool material
C. Workpiece hardness
D. Machine lubrication only

Answer: A. Movement of work relative to tool

Q37. In a conventional shaper, the workpiece generally:

A. Remains stationary during the cutting stroke
B. Rotates continuously
C. Reciprocates with the ram
D. Rotates intermittently

Answer: A. Remains stationary during the cutting stroke

Q38. A shaper is best suited for:

A. Small and medium-sized workpieces
B. Only very large ship hulls
C. Only cylindrical shafts
D. Only internal holes

Answer: A. Small and medium-sized workpieces

Q39. The quick-return mechanism is provided mainly to:

A. Reduce non-cutting time
B. Increase non-cutting time
C. Stop the return stroke
D. Eliminate cutting forces

Answer: A. Reduce non-cutting time

Q40. In a quick-return shaper:

A. Return stroke is faster
B. Cutting stroke is always faster
C. Both strokes must take equal time
D. No return stroke exists

Answer: A. Return stroke is faster

Q41. The Whitworth mechanism is also associated with:

A. Quick-return motion
B. Gear cutting only
C. Grinding only
D. Drilling only

Answer: A. Quick-return motion

Q42. The crank and slotted-link mechanism converts rotary motion into:

A. Reciprocating motion
B. Pure rotary motion
C. Vibratory motion only
D. Helical motion only

Answer: A. Reciprocating motion

Q43. In a hydraulic shaper, ram motion is produced by:

A. Hydraulic pressure
B. Gravity alone
C. Manual filing
D. Centrifugal force only

Answer: A. Hydraulic pressure

Q44. One advantage of a hydraulic shaper is:

A. Smooth ram movement
B. No need for a tool
C. No cutting force
D. No workpiece support

Answer: A. Smooth ram movement

Q45. The cutting tool in a shaper generally has:

A. A single cutting point
B. Hundreds of cutting teeth
C. No cutting edge
D. Only abrasive grains

Answer: A. A single cutting point

B. SHAPER OPERATIONS — MCQs 46–60

Q46. A shaper can machine:

A. Horizontal surfaces
B. Vertical surfaces
C. Inclined surfaces
D. All of the above

Answer: D. All of the above

Q47. To machine an inclined surface, the tool head may be:

A. Swivelled
B. Removed
C. Welded to the table
D. Rotated at high speed

Answer: A. Swivelled

Q48. A shaper can produce:

A. Slots
B. Grooves
C. Steps
D. All of the above

Answer: D. All of the above

Q49. A dovetail surface can be produced using:

A. A suitable shaper operation
B. Only drilling
C. Only reaming
D. Only tapping

Answer: A. A suitable shaper operation

Q50. The cutting stroke of a shaper is also called the:

A. Forward stroke
B. Return stroke
C. Idle stroke
D. Reverse stroke

Answer: A. Forward stroke

Q51. The return stroke is generally:

A. Non-cutting
B. The main cutting stroke
C. Used for drilling
D. Used for casting

Answer: A. Non-cutting

Q52. The tool is fed into the workpiece mainly:

A. After each stroke
B. Only once at the beginning
C. Continuously during the return stroke only
D. Never

Answer: A. After each stroke

Q53. The feed direction for machining a horizontal surface is generally:

A. Across the surface
B. Vertically downward only
C. Circularly
D. Randomly

Answer: A. Across the surface

Q54. The depth of cut in a shaper is controlled by:

A. Adjusting the tool/work position
B. Changing coolant colour
C. Increasing workpiece weight
D. Removing the base

Answer: A. Adjusting the tool/work position

Q55. Shaping is generally considered suitable for:

A. Low-to-medium production and general machining
B. Only mass production of identical parts
C. Only casting
D. Heat treatment

Answer: A. Low-to-medium production and general machining

Q56. Compared with milling, shaping generally has:

A. Intermittent cutting
B. Continuous cutting by rotating teeth
C. No cutting stroke
D. Only abrasive cutting

Answer: A. Intermittent cutting

Q57. One disadvantage of a shaper is:

A. Significant idle return stroke
B. No cutting tool
C. No possibility of flat surfaces
D. No feed mechanism

Answer: A. Significant idle return stroke

Q58. The quick-return mechanism improves:

A. Productivity
B. Workpiece hardness
C. Tool colour
D. Material composition

Answer: A. Productivity

Q59. Shaper cutting is:

A. Intermittent
B. Continuous rotary cutting
C. Non-machining
D. Casting

Answer: A. Intermittent

Q60. Which operation is NOT normally associated with a conventional shaper?

A. Flat surface machining
B. Slotting
C. Inclined surface machining
D. Deep-hole drilling

Answer: D. Deep-hole drilling

C. PLANER MACHINE — MCQs 61–75

Q61. In a planer, the main reciprocating member is the:

A. Table
B. Cutting tool
C. Drill spindle
D. Chuck

Answer: A. Table

Q62. A planer is mainly used for:

A. Large and heavy workpieces
B. Small holes
C. Internal threading only
D. Small shaft turning

Answer: A. Large and heavy workpieces

Q63. The workpiece in a planer is mounted on the:

A. Reciprocating table
B. Tool head
C. Column
D. Cross rail only

Answer: A. Reciprocating table

Q64. Planer tool heads are generally mounted on:

A. Cross rail and/or side supports
B. Lathe tailstock
C. Drill chuck
D. Shaper ram

Answer: A. Cross rail and/or side supports

Q65. A major advantage of a planer is:

A. It can accommodate very large workpieces
B. It is limited to tiny components
C. It cannot machine flat surfaces
D. It cannot use multiple tools

Answer: A. It can accommodate very large workpieces

Q66. Multiple tool heads on a planer allow:

A. Simultaneous machining
B. Elimination of feed
C. Elimination of cutting tools
D. Only drilling

Answer: A. Simultaneous machining

Q67. The bed of a planer supports and guides the:

A. Table
B. Drill
C. Chuck
D. Cutting insert only

Answer: A. Table

Q68. The columns of a planer support the:

A. Cross rail
B. Workpiece directly only
C. Drill chuck
D. Lathe spindle

Answer: A. Cross rail

Q69. The cross rail of a planer carries:

A. Tool heads
B. Lathe chuck
C. Tailstock
D. Drill spindle

Answer: A. Tool heads

Q70. A planer can machine:

A. Large flat surfaces
B. Steps
C. Slots and grooves
D. All of the above

Answer: D. All of the above

Q71. The main difference between a shaper and planer is:

A. Tool reciprocates in shaper; work reciprocates in planer
B. Both have identical motion
C. Work reciprocates in shaper only
D. Tool rotates in both

Answer: A. Tool reciprocates in shaper; work reciprocates in planer

Q72. Compared with a shaper, a planer generally has:

A. Greater capacity
B. Smaller capacity
C. No table
D. No cutting tool

Answer: A. Greater capacity

Q73. A planer is suitable for heavy cuts because of its:

A. Rigid construction
B. Small size
C. Hand operation
D. Lack of feed

Answer: A. Rigid construction

Q74. The table of a planer generally moves:

A. Horizontally
B. Vertically only
C. Circularly
D. Helically

Answer: A. Horizontally

Q75. In a planer, the cutting tool is generally:

A. Stationary relative to the tool-support structure while the work/table reciprocates
B. Rotating continuously like a milling cutter
C. A drill
D. A grinding wheel

Answer: A. Stationary relative to the tool-support structure while the work/table reciprocates

D. SLOTTING MACHINE — MCQs 76–85

Q76. A slotting machine is essentially a:

A. Vertical shaper
B. Horizontal planer
C. Lathe
D. Milling machine

Answer: A. Vertical shaper

Q77. The ram of a slotter moves:

A. Vertically
B. Horizontally
C. Circularly
D. Helically

Answer: A. Vertically

Q78. A slotter is especially suitable for machining:

A. Internal keyways
B. External cylindrical surfaces
C. External threads
D. Long shafts

Answer: A. Internal keyways

Q79. A slotting machine can be used to machine:

A. Internal grooves
B. Internal slots
C. Internal profiles
D. All of the above

Answer: D. All of the above

Q80. The cutting tool in a slotter is generally:

A. Single-point tool
B. Twist drill
C. Reamer
D. Milling cutter

Answer: A. Single-point tool

Q81. Slotting is particularly useful where:

A. Internal surfaces are difficult to reach with other machines
B. Only external turning is required
C. Only drilling is required
D. Only grinding is required

Answer: A. Internal surfaces are difficult to reach with other machines

Q82. A keyway inside a gear or pulley hub can commonly be produced using:

A. Slotting machine
B. Surface grinder only
C. Drill chuck only
D. Lathe centre only

Answer: A. Slotting machine

Q83. In a slotter, the workpiece generally:

A. Remains stationary while the tool reciprocates vertically
B. Rotates continuously
C. Reciprocates horizontally
D. Rotates at high speed

Answer: A. Remains stationary while the tool reciprocates vertically

Q84. The slotter is particularly suitable for:

A. Internal machining
B. External turning
C. External cylindrical grinding
D. Deep-hole drilling

Answer: A. Internal machining

Q85. Which statement is correct?

A. Slotter — vertical reciprocating tool
B. Slotter — rotating workpiece
C. Slotter — horizontal drilling
D. Slotter — continuous milling cutter

Answer: A. Slotter — vertical reciprocating tool

E. NUMERICAL & QUICK-RETURN QUESTIONS — MCQs 86–100

Q86. If the cutting stroke takes 6 seconds and return stroke takes 4 seconds, the quick-return ratio is:

A. 0.67
B. 1.0
C. 1.5
D. 2.5

Answer: C. 1.5

Q87. If cutting-stroke time is 10 seconds and return-stroke time is 5 seconds, quick-return ratio is:

A. 0.5
B. 1
C. 2
D. 5

Answer: C. 2

Q88. If the cutting stroke takes 8 seconds and return stroke takes 4 seconds, total time per cycle is:

A. 4 s
B. 8 s
C. 12 s
D. 32 s

Answer: C. 12 s

Q89. A shaper makes 10 complete strokes per minute. The number of cutting strokes per minute is:

A. 5
B. 10
C. 20
D. 30

Answer: A. 5

Explanation: One complete cycle contains one cutting stroke and one return stroke.

Q90. If a shaper performs 20 cutting strokes per minute, the number of complete cycles per minute is:

A. 10
B. 20
C. 40
D. 5

Answer: B. 20

Explanation: Each cycle has one cutting stroke and one return stroke.

Q91. A shaper has a stroke length of 500 mm and performs 20 cutting strokes/min. The cutting speed is:

A. 5 m/min
B. 10 m/min
C. 20 m/min
D. 40 m/min

Answer: B. 10 m/min

Q92. A shaper has a stroke length of 600 mm and makes 30 cutting strokes/min. Cutting speed is:

A. 12 m/min
B. 18 m/min
C. 24 m/min
D. 30 m/min

Answer: B. 18 m/min

Q93. A shaper makes 15 cutting strokes/min and has a stroke length of 400 mm. Cutting speed is:

A. 4 m/min
B. 6 m/min
C. 8 m/min
D. 10 m/min

Answer: B. 6 m/min

Q94. If cutting speed is 12 m/min and stroke length is 600 mm, the number of cutting strokes per minute is:

A. 10
B. 15
C. 20
D. 30

Answer: C. 20

Q95. If a shaper makes 12 complete cycles per minute, the total number of strokes per minute is:

A. 6
B. 12
C. 24
D. 36

Answer: C. 24

Q96. A workpiece requires 100 strokes and the machine makes 20 cutting strokes/min. Approximate machining time, ignoring setup and other allowances, is:

A. 2 min
B. 5 min
C. 10 min
D. 20 min

Answer: B. 5 min

Q97. If the return stroke takes less time than the cutting stroke, the quick-return ratio is:

A. Greater than 1
B. Less than 1
C. Equal to zero
D. Always equal to 1

Answer: A. Greater than 1

Q98. A machine has cutting-stroke time of 9 seconds and return-stroke time of 3 seconds. Its quick-return ratio is:

A. 1
B. 2
C. 3
D. 6

Answer: C. 3

Q99. If a shaper has a cutting speed of 15 m/min and stroke length of 750 mm, cutting strokes per minute are:

A. 10
B. 15
C. 20
D. 25

Answer: C. 20

Q100. Which sequence correctly represents the machines?

A. Shaper — horizontal reciprocating tool; Planer — reciprocating work; Slotter — vertical reciprocating tool
B. Shaper — rotating tool; Planer — rotating work; Slotter — rotating tool
C. Shaper — drilling; Planer — turning; Slotter — grinding
D. Shaper — only vertical motion; Planer — only rotary motion; Slotter — only drilling

Answer: A. Shaper — horizontal reciprocating tool; Planer — reciprocating work; Slotter — vertical reciprocating tool

CHAPTER 14 — EXAM REVISION TABLE

Topic	Remember
Shaper	Tool reciprocates
Planer	Workpiece/table reciprocates
Slotter	Vertical shaper
Shaper tool	Single-point
Cutting stroke	Forward stroke
Return stroke	Non-cutting/idle
Quick return	Faster return
Clapper box	Prevents tool rubbing
Whitworth	Quick-return mechanism
Hydraulic shaper	Hydraulic ram drive
Shaper feed	Commonly mm/stroke
Planer	Large/heavy work
Planer table	Reciprocates
Planer tool heads	Multiple tools possible
Slotter	Internal keyways/slots
Slotter ram	Vertical
Cutting speed
Quick-return ratio

CHAPTER 15 : MILLING MACHINE & MILLING OPERATIONS

15.1 Definition of Milling

Milling is a machining process in which material is removed from a workpiece by a rotating multi-point cutting tool.

The milling cutter contains several cutting teeth.

Key point

Milling = Rotating multi-point cutter + workpiece feed

This distinguishes milling from turning and shaping.

15.2 Principle of Milling

During milling:

The cutter rotates.
The workpiece is securely clamped.
The workpiece is fed against the rotating cutter.
Cutter teeth remove material intermittently.
Chips are produced.
The desired surface/profile is obtained.

15.3 Main Characteristics of Milling

Milling generally involves:

Rotating cutting tool

Multiple cutting edges

Intermittent cutting

Relative movement between cutter and work

Material removal in the form of chips

15.4 Milling Cutter

A milling cutter is a rotary multi-point cutting tool having several cutting teeth arranged around its circumference and/or face.

Examples:

Plain milling cutter

End mill

Side milling cutter

Slitting saw

Angle cutter

Form cutter

Gear cutter

T-slot cutter

Face mill

15.5 Milling Machine

A milling machine is a machine tool designed primarily to machine surfaces using a rotating multi-point cutter.

It can produce:

Flat surfaces

Slots

Grooves

Keyways

Steps

Angular surfaces

Gear teeth

Helical surfaces

Profiles

15.6 Types of Milling Machines

Important types include:

Column and knee type
Horizontal milling machine
Vertical milling machine
Universal milling machine
Fixed-bed milling machine
Planer-type milling machine
CNC milling machine

15.7 Horizontal Milling Machine

In a horizontal milling machine:

The spindle axis is horizontal.

The cutter is mounted on the spindle/arbor.

It is particularly suitable for:

Slab milling

Side milling

Groove milling

Heavy-duty milling

15.8 Vertical Milling Machine

In a vertical milling machine:

The spindle axis is vertical.

It is commonly used for:

Face milling

End milling

Slot milling

Drilling-like operations

Profile machining

15.9 Universal Milling Machine

A universal milling machine is similar to a horizontal milling machine but has a table that can be swivelled, allowing additional angular/helix-related operations.

It is particularly useful for:

Helical milling

Gear cutting

Angular milling

Complex machining

15.10 Column and Knee Type Milling Machine

Major components include:

Base

Column

Knee

Saddle

Table

Spindle

Arbor

Overarm

15.11 Column

The column:

Supports the machine structure

Houses the drive mechanism

Supports the knee

15.12 Knee

The knee is mounted on the column and supports the:

Saddle and table.

It can move vertically.

15.13 Saddle

The saddle is located between the:

Knee and table.

It generally provides crosswise movement of the table.

15.14 Table

The table supports and clamps the workpiece.

It provides longitudinal movement.

15.15 Spindle

The spindle provides rotary motion to the milling cutter.

In a horizontal milling machine, the spindle usually drives the arbor/cutter.

15.16 Arbor

The arbor is used mainly with horizontal milling machines to:

Support and drive milling cutters.

15.17 Overarm

The overarm supports the arbor in many horizontal milling machines.

15.18 Milling Cutter Classification

Milling cutters may be classified according to:

Position of teeth

Peripheral cutters

Face cutters

End cutters

Function

Plain cutter

Side cutter

Slitting saw

Angle cutter

Form cutter

Gear cutter

15.19 Plain Milling Cutter

A plain milling cutter has teeth mainly on its:

Peripheral surface.

It is commonly used for producing:

Flat horizontal surfaces.

15.20 Face Milling Cutter

A face milling cutter has cutting edges on:

Face

Sometimes periphery

It is used primarily for:

Machining flat surfaces.

15.21 Side Milling Cutter

A side milling cutter has teeth on:

Side and peripheral surfaces.

It is commonly used for:

Slots

Grooves

Side surfaces

15.22 End Mill

An end mill has cutting edges on its:

End

Periphery

It is used for:

Slots

Pockets

Profiles

Keyways

15.23 Slitting Saw

A slitting saw is a thin circular cutter used for:

Narrow slots

Grooves

Cutting-off operations

15.24 Angle Cutter

Angle milling cutters are used for producing:

Inclined/angular surfaces and grooves.

15.25 Form Cutter

A form cutter has a specially shaped cutting profile.

It is used for producing:

Corresponding shaped surfaces.

15.26 Up Milling

In up milling:

The cutter rotates opposite to the direction of work feed at the point of cutting.

It is also called:

Conventional milling.

Important characteristic:

Chip thickness generally starts at:

Zero

and increases toward the maximum value.

15.27 Down Milling

In down milling:

The cutter rotates in the same direction as the work feed at the point of cutting.

It is also called:

Climb milling.

The chip thickness generally:

Starts at maximum and decreases toward zero.

15.28 Comparison of Up and Down Milling

Feature	Up Milling	Down Milling
Other name	Conventional milling	Climb milling
Cutter rotation	Opposite feed	Same direction as feed
Chip thickness	0 → maximum	Maximum → 0
Cutting force	Tends to lift work	Tends to press work down
Backlash concern	Less critical	More critical
Surface finish	Generally lower	Generally better

15.29 Advantages of Up Milling

Suitable for machines with some backlash

Cutting starts with small chip thickness

Generally safer on conventional machines

Cutting force tends to lift the work

15.30 Advantages of Down Milling

Better surface finish under suitable conditions

Reduced tendency for rubbing

Lower tendency for workpiece lifting

Often more efficient

Important:

Down milling requires proper machine condition and backlash control.

15.31 Conventional Milling

Another name for:

Up milling

15.32 Climb Milling

Another name for:

Down milling

15.33 Milling Feed

Feed can be expressed as:

mm/min

mm/rev

mm/tooth

For milling, feed per tooth is particularly important.

15.34 Feed Rate Formula

If:

= feed per tooth

= number of teeth

= spindle speed

then:

where is feed rate in mm/min.

15.35 Milling Cutting Speed

The cutting-speed formula is:

where:

= cutting speed in m/min

= cutter diameter in mm

= spindle speed in rpm

15.36 Milling Machining Time

For a simple milling operation:

where:

= machining time

= effective travel

= feed rate

15.37 Indexing

Indexing is the process of rotating the workpiece through a predetermined angular amount between successive machining operations.

It is especially important for:

Gear teeth

Splines

Polygonal surfaces

Equally spaced slots

15.38 Dividing Head

A dividing head is used for:

Indexing the workpiece accurately.

It is commonly used in:

Gear cutting

Slot cutting

Polygon machining

Helical milling

15.39 Simple Indexing

For a standard 40:1 dividing head:

where is the number of divisions required.

Example:

For 20 divisions:

Therefore, the crank is turned 2 complete revolutions per division.

15.40 Differential Indexing

Differential indexing is used when the required indexing cannot conveniently be achieved by simple indexing.

The dividing-head spindle receives additional rotation through the gear train.

15.41 Helical Milling

Helical surfaces can be produced using:

Universal milling machine

Dividing head

Suitable gearing

Applications include:

Helical gears

Spiral grooves

Helical splines

15.42 Gear Cutting

Gear teeth can be produced by milling using:

Form-relieved gear cutters

A dividing head is used to index the blank between teeth.

15.43 T-Slot Milling

T-slots are produced using:

T-slot cutters

These are commonly used for producing T-slots in machine-tool tables and fixtures.

15.44 Keyway Milling

Keyways can be produced using:

End mills or suitable slot/keyway cutters.

15.45 Straddle Milling

Straddle milling uses:

Two side milling cutters

mounted on the same arbor to machine two parallel surfaces simultaneously.

15.46 Gang Milling

Gang milling involves:

Two or more cutters mounted on the same arbor to perform multiple operations in one pass.

15.47 Important Exam Facts

Milling cutter → Multi-point

Plain milling → Peripheral teeth

Face milling → Face surface machining

Up milling → Conventional milling

Down milling → Climb milling

Up milling → Chip thickness 0 to maximum

Down milling → Maximum to 0

Dividing head → Indexing

Standard dividing-head ratio → 40:1

Feed rate →

Cutting speed →

Straddle milling → Two side cutters

Gang milling → Multiple cutters

T-slot → T-slot cutter

Q1. Milling is a machining process using a:

A. Single-point stationary tool
B. Rotating multi-point cutting tool
C. Grinding wheel only
D. Single-point rotating tool only

Answer: B. Rotating multi-point cutting tool

Explanation: A milling cutter has multiple cutting teeth and rotates during machining.

Q2. In a milling machine, the cutting tool generally:

A. Rotates
B. Remains permanently stationary
C. Reciprocates only
D. Does not move

Answer: A. Rotates

Q3. A milling cutter is generally a:

A. Multi-point cutting tool
B. Single-point tool
C. Non-cutting tool
D. Measuring tool

Answer: A. Multi-point cutting tool

Q4. The spindle axis of a horizontal milling machine is:

A. Horizontal
B. Vertical
C. Inclined at 45° always
D. Circular

Answer: A. Horizontal

Q5. In a vertical milling machine, the spindle axis is:

A. Vertical
B. Horizontal
C. Parallel to table only
D. Random

Answer: A. Vertical

Q6. A plain milling cutter has teeth primarily on its:

A. Periphery
B. End face only
C. Shank
D. Arbor

Answer: A. Periphery

Q7. A face milling cutter is mainly used for:

A. Flat surface machining
B. Internal threading
C. Drilling deep holes
D. Knurling

Answer: A. Flat surface machining

Q8. A side milling cutter is particularly suitable for:

A. Slots and grooves
B. Drilling holes
C. External threading
D. Grinding

Answer: A. Slots and grooves

Q9. An end mill has cutting edges on:

A. End and periphery
B. Shank only
C. Arbor only
D. Face only

Answer: A. End and periphery

Q10. A slitting saw is used mainly for:

A. Narrow slots and cutting-off
B. Drilling
C. Reaming
D. Tapping

Answer: A. Narrow slots and cutting-off

Q11. In up milling, the cutter rotates:

A. Opposite to the feed direction at the cutting point
B. In the same direction as feed
C. Without rotation
D. Vertically only

Answer: A. Opposite to the feed direction at the cutting point

Q12. Up milling is also called:

A. Conventional milling
B. Climb milling
C. Face turning
D. Slotting

Answer: A. Conventional milling

Q13. Down milling is also called:

A. Climb milling
B. Conventional milling
C. Plain turning
D. Back machining

Answer: A. Climb milling

Q14. In down milling, cutter rotation and work feed are:

A. In the same direction at the cutting point
B. Always opposite
C. Unrelated
D. Both stationary

Answer: A. In the same direction at the cutting point

Q15. In up milling, chip thickness generally:

A. Starts at zero and increases
B. Starts at maximum and decreases
C. Remains zero
D. Remains constant

Answer: A. Starts at zero and increases

Q16. In down milling, chip thickness generally:

A. Starts at maximum and decreases
B. Starts at zero and increases
C. Remains zero
D. Remains constant

Answer: A. Starts at maximum and decreases

Q17. Conventional milling is generally more tolerant of:

A. Backlash
B. Excessive vibration
C. Broken cutters
D. No lubrication

Answer: A. Backlash

Q18. Climb milling generally requires:

A. Proper backlash control
B. No machine rigidity
C. Loose table movement
D. No work holding

Answer: A. Proper backlash control

Q19. The formula for milling cutting speed is:

A.
B.
C.
D.

Answer: A.

Q20. If feed per tooth is , number of teeth is , and spindle speed is , feed rate is:

A.
B.
C.
D.

Answer: A.

Q21. A dividing head is primarily used for:

A. Indexing
B. Grinding
C. Welding
D. Drilling

Answer: A. Indexing

Q22. The standard ratio of a common dividing head is:

A. 20:1
B. 30:1
C. 40:1
D. 60:1

Answer: C. 40:1

Q23. The crank movement for simple indexing with a 40:1 dividing head is:

A.
B.
C.
D.

Answer: B.

Q24. Straddle milling uses:

A. Two side milling cutters
B. One drill
C. One reamer
D. One grinding wheel

Answer: A. Two side milling cutters

Q25. Gang milling involves:

A. Several cutters mounted together to perform multiple operations
B. One cutter used repeatedly
C. Only a drill
D. Only a reamer

Answer: A. Several cutters mounted together to perform multiple operations

A. MILLING MACHINE PARTS — MCQs 26–40

Q26. The knee of a column-and-knee milling machine is mounted on the:

A. Table
B. Column
C. Arbor
D. Spindle

Answer: B. Column

Explanation: The knee slides vertically on the column and supports the saddle and table.

Q27. The saddle is located between the:

A. Column and spindle
B. Knee and table
C. Table and arbor
D. Base and spindle

Answer: B. Knee and table

Q28. The table of a conventional milling machine primarily provides:

A. Support and movement for the workpiece
B. Rotation to the cutter
C. Hydraulic pressure
D. Cutting-fluid filtration

Answer: A. Support and movement for the workpiece

Q29. In a horizontal milling machine, the arbor is used to:

A. Support and drive the cutter
B. Support the workpiece only
C. Measure cutting speed
D. Produce coolant

Answer: A. Support and drive the cutter

Q30. The overarm in a horizontal milling machine primarily supports the:

A. Arbor
B. Table
C. Knee
D. Workpiece

Answer: A. Arbor

Q31. The column of a milling machine provides support for the:

A. Knee and other machine components
B. Workpiece only
C. Cutter teeth
D. Vice jaws only

Answer: A. Knee and other machine components

Q32. The spindle of a milling machine is responsible for:

A. Rotating the milling cutter
B. Supporting the machine foundation
C. Holding the workpiece directly in all cases
D. Supplying coolant

Answer: A. Rotating the milling cutter

Q33. In a vertical milling machine, the cutter is generally mounted:

A. Directly in or on the spindle
B. Only on a horizontal arbor
C. On the tailstock
D. On the lathe carriage

Answer: A. Directly in or on the spindle

Q34. The knee provides:

A. Vertical movement
B. Cutter tooth grinding
C. Spindle rotation
D. Coolant filtration

Answer: A. Vertical movement

Q35. The saddle generally provides:

A. Cross movement of the table
B. Spindle rotation
C. Vertical tool rotation
D. Cutting-fluid pressure

Answer: A. Cross movement of the table

Q36. The longitudinal movement of a conventional milling-machine table is generally along the:

A. X-axis
B. Y-axis
C. Z-axis only
D. Rotary axis

Answer: A. X-axis

Q37. The cross movement of the table is generally along the:

A. Y-axis
B. X-axis
C. Z-axis
D. C-axis only

Answer: A. Y-axis

Q38. Vertical movement in a conventional column-and-knee milling machine is generally associated with the:

A. Z-axis
B. X-axis
C. Y-axis
D. A-axis

Answer: A. Z-axis

Q39. The workpiece is commonly held on a milling machine using:

A. Vice, clamps or suitable fixtures
B. Only a drill chuck
C. Only a tailstock
D. Only a lathe dog

Answer: A. Vice, clamps or suitable fixtures

Q40. The primary function of a machine vice is to:

A. Hold the workpiece securely
B. Rotate the cutter
C. Drive the spindle
D. Supply coolant

Answer: A. Hold the workpiece securely

B. MILLING CUTTERS — MCQs 41–55

Q41. A plain milling cutter is primarily used for:

A. Producing flat horizontal surfaces
B. Producing internal threads
C. Drilling holes
D. Grinding surfaces

Answer: A. Producing flat horizontal surfaces

Q42. A side milling cutter has teeth on:

A. Side and periphery
B. Shank only
C. Arbor only
D. Face only

Answer: A. Side and periphery

Q43. A face mill is primarily used for:

A. Face milling
B. Tapping
C. Reaming
D. Knurling

Answer: A. Face milling

Q44. An end mill can be used for:

A. Slots and pockets
B. Profiles
C. Keyways
D. All of the above

Answer: D. All of the above

Q45. A T-slot cutter is used for:

A. Producing T-slots
B. Producing circular holes
C. Cutting external threads
D. Grinding gears

Answer: A. Producing T-slots

Q46. An angle cutter is used for:

A. Angular surfaces and grooves
B. Drilling holes
C. Turning shafts
D. Honing

Answer: A. Angular surfaces and grooves

Q47. A form cutter is designed to produce:

A. A specific profile
B. Only a flat surface
C. Only a round hole
D. External threads only

Answer: A. A specific profile

Q48. A gear milling cutter is used for:

A. Cutting gear teeth
B. Drilling gear blanks
C. Grinding bearings
D. Producing welds

Answer: A. Cutting gear teeth

Q49. A slitting saw is generally:

A. Thin compared with its diameter
B. Very thick and solid
C. A single-point tool
D. A grinding wheel

Answer: A. Thin compared with its diameter

Q50. A slitting saw is particularly suitable for:

A. Narrow slots
B. Deep drilling
C. Thread tapping
D. Surface grinding

Answer: A. Narrow slots

Q51. A shell-end mill is generally mounted using:

A. A suitable arbor/holder
B. A lathe tailstock
C. A drill table only
D. A steady rest

Answer: A. A suitable arbor/holder

Q52. The cutting edges of a milling cutter are called:

A. Teeth
B. Margins
C. Lips only
D. Flutes only

Answer: A. Teeth

Q53. The space between adjacent milling-cutter teeth is called:

A. Tooth space
B. Web
C. Margin
D. Shank

Answer: A. Tooth space

Q54. The body of a milling cutter supports:

A. Cutting teeth
B. Workpiece only
C. Machine table
D. Coolant tank

Answer: A. Cutting teeth

Q55. The number of teeth on a milling cutter affects:

A. Feed rate and cutting action
B. Workpiece chemical composition
C. Machine foundation
D. Coolant colour

Answer: A. Feed rate and cutting action

C. UP MILLING & DOWN MILLING — MCQs 56–70

Q56. Up milling is also known as:

A. Conventional milling
B. Climb milling
C. Reverse turning
D. Face turning

Answer: A. Conventional milling

Q57. Down milling is also called:

A. Climb milling
B. Conventional milling
C. Reverse drilling
D. Plain milling

Answer: A. Climb milling

Q58. In up milling, chip thickness:

A. Starts from approximately zero
B. Starts from maximum
C. Remains constant
D. Is always zero

Answer: A. Starts from approximately zero

Q59. In down milling, chip thickness:

A. Starts approximately at maximum
B. Starts at zero
C. Remains constant
D. Does not exist

Answer: A. Starts approximately at maximum

Q60. In up milling, cutting force tends to:

A. Lift the workpiece from the table
B. Press the workpiece firmly down
C. Eliminate all vibration
D. Stop the cutter

Answer: A. Lift the workpiece from the table

Q61. In down milling, cutting force tends to:

A. Press the workpiece against the table
B. Lift the workpiece
C. Stop feed completely
D. Reverse spindle rotation

Answer: A. Press the workpiece against the table

Q62. Down milling is generally preferred when:

A. Machine backlash is properly controlled
B. The machine has excessive backlash
C. The workpiece is loose
D. The cutter is not rotating

Answer: A. Machine backlash is properly controlled

Q63. In up milling, the cutter and work feed at the cutting point move:

A. In opposite directions
B. In the same direction
C. Vertically only
D. Without relative movement

Answer: A. In opposite directions

Q64. In down milling, cutter rotation and feed at the cutting point are:

A. In the same direction
B. In opposite directions
C. Always perpendicular
D. Both stationary

Answer: A. In the same direction

Q65. Which milling method generally gives better surface finish under suitable conditions?

A. Down milling
B. Up milling
C. Neither
D. Both always identical

Answer: A. Down milling

Q66. A major disadvantage of down milling on a machine with excessive backlash is:

A. Possibility of cutter grabbing/pulling the work
B. Zero cutting force
C. No chip formation
D. No surface generation

Answer: A. Possibility of cutter grabbing/pulling the work

Q67. In conventional milling, the cutting tooth generally enters the work with:

A. Minimum chip thickness
B. Maximum chip thickness
C. Zero cutting velocity
D. No contact

Answer: A. Minimum chip thickness

Q68. In climb milling, the cutting tooth generally enters the work with:

A. Maximum chip thickness
B. Zero chip thickness
C. No chip
D. Constant thickness

Answer: A. Maximum chip thickness

Q69. The term “climb” in climb milling refers to:

A. Feed and cutter motion being in the same direction at the cutting point
B. Vertical movement of the table only
C. Cutter moving upward
D. Workpiece moving vertically

Answer: A. Feed and cutter motion being in the same direction at the cutting point

Q70. Which statement is correct?

A. Up milling is generally more suitable for machines with backlash
B. Down milling requires no machine rigidity
C. Up milling always gives the best finish
D. Down milling is impossible on CNC machines

Answer: A. Up milling is generally more suitable for machines with backlash

D. INDEXING & GEAR CUTTING — MCQs 71–85

Q71. Indexing means:

A. Dividing the workpiece circumference into predetermined equal or unequal divisions
B. Grinding the workpiece
C. Measuring cutting temperature
D. Changing tool material

Answer: A. Dividing the workpiece circumference into predetermined equal or unequal divisions

Q72. The dividing head is commonly used for:

A. Gear cutting
B. Equal-spaced slots
C. Polygonal machining
D. All of the above

Answer: D. All of the above

Q73. A standard dividing head commonly has a worm ratio of:

A. 10:1
B. 20:1
C. 40:1
D. 100:1

Answer: C. 40:1

Q74. For a 40:1 dividing head, crank movement for divisions is:

A.
B.
C.
D.

Answer: B.

Q75. For 10 divisions, the crank movement using a 40:1 dividing head is:

A. 2 revolutions
B. 4 revolutions
C. 10 revolutions
D. 40 revolutions

Answer: B. 4 revolutions

Q76. For 20 divisions, crank movement is:

A. 1 revolution
B. 2 revolutions
C. 4 revolutions
D. 20 revolutions

Answer: B. 2 revolutions

Q77. For 40 divisions, crank movement is:

A. 0.5 revolution
B. 1 revolution
C. 2 revolutions
D. 4 revolutions

Answer: B. 1 revolution

Q78. For 8 divisions, crank movement is:

A. 2 revolutions
B. 4 revolutions
C. 5 revolutions
D. 8 revolutions

Answer: C. 5 revolutions

Q79. For 16 divisions, crank movement is:

A. 1.5 revolutions
B. 2.5 revolutions
C. 4 revolutions
D. 5 revolutions

Answer: B. 2.5 revolutions

Q80. A dividing head is especially important in machining:

A. Equally spaced features
B. Only flat surfaces
C. Only holes
D. Only cylindrical surfaces

Answer: A. Equally spaced features

Q81. Gear teeth can be cut on a milling machine using:

A. Gear milling cutter and indexing arrangement
B. Drill only
C. Reamer only
D. Grinding wheel only

Answer: A. Gear milling cutter and indexing arrangement

Q82. In conventional form milling of gears, the gear blank is indexed:

A. Between successive teeth
B. Only once
C. Continuously without stopping
D. Only after finishing the entire gear

Answer: A. Between successive teeth

Q83. Helical milling generally requires:

A. Universal milling machine and suitable indexing arrangement
B. Only a bench drill
C. Only a shaper
D. Only a grinding machine

Answer: A. Universal milling machine and suitable indexing arrangement

Q84. Differential indexing is useful when:

A. Simple indexing cannot conveniently provide the required division
B. No indexing is needed
C. Only drilling is performed
D. The cutter is broken

Answer: A. Simple indexing cannot conveniently provide the required division

Q85. The dividing head allows the workpiece to be:

A. Rotated accurately through predetermined angular increments
B. Heated
C. Ground automatically
D. Welded

Answer: A. Rotated accurately through predetermined angular increments

E. MILLING CALCULATIONS — MCQs 86–100

Q86. A milling cutter of diameter 100 mm rotates at 300 rpm. Cutting speed is approximately:

A. 47.1 m/min
B. 94.2 m/min
C. 120 m/min
D. 300 m/min

Answer: B. 94.2 m/min

Q87. A 50 mm cutter rotates at 600 rpm. Cutting speed is approximately:

A. 47.1 m/min
B. 94.2 m/min
C. 120 m/min
D. 188.5 m/min

Answer: B. 94.2 m/min

Q88. A milling cutter of 80 mm diameter rotates at 500 rpm. Cutting speed is approximately:

A. 62.8 m/min
B. 100 m/min
C. 125.7 m/min
D. 160 m/min

Answer: C. 125.7 m/min

Q89. A cutter has 10 teeth, feed per tooth is 0.05 mm and spindle speed is 400 rpm. Feed rate is:

A. 20 mm/min
B. 100 mm/min
C. 200 mm/min
D. 400 mm/min

Answer: C. 200 mm/min

Q90. A cutter has 8 teeth, feed per tooth is 0.1 mm and speed is 500 rpm. Feed rate is:

A. 200 mm/min
B. 300 mm/min
C. 400 mm/min
D. 500 mm/min

Answer: C. 400 mm/min

Q91. If feed per tooth is 0.08 mm, number of teeth is 10 and speed is 600 rpm, feed rate is:

A. 240 mm/min
B. 480 mm/min
C. 600 mm/min
D. 800 mm/min

Answer: B. 480 mm/min

Q92. A workpiece requires an effective milling travel of 200 mm at a feed rate of 100 mm/min. Machining time is:

A. 0.5 min
B. 1 min
C. 2 min
D. 5 min

Answer: C. 2 min

Q93. If feed rate is 250 mm/min and effective travel is 500 mm, machining time is:

A. 1 min
B. 2 min
C. 3 min
D. 5 min

Answer: B. 2 min

Q94. A cutter has 12 teeth and runs at 300 rpm with a feed per tooth of 0.05 mm. Feed rate is:

A. 90 mm/min
B. 120 mm/min
C. 180 mm/min
D. 360 mm/min

Answer: C. 180 mm/min

Q95. If cutting speed is 62.8 m/min and cutter diameter is 40 mm, spindle speed is approximately:

A. 250 rpm
B. 500 rpm
C. 750 rpm
D. 1000 rpm

Answer: B. 500 rpm

Q96. If cutter diameter is doubled while rpm remains constant, cutting speed:

A. Doubles
B. Halves
C. Remains constant
D. Becomes zero

Answer: A. Doubles

Q97. If the number of cutter teeth is doubled while feed per tooth and rpm remain constant, feed rate:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q98. If feed per tooth is doubled while cutter teeth and rpm remain constant, feed rate:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q99. A 100 mm cutter has 10 teeth and rotates at 200 rpm. If feed per tooth is 0.1 mm, feed rate is:

A. 100 mm/min
B. 200 mm/min
C. 400 mm/min
D. 500 mm/min

Answer: B. 200 mm/min

Q100. Which combination is correct?

A. Milling — rotating multi-point cutter
B. Shaping — rotating multi-point cutter
C. Turning — stationary multi-point cutter
D. Drilling — stationary single-point cutter

Answer: A. Milling — rotating multi-point cutter

CHAPTER 15 — QUICK REVISION

Topic	Key Fact
Milling	Rotating multi-point machining
Cutter	Multi-point
Horizontal milling	Horizontal spindle
Vertical milling	Vertical spindle
Plain cutter	Peripheral teeth
Face cutter	Face machining
Side cutter	Slots/grooves
End mill	Slots/pockets/profiles
Slitting saw	Narrow slots/cut-off
Up milling	Conventional
Down milling	Climb
Up milling chip	Zero → maximum
Down milling chip	Maximum → zero
Dividing head	Indexing
Common ratio	40:1
Simple indexing
Straddle milling	Two side cutters
Gang milling	Multiple cutters
Feed rate
Cutting speed

Top of Form

Bottom of Form

CHAPTER 16 — GRINDING MACHINES & ABRASIVE PROCESSES

16.1 Definition of Grinding

Grinding is an abrasive machining process in which material is removed from a workpiece by the action of a large number of small, hard abrasive particles.

Unlike conventional cutting tools, a grinding wheel contains a large number of cutting points.

Key point

Grinding = Abrasive machining + large number of cutting edges

16.2 Principle of Grinding

In grinding:

The grinding wheel rotates at high speed.
Abrasive grains act as cutting edges.
The grains penetrate the workpiece surface.
Small chips are removed.
A highly accurate and good-quality surface is produced.

Grinding is generally used for finishing operations, although it can also be used for substantial material removal.

16.3 Main Characteristics of Grinding

Grinding generally involves:

Abrasive cutting

Very high wheel speed

Very small depth of cut

Large number of cutting edges

Small chips

High surface finish

High dimensional accuracy

16.4 Abrasive

An abrasive is a hard material capable of removing material from another surface by cutting, rubbing or scratching.

Common abrasives include:

Aluminium oxide

Silicon carbide

Diamond

Cubic boron nitride

16.5 Aluminium Oxide — Al₂O₃

Aluminium oxide is commonly used for grinding:

Steels

Wrought iron

Nickel alloys

Other ferrous materials

It is commonly designated as:

16.6 Silicon Carbide — SiC

Silicon carbide is commonly used for:

Cast iron

Aluminium

Brass

Bronze

Carbides

Non-ferrous materials

It is commonly designated as:

16.7 Diamond

Diamond is an extremely hard abrasive.

It is used for:

Carbides

Ceramics

Glass

Very hard non-ferrous materials

Precision applications

Diamond is generally not preferred for grinding ordinary steels because of chemical interaction at high temperature.

16.8 Cubic Boron Nitride — CBN

CBN is a very hard synthetic abrasive.

It is particularly suitable for:

Hardened steels

Tool steels

Superalloys

16.9 Grinding Wheel

A grinding wheel consists essentially of:

Abrasive grains
Bond
Pores/voids

Basic structure:

Abrasive grain + bond + pores

16.10 Functions of Abrasive Grain

The abrasive grain:

Performs the actual cutting action.

Each grain acts approximately as a small cutting edge.

16.11 Function of Bond

The bond:

Holds the abrasive grains together.

When grains become dull, appropriate wheel action allows worn grains to break away and expose fresh cutting edges.

16.12 Function of Pores

Pores provide spaces for:

Chip accommodation

Coolant passage

Air circulation

16.13 Grinding Wheel Specification

A grinding wheel specification generally indicates:

Abrasive type
Grain size
Grade
Structure
Bond

Example:

A 46 K 5 V

The exact notation can vary with the standard/manufacturer, but the concepts remain important.

16.14 Grain Size

Grain size indicates the approximate size of abrasive particles.

Coarse grains

Used for:

High material removal

Soft materials

Rough grinding

Large contact areas

Fine grains

Used for:

Finishing

Hard materials

Small contact areas

Better surface finish

16.15 Grinding Wheel Grade

Grade indicates the strength with which abrasive grains are held by the bond.

It is NOT a direct measure of abrasive hardness.

Soft-grade wheel

The grains are released relatively easily.

Suitable for:

Hard materials

Hard-grade wheel

The grains are held more strongly.

Suitable for:

Soft materials

16.16 Important Rule

Hard workpiece → Soft grinding wheel

Soft workpiece → Hard grinding wheel

This is one of the most frequently tested grinding principles.

16.17 Wheel Structure

Structure indicates the relative spacing between abrasive grains.

Open structure

Has more space between grains.

Advantages:

Better chip clearance

Better coolant access

Lower tendency for loading

Dense/close structure

Has relatively less space between grains.

Suitable for:

Fine finishing

Stronger support of grains

16.18 Grinding Wheel Bond

The bond holds abrasive grains together.

Common bonds include:

Vitrified

Resinoid

Rubber

Shellac

Silicate

Metal

16.19 Vitrified Bond

Vitrified bonds are widely used.

Advantages:

Good rigidity

Good dimensional accuracy

Good resistance to heat

Suitable for many general grinding operations

16.20 Resinoid Bond

Resinoid bonds are made using resin.

They are known for:

High strength

Good shock resistance

High-speed applications

16.21 Rubber Bond

Rubber bonds are used where:

High elasticity is required

Thin wheels are required

Certain finishing/cut-off applications are involved

16.22 Shellac Bond

Shellac bonds can provide:

Good surface finish

Elasticity

They are used in certain finishing operations.

16.23 Dressing

Dressing is the process of removing dull grains, loading material and bond from the wheel surface to expose fresh sharp abrasive grains.

Purpose:

Restore cutting ability

Remove loading

Maintain wheel condition

16.24 Truing

Truing is the process of restoring the geometrical shape and concentricity of a grinding wheel.

Difference:

Dressing → restores cutting condition

Truing → restores geometrical form

This distinction is very important in examinations.

16.25 Wheel Loading

Wheel loading occurs when:

Workpiece material becomes embedded in the spaces between abrasive grains.

It is particularly common when grinding:

Soft

Ductile

Sticky materials

16.26 Glazing

Glazing occurs when:

Abrasive grains become dull and the wheel surface becomes relatively smooth and shiny.

The wheel loses cutting ability.

16.27 Grinding Machines

Major types include:

Surface grinding machine
Cylindrical grinding machine
Internal grinding machine
Centreless grinding machine
Tool and cutter grinder
Universal grinding machine

16.28 Surface Grinding

Surface grinding is used primarily to produce:

Flat and accurate surfaces.

The workpiece may be held using:

Magnetic chuck

Mechanical fixture

Clamps

16.29 Cylindrical Grinding

Cylindrical grinding is used for:

External cylindrical surfaces.

The workpiece generally rotates while the grinding wheel also rotates.

16.30 Internal Grinding

Internal grinding is used for:

Internal cylindrical surfaces or bores.

A small grinding wheel is used inside the workpiece.

16.31 Centreless Grinding

In centreless grinding, the workpiece is not held between centres.

The main components are:

Grinding wheel
Regulating wheel
Work-rest blade

16.32 Principle of Centreless Grinding

The grinding wheel performs the cutting operation.

The regulating wheel:

Controls workpiece rotation

Controls longitudinal movement in through-feed grinding

The work-rest blade supports the workpiece.

16.33 Through-Feed Centreless Grinding

Used for:

Long cylindrical workpieces of uniform cross-section.

The workpiece passes continuously between the grinding wheel and regulating wheel.

16.34 In-Feed Centreless Grinding

Used for:

Workpieces having shoulders or complex profiles that cannot pass straight through.

The workpiece is fed radially into position.

16.35 End-Feed Centreless Grinding

Used for:

Tapered or similar workpieces where feeding is from one end.

16.36 Advantages of Centreless Grinding

No centre holes required

High production rate

Continuous operation possible

Suitable for mass production

Good dimensional accuracy

16.37 Grinding Wheel Speed

Grinding wheel speed is commonly expressed in:

m/s

The relationship is:

where:

= wheel peripheral speed in m/s

= wheel diameter in mm

= rpm

16.38 Important Grinding Safety

Grinding wheels operate at high speed.

Important precautions:

Inspect wheel before mounting.

Ensure correct mounting.

Use proper guards.

Use suitable eye/face protection.

Never exceed rated wheel speed.

Maintain correct work-rest clearance.

Avoid excessive pressure.

Stand safely during initial wheel run.

16.39 Ring Test

A vitrified grinding wheel is commonly subjected to a:

Ring test

before mounting to detect cracks.

A cracked wheel should never be used.

16.40 Grinding Wheel Balancing

Balancing is important because an unbalanced wheel can cause:

Vibration

Poor surface finish

Uneven wear

Reduced accuracy

Safety hazards

16.41 Grinding vs Milling

Feature	Grinding	Milling
Cutting tool	Abrasive wheel	Milling cutter
Cutting points	Very large number	Multiple teeth
Material removal	Small chips	Larger chips generally
Main use	Finishing/precision	General machining
Speed	Very high	Lower than grinding wheel speed
Accuracy	Very high	Depends on operation

16.42 Grinding vs Shaping

Grinding	Shaping
Abrasive cutting	Single-point cutting
Rotating wheel	Reciprocating tool
Very high speed	Relatively low speed
Fine finish	General machining

16.43 Important Exam Facts

Grinding → Abrasive machining

Abrasive → Cutting action

Bond → Holds grains

Pores → Chip/coolant space

Grade → Grain-holding strength

Hard workpiece → Soft wheel

Soft workpiece → Hard wheel

Dressing → Restores cutting ability

Truing → Restores geometry

Loading → Material embedded in wheel

Glazing → Dull grains

Surface grinding → Flat surfaces

Cylindrical grinding → External cylindrical surfaces

Internal grinding → Bores

Centreless grinding → No centres

CBN → Hardened steels

Diamond → Carbides/ceramics and many non-ferrous applications

Ring test → Crack detection

Q1. Grinding is primarily a:

A. Casting process
B. Abrasive machining process
C. Welding process
D. Forming process

Answer: B. Abrasive machining process

Explanation: Material is removed by abrasive grains acting as cutting edges.

Q2. A grinding wheel contains:

A. Only one cutting edge
B. Many abrasive cutting edges
C. No cutting edges
D. Only one large tooth

Answer: B. Many abrasive cutting edges

Q3. The main cutting action in grinding is performed by:

A. Bond
B. Abrasive grains
C. Pores
D. Wheel hub

Answer: B. Abrasive grains

Q4. The function of the bond in a grinding wheel is to:

A. Hold abrasive grains together
B. Perform all cutting
C. Cool the workpiece
D. Measure wheel speed

Answer: A. Hold abrasive grains together

Q5. Pores in a grinding wheel primarily provide:

A. Chip clearance and coolant space
B. Additional hardness
C. Spindle rotation
D. Workpiece support

Answer: A. Chip clearance and coolant space

Q6. Aluminium oxide is commonly designated as:

A. A
B. C
C. D
D. B

Answer: A. A

Q7. Silicon carbide is commonly designated as:

A. A
B. C
C. V
D. R

Answer: B. C

Q8. Aluminium oxide is particularly suitable for grinding:

A. Steels
B. Only glass
C. Only diamond
D. Only wood

Answer: A. Steels

Q9. Silicon carbide is commonly used for grinding:

A. Cast iron and non-ferrous materials
B. Only soft steel
C. Only rubber
D. Only wood

Answer: A. Cast iron and non-ferrous materials

Q10. CBN is particularly suitable for:

A. Hardened steels
B. Soft wood
C. Plastic only
D. Rubber only

Answer: A. Hardened steels

Q11. Diamond abrasive is commonly used for grinding:

A. Carbides and ceramics
B. Ordinary mild steel as the universal choice
C. Wood
D. Rubber

Answer: A. Carbides and ceramics

Q12. The grade of a grinding wheel indicates:

A. Strength with which grains are held
B. Grain size only
C. Wheel diameter
D. Wheel speed only

Answer: A. Strength with which grains are held

Q13. For grinding a hard material, the preferred wheel grade is generally:

A. Soft
B. Hard
C. Extra-hard in every case
D. No bond

Answer: A. Soft

Q14. For grinding a soft material, a generally suitable wheel grade is:

A. Hard
B. Soft
C. No grade
D. Liquid

Answer: A. Hard

Q15. Fine abrasive grains are generally used for:

A. Fine finishing
B. Very rough stock removal only
C. Casting
D. Welding

Answer: A. Fine finishing

Q16. Coarse abrasive grains are generally suitable for:

A. High material removal
B. Final ultra-fine finishing only
C. Measuring
D. Inspection

Answer: A. High material removal

Q17. Dressing of a grinding wheel is performed to:

A. Restore cutting ability
B. Increase workpiece diameter
C. Change machine spindle direction
D. Measure hardness

Answer: A. Restore cutting ability

Q18. Truing is primarily performed to:

A. Restore wheel geometry
B. Increase abrasive hardness
C. Reduce workpiece temperature only
D. Change grain type

Answer: A. Restore wheel geometry

Q19. Wheel loading occurs when:

A. Work material becomes embedded in the wheel
B. Abrasive grains become sharper
C. Wheel becomes perfectly balanced
D. Bond disappears completely

Answer: A. Work material becomes embedded in the wheel

Q20. Glazing of a grinding wheel is associated with:

A. Dull abrasive grains
B. Fresh sharp grains
C. Excessive pores only
D. New wheel mounting

Answer: A. Dull abrasive grains

Q21. Surface grinding is primarily used to produce:

A. Flat surfaces
B. Deep holes only
C. External threads
D. Gear teeth only

Answer: A. Flat surfaces

Q22. Cylindrical grinding is mainly used for:

A. External cylindrical surfaces
B. Flat surfaces only
C. Internal threads only
D. Square holes

Answer: A. External cylindrical surfaces

Q23. Internal grinding is used mainly for:

A. Internal cylindrical surfaces
B. External flat surfaces
C. Gear teeth only
D. Welding joints

Answer: A. Internal cylindrical surfaces

Q24. In centreless grinding, the workpiece is:

A. Not held between centres
B. Always held between two centres
C. Welded to the machine
D. Held only by a chuck

Answer: A. Not held between centres

Q25. The three major elements in centreless grinding are:

A. Grinding wheel, regulating wheel and work-rest blade
B. Chuck, tailstock and carriage
C. Drill, vice and table
D. Cutter, arbor and overarm

Answer: A. Grinding wheel, regulating wheel and work-rest blade

A. GRINDING WHEELS & SPECIFICATION — MCQs 26–45

Q26. Which of the following is NOT a basic component of a grinding wheel?

A. Abrasive grains
B. Bond
C. Pores
D. Gear teeth

Answer: D. Gear teeth

Explanation: A grinding wheel consists essentially of abrasive grains held by a bond with pores between them.

Q27. The letter indicating the abrasive type in a grinding-wheel specification is generally placed:

A. First
B. Last
C. In the middle only
D. After the wheel diameter

Answer: A. First

Q28. In the specification A 46 K 5 V, “A” commonly represents:

A. Aluminium oxide
B. Abrasive size
C. Artificial diamond
D. Aluminium alloy

Answer: A. Aluminium oxide

Q29. In the specification A 46 K 5 V, “46” represents:

A. Grain size
B. Wheel diameter
C. Wheel speed
D. Grade

Answer: A. Grain size

Q30. In the same specification, “K” generally represents:

A. Grade
B. Grain size
C. Bond
D. Diameter

Answer: A. Grade

Q31. In the specification A 46 K 5 V, “V” represents:

A. Vitrified bond
B. Very coarse grain
C. Velocity
D. Volume

Answer: A. Vitrified bond

Q32. Which grinding-wheel characteristic indicates the relative spacing of abrasive grains?

A. Structure
B. Grade
C. Diameter
D. Speed

Answer: A. Structure

Q33. A grinding wheel with more space between abrasive grains is called:

A. Open-structure wheel
B. Closed-structure wheel
C. Solid wheel
D. Dense wheel

Answer: A. Open-structure wheel

Q34. An open-structure grinding wheel is particularly useful where:

A. Chip clearance is important
B. No chips are produced
C. Only polishing is required
D. The workpiece is stationary forever

Answer: A. Chip clearance is important

Q35. A close-structure wheel contains:

A. Relatively closely spaced abrasive grains
B. No abrasive grains
C. Only pores
D. Only bond

Answer: A. Relatively closely spaced abrasive grains

Q36. Which bond is commonly used for general-purpose grinding wheels?

A. Vitrified
B. Paper
C. Wood
D. Plastic film

Answer: A. Vitrified

Q37. Vitrified bonds are made primarily from:

A. Ceramic materials
B. Rubber only
C. Shellac only
D. Steel

Answer: A. Ceramic materials

Q38. Resinoid bonds are based primarily on:

A. Synthetic resin
B. Ceramic
C. Rubber only
D. Wood

Answer: A. Synthetic resin

Q39. Resinoid wheels are particularly suitable for:

A. High-speed applications
B. Only hand filing
C. Casting
D. Welding

Answer: A. High-speed applications

Q40. Rubber-bonded grinding wheels are particularly useful where:

A. Elasticity is required
B. No flexibility is required
C. No abrasive is needed
D. Only drilling is performed

Answer: A. Elasticity is required

Q41. Shellac-bonded wheels are often used when:

A. Good surface finish is required
B. Very heavy rough machining is always required
C. No finishing is required
D. Only drilling is required

Answer: A. Good surface finish is required

Q42. Which bond generally provides high dimensional accuracy and rigidity?

A. Vitrified
B. Rubber
C. Shellac
D. Leather

Answer: A. Vitrified

Q43. The grade of a grinding wheel is mainly determined by:

A. Bond strength and holding action
B. Wheel diameter only
C. Grain colour
D. Spindle length

Answer: A. Bond strength and holding action

Q44. Increasing the grade from soft toward hard means:

A. Abrasive grains are held more strongly
B. Grain size necessarily becomes larger
C. Wheel diameter increases
D. Speed becomes zero

Answer: A. Abrasive grains are held more strongly

Q45. Which combination is generally correct?

A. Hard workpiece — soft wheel
B. Hard workpiece — hard wheel
C. Soft workpiece — soft wheel only
D. Wheel grade has no relation to workpiece hardness

Answer: A. Hard workpiece — soft wheel

B. GRINDING MACHINE TYPES — MCQs 46–60

Q46. A surface grinding machine is mainly used for:

A. Flat surfaces
B. Deep internal threads
C. Gear hobbing
D. Turning shafts

Answer: A. Flat surfaces

Q47. A cylindrical grinding machine is mainly used for:

A. External cylindrical surfaces
B. Flat surfaces only
C. T-slots
D. Keyway broaching

Answer: A. External cylindrical surfaces

Q48. An internal grinding machine is used to grind:

A. Internal surfaces/bores
B. External threads only
C. Flat plates only
D. Gear teeth only

Answer: A. Internal surfaces/bores

Q49. In cylindrical grinding, the workpiece commonly:

A. Rotates about its axis
B. Remains permanently stationary
C. Reciprocates vertically only
D. Is melted

Answer: A. Rotates about its axis

Q50. A universal cylindrical grinder can generally perform:

A. External and internal grinding operations
B. Only drilling
C. Only surface milling
D. Only welding

Answer: A. External and internal grinding operations

Q51. Centreless grinding differs from cylindrical grinding mainly because:

A. The workpiece is not supported between centres
B. The wheel does not rotate
C. No abrasive is used
D. No material is removed

Answer: A. The workpiece is not supported between centres

Q52. The regulating wheel in centreless grinding primarily controls:

A. Workpiece rotation and feed
B. Abrasive composition
C. Wheel dressing only
D. Coolant temperature only

Answer: A. Workpiece rotation and feed

Q53. The work-rest blade in centreless grinding:

A. Supports the workpiece
B. Rotates the grinding wheel
C. Dresses the wheel
D. Measures wheel speed

Answer: A. Supports the workpiece

Q54. Through-feed centreless grinding is best suited for:

A. Long cylindrical components without interruptions
B. Components with large shoulders that block through-feed
C. Square plates
D. Flat sheets only

Answer: A. Long cylindrical components without interruptions

Q55. In-feed centreless grinding is suitable for:

A. Components with shoulders or formed profiles
B. Only long uniform shafts
C. Flat plates
D. Drill bits only

Answer: A. Components with shoulders or formed profiles

Q56. End-feed centreless grinding is particularly suitable for:

A. Certain tapered workpieces
B. Flat plates
C. Square holes
D. Gear hobbing

Answer: A. Certain tapered workpieces

Q57. A major advantage of centreless grinding is:

A. High production rate
B. Requirement of centre holes
C. Very low accuracy
D. No continuous operation

Answer: A. High production rate

Q58. Centreless grinding is particularly suitable for:

A. Mass production of cylindrical components
B. Only one-off casting repair
C. Welding operations
D. Sheet-metal bending

Answer: A. Mass production of cylindrical components

Q59. A tool-and-cutter grinder is used mainly for:

A. Sharpening and grinding cutting tools
B. Welding tools
C. Casting tools
D. Measuring tools only

Answer: A. Sharpening and grinding cutting tools

Q60. Surface grinding generally provides:

A. High dimensional accuracy and good surface finish
B. Only rough surfaces
C. No dimensional control
D. Only curved surfaces

Answer: A. High dimensional accuracy and good surface finish

C. DRESSING, TRUING & GRINDING DEFECTS — MCQs 61–75

Q61. Dressing of a grinding wheel is performed to:

A. Expose fresh abrasive grains
B. Increase workpiece hardness
C. Increase workpiece diameter
D. Reduce spindle speed to zero

Answer: A. Expose fresh abrasive grains

Q62. Truing primarily restores:

A. Geometrical shape of the wheel
B. Workpiece chemical composition
C. Wheel colour
D. Coolant concentration

Answer: A. Geometrical shape of the wheel

Q63. A grinding wheel may require dressing when it becomes:

A. Loaded or dull
B. Newly mounted only
C. Smaller than the workpiece
D. Completely absent

Answer: A. Loaded or dull

Q64. Glazing is associated with:

A. Dull abrasive grains
B. Fresh sharp grains
C. Excessive chip space
D. Broken machine table

Answer: A. Dull abrasive grains

Q65. Loading is more likely when grinding:

A. Soft and ductile materials
B. Extremely brittle materials only
C. Glass only
D. Ceramics only

Answer: A. Soft and ductile materials

Q66. One common remedy for wheel loading is:

A. Proper dressing
B. Increasing workpiece hardness
C. Removing all abrasive grains
D. Stopping the spindle permanently

Answer: A. Proper dressing

Q67. Burn marks on a ground surface may result from:

A. Excessive heat generation
B. No contact between wheel and work
C. Insufficient wheel rotation in every case
D. Excessive workpiece hardness only

Answer: A. Excessive heat generation

Q68. Grinding burn can often be reduced by:

A. Proper coolant and suitable grinding parameters
B. Increasing pressure indefinitely
C. Blocking coolant flow
D. Using a cracked wheel

Answer: A. Proper coolant and suitable grinding parameters

Q69. Chatter marks on a ground surface are commonly associated with:

A. Vibration
B. Perfect wheel balance
C. No cutting action
D. Proper dressing only

Answer: A. Vibration

Q70. An unbalanced grinding wheel can cause:

A. Vibration
B. Improved finish automatically
C. Zero cutting force
D. Increased workpiece strength

Answer: A. Vibration

Q71. Dressing can help to correct:

A. Loading and glazing
B. Workpiece chemical composition
C. Machine foundation
D. Gear ratio

Answer: A. Loading and glazing

Q72. Truing is especially important when the wheel:

A. Loses its desired geometrical shape
B. Is perfectly round and balanced
C. Has no abrasive
D. Is not rotating

Answer: A. Loses its desired geometrical shape

Q73. Excessive grinding pressure can cause:

A. Excessive heat and wheel wear
B. Zero temperature
C. No material removal
D. Automatic balancing

Answer: A. Excessive heat and wheel wear

Q74. Poor grinding finish can result from:

A. Vibration, improper dressing or unsuitable parameters
B. Proper wheel selection only
C. Correct balancing only
D. Perfect coolant supply only

Answer: A. Vibration, improper dressing or unsuitable parameters

Q75. The main purpose of coolant in grinding is to:

A. Reduce heat and flush chips
B. Increase wheel cracking
C. Stop material removal
D. Harden the machine bed

Answer: A. Reduce heat and flush chips

D. GRINDING SAFETY — MCQs 76–85

Q76. Before mounting a vitrified grinding wheel, a commonly recommended inspection is:

A. Ring test
B. Tensile test
C. Compression test only
D. Charpy test

Answer: A. Ring test

Q77. A grinding wheel that fails inspection or is found cracked should be:

A. Rejected and not used
B. Used at half speed
C. Used without a guard
D. Used only for rough grinding

Answer: A. Rejected and not used

Q78. A grinding machine should be operated with:

A. Appropriate wheel guard
B. Guard removed
C. Loose workpiece
D. Damaged wheel

Answer: A. Appropriate wheel guard

Q79. The maximum permissible wheel speed should:

A. Not be exceeded
B. Always be doubled
C. Be ignored
D. Be selected randomly

Answer: A. Not be exceeded

Q80. During grinding, the operator should use:

A. Appropriate eye/face protection
B. No protection
C. Only cotton gloves near a rotating wheel
D. Loose clothing

Answer: A. Appropriate eye/face protection

Q81. The work-rest on a bench grinding machine should be:

A. Properly adjusted with a small safe clearance
B. Extremely far from the wheel
C. Touching the wheel continuously
D. Removed

Answer: A. Properly adjusted with a small safe clearance

Q82. A grinding wheel should be mounted:

A. Correctly and securely
B. Loosely
C. With damaged flanges
D. Without inspection

Answer: A. Correctly and securely

Q83. Standing directly in the plane of a newly mounted wheel during initial start-up should be:

A. Avoided
B. Required
C. Done without protection
D. Done with maximum pressure

Answer: A. Avoided

Q84. A grinding wheel should be allowed to reach proper operating condition before:

A. Applying the workpiece
B. Mounting the wheel
C. Inspecting the guard
D. Switching on coolant

Answer: A. Applying the workpiece

Q85. The most important reason for grinding-wheel guards is:

A. Protection from wheel fragments and contact hazards
B. Increasing workpiece hardness
C. Increasing grain size
D. Reducing machine weight

Answer: A. Protection from wheel fragments and contact hazards

E. NUMERICAL & CONCEPTUAL MCQs — 86–100

Q86. A grinding wheel of diameter 200 mm rotates at 3000 rpm. Its peripheral speed is approximately:

A. 15.7 m/s
B. 31.4 m/s
C. 62.8 m/s
D. 100 m/s

Answer: B. 31.4 m/s

Q87. A 300 mm diameter wheel rotates at 2000 rpm. Its peripheral speed is approximately:

A. 15.7 m/s
B. 31.4 m/s
C. 62.8 m/s
D. 94.2 m/s

Answer: B. 31.4 m/s

Q88. A grinding wheel has a diameter of 400 mm and rotates at 1500 rpm. Peripheral speed is approximately:

A. 15.7 m/s
B. 31.4 m/s
C. 50 m/s
D. 75 m/s

Answer: B. 31.4 m/s

Q89. If grinding-wheel diameter remains constant and rpm is doubled, peripheral speed:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes one-fourth

Answer: A. Doubles

Q90. If wheel diameter is doubled at constant rpm, peripheral speed:

A. Doubles
B. Halves
C. Remains constant
D. Becomes zero

Answer: A. Doubles

Q91. A 250 mm grinding wheel rotates at 2400 rpm. Peripheral speed is approximately:

A. 10 m/s
B. 20 m/s
C. 31.4 m/s
D. 50 m/s

Answer: B. 31.4 m/s

Note: The closest exact value is 31.4 m/s.

Q92. A grinding wheel has a peripheral speed of 25 m/s and diameter 200 mm. Its approximate rpm is:

A. 1194 rpm
B. 2387 rpm
C. 4775 rpm
D. 7500 rpm

Answer: B. 2387 rpm

Q93. Which abrasive is generally preferred for grinding hardened steel?

A. CBN
B. Wood
C. Rubber
D. Graphite

Answer: A. CBN

Q94. Which abrasive is commonly preferred for grinding aluminium oxide ceramics and many carbide applications?

A. Diamond
B. Aluminium oxide only
C. Wood
D. Cast iron

Answer: A. Diamond

Q95. A soft-grade wheel is selected for hard material mainly because:

A. Dull grains can break away more readily and expose fresh grains
B. Hard materials require no cutting
C. Soft wheels contain no abrasive
D. It eliminates all heat

Answer: A. Dull grains can break away more readily and expose fresh grains

Q96. In centreless grinding, the regulating wheel generally has:

A. Lower speed than the grinding wheel
B. Higher speed than the grinding wheel
C. Exactly the same function as the grinding wheel
D. No rotation

Answer: A. Lower speed than the grinding wheel

Q97. The regulating wheel in centreless grinding controls the:

A. Workpiece rotational speed and feed
B. Abrasive grain size
C. Wheel bond
D. Wheel diameter

Answer: A. Workpiece rotational speed and feed

Q98. Which process is particularly suitable for producing large quantities of identical cylindrical components?

A. Through-feed centreless grinding
B. Manual filing
C. Hand scraping
D. Shaping only

Answer: A. Through-feed centreless grinding

Q99. Grinding is capable of achieving high accuracy mainly because:

A. Very small material removal can be controlled
B. The workpiece is always melted
C. The wheel has only one tooth
D. No cutting occurs

Answer: A. Very small material removal can be controlled

Q100. Which combination is correct?

A. Dressing — cutting ability; Truing — geometrical accuracy
B. Dressing — workpiece heating; Truing — coolant supply
C. Dressing — gear cutting; Truing — drilling
D. Dressing — welding; Truing — casting

Answer: A. Dressing — cutting ability; Truing — geometrical accuracy

CHAPTER 16 — COMPLETE REVISION TABLE

Topic	Important Point
Grinding	Abrasive machining
Abrasive	Performs cutting
Bond	Holds grains
Pores	Chip/coolant space
Aluminium oxide	A
Silicon carbide	C
CBN	Hardened steels
Diamond	Carbides/ceramics
Grade	Grain-holding strength
Structure	Grain spacing
Hard workpiece	Soft wheel
Soft workpiece	Hard wheel
Dressing	Restores cutting ability
Truing	Restores geometry
Loading	Material embedded in wheel
Glazing	Dull grains
Surface grinding	Flat surfaces
Cylindrical grinding	External cylindrical surfaces
Internal grinding	Internal surfaces
Centreless grinding	No centres
Through-feed	Long uniform components
In-feed	Shouldered/profiled components
Regulating wheel	Controls work rotation/feed
Work-rest blade	Supports work
Ring test	Crack detection
Wheel guard	Safety
Wheel speed	Do not exceed rated speed

CHAPTER 17 — DRILLING, BORING, REAMING & TAPPING

17.1 Definition of Drilling

Drilling is a machining process used to produce a circular hole in a solid workpiece by means of a rotating multi-point cutting tool called a drill.

Key point

Drilling = Producing a new circular hole using a rotating drill.

17.2 Principle of Drilling

During drilling:

The drill rotates.
The drill is fed axially into the workpiece.
Cutting edges remove material.
Chips travel through the drill flutes.
A cylindrical hole is produced.

A conventional twist drill normally has two main cutting lips.

17.3 Main Applications of Drilling

Drilling is used to:

Produce new holes

Prepare holes for bolts

Prepare holes for tapping

Prepare holes for reaming

Produce holes for shafts and pins

Produce holes for assembly

17.4 Drilling Machines

Important types include:

Portable drilling machine
Bench drilling machine
Pillar drilling machine
Sensitive drilling machine
Radial drilling machine
Gang drilling machine
Multi-spindle drilling machine
CNC drilling machine

17.5 Portable Drilling Machine

A portable drill is:

Lightweight

Easily movable

Suitable for field work

Used for relatively small holes

It is particularly useful when the workpiece is:

Too large or inconvenient to move to a fixed machine.

17.6 Sensitive Drilling Machine

A sensitive drilling machine is designed for:

Small holes

Light cutting operations

High-speed drilling

Hand-controlled feed

The operator can sense the drilling pressure through the feed mechanism.

17.7 Bench Drilling Machine

A bench drill is mounted on a:

Workbench or bench.

It is commonly used for:

Small components

Small holes

Light-duty drilling

17.8 Pillar Drilling Machine

A pillar drilling machine has a rigid vertical column and is used for:

Larger workpieces

More accurate drilling

Medium-duty operations

17.9 Radial Drilling Machine

A radial drilling machine has a:

Radial arm and drill head.

Its major advantage is that the drill head can be positioned over different locations of a large workpiece without moving the workpiece itself.

It is especially suitable for:

Large and heavy workpieces.

17.10 Gang Drilling Machine

A gang drilling machine has:

Several drilling heads arranged in a row.

Different operations can be performed successively at different stations.

For example:

Drilling → Counterboring → Reaming → Tapping

17.11 Multi-Spindle Drilling Machine

A multi-spindle machine has:

Multiple spindles.

It is useful for:

Simultaneous drilling of several holes

Mass production

High productivity

17.12 Twist Drill

The most commonly used drill is the:

Twist drill.

A twist drill generally has:

Two cutting lips

Two helical flutes

Web

Shank

Point

17.13 Drill Shank

The shank is the portion used to:

Hold the drill in the machine spindle or chuck.

Two common types are:

Straight shank

Taper shank

17.14 Straight-Shank Drill

A straight-shank drill has a cylindrical shank.

It is commonly held in:

Drill chuck.

17.15 Taper-Shank Drill

A taper-shank drill has a tapered shank.

It can be directly mounted in:

A matching tapered spindle/socket.

17.16 Drill Flutes

The flutes are helical grooves running along the drill.

Functions:

Provide chip space

Form cutting edges

Allow coolant/lubricant access

Help remove chips

17.17 Drill Point

The point is the cutting end of the drill.

It includes:

Cutting lips

Chisel edge

Point geometry

17.18 Chisel Edge

The chisel edge is located at the centre of a conventional twist drill.

It:

Extrudes/ploughs material rather than cutting efficiently

Requires considerable thrust

Produces relatively poor cutting action at the centre

17.19 Drill Web

The web is the central portion between the flutes.

It provides:

Strength to the drill.

17.20 Point Angle

The included point angle of a conventional twist drill for general-purpose drilling of many steels is approximately:

However, the optimum point angle depends on the work material and application.

17.21 Helix Angle

The helix angle is associated with the inclination of the drill flute relative to the drill axis.

It affects:

Chip removal

Cutting action

Drill strength

17.22 Drill Materials

Common drill materials include:

High-speed steel (HSS)

Carbides

Cobalt high-speed steel

Carbide-tipped materials

HSS is widely used because of its:

Toughness

Heat resistance

Good cutting performance

17.23 Drilling Speed

The cutting speed for drilling is generally calculated from the drill diameter and spindle speed:

where:

= cutting speed in m/min

= drill diameter in mm

= spindle speed in rpm

17.24 Spindle Speed

Rearranging the formula:

17.25 Drilling Feed

Feed in drilling is commonly expressed as:

mm/rev

The feed rate is:

where:

= feed in mm/rev

= rpm

= feed rate in mm/min

17.26 Drilling Time

Approximate drilling time can be calculated as:

where represents the effective drilling length.

In practical calculations, approach and breakthrough allowances may also need to be considered.

17.27 Counterboring

Counterboring is the operation of enlarging the upper portion of an existing hole to produce a cylindrical recess.

It is commonly used to:

Accommodate a socket-head cap screw or bolt head.

17.28 Countersinking

Countersinking produces a conical enlargement at the entrance of a hole.

It is commonly used to:

Accommodate a countersunk-head screw.

17.29 Spot Facing

Spot facing produces:

A flat seating surface around a hole.

It is particularly useful when the original surface is:

Rough

Uneven

Cast

Forged

17.30 Boring

Boring is the process of enlarging and/or improving the accuracy of an existing hole using a single-point or suitable boring tool.

Important distinction:

Drilling → creates a new hole

Boring → enlarges an existing hole

17.31 Reaming

Reaming is a finishing operation used to slightly enlarge an existing hole and improve its dimensional accuracy and surface finish.

A reamer removes:

A small amount of material.

17.32 Reamer

A reamer is a:

Multi-edge finishing tool.

It is not normally used for making a hole from solid material.

17.33 Types of Reamers

Common types:

Hand reamer

Machine reamer

Adjustable reamer

Expansion reamer

Taper reamer

17.34 Tapping

Tapping is the process of producing internal threads in a hole using a tap.

The hole is first drilled to an appropriate tapping size.

17.35 Tap

A tap is a:

Thread-cutting tool used to produce internal threads.

17.36 Types of Hand Taps

A traditional hand-tapping set commonly includes:

Taper tap
Second/intermediate tap
Plug/bottoming tap

17.37 Taper Tap

The taper tap has a relatively long chamfer.

It is generally used:

First in hand tapping.

17.38 Second Tap

The second tap has an intermediate chamfer.

It is used:

After the taper tap.

17.39 Bottoming/Plug Tap

A bottoming tap is used when threads are required:

Close to the bottom of a blind hole.

17.40 Blind Hole

A blind hole:

Does not pass completely through the workpiece.

17.41 Through Hole

A through hole:

Passes completely through the workpiece.

17.42 Tapping Drill Size

For a simple metric approximation:

Example:

For M10 × 1.5:

So the approximate tap-drill size is:

8.5 mm

Actual recommended sizes should follow the relevant standard and thread percentage requirement.

17.43 Drilling Defects

Common drilling problems include:

Oversized holes

Oversized/undersized or inaccurate holes

Rough surface

Chipped cutting edges

Drill wandering

Excessive burrs

Poor chip evacuation

Drill breakage

17.44 Drill Wandering

Drill wandering may result from:

Poor centering

Improper drill point

Uneven workpiece surface

Excessive clearance or incorrect geometry

Improper setup

17.45 Burr Formation

Burrs are commonly produced:

At the breakthrough side of a drilled hole.

Proper support, tooling and cutting parameters can reduce burr formation.

17.46 Important Comparison

Operation	Main Purpose
Drilling	Produce new hole
Boring	Enlarge existing hole
Reaming	Improve size/finish
Counterboring	Cylindrical recess
Countersinking	Conical recess
Spot facing	Flat seating surface
Tapping	Internal thread

Q1. Drilling is primarily used to:

A. Produce a new circular hole
B. Produce external threads
C. Grind a surface
D. Produce gear teeth

Answer: A. Produce a new circular hole

Explanation: Drilling removes material from a solid workpiece to create a hole.

Q2. The commonly used tool for drilling is:

A. Twist drill
B. Reamer
C. Tap
D. Broach

Answer: A. Twist drill

Q3. A conventional twist drill is generally a:

A. Two-lip cutting tool
B. Single-point tool
C. Grinding wheel
D. Forming tool without cutting edges

Answer: A. Two-lip cutting tool

Q4. The flutes of a twist drill are used primarily for:

A. Chip removal
B. Holding the workpiece
C. Measuring hole diameter
D. Producing coolant

Answer: A. Chip removal

Q5. The shank of a drill is used to:

A. Hold the drill
B. Remove chips
C. Cut the hole directly
D. Measure the hole

Answer: A. Hold the drill

Q6. A straight-shank drill is commonly held in a:

A. Drill chuck
B. Lathe tailstock only
C. Magnetic chuck
D. Dividing head

Answer: A. Drill chuck

Q7. A taper-shank drill can be mounted in:

A. A matching tapered spindle/socket
B. A flat table only
C. A machine vice
D. A surface plate

Answer: A. A matching tapered spindle/socket

Q8. The web of a twist drill provides:

A. Strength to the drill
B. Coolant only
C. Workpiece support
D. Thread cutting

Answer: A. Strength to the drill

Q9. The chisel edge of a twist drill is located:

A. Near the centre of the drill point
B. At the shank end
C. At the top of the flute only
D. On the machine table

Answer: A. Near the centre of the drill point

Q10. The conventional point angle of a general-purpose twist drill is approximately:

A. 60°
B. 90°
C. 118°
D. 180°

Answer: C. 118°

Q11. A radial drilling machine is particularly suitable for:

A. Large and heavy workpieces
B. Very small watch components only
C. Grinding operations
D. Gear hobbing

Answer: A. Large and heavy workpieces

Q12. The major advantage of a radial drilling machine is:

A. Drill head can be positioned over different locations of a large workpiece
B. It cannot move
C. It uses no spindle
D. It cannot drill large holes

Answer: A. Drill head can be positioned over different locations of a large workpiece

Q13. A gang drilling machine has:

A. Several drilling stations/heads
B. Only one spindle
C. No table
D. Only a grinding wheel

Answer: A. Several drilling stations/heads

Q14. A multi-spindle drilling machine is mainly used to:

A. Drill multiple holes simultaneously or efficiently
B. Perform only grinding
C. Cut external threads
D. Perform casting

Answer: A. Drill multiple holes simultaneously or efficiently

Q15. A sensitive drilling machine is particularly suitable for:

A. Small holes and light work
B. Very large castings only
C. Heavy planing
D. Gear grinding

Answer: A. Small holes and light work

Q16. The cutting speed in drilling is given by:

A.
B.
C.
D.

Answer: A.

Q17. The feed rate in drilling, when feed is mm/rev and spindle speed is rpm, is:

A.
B.
C.
D.

Answer: B.

Q18. Boring is used to:

A. Enlarge an existing hole
B. Create a hole from solid material only
C. Produce external threads
D. Grind a flat surface

Answer: A. Enlarge an existing hole

Q19. Reaming is primarily a:

A. Finishing operation
B. Rough casting operation
C. Welding operation
D. Forging operation

Answer: A. Finishing operation

Q20. Compared with drilling, reaming generally removes:

A. A small amount of material
B. A very large amount
C. No material
D. The entire workpiece

Answer: A. A small amount of material

Q21. Counterboring produces a:

A. Cylindrical recess
B. Conical recess
C. Thread
D. Square hole

Answer: A. Cylindrical recess

Q22. Countersinking produces a:

A. Conical recess
B. Cylindrical recess
C. Keyway
D. Flat slot

Answer: A. Conical recess

Q23. Spot facing produces:

A. A flat seating surface around a hole
B. An internal thread
C. A conical hole
D. A gear tooth

Answer: A. A flat seating surface around a hole

Q24. Tapping is used to produce:

A. Internal threads
B. External threads
C. Flat surfaces
D. Gear teeth

Answer: A. Internal threads

Q25. Which sequence is generally correct for producing an accurate threaded hole?

A. Drill → ream/prepare as required → tap
B. Tap → drill → grind
C. Grind → drill → tap
D. Countersink → weld → tap

Answer: A. Drill → ream/prepare as required → tap

A. DRILL NOMENCLATURE & GEOMETRY — Q26–40

Q26. The angle between the two cutting lips of a standard twist drill is approximately:

A. 60°
B. 90°
C. 118°
D. 150°

Answer: C. 118°

Explanation: A standard general-purpose twist drill commonly uses a point angle of about 118°.

Q27. The chisel edge of a twist drill mainly produces:

A. Efficient shearing
B. Ploughing action
C. Grinding action
D. Thread cutting

Answer: B. Ploughing action

Explanation: The chisel edge has an unfavourable cutting geometry and mainly pushes/ploughs material at the centre.

Q28. The main function of drill flutes is:

A. Chip removal
B. Work holding
C. Measuring depth
D. Increasing workpiece hardness

Answer: A. Chip removal

Explanation: The helical flutes provide space for chips and assist their evacuation.

Q29. The web of a twist drill is located:

A. Between the flutes
B. At the extreme end of the shank
C. Outside the workpiece
D. On the machine table

Answer: A. Between the flutes

Q30. Increasing the web thickness of a drill generally:

A. Increases drill strength
B. Eliminates all thrust
C. Removes the flutes
D. Makes the drill flexible

Answer: A. Increases drill strength

Explanation: A thicker web provides greater core strength but can increase thrust unless appropriate geometry is used.

Q31. The lip clearance angle of a drill is provided mainly to:

A. Prevent rubbing of the flank against the hole surface
B. Increase drill diameter
C. Hold the drill in the chuck
D. Increase workpiece hardness

Answer: A. Prevent rubbing of the flank against the hole surface

Q32. The helix of a twist drill mainly assists:

A. Chip evacuation
B. Workpiece clamping
C. Measurement
D. Grinding-wheel balancing

Answer: A. Chip evacuation

Q33. A drill with a larger helix angle is generally useful for:

A. Soft and ductile materials
B. Very brittle materials only
C. Concrete only
D. Glass only

Answer: A. Soft and ductile materials

Explanation: Higher helix drills generally provide better chip evacuation for ductile materials.

Q34. A low-helix drill is generally suitable for:

A. Hard and brittle materials
B. Soft plastics only
C. Rubber only
D. Wood only

Answer: A. Hard and brittle materials

Q35. The drill point is the:

A. Cutting end of the drill
B. Holding end of the drill
C. Machine spindle
D. Work-rest

Answer: A. Cutting end of the drill

Q36. The drill margin primarily helps to:

A. Guide the drill in the hole
B. Remove the entire chip
C. Hold the drill in the chuck
D. Measure spindle speed

Answer: A. Guide the drill in the hole

Q37. The cutting lips of a twist drill are formed at the intersection of:

A. Flank and face
B. Shank and web
C. Margin and shank
D. Web and shank only

Answer: A. Flank and face

Q38. The land of a twist drill is the:

A. Surface between the flute and margin
B. Central web only
C. Shank
D. Point angle

Answer: A. Surface between the flute and margin

Q39. The margin of a drill provides:

A. Guidance and support
B. Thread cutting
C. Workpiece clamping
D. Coolant generation

Answer: A. Guidance and support

Q40. A twist drill is called a multi-point cutting tool because:

A. It has more than one cutting edge
B. It has no cutting edge
C. It has one cutting edge only
D. It performs only forming

Answer: A. It has more than one cutting edge

B. DRILL MATERIALS & MACHINE SELECTION — Q41–55

Q41. HSS stands for:

A. High Speed Steel
B. High Strength Shaft
C. Hard Surface Steel
D. Heat Stabilized System

Answer: A. High Speed Steel

Q42. HSS drills are widely used because they have:

A. Good toughness and hot hardness
B. No hardness
C. No wear resistance
D. No cutting capability

Answer: A. Good toughness and hot hardness

Q43. Carbide drills are particularly advantageous for:

A. High-speed machining
B. Hand filing
C. Wood carving only
D. Welding

Answer: A. High-speed machining

Q44. Compared with HSS, carbide is generally:

A. Harder and more wear resistant but more brittle
B. Softer and more ductile
C. Less heat resistant
D. Completely flexible

Answer: A. Harder and more wear resistant but more brittle

Q45. A bench drilling machine is generally used for:

A. Small and medium-sized components
B. Huge structures only
C. Rolling mills
D. Forging only

Answer: A. Small and medium-sized components

Q46. A pillar drilling machine generally provides:

A. Greater rigidity than a small bench drill
B. No spindle movement
C. Only hand filing
D. No feed mechanism

Answer: A. Greater rigidity than a small bench drill

Q47. The radial drilling machine is especially useful when:

A. The workpiece is large and heavy
B. The workpiece is extremely small only
C. No positioning is required
D. Only tapping is performed

Answer: A. The workpiece is large and heavy

Q48. In a radial drilling machine, the radial arm allows:

A. Positioning of the drill head
B. Rotation of the workpiece only
C. Grinding of the drill
D. Measurement of diameter

Answer: A. Positioning of the drill head

Q49. A portable drilling machine is advantageous when:

A. The workpiece cannot conveniently be moved to a fixed drill
B. Extremely high precision is always required
C. Only automatic production is required
D. No drilling is required

Answer: A. The workpiece cannot conveniently be moved to a fixed drill

Q50. A sensitive drilling machine is primarily designed for:

A. Small-diameter holes
B. Large forgings only
C. Heavy milling
D. Grinding

Answer: A. Small-diameter holes

Q51. A gang drilling machine is useful when:

A. Several successive drilling operations are required
B. Only one operation is ever required
C. No hole is required
D. Only grinding is performed

Answer: A. Several successive drilling operations are required

Q52. A multi-spindle drilling machine is particularly suitable for:

A. Mass production
B. One-off artistic work only
C. Manual filing
D. Casting

Answer: A. Mass production

Q53. The primary purpose of a drill chuck is to:

A. Hold a drill securely
B. Produce threads
C. Grind the drill
D. Support a grinding wheel

Answer: A. Hold a drill securely

Q54. A taper-shank drill is advantageous because:

A. It can be mounted in a matching tapered spindle/socket
B. It cannot transmit torque
C. It requires no spindle
D. It is used only for grinding

Answer: A. It can be mounted in a matching tapered spindle/socket

Q55. A drill drift is commonly used for:

A. Removing a taper-shank drill from its socket
B. Sharpening a drill point
C. Measuring hole depth
D. Cutting threads

Answer: A. Removing a taper-shank drill from its socket

C. DRILLING PARAMETERS & NUMERICALS — Q56–70

Q56. The cutting-speed formula for drilling is:

A.
B.
C.
D.

Answer: A.

Q57. In the drilling-speed formula, D is normally expressed in:

A. mm
B. cm only
C. m only
D. inches only

Answer: A. mm

Q58. If drill diameter increases while cutting speed remains constant, spindle speed should:

A. Decrease
B. Increase
C. Remain necessarily unchanged
D. Become infinite

Answer: A. Decrease

Explanation:

Therefore, is inversely proportional to at constant cutting speed.

Q59. A 20 mm drill runs at 1000 rpm. The approximate cutting speed is:

A. 31.4 m/min
B. 62.8 m/min
C. 100 m/min
D. 200 m/min

Answer: B. 62.8 m/min

Q60. A 10 mm drill runs at 1000 rpm. Cutting speed is approximately:

A. 15.7 m/min
B. 31.4 m/min
C. 62.8 m/min
D. 100 m/min

Answer: B. 31.4 m/min

Q61. A 50 mm drill operates at 400 rpm. Cutting speed is approximately:

A. 31.4 m/min
B. 62.8 m/min
C. 100 m/min
D. 125.6 m/min

Answer: A. 62.8 m/min

Q62. If a 25 mm drill operates at 800 rpm, its cutting speed is approximately:

A. 31.4 m/min
B. 62.8 m/min
C. 75 m/min
D. 100 m/min

Answer: B. 62.8 m/min

Q63. A drill has a cutting speed of 30 m/min and diameter 10 mm. Approximate spindle speed is:

A. 477 rpm
B. 955 rpm
C. 1910 rpm
D. 3000 rpm

Answer: C. 955 rpm

Correction: The correct option is B. 955 rpm.

Q64. If feed is 0.2 mm/rev and spindle speed is 1000 rpm, feed rate is:

A. 20 mm/min
B. 100 mm/min
C. 200 mm/min
D. 500 mm/min

Answer: C. 200 mm/min

Q65. If feed is 0.1 mm/rev and spindle speed is 1500 rpm, feed rate is:

A. 100 mm/min
B. 150 mm/min
C. 300 mm/min
D. 1500 mm/min

Answer: B. 150 mm/min

Q66. If spindle speed is doubled while feed per revolution remains constant, feed rate:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q67. Drilling time is approximately determined from:

A. Drilling length ÷ feed rate
B. Drill diameter × speed
C. Feed ÷ speed
D. Diameter + speed

Answer: A. Drilling length ÷ feed rate

Q68. A hole requires an effective drilling length of 40 mm. If feed rate is 100 mm/min, approximate drilling time is:

A. 0.2 min
B. 0.4 min
C. 2.5 min
D. 4 min

Answer: B. 0.4 min

Q69. If the feed per revolution is increased while all other conditions remain constant, material removal rate generally:

A. Increases
B. Decreases to zero
C. Remains necessarily unchanged
D. Becomes negative

Answer: A. Increases

Q70. Excessive feed during drilling may result in:

A. Higher thrust and possible drill failure
B. Zero cutting force
C. No chips
D. Automatic improvement in accuracy

Answer: A. Higher thrust and possible drill failure

D. BORING, REAMING & HOLE-FINISHING OPERATIONS — Q71–82

Q71. Boring is normally performed on:

A. An existing hole
B. A solid surface without a hole
C. A grinding wheel
D. A welding electrode

Answer: A. An existing hole

Q72. Boring can be used to improve:

A. Hole size and alignment
B. Only external surface colour
C. Workpiece weight
D. Casting temperature

Answer: A. Hole size and alignment

Q73. A conventional boring operation commonly uses:

A. A single-point cutting tool
B. A grinding wheel only
C. A twist drill only
D. A tap only

Answer: A. A single-point cutting tool

Q74. Reaming is mainly performed to obtain:

A. Better dimensional accuracy and surface finish
B. A completely new large hole
C. External threads
D. A casting cavity

Answer: A. Better dimensional accuracy and surface finish

Q75. A reamer generally removes:

A. A small amount of material
B. The entire workpiece
C. No material
D. More material than rough drilling in normal use

Answer: A. A small amount of material

Q76. A reamer should normally be used after:

A. A hole has already been produced close to the required size
B. The workpiece has been melted
C. The surface has been welded
D. No hole exists

Answer: A. A hole has already been produced close to the required size

Q77. A hand reamer is operated primarily by:

A. Hand rotation
B. Grinding-wheel rotation
C. Lathe chuck only
D. Welding current

Answer: A. Hand rotation

Q78. A machine reamer is designed to be used:

A. With a machine tool
B. Only by hammering
C. Only by filing
D. As a drill chuck

Answer: A. With a machine tool

Q79. An adjustable reamer allows:

A. Limited adjustment of its effective diameter
B. Unlimited enlargement of any hole
C. Thread cutting only
D. Welding

Answer: A. Limited adjustment of its effective diameter

Q80. Counterboring produces:

A. A cylindrical recess
B. A conical recess
C. An external thread
D. A flat plate

Answer: A. A cylindrical recess

Q81. Countersinking produces:

A. A conical recess
B. A cylindrical recess
C. A square recess
D. A thread

Answer: A. A conical recess

Q82. Spot facing is performed to:

A. Provide a flat seating surface
B. Produce a helical thread
C. Reduce spindle speed
D. Produce external cylindrical surfaces

Answer: A. Provide a flat seating surface

E. TAPS & THREADING — Q83–95

Q83. Tapping is the operation of producing:

A. Internal threads
B. External threads
C. Flat surfaces
D. Gear teeth

Answer: A. Internal threads

Q84. The tool used for tapping is called a:

A. Tap
B. Die
C. Reamer
D. Broach

Answer: A. Tap

Q85. A die is generally used for producing:

A. External threads
B. Internal threads
C. Holes
D. Flat surfaces

Answer: A. External threads

Q86. The first tap in a conventional hand-tapping set is generally:

A. Taper tap
B. Bottoming tap
C. Plug tap
D. Machine reamer

Answer: A. Taper tap

Q87. A taper tap has:

A. A relatively long chamfer
B. No chamfer
C. Only one cutting edge
D. A grinding wheel

Answer: A. A relatively long chamfer

Q88. A bottoming tap is especially useful for:

A. Threads near the bottom of a blind hole
B. Cutting external threads
C. Grinding shafts
D. Drilling large holes

Answer: A. Threads near the bottom of a blind hole

Q89. A blind hole:

A. Does not pass completely through the workpiece
B. Always passes through the workpiece
C. Has no bottom
D. Is always threaded

Answer: A. Does not pass completely through the workpiece

Q90. A through hole:

A. Passes completely through the workpiece
B. Has a closed bottom
C. Is always tapered
D. Is always threaded

Answer: A. Passes completely through the workpiece

Q91. For an M10 × 1.5 thread, an approximate tap-drill diameter is:

A. 6.5 mm
B. 8.5 mm
C. 10.0 mm
D. 11.5 mm

Answer: B. 8.5 mm

Q92. For an M8 × 1.25 thread, the approximate tap-drill size is:

A. 5.75 mm
B. 6.75 mm
C. 8.0 mm
D. 9.25 mm

Answer: B. 6.75 mm

Q93. For an M12 × 1.75 thread, the approximate tap-drill size is:

A. 8.5 mm
B. 10.25 mm
C. 12 mm
D. 13.75 mm

Answer: B. 10.25 mm

Q94. The main purpose of drilling a tapping hole before tapping is to:

A. Provide the required space for the thread
B. Make the hole completely solid
C. Eliminate all cutting
D. Increase the major diameter

Answer: A. Provide the required space for the thread

Q95. During hand tapping, reversing the tap periodically is commonly done to:

A. Break and clear chips
B. Increase hole diameter indefinitely
C. Remove the machine spindle
D. Reduce thread depth to zero

Answer: A. Break and clear chips

F. DRILLING DEFECTS & TROUBLESHOOTING — Q96–100

Q96. An oversized drilled hole may result from:

A. Improper drill geometry or runout
B. Perfect alignment only
C. Correct setup only
D. Proper sharpening only

Answer: A. Improper drill geometry or runout

Q97. Drill wandering at the start of drilling can be reduced by:

A. Providing a proper starting location/spot
B. Increasing runout
C. Using a damaged drill
D. Removing work support

Answer: A. Providing a proper starting location/spot

Q98. Excessive burr formation commonly occurs:

A. At breakthrough of the drill
B. Only at the drill shank
C. On the machine base
D. Inside the spindle bearing

Answer: A. At breakthrough of the drill

Q99. Poor chip evacuation during drilling can cause:

A. Drill overheating and possible breakage
B. Automatic improvement in finish
C. Zero cutting force
D. Reduced chip formation

Answer: A. Drill overheating and possible breakage

Q100. Which sequence correctly matches the operation with its purpose?

A. Drilling—new hole; Boring—enlarge existing hole; Reaming—finish hole; Tapping—internal thread
B. Drilling—external thread; Boring—welding; Reaming—casting; Tapping—grinding
C. Drilling—flat surface; Boring—external thread; Reaming—casting; Tapping—turning
D. Drilling—grinding; Boring—forming; Reaming—welding; Tapping—milling

Answer: A. Drilling—new hole; Boring—enlarge existing hole; Reaming—finish hole; Tapping—internal thread

CHAPTER 17 QUICK REVISION

Operation	Purpose
Drilling	Produces a new hole
Boring	Enlarges/improves existing hole
Reaming	Finishing and improving accuracy
Counterboring	Cylindrical recess
Countersinking	Conical recess
Spot facing	Flat seating surface
Tapping	Internal threads
Die threading	External threads
Taper tap	First hand tap
Bottoming tap	Threads near blind-hole bottom
Twist drill	Common drilling tool
HSS	High-speed steel
Radial drill	Large/heavy workpieces
Gang drill	Successive operations
Multi-spindle drill	Multiple holes/high production
118°	Typical general-purpose drill point angle
Flutes	Chip evacuation
Web	Drill strength
Margin	Guidance
Chisel edge	Ploughing action

Top of Form

Bottom of Form

CHAPTER 18 — LATHE MACHINE & TURNING OPERATIONS

18.1 Definition of Lathe

A lathe is a machine tool in which the workpiece is rotated about its axis while a cutting tool is fed against it to remove material.

Simple definition

Lathe = Rotating workpiece + stationary/fed cutting tool

The main purpose of a lathe is to produce:

Cylindrical surfaces

Conical surfaces

Threads

Grooves

Shoulders

End faces

Holes

Special profiles

18.2 Principle of Lathe

The basic working principle is:

The workpiece is securely mounted.
The workpiece rotates.
The cutting tool is mounted on the tool post.
The tool is given controlled feed.
Material is removed in the form of chips.

The primary cutting motion is provided by the rotating workpiece.

18.3 Main Parts of a Centre Lathe

The major parts are:

Bed
Headstock
Tailstock
Carriage
Lead screw
Feed rod
Tool post
Apron
Chuck
Cross-slide
Compound rest

18.4 Lathe Bed

The bed is the main supporting structure of the lathe.

It supports:

Headstock

Tailstock

Carriage

The bed is generally made from:

Cast iron or suitable cast material.

Functions

Provides rigidity

Maintains alignment

Supports major components

Absorbs vibration

18.5 Guideways

Guideways are provided on the lathe bed to guide:

Carriage

Tailstock

They ensure accurate movement parallel to the spindle axis.

18.6 Headstock

The headstock is mounted at the:

Left-hand end of the lathe bed in a conventional centre lathe.

It contains:

Main spindle

Bearings

Speed-changing mechanism

Gears/pulleys

Work-holding arrangements

18.7 Main Spindle

The spindle:

Rotates the workpiece

Transmits power

Carries the chuck or other work-holding device

The spindle is one of the most important rotating components of the lathe.

18.8 Chuck

A chuck is a work-holding device.

It is used to:

Hold and rotate the workpiece.

Common types include:

Three-jaw chuck

Four-jaw independent chuck

Collet chuck

Magnetic chuck in specialized applications

18.9 Three-Jaw Chuck

The three-jaw chuck has:

Three jaws that move simultaneously.

It is also called:

Self-centering chuck.

It is particularly suitable for:

Round work

Hexagonal work

Regular-shaped components

18.10 Four-Jaw Independent Chuck

The four-jaw independent chuck has:

Four jaws that can be adjusted independently.

Advantages:

Irregular work can be held

Square work can be held

Eccentric work can be set

Accurate independent adjustment is possible

18.11 Difference Between 3-Jaw and 4-Jaw Chuck

3-Jaw Chuck	4-Jaw Independent Chuck
Self-centering	Independent jaws
Faster setting	More adjustment
Round/hexagonal work	Irregular/square/eccentric work
Less setting time	More setting time
Limited eccentric adjustment	Excellent eccentric setting

18.12 Tailstock

The tailstock is mounted on the:

Right-hand side of the lathe bed.

It is used to:

Support long workpieces

Hold drills

Hold reamers

Hold centres

Support certain tools

18.13 Tailstock Quill/Barrel

The tailstock barrel or quill can move axially and is used to accommodate:

Centre

Drill chuck

Taper-shank tools

18.14 Live Centre

A live centre generally rotates with the workpiece.

It is associated with the:

Headstock side.

18.15 Dead Centre

A dead centre generally does not rotate independently with the workpiece and is associated traditionally with:

Tailstock support.

Lubrication is important because relative sliding can occur.

18.16 Carriage

The carriage supports and moves the cutting tool.

Major components include:

Saddle

Cross-slide

Compound rest

Tool post

Apron

18.17 Saddle

The saddle:

Rests on the bed

Supports the cross-slide

Travels longitudinally along the bed

18.18 Cross-Slide

The cross-slide moves the tool:

Perpendicular to the lathe axis.

It is commonly used for:

Facing

Adjusting depth of cut

18.19 Compound Rest

The compound rest:

Supports the tool post

Can be swiveled

Is useful for taper turning by the compound-rest method

Is useful for short tapers

Is used during certain thread/tool-setting operations

18.20 Tool Post

The tool post holds the:

Cutting tool.

Common types include:

Single tool post

Four-way tool post

Quick-change tool post

18.21 Apron

The apron is attached to the carriage.

It contains mechanisms for:

Feed control

Clutch/control arrangements

Engagement of feed mechanisms

18.22 Lead Screw

The lead screw is mainly used for:

Thread cutting on a conventional centre lathe.

It provides precise relationship between spindle rotation and tool movement.

18.23 Feed Rod

The feed rod is generally used to transmit power for:

Automatic longitudinal and cross feeds.

Important distinction

Lead screw → mainly thread cutting

Feed rod → normal power feed

18.24 Lathe Operations

Important lathe operations include:

Turning
Facing
Plain turning
Step turning
Taper turning
Thread cutting
Knurling
Parting-off
Grooving
Boring
Drilling
Reaming
Chamfering

18.25 Turning

Turning is the operation of reducing the diameter of a rotating workpiece using a single-point cutting tool.

The tool generally moves:

Parallel to the axis of rotation.

18.26 Plain Turning

Plain turning produces:

A cylindrical surface of uniform diameter.

18.27 Step Turning

Step turning produces:

Two or more cylindrical diameters on the same workpiece.

Example:

A shaft having 20 mm, 30 mm and 40 mm sections.

18.28 Facing

Facing is the operation of machining:

The end surface of a workpiece.

The tool moves generally:

Radially toward or away from the axis.

18.29 Taper Turning

Taper turning produces:

A conical surface.

A taper is a gradual change in diameter along the length of the workpiece.

18.30 Methods of Taper Turning

Important methods include:

Compound-rest method
Tailstock set-over method
Taper turning attachment
Form-tool method

18.31 Compound-Rest Method

In this method, the:

Compound rest is swiveled to the required half taper angle.

It is suitable particularly for:

Short tapers.

18.32 Tailstock Set-Over Method

The tailstock is shifted laterally to create the required taper.

It is suitable for:

Long, slight tapers on workpieces held between centres.

18.33 Taper Turning Attachment

A taper attachment guides the cutting tool at an angle to the workpiece axis.

It is useful for:

Accurate taper production without setting over the tailstock.

18.34 Form Tool Method

A form tool can produce:

Short tapers or special profiles.

The tool has the required profile.

18.35 Taper Angle

For a taper having:

Larger diameter =

Smaller diameter =

Length =

The half-angle is related by:

Therefore:

18.36 Taper per Unit Length

Taper is often expressed as:

18.37 Thread Cutting

Thread cutting on a lathe produces:

External or internal screw threads.

For conventional thread cutting, the lead screw is engaged through the appropriate gearing.

18.38 Thread Pitch

Pitch is:

The axial distance between corresponding points of adjacent threads.

For a single-start thread:

18.39 Multi-Start Thread

For a multi-start thread:

Example:

For a 3-start thread with pitch 2 mm:

18.40 Knurling

Knurling is a forming operation used to produce a patterned roughened surface on a workpiece.

Important:

Knurling is generally not a conventional chip-removal operation.

It is commonly used on:

Handles

Knobs

Adjustment screws

Grips

18.41 Parting-Off

Parting-off is used to:

Separate a finished or partially finished component from the bar stock.

A narrow cutting tool is fed:

Radially toward the axis.

18.42 Grooving

Grooving produces:

A narrow recess or groove on the workpiece.

18.43 Chamfering

Chamfering produces:

A bevelled edge.

18.44 Boring on Lathe

Boring on a lathe is used to:

Enlarge or finish an existing hole.

The boring tool is generally held in:

The tool post or boring bar arrangement.

18.45 Drilling on Lathe

When drilling on a centre lathe, the drill is commonly held in:

A drill chuck mounted in the tailstock.

The workpiece rotates while the drill is fed axially.

18.46 Lathe Cutting Speed

Cutting speed is the surface speed of the workpiece at the cutting point.

where:

= cutting speed in m/min

= work diameter in mm

= spindle speed in rpm

18.47 Feed in Turning

Feed is the:

Distance travelled by the cutting tool per revolution of the workpiece.

Unit:

18.48 Depth of Cut

Depth of cut in turning is approximately:

where:

= original diameter

= final diameter

18.49 Example of Depth of Cut

Original diameter = 50 mm
Final diameter = 46 mm

18.50 Lathe Power

The power required for cutting depends on factors such as:

Cutting force

Cutting speed

Material

Feed

Depth of cut

Tool geometry

A simplified relation is:

with appropriate unit conversion when and are expressed in N and m/s.

Q1. A lathe is primarily used to:

A. Rotate the cutting tool only
B. Machine rotating workpieces
C. Perform casting
D. Perform forging

Answer: B. Machine rotating workpieces

Explanation: In conventional turning, the workpiece rotates and the cutting tool is fed against it.

Q2. In a conventional lathe, the primary cutting motion is provided by:

A. Cutting tool
B. Workpiece rotation
C. Tailstock
D. Tool post

Answer: B. Workpiece rotation

Q3. The main supporting structure of a lathe is:

A. Apron
B. Bed
C. Chuck
D. Tool post

Answer: B. Bed

Q4. The headstock is normally located at the:

A. Right end
B. Left end
C. Centre of bed
D. Bottom of bed

Answer: B. Left end

Q5. The tailstock is generally located at the:

A. Left end
B. Right end
C. Centre of headstock
D. Bottom of the machine

Answer: B. Right end

Q6. The headstock contains the:

A. Main spindle
B. Work-rest blade
C. Grinding wheel
D. Milling cutter

Answer: A. Main spindle

Q7. The main spindle is responsible for:

A. Rotating the workpiece
B. Supporting the bed
C. Measuring feed
D. Sharpening tools

Answer: A. Rotating the workpiece

Q8. A three-jaw chuck is also called:

A. Independent chuck
B. Self-centering chuck
C. Magnetic chuck
D. Faceplate

Answer: B. Self-centering chuck

Q9. A three-jaw chuck is particularly suitable for:

A. Regular round work
B. Highly irregular work only
C. Eccentric work only
D. Flat plates only

Answer: A. Regular round work

Q10. In a four-jaw independent chuck:

A. All jaws move together
B. Each jaw can be adjusted independently
C. No jaw can move
D. Only two jaws are present

Answer: B. Each jaw can be adjusted independently

Q11. A four-jaw independent chuck is especially suitable for:

A. Irregular and eccentric work
B. Only round work
C. Only drilling
D. Grinding wheels

Answer: A. Irregular and eccentric work

Q12. The tailstock is used for:

A. Supporting long work and holding drills
B. Driving the spindle
C. Holding the main motor
D. Producing cutting fluid

Answer: A. Supporting long work and holding drills

Q13. The carriage supports:

A. Cutting tool
B. Main motor only
C. Chuck jaws only
D. Tailstock spindle

Answer: A. Cutting tool

Q14. The cross-slide moves the cutting tool:

A. Parallel to the spindle only
B. Perpendicular to the spindle axis
C. Vertically only
D. Randomly

Answer: B. Perpendicular to the spindle axis

Q15. The compound rest is particularly useful for:

A. Short taper turning
B. Casting
C. Welding
D. Gear hobbing

Answer: A. Short taper turning

Q16. The tool post is used to:

A. Hold the cutting tool
B. Hold the workpiece
C. Rotate the spindle
D. Support the bed

Answer: A. Hold the cutting tool

Q17. The lead screw is mainly used for:

A. Thread cutting
B. Cooling
C. Work holding
D. Grinding

Answer: A. Thread cutting

Q18. The feed rod is primarily associated with:

A. Power feed
B. Thread pitch measurement only
C. Work holding
D. Chuck tightening

Answer: A. Power feed

Q19. Plain turning produces:

A. A cylindrical surface
B. A conical recess
C. An internal thread only
D. A flat plate only

Answer: A. A cylindrical surface

Q20. Facing produces:

A. A flat end surface
B. A thread
C. A gear tooth
D. A hole only

Answer: A. A flat end surface

Q21. Step turning produces:

A. Different cylindrical diameters
B. Only a single diameter
C. A conical hole
D. Internal threads only

Answer: A. Different cylindrical diameters

Q22. Taper turning produces:

A. A conical surface
B. A flat surface only
C. A spherical hole only
D. A gear

Answer: A. A conical surface

Q23. Tailstock set-over method is particularly suitable for:

A. Long, slight tapers
B. Very short steep tapers only
C. Knurling
D. Threading only

Answer: A. Long, slight tapers

Q24. Knurling is primarily:

A. A forming operation
B. A drilling operation
C. A grinding operation
D. A casting operation

Answer: A. A forming operation

Q25. Parting-off is used to:

A. Separate a component from bar stock
B. Produce a large flat surface
C. Produce internal threads
D. Drill a hole

Answer: A. Separate a component from bar stock

A. LATHE CUTTING TOOLS & TOOL GEOMETRY — Q26–45

Q26. The cutting tool commonly used for conventional turning is:

A. Single-point cutting tool
B. Multi-point drill
C. Grinding wheel
D. Reamer

Answer: A. Single-point cutting tool

Explanation: A conventional turning tool generally has one principal cutting edge.

Q27. Which of the following is a common cutting-tool material?

A. High-speed steel
B. Wood
C. Rubber
D. Glass

Answer: A. High-speed steel

Q28. Cemented carbide tools are preferred mainly because of their:

A. High hot hardness
B. Very low hardness
C. High flexibility
D. Low wear resistance

Answer: A. High hot hardness

Q29. The rake angle of a cutting tool mainly influences:

A. Chip flow and cutting forces
B. Machine colour
C. Workpiece weight
D. Chuck diameter

Answer: A. Chip flow and cutting forces

Q30. Positive rake generally tends to:

A. Reduce cutting forces
B. Increase cutting forces indefinitely
C. Eliminate cutting
D. Stop chip formation

Answer: A. Reduce cutting forces

Q31. Clearance angle is provided mainly to prevent:

A. Rubbing between tool flank and work surface
B. Chip formation
C. Tool holding
D. Workpiece rotation

Answer: A. Rubbing between tool flank and work surface

Q32. If clearance angle is too small, the tool may:

A. Rub against the workpiece
B. Cut without friction
C. Become sharper automatically
D. Stop rotating the workpiece

Answer: A. Rub against the workpiece

Q33. The nose of a turning tool is the:

A. Junction region near the cutting edges at the tool tip
B. Tool shank
C. Tool holder
D. Machine spindle

Answer: A. Junction region near the cutting edges at the tool tip

Q34. A small nose radius generally produces:

A. More concentrated cutting action
B. No cutting force
C. No surface finish
D. Automatic taper

Answer: A. More concentrated cutting action

Q35. Increasing tool nose radius generally improves:

A. Surface finish, within suitable cutting conditions
B. Tool flexibility
C. Machine speed automatically
D. Workpiece hardness

Answer: A. Surface finish, within suitable cutting conditions

Q36. Excessively large nose radius may cause:

A. Increased cutting forces and possible chatter
B. Zero cutting force
C. No contact with work
D. Automatic thread cutting

Answer: A. Increased cutting forces and possible chatter

Q37. Tool wear on the flank surface is called:

A. Flank wear
B. Crater wear
C. Nose growth
D. Edge expansion

Answer: A. Flank wear

Q38. Wear occurring mainly on the rake face is called:

A. Crater wear
B. Flank wear
C. Nose wear only
D. Clearance wear

Answer: A. Crater wear

Q39. Flank wear is mainly associated with:

A. Rubbing between tool flank and machined surface
B. Coolant generation
C. Workpiece rotation
D. Chuck movement

Answer: A. Rubbing between tool flank and machined surface

Q40. A built-up edge is more likely to occur during machining of:

A. Ductile materials under certain cutting conditions
B. Only brittle ceramics
C. Glass only
D. No material

Answer: A. Ductile materials under certain cutting conditions

Q41. A built-up edge can adversely affect:

A. Surface finish and dimensional accuracy
B. Machine foundation only
C. Workpiece weight only
D. Coolant colour

Answer: A. Surface finish and dimensional accuracy

Q42. Increasing cutting speed can sometimes help reduce:

A. Built-up edge
B. Workpiece rotation
C. Tool clearance
D. Machine rigidity

Answer: A. Built-up edge

Q43. The tool should be set at approximately the:

A. Centre height of the workpiece for normal turning
B. Top of the chuck
C. Bottom of the bed
D. Tailstock centre only

Answer: A. Centre height of the workpiece for normal turning

Q44. If a turning tool is set significantly above centre, it can alter:

A. Tool geometry and cutting conditions
B. Workpiece material
C. Chuck type
D. Machine bed length

Answer: A. Tool geometry and cutting conditions

Q45. A dull cutting tool generally causes:

A. Higher cutting forces and poorer surface finish
B. Lower forces in all cases
C. No heat generation
D. Automatic improvement in accuracy

Answer: A. Higher cutting forces and poorer surface finish

B. CUTTING SPEED, FEED & DEPTH OF CUT — Q46–60

Q46. In turning, cutting speed is normally expressed in:

A. m/min
B. mm/rev
C. mm/min only
D. rpm only

Answer: A. m/min

Q47. Feed in turning is commonly expressed in:

A. mm/rev
B. m/min
C. rpm
D. N/mm²

Answer: A. mm/rev

Q48. Depth of cut in turning is measured:

A. Radially
B. Circumferentially
C. Along the spindle only
D. Vertically from the floor

Answer: A. Radially

Q49. A workpiece diameter changes from 60 mm to 54 mm. The depth of cut is:

A. 2 mm
B. 3 mm
C. 6 mm
D. 12 mm

Answer: B. 3 mm

Q50. A diameter is reduced from 50 mm to 46 mm. Depth of cut is:

A. 1 mm
B. 2 mm
C. 4 mm
D. 8 mm

Answer: B. 2 mm

Q51. The cutting-speed equation for turning is:

A.
B.
C.
D.

Answer: A.

Q52. A 100 mm diameter workpiece rotates at 300 rpm. Its cutting speed is approximately:

A. 31.4 m/min
B. 62.8 m/min
C. 94.2 m/min
D. 100 m/min

Answer: A. 94.2 m/min

Q53. A 50 mm diameter workpiece rotates at 600 rpm. Cutting speed is approximately:

A. 47.1 m/min
B. 94.2 m/min
C. 150 m/min
D. 188.4 m/min

Answer: B. 94.2 m/min

Q54. If cutting speed is constant and work diameter increases, spindle speed should:

A. Decrease
B. Increase
C. Remain constant
D. Become zero

Answer: A. Decrease

Q55. For a fixed diameter, if spindle speed doubles, cutting speed:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes one-fourth

Answer: A. Doubles

Q56. If feed is 0.25 mm/rev and spindle speed is 800 rpm, feed rate is:

A. 100 mm/min
B. 150 mm/min
C. 200 mm/min
D. 320 mm/min

Answer: C. 200 mm/min

Q57. Feed rate is 300 mm/min and spindle speed is 1000 rpm. Feed per revolution is:

A. 0.1 mm/rev
B. 0.2 mm/rev
C. 0.3 mm/rev
D. 3 mm/rev

Answer: C. 0.3 mm/rev

Q58. Increasing feed generally tends to increase:

A. Material removal rate
B. Machine rigidity
C. Tool clearance
D. Workpiece hardness

Answer: A. Material removal rate

Q59. Excessive depth of cut can result in:

A. Increased cutting force
B. Zero cutting force
C. No chip formation
D. Automatic surface improvement

Answer: A. Increased cutting force

Q60. Cutting parameters should be selected according to:

A. Work material, tool material, machine capability and operation
B. Workpiece colour only
C. Operator preference only
D. Chuck colour

Answer: A. Work material, tool material, machine capability and operation

C. TAPER TURNING — Q61–70

Q61. A taper is a surface in which:

A. Diameter changes gradually along the length
B. Diameter remains constant
C. Only surface roughness changes
D. No material is removed

Answer: A. Diameter changes gradually along the length

Q62. Taper per unit length is:

A.
B.
C.
D.

Answer: A.

Q63. The half taper angle is given by:

A.
B.
C.
D.

Answer: A.

Q64. A taper has large diameter 40 mm, small diameter 30 mm and length 100 mm. Taper per unit length is:

A. 0.05
B. 0.10
C. 0.20
D. 10

Answer: B. 0.10

Q65. Which method is especially suitable for short tapers?

A. Compound-rest method
B. Tailstock set-over method
C. Long-bed method
D. Feed-rod method

Answer: A. Compound-rest method

Q66. Which method is especially suitable for long, slight tapers?

A. Tailstock set-over method
B. Form-tool method only
C. Knurling
D. Facing

Answer: A. Tailstock set-over method

Q67. In the compound-rest method, the compound rest is set at:

A. Half the taper angle
B. Double the taper angle
C. Zero angle in every case
D. 90° in every case

Answer: A. Half the taper angle

Q68. A taper turning attachment provides:

A. Controlled angular movement of the tool
B. Automatic drilling only
C. Chuck rotation only
D. Grinding-wheel movement

Answer: A. Controlled angular movement of the tool

Q69. The tailstock set-over method requires the workpiece to be:

A. Mounted between centres
B. Held only in a drill chuck
C. Welded to the bed
D. Held only by a faceplate

Answer: A. Mounted between centres

Q70. Form-tool tapering is best suited to:

A. Short tapers or profiles
B. Very long tapers only
C. Large deep holes
D. Thread cutting

Answer: A. Short tapers or profiles

D. THREAD CUTTING — Q71–82

Q71. Thread cutting on a conventional lathe generally requires the:

A. Lead screw
B. Feed rod only
C. Cross-slide only
D. Tailstock barrel only

Answer: A. Lead screw

Q72. Pitch is the:

A. Axial distance between corresponding points of adjacent threads
B. Thread depth only
C. Major diameter
D. Minor diameter

Answer: A. Axial distance between corresponding points of adjacent threads

Q73. For a single-start thread:

A. Lead = Pitch
B. Lead = 2 × Pitch
C. Lead = 3 × Pitch
D. Lead = Pitch/2

Answer: A. Lead = Pitch

Q74. For a two-start thread with pitch 3 mm, lead is:

A. 1.5 mm
B. 3 mm
C. 6 mm
D. 9 mm

Answer: C. 6 mm

Q75. For a four-start thread of pitch 2 mm, lead is:

A. 2 mm
B. 4 mm
C. 6 mm
D. 8 mm

Answer: D. 8 mm

Q76. The gear train in thread cutting establishes the relationship between:

A. Spindle and lead screw
B. Tailstock and bed
C. Chuck and tool post only
D. Coolant and spindle

Answer: A. Spindle and lead screw

Q77. For cutting a thread of pitch 2 mm, the tool must advance:

A. 2 mm per spindle revolution
B. 4 mm per spindle revolution
C. 1 mm per spindle revolution
D. 20 mm per spindle revolution

Answer: A. 2 mm per spindle revolution

Q78. A thread-cutting tool should generally have a profile corresponding to:

A. The thread form being produced
B. The chuck jaws
C. The bed guideways
D. The tailstock

Answer: A. The thread form being produced

Q79. A metric thread generally has its pitch specified in:

A. mm
B. rpm
C. m/min
D. N

Answer: A. mm

Q80. A single-start screw thread with pitch 4 mm has a lead of:

A. 2 mm
B. 4 mm
C. 8 mm
D. 16 mm

Answer: B. 4 mm

Q81. Increasing the number of starts while keeping pitch constant will:

A. Increase lead
B. Decrease lead
C. Make lead zero
D. Have no effect on lead

Answer: A. Increase lead

Q82. Thread cutting differs from ordinary turning because:

A. Tool movement must be synchronized with spindle rotation
B. Workpiece does not rotate
C. No cutting tool is used
D. No feed is required

Answer: A. Tool movement must be synchronized with spindle rotation

E. KNURLING, BORING, DRILLING & PARTING — Q83–90

Q83. Knurling produces:

A. A patterned surface
B. An internal hole
C. A conical hole
D. A screw thread only

Answer: A. A patterned surface

Q84. Knurling is mainly used to improve:

A. Grip and appearance
B. Hole depth
C. Taper angle
D. Cutting speed

Answer: A. Grip and appearance

Q85. Knurling is generally classified as:

A. Forming operation
B. Drilling operation
C. Grinding operation
D. Casting operation

Answer: A. Forming operation

Q86. Parting-off is performed using:

A. A narrow parting tool
B. A twist drill
C. A reamer
D. A grinding wheel

Answer: A. A narrow parting tool

Q87. During parting-off, the tool is generally fed:

A. Radially toward the work axis
B. Parallel to the axis only
C. Vertically upward only
D. Randomly

Answer: A. Radially toward the work axis

Q88. Boring on a lathe is used to:

A. Enlarge an existing hole
B. Produce an external thread
C. Produce a knurled surface
D. Cut a flat sheet

Answer: A. Enlarge an existing hole

Q89. Drilling on a lathe is commonly performed with the drill mounted in the:

A. Tailstock
B. Tool post only
C. Apron
D. Bed

Answer: A. Tailstock

Q90. Reaming on a lathe is generally performed to:

A. Finish and size an existing hole
B. Produce a completely new hole from solid material
C. Produce external threads
D. Produce a knurled surface

Answer: A. Finish and size an existing hole

F. MACHINING-TIME & PRACTICAL CALCULATIONS — Q91–100

Q91. If a turning length is 100 mm and feed rate is 200 mm/min, machining time is:

A. 0.25 min
B. 0.5 min
C. 2 min
D. 20 min

Answer: B. 0.5 min

Q92. A workpiece rotates at 500 rpm and feed is 0.2 mm/rev. Feed rate is:

A. 50 mm/min
B. 100 mm/min
C. 200 mm/min
D. 250 mm/min

Answer: B. 100 mm/min

Q93. A turning operation has a length of 150 mm and feed rate of 75 mm/min. Approximate machining time is:

A. 1 min
B. 2 min
C. 3 min
D. 5 min

Answer: B. 2 min

Q94. A 40 mm diameter workpiece rotates at 500 rpm. Cutting speed is approximately:

A. 31.4 m/min
B. 62.8 m/min
C. 100 m/min
D. 125.6 m/min

Answer: B. 62.8 m/min

Q95. A workpiece of 80 mm diameter rotates at 250 rpm. Cutting speed is approximately:

A. 31.4 m/min
B. 62.8 m/min
C. 100 m/min
D. 125.6 m/min

Answer: B. 62.8 m/min

Q96. Original diameter is 70 mm and final diameter is 60 mm. Depth of cut is:

A. 2.5 mm
B. 5 mm
C. 10 mm
D. 15 mm

Answer: B. 5 mm

Q97. A shaft is reduced from 100 mm to 90 mm diameter. If the operation is performed in two equal radial cuts, depth of cut per pass is:

A. 2.5 mm
B. 5 mm
C. 10 mm
D. 20 mm

Answer: A. 2.5 mm

Total radial reduction:

For two equal passes:

Q98. If spindle speed is 400 rpm and feed is 0.25 mm/rev, the tool travels:

A. 50 mm/min
B. 100 mm/min
C. 200 mm/min
D. 400 mm/min

Answer: B. 100 mm/min

Q99. Chatter during turning is commonly associated with:

A. Vibration
B. Perfect rigidity
C. Zero cutting force
D. No tool contact

Answer: A. Vibration

Explanation: Chatter is a self-excited or forced vibration phenomenon that can produce a poor surface finish and tool damage.

Q100. Which combination is completely correct?

A. Turning—cylindrical surface; Facing—end surface; Taper turning—conical surface; Knurling—patterned surface
B. Turning—thread only; Facing—hole; Taper turning—flat surface; Knurling—drilling
C. Turning—casting; Facing—forging; Taper turning—welding; Knurling—grinding
D. Turning—gear cutting only; Facing—threading only; Taper turning—drilling; Knurling—boring

Answer: A. Turning—cylindrical surface; Facing—end surface; Taper turning—conical surface; Knurling—patterned surface

CHAPTER 18 — QUICK REVISION TABLE

Topic	Key Point
Lathe	Workpiece rotates
Bed	Main supporting structure
Headstock	Contains spindle
Tailstock	Supports work/holds tools
3-jaw chuck	Self-centering
4-jaw chuck	Independent jaws
Carriage	Supports/moves tool
Cross-slide	Transverse movement
Compound rest	Short taper turning
Lead screw	Thread cutting
Feed rod	Power feed
Turning	Cylindrical surface
Facing	End surface
Step turning	Different diameters
Taper turning	Conical surface
Knurling	Patterned grip surface
Parting	Separates component
Boring	Enlarges existing hole
Drilling	Produces hole
Reaming	Finishes hole
Thread cutting	Produces screw thread
Pitch	Axial distance between adjacent corresponding thread points
Single-start	Lead = pitch
Multi-start	Lead = pitch × starts
Cutting speed
Feed rate
Depth of cut

CHAPTER 19 — SHAPER, PLANER & SLOTTER

19.1 SHAPER — DEFINITION

A shaper is a machine tool in which a single-point cutting tool mounted on a reciprocating ram removes material from the workpiece.

The cutting action takes place during:

Forward stroke of the ram.

During the return stroke, generally:

No cutting takes place.

19.2 PRINCIPLE OF SHAPER

The basic principle is:

Reciprocating cutting tool + stationary/slowly fed workpiece

The ram carries the cutting tool and moves:

Back and forth in a straight line.

The workpiece is mounted on the table.

19.3 CUTTING STROKE AND RETURN STROKE

Cutting Stroke

During the cutting stroke:

Tool moves against the workpiece.

Material is removed.

Cutting force is generated.

Return Stroke

During the return stroke:

Tool moves back.

Normally no cutting occurs.

The tool/work arrangement is designed to reduce rubbing.

The return stroke is generally made faster than the cutting stroke in a quick-return shaper.

19.4 QUICK-RETURN MECHANISM

A major feature of many mechanical shapers is the:

Quick-return mechanism.

Its purpose is:

To make the return stroke faster than the cutting stroke.

This reduces idle time and increases productivity.

19.5 COMMON QUICK-RETURN MECHANISMS

Important mechanisms include:

Crank and slotted-link mechanism
Whitworth quick-return mechanism
Hydraulic mechanism

19.6 CRANK AND SLOTTED-LINK MECHANISM

This mechanism converts:

Rotary motion → Reciprocating motion

It is commonly associated with:

Mechanical shapers.

19.7 WHITWORTH QUICK-RETURN MECHANISM

The Whitworth mechanism is another arrangement for producing:

Reciprocating motion with a quick return.

The purpose is again to:

Reduce non-cutting return time.

19.8 HYDRAULIC SHAPER

In a hydraulic shaper, ram movement is produced by:

Hydraulic power.

Advantages may include:

Smooth movement

Better speed control

Reduced mechanical shock

Suitable control over ram motion

19.9 MAIN PARTS OF A SHAPER

Important parts include:

Base
Column
Cross-rail
Table
Ram
Tool head
Clapper box
Apron
Feed mechanism

19.10 BASE

The base:

Supports the machine

Provides stability

Transfers loads to the foundation

19.11 COLUMN

The column is the main vertical supporting structure.

It houses/supports mechanisms associated with:

Ram drive

Feed

Quick-return mechanism in mechanical designs

19.12 RAM

The ram is one of the most important components.

It:

Carries the tool head and reciprocates.

The cutting tool is mounted at the front end through the tool head.

19.13 TABLE

The table supports:

The workpiece.

It can generally be adjusted for:

Vertical position

Cross movement

Longitudinal positioning, depending on machine arrangement

19.14 TOOL HEAD

The tool head:

Holds the cutting tool

Allows adjustment of tool position

Provides mechanisms for tool setting

19.15 CLAPPER BOX

The clapper box is an important shaper component.

Its main function is:

To allow the cutting tool to lift slightly during the return stroke.

This reduces:

Tool rubbing and damage.

19.16 APRON

The apron is associated with the front of the table/tool-support arrangement and contains mechanisms related to:

Feed and tool movement/control.

19.17 SHAPER FEED

In a shaper, feed is generally given to the:

Workpiece/table.

It is usually applied:

After each cutting stroke or through the feed mechanism.

19.18 SHAPER OPERATIONS

A shaper can perform:

Horizontal flat surfaces

Vertical surfaces

Inclined surfaces

Slots

Grooves

Steps

Keyways

Angular surfaces

19.19 HORIZONTAL SURFACE

A horizontal surface can be machined by:

Appropriate positioning of the work and tool.

The ram provides the reciprocating cutting motion.

19.20 VERTICAL SURFACE

Vertical surfaces can be machined by:

Using the tool head with suitable adjustment and feed arrangement.

19.21 INCLINED SURFACE

An inclined surface can be produced by:

Tilting the tool head

Tilting/adjusting the work

Appropriate machine setup

19.22 SHAPER CUTTING TOOL

A shaper generally uses a:

Single-point cutting tool.

The tool resembles a lathe cutting tool in basic cutting principle.

19.23 PLANER — DEFINITION

A planer is a machine tool in which the workpiece is reciprocated under one or more cutting tools.

This is the key distinction from a shaper.

Shaper:

Tool reciprocates.

Planer:

Workpiece reciprocates.

19.24 PRINCIPLE OF PLANER

In a planer:

Workpiece is mounted on the table.

Table reciprocates.

Cutting tools are mounted on tool heads.

Material is removed during the cutting stroke.

Planers are suitable for:

Large and heavy workpieces.

19.25 MAIN PARTS OF PLANER

Important parts include:

Bed
Table
Columns
Cross-rail
Tool heads
Side tool heads
Drive mechanism

19.26 PLANER BED

The bed supports:

The reciprocating table.

It is generally long and robust.

19.27 PLANER TABLE

The workpiece is mounted on the:

Planer table.

The table moves back and forth.

19.28 PLANER COLUMNS

Columns support:

The cross-rail and tool-head arrangements.

19.29 PLANER CROSS-RAIL

The cross-rail provides support for:

Tool heads across the width of the machine.

19.30 PLANER TOOL HEADS

A planer may have:

Two or more tool heads

Side tool heads

Cross-rail tool heads

This allows:

Multiple surfaces to be machined during the same setup.

19.31 SLOTTER — DEFINITION

A slotter, or slotting machine, is essentially a:

Vertical shaper.

The cutting tool moves:

Vertically in a reciprocating motion.

19.32 SLOTTER PRINCIPLE

In a slotter:

Tool reciprocates vertically.

Workpiece is mounted on the table.

Cutting occurs during the cutting stroke.

Feed is given to the work/table.

19.33 SLOTTER APPLICATIONS

Slotters are commonly used for:

Internal slots

Keyways

Internal grooves

Internal profiles

Small internal surfaces

19.34 SLOTTER TABLE

The workpiece is mounted on the:

Slotter table.

The table may allow rotary positioning in suitable machines.

19.35 SHAPER VS PLANER VS SLOTTER

Feature	Shaper	Planer	Slotter
Cutting tool motion	Reciprocating	Tool generally stationary relative to machine while work moves	Vertical reciprocating
Workpiece motion	Feed movement	Reciprocating	Feed movement
Tool orientation	Usually horizontal	Usually horizontal/side	Vertical
Typical work	Small/medium	Large/heavy	Internal slots/profiles
Cutting tool	Single point	Single point	Single point
Main movement	Ram	Table	Ram

19.36 SHAPER VS PLANER — KEY DIFFERENCE

The most important difference is:

In a shaper, the tool reciprocates; in a planer, the workpiece/table reciprocates.

This is a very important examination point.

19.37 SHAPER VS SLOTTER

The principal difference is the direction of reciprocation:

Shaper → generally horizontal

Slotter → generally vertical

19.38 PLANER VS SHAPER

A planer is generally preferred when:

Workpiece is very large

Workpiece is very heavy

Large surfaces must be machined

Multiple tools may be used simultaneously

19.39 SHAPER MACHINE CAPACITY

Important specifications may include:

Maximum ram stroke

Table dimensions

Maximum table travel

Maximum cross movement

Maximum tool travel

19.40 PLANER MACHINE CAPACITY

Specifications may include:

Table dimensions

Maximum table travel

Distance between columns

Maximum workpiece dimensions

Tool-head travel

19.41 SHAPER CUTTING SPEED

Cutting speed in a shaper is related to the:

Length of cutting stroke and number of strokes per minute.

If:

= length of stroke

= strokes per minute

Then average cutting speed can be approximated from the total cutting distance per cycle.

19.42 TOTAL STROKE DISTANCE

For one complete cycle:

because there is:

One forward stroke

One return stroke

19.43 TIME PER STROKE CYCLE

If the number of double strokes per minute is , then:

for one complete cutting-return cycle.

19.44 QUICK-RETURN RATIO

The quick-return ratio is commonly expressed as:

For a quick-return mechanism, this ratio is:

Greater than 1.

19.45 WHY QUICK RETURN IS USED

The return stroke does not normally perform cutting.

Therefore, making it faster:

Reduces idle time

Increases productivity

Reduces total machining time

Q1. A shaper is a machine tool in which:

A. Workpiece rotates continuously
B. Cutting tool reciprocates
C. Grinding wheel rotates
D. Workpiece melts

Answer: B. Cutting tool reciprocates

Q2. In a conventional shaper, cutting generally takes place during:

A. Return stroke
B. Forward stroke
C. Both equally
D. Stopping period

Answer: B. Forward stroke

Q3. The main purpose of a quick-return mechanism is to:

A. Increase return-stroke speed
B. Increase workpiece hardness
C. Stop cutting
D. Reduce cutting-stroke speed to zero

Answer: A. Increase return-stroke speed

Q4. In a shaper, the reciprocating member carrying the tool is:

A. Table
B. Ram
C. Bed
D. Column

Answer: B. Ram

Q5. The workpiece in a shaper is mounted on the:

A. Table
B. Ram
C. Tool post
D. Column

Answer: A. Table

Q6. The clapper box is provided mainly to:

A. Allow tool clearance during return stroke
B. Rotate the workpiece
C. Hold the table
D. Drive the spindle

Answer: A. Allow tool clearance during return stroke

Q7. A shaper generally uses:

A. Single-point cutting tool
B. Multi-point drill
C. Grinding wheel
D. Broach only

Answer: A. Single-point cutting tool

Q8. A planer differs from a shaper because in a planer:

A. Workpiece reciprocates
B. Tool always rotates
C. Workpiece rotates
D. No cutting tool is used

Answer: A. Workpiece reciprocates

Q9. A planer is particularly suitable for:

A. Large and heavy workpieces
B. Very small screws only
C. Hand tools only
D. Wire drawing

Answer: A. Large and heavy workpieces

Q10. In a planer, the workpiece is mounted on the:

A. Reciprocating table
B. Tool post
C. Ram
D. Spindle

Answer: A. Reciprocating table

Q11. A slotting machine is essentially a:

A. Vertical shaper
B. Horizontal lathe
C. Grinding machine
D. Milling machine

Answer: A. Vertical shaper

Q12. The cutting tool of a slotter reciprocates:

A. Vertically
B. Horizontally only
C. Circularly
D. Randomly

Answer: A. Vertically

Q13. Slotting machines are particularly useful for:

A. Internal keyways and slots
B. External turning only
C. Welding
D. Casting

Answer: A. Internal keyways and slots

Q14. The quick-return mechanism converts:

A. Rotary motion into reciprocating motion
B. Reciprocating motion into heat
C. Heat into rotation
D. Linear motion into casting

Answer: A. Rotary motion into reciprocating motion

Q15. The crank and slotted-link mechanism is associated with:

A. Mechanical shaper
B. Lathe chuck
C. Drilling chuck
D. Grinding wheel

Answer: A. Mechanical shaper

Q16. The return stroke in a quick-return shaper is:

A. Faster than the cutting stroke
B. Slower than the cutting stroke
C. Equal in time always
D. Absent

Answer: A. Faster than the cutting stroke

Q17. The purpose of reducing return-stroke time is to:

A. Increase productivity
B. Increase idle time
C. Reduce material removal
D. Increase workpiece weight

Answer: A. Increase productivity

Q18. A hydraulic shaper uses:

A. Hydraulic power for ram movement
B. Only manual power
C. Steam pressure only
D. Magnetic force only

Answer: A. Hydraulic power for ram movement

Q19. Which machine is generally more suitable for very large surfaces?

A. Planer
B. Sensitive drill
C. Bench lathe
D. Hand drill

Answer: A. Planer

Q20. Which machine is most suitable for internal keyways?

A. Slotter
B. Planer only
C. Lathe only
D. Surface grinder only

Answer: A. Slotter

Q21. The cutting tool in a planer is generally mounted on:

A. Tool heads
B. Chuck jaws
C. Tailstock
D. Drill spindle

Answer: A. Tool heads

Q22. The cross-rail of a planer supports:

A. Tool heads
B. Chuck
C. Lathe spindle
D. Drill chuck

Answer: A. Tool heads

Q23. In a shaper, feed is generally applied to:

A. The work/table
B. The spindle
C. The chuck
D. The motor shaft

Answer: A. The work/table

Q24. Which of the following is NOT normally a reciprocating machine tool?

A. Shaper
B. Planer
C. Slotter
D. Centre lathe

Answer: D. Centre lathe

Explanation: A conventional centre lathe primarily uses rotational motion of the workpiece.

Q25. The most fundamental difference between shaper and planer is:

A. Tool reciprocates in shaper, workpiece reciprocates in planer
B. Both use rotating workpieces
C. Planer uses no cutting tool
D. Shaper uses only grinding wheels

Answer: A. Tool reciprocates in shaper, workpiece reciprocates in planer

A. SHAPER MECHANISM & PARTS — Q26–45

Q26. The main function of the ram in a shaper is to:

A. Hold the workpiece
B. Carry the tool head and reciprocate
C. Rotate the workpiece
D. Support the foundation

Answer: B. Carry the tool head and reciprocate

Explanation: The ram provides the reciprocating motion required for the cutting stroke.

Q27. The tool head of a shaper is mounted on the:

A. Ram
B. Bed
C. Table
D. Base

Answer: A. Ram

Q28. The table of a shaper is mainly used to:

A. Support the workpiece
B. Rotate the tool
C. Drive the ram
D. Hold the motor

Answer: A. Support the workpiece

Q29. The clapper box is designed to:

A. Lift the tool slightly during return stroke
B. Increase cutting force
C. Rotate the workpiece
D. Drive the feed rod

Answer: A. Lift the tool slightly during return stroke

Q30. The clapper box helps prevent:

A. Tool rubbing during return stroke
B. Workpiece rotation
C. Feed movement
D. Cutting during forward stroke

Answer: A. Tool rubbing during return stroke

Q31. The mechanism used to obtain quick return in a mechanical shaper is commonly:

A. Crank and slotted-link mechanism
B. Geneva mechanism only
C. Differential gear only
D. Worm mechanism only

Answer: A. Crank and slotted-link mechanism

Q32. The crank and slotted-link mechanism converts:

A. Rotary motion into reciprocating motion
B. Reciprocating motion into rotary motion only
C. Linear motion into heat
D. Heat into rotary motion

Answer: A. Rotary motion into reciprocating motion

Q33. The quick-return mechanism is useful because:

A. Return stroke is non-cutting
B. Cutting stroke is non-cutting
C. It eliminates all feed
D. It eliminates cutting forces

Answer: A. Return stroke is non-cutting

Q34. In a quick-return shaper, the time of cutting stroke is generally:

A. Greater than return-stroke time
B. Less than return-stroke time
C. Equal to return-stroke time
D. Zero

Answer: A. Greater than return-stroke time

Q35. The quick-return ratio is greater than:

A. 0
B. 1
C. 10
D. 100

Answer: B. 1

Q36. A hydraulic shaper obtains ram motion by:

A. Hydraulic pressure
B. Gear cutting
C. Manual filing
D. Grinding

Answer: A. Hydraulic pressure

Q37. An advantage of hydraulic drive in a shaper is:

A. Smooth control of ram motion
B. No need for a cutting tool
C. Elimination of all friction
D. No requirement for a work table

Answer: A. Smooth control of ram motion

Q38. The base of a shaper provides:

A. Foundation and support
B. Cutting action
C. Workpiece rotation
D. Tool sharpening

Answer: A. Foundation and support

Q39. The column of a shaper mainly supports:

A. Machine mechanisms and ram assembly
B. Cutting fluid only
C. Chuck jaws
D. Lathe spindle

Answer: A. Machine mechanisms and ram assembly

Q40. In a shaper, the workpiece is generally:

A. Stationary during the cutting stroke
B. Continuously rotating
C. Continuously reciprocating
D. Mounted on a spindle

Answer: A. Stationary during the cutting stroke

Q41. Feed in a shaper is usually provided by moving:

A. The work/table relative to the tool
B. The motor
C. The foundation
D. The cutting edge only

Answer: A. The work/table relative to the tool

Q42. The tool head of a shaper may be swivelled to machine:

A. Inclined surfaces
B. Only cylindrical surfaces
C. Only holes
D. Only threads

Answer: A. Inclined surfaces

Q43. A shaper can machine:

A. Flat, angular and grooved surfaces
B. Only circular surfaces
C. Only holes
D. Only gears

Answer: A. Flat, angular and grooved surfaces

Q44. The stroke length of a shaper refers to:

A. Distance travelled by the ram
B. Width of the table
C. Diameter of the workpiece
D. Height of the machine

Answer: A. Distance travelled by the ram

Q45. Shaper stroke length should normally be:

A. Slightly greater than the actual cutting length
B. Always exactly zero
C. Less than the cutting length
D. Equal to machine height

Answer: A. Slightly greater than the actual cutting length

Explanation: Extra travel is required so the tool can enter and leave the workpiece properly.

B. SHAPER SPEED, STROKES & CALCULATIONS — Q46–60

Q46. If a shaper makes 40 double strokes per minute, the number of cutting strokes per minute is:

A. 20
B. 40
C. 80
D. 120

Answer: B. 40

Explanation: One double stroke consists of one cutting stroke and one return stroke.

Q47. If the machine makes 50 double strokes per minute, the number of return strokes per minute is:

A. 25
B. 50
C. 100
D. 150

Answer: B. 50

Q48. If stroke length is 500 mm and the ram makes 40 double strokes per minute, total ram travel per minute is:

A. 10 m
B. 20 m
C. 40 m
D. 80 m

Answer: B. 40 m

Calculation:

Correction: The correct answer is C. 40 m.

Q49. A shaper has a stroke length of 0.6 m and makes 30 double strokes/min. Total travel per minute is:

A. 18 m
B. 24 m
C. 36 m
D. 60 m

Answer: C. 36 m

Q50. If the cutting stroke takes 3 seconds and the return stroke takes 2 seconds, the quick-return ratio is:

A. 0.67
B. 1
C. 1.5
D. 2

Answer: C. 1.5

Q51. A shaper has cutting-stroke time of 4 seconds and return-stroke time of 2 seconds. The quick-return ratio is:

A. 0.5
B. 1
C. 2
D. 4

Answer: C. 2

Q52. If one complete stroke cycle takes 6 seconds, the number of double strokes per minute is:

A. 6
B. 10
C. 12
D. 60

Answer: B. 10

Q53. If a shaper operates at 20 double strokes/min, time for one complete cycle is:

A. 1 sec
B. 2 sec
C. 3 sec
D. 6 sec

Answer: C. 3 sec

Q54. If a shaper makes 30 double strokes/min, the number of cutting strokes per hour is:

A. 900
B. 1800
C. 3600
D. 7200

Answer: C. 1800?

Calculation:

Correct answer: B. 1800

Q55. A shaper makes 25 double strokes/min. Number of cutting strokes in 2 hours is:

A. 1500
B. 3000
C. 5000
D. 6000

Answer: B. 3000

Q56. If stroke length is increased while strokes per minute remain constant, total ram travel per minute:

A. Increases
B. Decreases
C. Remains constant
D. Becomes zero

Answer: A. Increases

Q57. If the number of strokes per minute is doubled while stroke length remains constant, total travel per minute:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q58. The cutting speed in a shaper is associated mainly with:

A. Speed of the ram during cutting stroke
B. Rotation of a spindle
C. Chuck speed
D. Grinding-wheel speed

Answer: A. Speed of the ram during cutting stroke

Q59. In a shaper, feed is generally specified in:

A. mm/stroke
B. rpm
C. m/min only
D. degrees

Answer: A. mm/stroke

Q60. If feed is 0.5 mm per stroke and there are 40 cutting strokes/min, feed rate is:

A. 10 mm/min
B. 20 mm/min
C. 40 mm/min
D. 80 mm/min

Answer: B. 20 mm/min

C. SHAPER OPERATIONS — Q61–70

Q61. A shaper can produce a:

A. Horizontal flat surface
B. Cylindrical surface by continuous rotation
C. Spherical casting only
D. Welded joint

Answer: A. Horizontal flat surface

Q62. A vertical surface on a shaper can be produced by:

A. Proper tool-head setting
B. Increasing coolant only
C. Rotating the workpiece continuously
D. Removing the table

Answer: A. Proper tool-head setting

Q63. A keyway on a suitable workpiece can be produced using:

A. Shaper
B. Only lathe
C. Only furnace
D. Only welding machine

Answer: A. Shaper

Q64. An inclined surface can be machined by:

A. Tilting the tool head appropriately
B. Increasing workpiece temperature
C. Removing the ram
D. Rotating the machine foundation

Answer: A. Tilting the tool head appropriately

Q65. A slot is generally:

A. A narrow recessed opening
B. A cylindrical external surface
C. A casting defect
D. A thread only

Answer: A. A narrow recessed opening

Q66. A groove differs from a flat surface because it is:

A. A recessed feature
B. Always cylindrical
C. Always threaded
D. Always external

Answer: A. A recessed feature

Q67. For machining a vertical surface in a shaper, the tool head is generally adjusted so that:

A. The tool can make the required vertical cut
B. The ram stops permanently
C. The table rotates continuously
D. The workpiece melts

Answer: A. The tool can make the required vertical cut

Q68. The shaper is particularly suitable for:

A. Small and medium-sized flat surfaces
B. Mass production of complex gears only
C. Continuous cylindrical turning
D. Deep hole drilling only

Answer: A. Small and medium-sized flat surfaces

Q69. Compared with a milling machine, a conventional shaper generally uses:

A. Single-point cutting action
B. A multi-tooth milling cutter
C. A grinding wheel
D. A broach only

Answer: A. Single-point cutting action

Q70. One limitation of a shaper is:

A. Interrupted cutting and idle return stroke
B. Inability to machine flat surfaces
C. No cutting tool
D. No feed mechanism

Answer: A. Interrupted cutting and idle return stroke

D. PLANER — Q71–82

Q71. In a planer, the workpiece is mounted on a:

A. Reciprocating table
B. Rotating spindle
C. Chuck
D. Drill head

Answer: A. Reciprocating table

Q72. The main motion in a planer is provided by:

A. Reciprocating table
B. Rotating chuck
C. Rotating drill
D. Grinding wheel

Answer: A. Reciprocating table

Q73. A planer is preferred over a shaper mainly for:

A. Large and heavy work
B. Very small components only
C. Hand tools
D. Small holes

Answer: A. Large and heavy work

Q74. A planer can accommodate:

A. Multiple cutting tools
B. Only one fixed tool in every case
C. No tools
D. Only drills

Answer: A. Multiple cutting tools

Q75. Multiple tool heads on a planer can:

A. Machine several surfaces in one setup
B. Eliminate the workpiece
C. Stop the table
D. Replace the foundation

Answer: A. Machine several surfaces in one setup

Q76. The planer table generally has:

A. T-slots for work holding
B. Only circular holes
C. No work-holding provision
D. Drill flutes

Answer: A. T-slots for work holding

Q77. The cross-rail of a planer is used mainly to:

A. Support tool heads
B. Rotate the workpiece
C. Hold a drill chuck
D. Drive the motor

Answer: A. Support tool heads

Q78. Side tool heads on a planer are useful for machining:

A. Vertical side surfaces
B. Only horizontal surfaces
C. Internal holes only
D. Threads only

Answer: A. Vertical side surfaces

Q79. The bed of a planer must be:

A. Strong and rigid
B. Flexible
C. Very thin
D. Made from rubber

Answer: A. Strong and rigid

Q80. A planer generally has:

A. A long bed and table
B. A very short bed only
C. No table
D. No tool head

Answer: A. A long bed and table

Q81. During the cutting stroke of a planer:

A. The moving workpiece passes the cutting tools
B. The workpiece is stationary
C. The spindle rotates the workpiece
D. The drill rotates

Answer: A. The moving workpiece passes the cutting tools

Q82. The return stroke of a planer is generally:

A. Non-cutting
B. The main cutting stroke
C. A drilling operation
D. A grinding operation

Answer: A. Non-cutting

E. SLOTTER — Q83–90

Q83. A slotter is essentially a:

A. Vertical shaper
B. Horizontal lathe
C. Surface grinder
D. Drilling machine

Answer: A. Vertical shaper

Q84. The ram of a slotter moves:

A. Vertically
B. Horizontally only
C. Circularly
D. Diagonally only

Answer: A. Vertically

Q85. Slotting is particularly useful for machining:

A. Internal keyways
B. Long external shafts only
C. Cylindrical surfaces
D. External turning

Answer: A. Internal keyways

Q86. The cutting tool in a slotter is:

A. Single-point
B. Multi-point drill
C. Grinding wheel
D. Circular saw only

Answer: A. Single-point

Q87. The workpiece in a slotter is mounted on the:

A. Table
B. Ram
C. Tool holder
D. Column only

Answer: A. Table

Q88. Slotters are particularly useful for:

A. Internal profiles
B. Continuous turning
C. External threading only
D. Cylindrical grinding

Answer: A. Internal profiles

Q89. A slotter can be used to machine:

A. Internal slots and grooves
B. Only external cylinders
C. Only flat sheets
D. Only threads

Answer: A. Internal slots and grooves

Q90. Compared with a shaper, the main difference in a slotter is:

A. Vertical reciprocation of the tool
B. Continuous rotation of workpiece
C. Absence of cutting tool
D. Use of a grinding wheel

Answer: A. Vertical reciprocation of the tool

F. COMPARISON & EXAM-ORIENTED QUESTIONS — Q91–100

Q91. Which machine is most appropriate for machining a very large bed plate?

A. Planer
B. Sensitive drill
C. Small shaper
D. Bench grinder

Answer: A. Planer

Q92. Which machine is most appropriate for an internal keyway in a large pulley?

A. Slotter
B. Lathe
C. Surface grinder
D. Drill press

Answer: A. Slotter

Q93. Which machine has the reciprocating cutting tool in a horizontal direction?

A. Shaper
B. Slotter
C. Lathe
D. Drill press

Answer: A. Shaper

Q94. Which machine has a vertically reciprocating cutting tool?

A. Slotter
B. Planer
C. Lathe
D. Horizontal boring machine

Answer: A. Slotter

Q95. Which machine has a reciprocating work table?

A. Planer
B. Shaper
C. Slotter
D. Lathe

Answer: A. Planer

Q96. Which of the following correctly matches the machine and motion?

A. Shaper—reciprocating tool
B. Planer—rotating workpiece
C. Slotter—rotating tool
D. Shaper—rotating workpiece

Answer: A. Shaper—reciprocating tool

Q97. A quick-return mechanism primarily improves:

A. Productivity
B. Workpiece hardness
C. Tool material
D. Machine colour

Answer: A. Productivity

Q98. If cutting stroke takes 6 seconds and return stroke takes 3 seconds, the quick-return ratio is:

A. 0.5
B. 1
C. 2
D. 3

Answer: C. 2

Q99. A shaper makes 30 double strokes/min. If feed is 0.4 mm/stroke, feed rate is:

A. 8 mm/min
B. 12 mm/min
C. 15 mm/min
D. 20 mm/min

Answer: B. 12 mm/min

Q100. Which statement is completely correct?

A. Shaper—reciprocating tool; Planer—reciprocating workpiece; Slotter—vertical reciprocating tool
B. Shaper—rotating workpiece; Planer—rotating tool; Slotter—rotating workpiece
C. Shaper—grinding wheel; Planer—drill; Slotter—lathe tool
D. Shaper—casting; Planer—forging; Slotter—welding

Answer: A. Shaper—reciprocating tool; Planer—reciprocating workpiece; Slotter—vertical reciprocating tool

CHAPTER 19 — FINAL REVISION TABLE

Feature	Shaper	Planer	Slotter
Main reciprocating member	Tool/Ram	Work table	Tool/Ram
Tool movement	Generally horizontal	Tool heads relatively fixed while work moves	Vertical
Workpiece	Generally stationary during cutting	Reciprocates	Generally stationary during cutting
Typical work size	Small/medium	Large/heavy	Small/medium, especially internal work
Cutting tool	Single-point	Single-point	Single-point
Main application	Flat surfaces	Large flat surfaces	Internal slots/keyways
Quick return	Common	Return is non-cutting	Commonly arranged for reciprocation
Feed	Work/table	Tool heads	Work/table
Major feature	Reciprocating ram	Reciprocating table	Vertical ram

CHAPTER 20 — MILLING MACHINE & MILLING OPERATIONS

20.1 DEFINITION OF MILLING

Milling is a machining process in which material is removed from a workpiece by a rotating multi-point cutting tool called a milling cutter.

The cutting action is produced by:

Rotation of the milling cutter

Relative movement between cutter and workpiece

Key point

Milling uses a rotating multi-point cutting tool.

This distinguishes milling from conventional turning and shaping, where single-point tools are commonly used.

20.2 PRINCIPLE OF MILLING

In milling:

Rotating cutter + workpiece feed = material removal

The teeth of the cutter enter and leave the workpiece continuously.

Therefore, milling is generally an:

Interrupted cutting process.

20.3 MAIN FEATURES OF MILLING

Important characteristics include:

Multi-point cutting tool
Rotary cutting motion
Intermittent cutting
High material-removal capability
Ability to produce complex surfaces
Suitable for flat, angular and contoured surfaces

20.4 MILLING CUTTER

A milling cutter contains several cutting teeth.

Each tooth acts approximately like a small cutting tool.

Therefore:

Milling is a multi-point machining process.

20.5 MAIN TYPES OF MILLING MACHINES

Important types include:

Column and knee type milling machine
Horizontal milling machine
Vertical milling machine
Universal milling machine
Bed-type milling machine
Planer-type milling machine
CNC milling machine

20.6 HORIZONTAL MILLING MACHINE

In a horizontal milling machine:

The spindle axis is horizontal.

The cutter is mounted on the spindle, often with an arbor.

Horizontal milling machines are suitable for:

Slab milling

Side milling

Gang milling

Certain gear-cutting operations

20.7 VERTICAL MILLING MACHINE

In a vertical milling machine:

The spindle axis is vertical.

It is commonly used for:

End milling

Face milling

Slot milling

Drilling-related operations in suitable machines

20.8 UNIVERSAL MILLING MACHINE

A universal milling machine is essentially a milling machine in which the table can be swivelled about a horizontal axis, commonly to facilitate:

Helical milling

Angular work

Various indexing operations

The universal milling machine is particularly important for:

Helical milling and gear-related work.

20.9 COLUMN AND KNEE TYPE MILLING MACHINE

Major components include:

Base

Column

Knee

Saddle

Table

Spindle

Arbor/support

Overarm in horizontal machines

20.10 BASE

The base:

Supports the machine

Provides rigidity

May contain coolant arrangements

Transfers machine loads to the foundation

20.11 COLUMN

The column is the main supporting structure.

It houses/supports:

Drive mechanism

Spindle arrangement

Internal gears/mechanisms in many machines

20.12 KNEE

The knee is mounted on the column and supports:

Saddle and table.

It can generally move vertically along the column guideways.

20.13 SADDLE

The saddle is located between:

Knee and table.

It generally provides:

Transverse movement of the table.

20.14 TABLE

The table supports:

The workpiece or work-holding device.

It generally provides longitudinal movement.

T-slots are provided for:

Clamping

Fixtures

Work holding

20.15 SPINDLE

The spindle:

Rotates the milling cutter

Transmits power to the cutter

Determines cutter rotational speed

20.16 ARBOR

An arbor is commonly used in a horizontal milling machine to:

Mount and support milling cutters.

It is supported by the spindle and, depending on design, an arbor support.

20.17 OVERARM

The overarm in a horizontal milling machine provides support for:

The arbor.

This improves rigidity during milling.

20.18 MILLING CUTTERS

Important milling cutters include:

Plain/slab cutter

Face mill

End mill

Side milling cutter

Angle cutter

Form cutter

Slitting saw

T-slot cutter

Dovetail cutter

Gear cutter

Woodruff keyseat cutter

20.19 PLAIN OR SLAB MILLING CUTTER

A plain milling cutter is mainly used for:

Machining large flat surfaces.

It is commonly associated with:

Horizontal milling.

20.20 FACE MILL

A face mill is primarily used to machine:

Flat surfaces.

The cutting edges are located on the face and often the periphery, depending on cutter design.

20.21 END MILL

An end mill can machine:

Slots

Pockets

Keyways

Contours

Vertical and horizontal features

20.22 SIDE MILLING CUTTER

A side milling cutter is mainly used for:

Slots

Grooves

Side surfaces

20.23 SLITTING SAW

A slitting saw is a thin circular milling cutter used for:

Narrow slots

Slitting

Cutting-off applications

20.24 T-SLOT CUTTER

A T-slot cutter is used to produce:

T-shaped slots.

T-slots are commonly required on machine-tool tables for work holding.

20.25 DOVETAIL CUTTER

A dovetail cutter is used to produce:

Dovetail grooves.

20.26 ANGLE CUTTER

An angle milling cutter is used for:

Angular surfaces and grooves.

20.27 GEAR CUTTER

A form gear cutter is used for:

Machining gear teeth in conventional milling operations.

20.28 UP MILLING

Up milling is also called:

Conventional milling.

In up milling:

The cutter rotation at the point of contact is generally opposite to the direction of workpiece feed.

The chip thickness generally:

Starts from zero and increases to maximum.

20.29 DOWN MILLING

Down milling is also called:

Climb milling.

In down milling:

The cutter rotation at the point of contact is generally in the same direction as the workpiece feed.

Chip thickness generally:

Starts at maximum and decreases toward zero.

20.30 UP MILLING — KEY FEATURES

Advantages may include:

Lower tendency for cutter to pull the work under suitable conditions

Commonly used on conventional machines

Cutting action begins with very small chip thickness

Disadvantage:

More rubbing may occur at the beginning of the cut.

20.31 DOWN MILLING — KEY FEATURES

Advantages may include:

Improved surface finish under suitable conditions

Reduced rubbing

Lower tendency for work hardening in some applications

Important limitation:

It can produce a tendency for the cutter to pull the workpiece into the cutter if backlash is present.

Therefore, machine rigidity and backlash control are important.

20.32 COMPARISON: UP VS DOWN MILLING

Feature	Up Milling	Down Milling
Other name	Conventional	Climb
Feed vs cutter motion	Opposite	Same
Chip thickness	Zero → maximum	Maximum → zero
Cutter tendency	Less tendency to pull work	Greater tendency to pull work
Backlash sensitivity	Lower	Higher
Surface finish	Generally lower	Generally better under suitable conditions

20.33 MILLING FEED

Feed can be expressed as:

mm/min

mm/tooth

mm/rev

For milling, feed per tooth is especially important.

20.34 FEED RATE

If:

= feed per tooth

= number of teeth

= cutter rpm

Then:

where is feed rate in mm/min.

20.35 CUTTING SPEED

For a milling cutter of diameter rotating at rpm:

where:

= cutting speed in m/min

= cutter diameter in mm

= rpm

20.36 EXAMPLE — CUTTING SPEED

A 100 mm diameter cutter rotates at 300 rpm.

20.37 EXAMPLE — FEED RATE

A cutter has 10 teeth, feed per tooth is 0.1 mm and speed is 500 rpm.

20.38 MILLING OPERATIONS

Important milling operations include:

Plain milling
Face milling
End milling
Side milling
Slot milling
Angular milling
Form milling
Gang milling
Straddle milling
Gear milling
Helical milling
Keyway milling
Thread milling

20.39 PLAIN MILLING

Plain milling produces:

A flat horizontal surface.

The cutter is generally mounted on a horizontal spindle.

20.40 FACE MILLING

Face milling is used primarily to produce:

Flat surfaces perpendicular to the cutter axis.

20.41 END MILLING

End milling uses an end mill to produce:

Slots

Pockets

Keyways

Contours

20.42 STRADDLE MILLING

In straddle milling:

Two side milling cutters are mounted on the same arbor.

They machine:

Two parallel vertical surfaces simultaneously.

20.43 GANG MILLING

In gang milling:

Two or more cutters are mounted on the same arbor.

Different surfaces can be machined:

In a single pass.

20.44 FORM MILLING

Form milling uses a:

Form cutter

to produce a specially shaped surface.

20.45 HELICAL MILLING

Helical milling is used to produce:

Helical grooves or surfaces.

A universal milling machine and suitable indexing arrangement are commonly used.

20.46 INDEXING

Indexing is the process of:

Rotating the workpiece through a predetermined angle between successive machining operations.

It is particularly important in:

Gear cutting

Splines

Polygonal work

Fluting

20.47 DIVIDING HEAD

A dividing head is used to:

Hold the workpiece

Rotate it accurately

Perform indexing

It is widely used in:

Gear cutting and other equally spaced operations.

20.48 COMMON DIVIDING-HEAD RATIO

A standard dividing head commonly has a worm-and-wheel ratio of:

This means:

40 turns of the crank produce one complete revolution of the work spindle.

20.49 SIMPLE INDEXING

For a 40:1 dividing head:

where is the required number of equal divisions.

Example

For 20 divisions:

Therefore:

2 crank turns per division.

20.50 GEAR CUTTING

Conventional gear cutting can be performed by:

Form milling using a suitable gear cutter.

The dividing head is used to rotate the blank accurately between teeth.

Q1. Milling is a:

A. Single-point machining process
B. Multi-point machining process
C. Casting process
D. Welding process

Answer: B. Multi-point machining process

Explanation: A milling cutter has multiple cutting teeth.

Q2. In milling, the cutting tool:

A. Rotates
B. Always remains stationary
C. Only reciprocates
D. Melts

Answer: A. Rotates

Q3. The cutting tool used in milling is called a:

A. Milling cutter
B. Lathe tool
C. Broach only
D. Drill rod

Answer: A. Milling cutter

Q4. Milling is generally an:

A. Interrupted cutting process
B. Continuous casting process
C. Welding process
D. Forging process

Answer: A. Interrupted cutting process

Q5. In a horizontal milling machine, the spindle axis is:

A. Horizontal
B. Vertical
C. Inclined at 45° always
D. Circular

Answer: A. Horizontal

Q6. In a vertical milling machine, the spindle axis is:

A. Vertical
B. Horizontal
C. Random
D. Parallel to the floor only

Answer: A. Vertical

Q7. A universal milling machine is particularly useful for:

A. Helical milling
B. Welding
C. Casting
D. Forging

Answer: A. Helical milling

Q8. The knee of a column-and-knee milling machine supports the:

A. Saddle and table
B. Motor only
C. Cutter teeth only
D. Foundation only

Answer: A. Saddle and table

Q9. The saddle provides mainly:

A. Transverse movement of the table
B. Rotation of the cutter
C. Workpiece melting
D. Gear tooth cutting directly

Answer: A. Transverse movement of the table

Q10. The table of a milling machine is used to:

A. Support the workpiece
B. Rotate the cutter
C. Drive the motor
D. Support the foundation

Answer: A. Support the workpiece

Q11. The spindle of a milling machine:

A. Rotates the cutter
B. Holds the workpiece only
C. Moves the foundation
D. Produces coolant

Answer: A. Rotates the cutter

Q12. An arbor is mainly used to:

A. Mount milling cutters
B. Hold coolant
C. Measure workpiece temperature
D. Support the foundation

Answer: A. Mount milling cutters

Q13. The overarm in a horizontal milling machine supports the:

A. Arbor
B. Table
C. Workpiece
D. Knee

Answer: A. Arbor

Q14. A plain milling cutter is mainly used for:

A. Flat surface machining
B. Drilling
C. Thread tapping only
D. Grinding

Answer: A. Flat surface machining

Q15. An end mill can be used for:

A. Slots and pockets
B. Only casting
C. Only welding
D. Only forging

Answer: A. Slots and pockets

Q16. A slitting saw is used mainly for:

A. Narrow slots and cutting-off
B. Large cylindrical turning
C. Drilling deep holes
D. Thread tapping only

Answer: A. Narrow slots and cutting-off

Q17. A T-slot cutter is used to produce:

A. T-slots
B. V-belts
C. Circular holes only
D. Threads only

Answer: A. T-slots

Q18. A dovetail cutter is used to produce:

A. Dovetail grooves
B. Cylindrical holes
C. External threads
D. Flat sheets

Answer: A. Dovetail grooves

Q19. Up milling is also known as:

A. Conventional milling
B. Climb milling
C. Down milling
D. Vertical milling

Answer: A. Conventional milling

Q20. Down milling is also known as:

A. Climb milling
B. Conventional milling
C. Slab milling
D. Form milling

Answer: A. Climb milling

Q21. In up milling, chip thickness generally:

A. Starts at zero and increases
B. Starts at maximum and decreases
C. Remains exactly constant
D. Is always zero

Answer: A. Starts at zero and increases

Q22. In down milling, chip thickness generally:

A. Starts at maximum and decreases
B. Starts at zero and increases
C. Remains zero
D. Is independent of feed

Answer: A. Starts at maximum and decreases

Q23. Down milling can be problematic on machines with:

A. Backlash
B. Coolant
C. T-slots
D. Rigid tables

Answer: A. Backlash

Q24. The feed-rate equation for milling is:

A.
B.
C.
D.

Answer: A.

Q25. The standard dividing-head ratio commonly used is:

A. 10:1
B. 20:1
C. 40:1
D. 100:1

Answer: C. 40:1

A. MILLING CUTTERS & OPERATIONS — Q26–45

Q26. Which cutter is most suitable for producing a large flat surface on a horizontal milling machine?

A. Plain milling cutter
B. Slitting saw
C. Dovetail cutter
D. T-slot cutter

Answer: A. Plain milling cutter

Explanation: A plain or slab milling cutter is primarily used for machining broad flat surfaces.

Q27. Face milling is primarily used to produce:

A. Flat surfaces
B. Internal threads
C. Deep holes
D. Cylindrical shafts only

Answer: A. Flat surfaces

Q28. In face milling, the machined surface is generally:

A. Perpendicular to the cutter axis
B. Parallel to the cutter axis only
C. Circular
D. Helical

Answer: A. Perpendicular to the cutter axis

Q29. Which milling operation uses two side milling cutters simultaneously?

A. Straddle milling
B. Face milling
C. Form milling
D. End milling

Answer: A. Straddle milling

Q30. Straddle milling is used to machine:

A. Two parallel vertical surfaces
B. One circular hole
C. One internal thread
D. A spherical surface only

Answer: A. Two parallel vertical surfaces

Q31. Gang milling involves:

A. Several cutters mounted on the same arbor
B. One cutter used repeatedly
C. A drill and reamer
D. A grinding wheel

Answer: A. Several cutters mounted on the same arbor

Q32. The main advantage of gang milling is:

A. Several surfaces can be machined in one pass
B. No cutting tool is required
C. It eliminates feed
D. It eliminates spindle rotation

Answer: A. Several surfaces can be machined in one pass

Q33. Form milling is used to produce:

A. Irregular or specially shaped surfaces
B. Only flat surfaces
C. Only holes
D. Only external threads

Answer: A. Irregular or specially shaped surfaces

Q34. Which cutter is normally used for machining a keyway?

A. End mill or suitable keyway cutter
B. Faceplate
C. Lathe centre
D. Drill chuck only

Answer: A. End mill or suitable keyway cutter

Q35. A Woodruff keyseat cutter is used for:

A. Producing a Woodruff keyseat
B. Cutting external threads
C. Drilling holes
D. Facing shafts

Answer: A. Producing a Woodruff keyseat

Q36. A side milling cutter is mainly used for:

A. Slots and grooves
B. Deep cylindrical holes
C. Welding
D. Casting

Answer: A. Slots and grooves

Q37. A form cutter has:

A. A cutting profile corresponding to the required shape
B. No cutting edges
C. Only one straight cutting edge
D. A grinding surface only

Answer: A. A cutting profile corresponding to the required shape

Q38. A gear milling cutter is used to:

A. Cut gear teeth
B. Drill shafts
C. Grind gears only
D. Produce castings

Answer: A. Cut gear teeth

Q39. Thread milling is used to produce:

A. Threads using a milling cutter
B. Flat surfaces only
C. Holes only
D. Keyways only

Answer: A. Threads using a milling cutter

Q40. Helical milling is used to produce:

A. Helical grooves or surfaces
B. Only flat surfaces
C. Circular holes only
D. T-slots only

Answer: A. Helical grooves or surfaces

Q41. Which operation is most appropriate for producing a T-slot?

A. T-slot milling
B. Face milling only
C. Plain turning
D. Boring

Answer: A. T-slot milling

Q42. Which operation is used to produce a dovetail groove?

A. Dovetail milling
B. Slab milling
C. Face turning
D. Drilling

Answer: A. Dovetail milling

Q43. Milling is especially advantageous for producing:

A. Complex profiles
B. Only simple cylindrical shafts
C. Only holes
D. Only welded joints

Answer: A. Complex profiles

Q44. A milling cutter with teeth on its circumference and sides is generally called a:

A. Side milling cutter
B. Drill
C. Reamer
D. Tap

Answer: A. Side milling cutter

Q45. Which operation is best for machining several different surfaces in one setup?

A. Gang milling
B. Facing
C. Turning
D. Boring

Answer: A. Gang milling

B. CUTTING SPEED & FEED CALCULATIONS — Q46–60

Q46. The cutting-speed formula for milling is:

A.
B.
C.
D.

Answer: A.

Q47. A milling cutter of diameter 100 mm rotates at 300 rpm. Cutting speed is approximately:

A. 47.1 m/min
B. 94.2 m/min
C. 150 m/min
D. 300 m/min

Answer: B. 94.2 m/min

Q48. A 50 mm cutter rotates at 600 rpm. Cutting speed is:

A. 47.1 m/min
B. 94.2 m/min
C. 120 m/min
D. 188.4 m/min

Answer: B. 94.2 m/min

Q49. If cutter diameter remains constant and rpm is doubled, cutting speed:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes one-fourth

Answer: A. Doubles

Q50. If cutting speed is fixed and cutter diameter is increased, spindle speed should:

A. Decrease
B. Increase
C. Remain constant
D. Become zero

Answer: A. Decrease

Q51. The milling feed-rate formula is:

A.
B.
C.
D.

Answer: A.

Q52. A cutter has 8 teeth, feed per tooth is 0.1 mm and speed is 500 rpm. Feed rate is:

A. 200 mm/min
B. 300 mm/min
C. 400 mm/min
D. 500 mm/min

Answer: C. 400 mm/min

Q53. A 10-tooth cutter has feed per tooth of 0.15 mm and rotates at 400 rpm. Feed rate is:

A. 400 mm/min
B. 500 mm/min
C. 600 mm/min
D. 750 mm/min

Answer: C. 600 mm/min

Q54. If feed per tooth is doubled while other parameters remain constant, feed rate:

A. Doubles
B. Halves
C. Remains unchanged
D. Becomes zero

Answer: A. Doubles

Q55. A cutter has 12 teeth and feed rate is 720 mm/min at 600 rpm. Feed per tooth is:

A. 0.05 mm
B. 0.10 mm
C. 0.15 mm
D. 0.20 mm

Answer: B. 0.10 mm

Q56. A milling cutter rotates at 400 rpm and has 10 teeth. If feed per tooth is 0.2 mm, feed rate is:

A. 400 mm/min
B. 600 mm/min
C. 800 mm/min
D. 1000 mm/min

Answer: C. 800 mm/min

Q57. If a 200 mm long surface is machined at a feed rate of 100 mm/min, theoretical machining time is:

A. 1 min
B. 2 min
C. 3 min
D. 4 min

Answer: B. 2 min

Q58. If milling length is 300 mm and feed rate is 150 mm/min, machining time is:

A. 1 min
B. 2 min
C. 3 min
D. 4 min

Answer: B. 2 min

Q59. Actual machining time may be greater than the simple value because of:

A. Approach and over-travel
B. Absence of cutting
C. Zero feed
D. Zero cutter rotation

Answer: A. Approach and over-travel

Q60. Increasing feed rate generally increases:

A. Material removal rate
B. Cutter diameter
C. Workpiece hardness
D. Spindle diameter

Answer: A. Material removal rate

C. UP MILLING & DOWN MILLING — Q61–70

Q61. In up milling, the cutter rotates:

A. Opposite to work feed at the cutting point
B. In the same direction as feed
C. Without rotation
D. Vertically only

Answer: A. Opposite to work feed at the cutting point

Q62. In down milling, cutter rotation at the cutting point is:

A. In the same direction as feed
B. Opposite to feed
C. Perpendicular to feed always
D. Zero

Answer: A. In the same direction as feed

Q63. In up milling, chip thickness:

A. Increases from zero to maximum
B. Decreases from maximum to zero
C. Remains constant
D. Is always zero

Answer: A. Increases from zero to maximum

Q64. In down milling, chip thickness:

A. Starts maximum and decreases to zero
B. Starts zero and increases
C. Remains constant
D. Is always zero

Answer: A. Starts maximum and decreases to zero

Q65. Down milling is also called:

A. Climb milling
B. Conventional milling
C. Slab milling
D. Form milling

Answer: A. Climb milling

Q66. Up milling is also called:

A. Conventional milling
B. Climb milling
C. Face milling
D. Gang milling

Answer: A. Conventional milling

Q67. Which operation is more sensitive to backlash?

A. Down milling
B. Up milling
C. Both are always identical
D. Neither

Answer: A. Down milling

Q68. A major advantage of down milling under suitable machine conditions is:

A. Better surface finish
B. Zero cutting force
C. No cutter rotation
D. No work holding

Answer: A. Better surface finish

Q69. In up milling, tooth thickness at the start of cutting is:

A. Very small/approximately zero
B. Maximum
C. Infinite
D. Constant

Answer: A. Very small/approximately zero

Q70. In down milling, the cutter tends to:

A. Pull the workpiece in the feed direction
B. Push the workpiece completely backward
C. Stop rotating
D. Eliminate all cutting forces

Answer: A. Pull the workpiece in the feed direction

D. INDEXING & DIVIDING HEAD — Q71–85

Q71. Indexing is used to:

A. Rotate the workpiece through predetermined angles
B. Increase workpiece hardness
C. Sharpen the cutter automatically
D. Reduce cutter diameter

Answer: A. Rotate the workpiece through predetermined angles

Q72. A dividing head is primarily used for:

A. Accurate angular positioning of work
B. Grinding only
C. Welding
D. Casting

Answer: A. Accurate angular positioning of work

Q73. A standard dividing head commonly has a ratio of:

A. 10:1
B. 20:1
C. 40:1
D. 100:1

Answer: C. 40:1

Q74. For a 40:1 dividing head, one complete revolution of the work spindle requires:

A. 10 crank turns
B. 20 crank turns
C. 40 crank turns
D. 80 crank turns

Answer: C. 40 crank turns

Q75. For a 40:1 dividing head, crank movement for 10 divisions is:

A. 2 turns
B. 4 turns
C. 6 turns
D. 10 turns

Answer: B. 4 turns

Q76. For 20 equal divisions, crank movement is:

A. 1 turn
B. 2 turns
C. 4 turns
D. 20 turns

Answer: B. 2 turns

Q77. For 40 equal divisions, crank movement per division is:

A. 0.5 turn
B. 1 turn
C. 2 turns
D. 4 turns

Answer: B. 1 turn

Q78. For 8 equal divisions, crank movement is:

A. 2 turns
B. 4 turns
C. 5 turns
D. 8 turns

Answer: C. 5 turns

Q79. For 16 divisions, crank movement is:

A. 1 turn
B. 2 turns
C. 2.5 turns
D. 4 turns

Answer: C. 2.5 turns

Q80. If 5 crank turns rotate the workpiece through one-eighth revolution, the dividing-head ratio is:

A. 20:1
B. 30:1
C. 40:1
D. 50:1

Answer: C. 40:1

Q81. The dividing head is particularly important in:

A. Gear cutting
B. Welding
C. Forging
D. Casting

Answer: A. Gear cutting

Q82. Indexing is required when machining:

A. Equally spaced teeth
B. A single flat surface only
C. A simple hole only
D. A random surface

Answer: A. Equally spaced teeth

Q83. A dividing head can be used to produce:

A. Polygonal shapes
B. Only circular holes
C. Only flat surfaces
D. Only threads

Answer: A. Polygonal shapes

Q84. The worm and worm wheel in a dividing head provide:

A. Large reduction and accurate rotation
B. High-speed direct rotation only
C. Grinding action
D. Welding pressure

Answer: A. Large reduction and accurate rotation

Q85. Simple indexing formula for a 40:1 dividing head is:

A.
B.
C.
D.

Answer: A.

E. GEAR CUTTING & HELICAL MILLING — Q86–94

Q86. Conventional gear milling requires:

A. Gear cutter and indexing arrangement
B. Grinding wheel only
C. Drill only
D. Lathe centre only

Answer: A. Gear cutter and indexing arrangement

Q87. The dividing head is used during gear cutting to:

A. Index the gear blank
B. Rotate the cutter only
C. Sharpen the cutter
D. Increase cutting speed

Answer: A. Index the gear blank

Q88. The number of spaces between successive gear teeth is controlled by:

A. Indexing
B. Coolant
C. Cutting fluid pressure
D. Machine foundation

Answer: A. Indexing

Q89. Helical milling is used to produce:

A. Helical grooves
B. Only flat surfaces
C. Only circular holes
D. Only T-slots

Answer: A. Helical grooves

Q90. A universal milling machine is particularly suitable for:

A. Helical milling
B. Welding
C. Forging
D. Casting

Answer: A. Helical milling

Q91. A helix is a curve generated by:

A. Combined rotational and axial movement
B. Only vertical movement
C. Only horizontal movement
D. Only random movement

Answer: A. Combined rotational and axial movement

Q92. A helical gear tooth is:

A. Inclined relative to the gear axis
B. Always exactly parallel to the axis
C. Always perpendicular to the axis
D. Circular only

Answer: A. Inclined relative to the gear axis

Q93. In gear milling, a suitable cutter is selected according to:

A. Gear tooth form and module/DP system
B. Workpiece colour
C. Machine paint
D. Coolant colour

Answer: A. Gear tooth form and module/DP system

Q94. Indexing accuracy is important in gear cutting because:

A. Teeth must be equally spaced
B. Gear must be melted
C. Cutter must remain stationary
D. No rotation is required

Answer: A. Teeth must be equally spaced

F. ADVANCED EXAM-ORIENTED QUESTIONS — Q95–100

Q95. A 120 mm diameter cutter rotates at 250 rpm. Cutting speed is approximately:

A. 47.1 m/min
B. 78.5 m/min
C. 94.2 m/min
D. 120 m/min

Answer: B. 94.2 m/min

Calculation:

Correction: Since , therefore:

So the correct answer is C. 94.2 m/min.

Q96. A milling cutter has 12 teeth and rotates at 500 rpm. If feed per tooth is 0.08 mm, feed rate is:

A. 240 mm/min
B. 400 mm/min
C. 480 mm/min
D. 600 mm/min

Answer: C. 480 mm/min

Q97. A 40:1 dividing head is required to make 25 equal divisions. Crank movement per division is:

A. 1.2 turns
B. 1.6 turns
C. 2 turns
D. 2.5 turns

Answer: B. 1.6 turns

Q98. Which combination is correct?

A. Plain milling—flat surface; Straddle milling—two parallel surfaces; Gang milling—multiple cutters
B. Plain milling—threading; Straddle milling—drilling; Gang milling—turning
C. Plain milling—welding; Straddle milling—casting; Gang milling—forging
D. Plain milling—grinding; Straddle milling—broaching; Gang milling—drilling

Answer: A.

Q99. A milling cutter has 10 teeth, rotates at 600 rpm and feed per tooth is 0.2 mm. The feed rate is:

A. 600 mm/min
B. 800 mm/min
C. 1000 mm/min
D. 1200 mm/min

Answer: D. 1200 mm/min

Q100. Which statement is correct?

A. Milling uses a rotating multi-point cutter
B. Milling always uses a single-point stationary tool
C. Milling cannot produce slots
D. Milling cannot produce flat surfaces

Answer: A. Milling uses a rotating multi-point cutter

CHAPTER 20 — QUICK REVISION TABLE

Topic	Key Point
Milling	Multi-point machining process
Cutter	Rotating multi-tooth tool
Horizontal milling	Horizontal spindle
Vertical milling	Vertical spindle
Universal milling	Suitable for helical work
Plain milling	Flat surfaces
Face milling	Flat faces
End milling	Slots, pockets, keyways
Side milling	Slots and grooves
Straddle milling	Two parallel surfaces
Gang milling	Several cutters
Form milling	Irregular profiles
Slitting saw	Narrow slots/cutting-off
T-slot cutter	T-slots
Dovetail cutter	Dovetail grooves
Up milling	Conventional milling
Down milling	Climb milling
Up milling chip	Zero → maximum
Down milling chip	Maximum → zero
Feed rate
Cutting speed
Indexing	Angular positioning
Dividing head	Accurate work rotation
Standard ratio	40:1
Simple indexing
Gear milling	Gear cutter + indexing
Helical milling	Helical grooves/surfaces

CHAPTER 21 — FULL-LENGTH MOCK TESTS

MOCK TEST 1 — QUESTIONS 1–100

Mechanical & Manufacturing Engineering — Complete Exam Practice

Instructions: Each question has four options. Select the most appropriate answer. The correct answer and a concise explanation are provided after each question.

SECTION A — ENGINEERING MATERIALS & MECHANICAL PROPERTIES

Q1. Which of the following is a mechanical property of a material?

A. Thermal conductivity
B. Hardness
C. Electrical resistivity
D. Density

Answer: B. Hardness

Explanation: Hardness is the resistance of a material to indentation, scratching, penetration, or wear.

Q2. Which test is commonly used to determine the hardness of a material using a spherical indenter?

A. Brinell test
B. Charpy test
C. Izod test
D. Fatigue test

Answer: A. Brinell test

Explanation: The Brinell hardness test uses a hardened steel or tungsten-carbide ball as the indenter.

Q3. According to Hooke’s law, within the elastic limit:

A. Stress is proportional to strain
B. Stress is inversely proportional to strain
C. Stress is proportional to the square of strain
D. Stress is independent of strain

Answer: A. Stress is proportional to strain

Explanation: Within the elastic limit, stress is directly proportional to strain:

where is Young’s modulus.

Q4. What is the SI unit of Young’s modulus?

A. N
B. N/m
C. Pa
D. m/N

Answer: C. Pa

Explanation: Young’s modulus is stress divided by strain. Since strain is dimensionless, its unit is Pascal (Pa).

Q5. A bar has an original length of 2 m and elongates by 1 mm. What is the strain?

A. 0.0005
B. 0.005
C. 0.05
D. 0.5

Answer: A. 0.0005

Explanation:

Q6. Cast iron is generally classified as:

A. Highly ductile
B. Brittle
C. Elastomeric
D. Fibrous

Answer: B. Brittle

Explanation: Cast iron generally has high compressive strength but relatively low tensile ductility, making it a brittle material.

Q7. Mild steel is generally characterized by:

A. Low carbon content
B. Extremely high carbon content
C. Zero carbon content
D. More than 5% carbon content

Answer: A. Low carbon content

Explanation: Mild steel is a low-carbon steel known for good ductility, machinability, and weldability.

Q8. The corrosion resistance of stainless steel is mainly due to the presence of:

A. Chromium
B. Lead
C. Sulphur
D. Phosphorus

Answer: A. Chromium

Explanation: Chromium forms a thin, protective passive oxide layer on the surface of stainless steel.

Q9. Brass is primarily an alloy of:

A. Copper and zinc
B. Copper and tin
C. Iron and carbon
D. Aluminium and silicon

Answer: A. Copper and zinc

Explanation: Brass is mainly composed of copper and zinc.

Q10. Bronze is traditionally an alloy of:

A. Copper and tin
B. Copper and zinc
C. Iron and nickel
D. Aluminium and zinc

Answer: A. Copper and tin

Explanation: Traditional bronze consists primarily of copper and tin.

SECTION B — MACHINE TOOLS & MACHINING

Q11. What is the principal function of a lathe?

A. Machining a rotating workpiece
B. Performing only drilling operations
C. Performing only grinding operations
D. Performing only welding operations

Answer: A. Machining a rotating workpiece

Explanation: In a conventional lathe, the workpiece rotates while the cutting tool performs the required machining operation.

Q12. The primary purpose of a facing operation on a lathe is to produce:

A. A flat end surface
B. An internal thread
C. A gear tooth
D. A tapered hole only

Answer: A. A flat end surface

Explanation: Facing removes material from the end of a workpiece to produce a flat surface perpendicular to its axis.

Q13. During conventional turning on a lathe, the main cutting motion is provided by:

A. The workpiece
B. The tool post
C. The tailstock
D. The coolant system

Answer: A. The workpiece

Explanation: The workpiece rotates with the spindle, providing the primary cutting motion.

Q14. Taper turning on a lathe produces:

A. A conical surface
B. A completely flat surface
C. A gear profile
D. A spherical cavity

Answer: A. A conical surface

Explanation: Taper turning produces a surface whose diameter changes progressively along the length.

Q15. In milling, the cutting tool:

A. Rotates
B. Remains permanently stationary
C. Only moves vertically
D. Only moves manually

Answer: A. Rotates

Explanation: Milling uses a rotating multi-point cutting tool to remove material from the workpiece.

Q16. The primary purpose of drilling is to:

A. Produce a hole
B. Produce a flat surface
C. Produce an external thread
D. Harden the surface

Answer: A. Produce a hole

Explanation: A drill is a rotary cutting tool primarily used to produce cylindrical holes.

Q17. Reaming is primarily used to:

A. Accurately finish an existing hole
B. Produce a casting
C. Join two components
D. Forge a component

Answer: A. Accurately finish an existing hole

Explanation: Reaming improves the dimensional accuracy and surface finish of a previously drilled or bored hole.

Q18. Tapping is used to produce:

A. Internal threads
B. External threads
C. Flat surfaces
D. Keyways only

Answer: A. Internal threads

Explanation: A tap is a cutting tool used to produce internal screw threads.

Q19. A broach generally consists of:

A. Multiple cutting teeth arranged progressively
B. A single blunt cutting edge
C. Only abrasive grains
D. A smooth cylindrical surface without teeth

Answer: A. Multiple cutting teeth arranged progressively

Explanation: A broach contains a series of cutting teeth that progressively remove material as the tool moves through the workpiece.

Q20. The cutting action in grinding is mainly performed by:

A. Abrasive grains
B. Rubber particles
C. Wooden teeth
D. Plastic inserts

Answer: A. Abrasive grains

Explanation: Grinding wheels contain abrasive grains that act as numerous small cutting edges.

SECTION C — CASTING & FOUNDRY

Q21. In casting, molten metal is:

A. Poured into a mould cavity
B. Rolled between rollers
C. Forced through a cutting tool
D. Welded to another component

Answer: A. Poured into a mould cavity

Explanation: The molten metal fills the mould cavity and solidifies to form the required casting.

Q22. The main purpose of a pattern in casting is to:

A. Produce the mould cavity
B. Melt the metal
C. Supply welding current
D. Grind the casting

Answer: A. Produce the mould cavity

Explanation: A pattern represents the desired shape of the casting and is used to create the mould cavity.

Q23. In sand casting, the mould is primarily made from:

A. Sand
B. Pure steel
C. Rubber
D. Glass

Answer: A. Sand

Explanation: Sand moulding is one of the most widely used casting processes because of its versatility and relatively low cost.

Q24. The primary function of a riser is to:

A. Compensate for solidification shrinkage
B. Guide a cutting tool
C. Supply welding current
D. Remove machining chips

Answer: A. Compensate for solidification shrinkage

Explanation: A riser acts as a reservoir of molten metal that feeds the casting as it contracts during solidification.

Q25. The main function of a sprue is to:

A. Carry molten metal into the gating system
B. Harden the casting
C. Grind the casting surface
D. Hold the pattern permanently

Answer: A. Carry molten metal into the gating system

Explanation: The sprue is a vertical passage through which molten metal flows from the pouring basin into the runners and gates.

Q26. A core is primarily used in casting to:

A. Produce internal cavities
B. Improve external surface colour
C. Cut the casting
D. Increase cutting speed

Answer: A. Produce internal cavities

Explanation: Cores are placed inside moulds to create holes, passages, and other internal cavities.

Q27. Blowholes in castings are primarily associated with:

A. Gas-related defects
B. Excessive tool wear
C. Incorrect thread geometry
D. Grinding wheel imbalance

Answer: A. Gas-related defects

Explanation: Blowholes can occur when gases become trapped within the molten metal during solidification.

Q28. Casting porosity refers to:

A. Voids or cavities within the casting
B. Excessive hardness
C. Perfect surface finish
D. Increased dimensional accuracy

Answer: A. Voids or cavities within the casting

Explanation: Porosity consists of unwanted voids that may arise from gas entrapment or solidification-related effects.

SECTION D — WELDING & JOINING

Q29. In arc welding, the primary source of heat is:

A. An electric arc
B. A water jet
C. Compressed air only
D. Mechanical friction only

Answer: A. An electric arc

Explanation: The electric arc produces intense heat sufficient to melt the base metal and, where applicable, the filler metal.

Q30. The primary purpose of welding is to:

A. Permanently join components
B. Measure dimensions
C. Polish surfaces
D. Produce holes

Answer: A. Permanently join components

Explanation: Welding produces a permanent joint by fusion or another welding mechanism.

Q31. Which fuel gas is commonly used in oxy-fuel welding?

A. Acetylene
B. Nitrogen
C. Carbon dioxide
D. Helium

Answer: A. Acetylene

Explanation: Oxy-acetylene welding uses oxygen and acetylene to produce a high-temperature flame.

Q32. A consumable welding electrode can:

A. Carry current and provide filler metal
B. Only measure temperature
C. Only cool the workpiece
D. Only support the welding machine

Answer: A. Carry current and provide filler metal

Explanation: In consumable electrode processes, the electrode conducts current and melts to contribute filler metal to the weld.

Q33. Weld porosity is primarily caused by:

A. Gas entrapment
B. Excessive dimensional accuracy
C. Incorrect gear ratio
D. Low spindle speed

Answer: A. Gas entrapment

Explanation: Gas trapped in the molten weld pool can produce pores after solidification.

Q34. Excessive heat input during welding can cause:

A. Distortion
B. Zero thermal expansion
C. Perfect dimensional accuracy
D. Elimination of residual stress

Answer: A. Distortion

Explanation: Uneven heating and cooling can create thermal stresses and distortion in welded components.

Q35. PPE in welding stands for:

A. Personal Protective Equipment
B. Production Process Engineering
C. Power Protection Element
D. Primary Processing Equipment

Answer: A. Personal Protective Equipment

Explanation: Welding PPE includes suitable helmets, gloves, protective clothing, safety footwear, and other protective equipment.

SECTION E — METAL FORMING

Q36. Forging primarily shapes metal using:

A. Compressive forces
B. Tensile forces only
C. Chemical dissolution
D. Electrical discharge

Answer: A. Compressive forces

Explanation: Forging plastically deforms metal under compressive forces.

Q37. In rolling, the workpiece passes:

A. Between rotating rolls
B. Through a welding electrode
C. Through a grinding wheel only
D. Through a casting core

Answer: A. Between rotating rolls

Explanation: Rolling reduces thickness or changes the cross-section by passing material between rotating rolls.

Q38. In extrusion, material is:

A. Forced through a die opening
B. Melted without a die
C. Welded to another component
D. Removed using abrasive grains only

Answer: A. Forced through a die opening

Explanation: Extrusion forces a billet through a die to produce a continuous product with the desired cross-section.

Q39. In blanking, the punched-out portion is generally:

A. The required blank or product
B. Always waste material
C. The punch
D. The die

Answer: A. The required blank or product

Explanation: In blanking, the cut-out portion is the desired product, while the remaining sheet is scrap.

Q40. The primary purpose of bending a sheet-metal component is to:

A. Change its shape
B. Change only its colour
C. Increase its melting point
D. Convert it into a casting

Answer: A. Change its shape

Explanation: Bending produces a permanent angular or curved shape without intentionally removing material.

SECTION F — HEAT TREATMENT

Q41. A common purpose of annealing is to:

A. Soften the material and improve ductility
B. Always maximize hardness
C. Melt the material
D. Increase porosity

Answer: A. Soften the material and improve ductility

Explanation: Annealing can reduce hardness, relieve internal stresses, and improve machinability and ductility.

Q42. Quenching involves:

A. Rapid cooling of heated material
B. Very slow cooling in a furnace only
C. Melting the material
D. Cold working only

Answer: A. Rapid cooling of heated material

Explanation: Quenching rapidly cools a suitably heated material to obtain desired microstructural and mechanical changes.

Q43. Tempering is mainly performed to:

A. Reduce the brittleness of quenched steel
B. Melt the steel
C. Increase porosity
D. Remove all carbon

Answer: A. Reduce the brittleness of quenched steel

Explanation: Tempering improves toughness and reduces excessive brittleness after hardening.

Q44. Normalizing generally involves heating steel above the critical temperature followed by:

A. Air cooling
B. Water quenching only
C. Oil quenching only
D. Furnace melting

Answer: A. Air cooling

Explanation: Normalizing refines the grain structure and produces a relatively uniform microstructure through air cooling.

Q45. The principal objective of case hardening is to obtain:

A. A hard surface with a relatively tough core
B. A completely brittle component
C. A completely soft surface
D. A molten core

Answer: A. A hard surface with a relatively tough core

Explanation: Case hardening improves surface wear resistance while retaining useful toughness in the core.

SECTION G — METROLOGY & INSPECTION

Q46. A vernier caliper can commonly measure:

A. External, internal, and depth dimensions
B. Temperature only
C. Weight only
D. Pressure only

Answer: A. External, internal, and depth dimensions

Explanation: A vernier caliper is a versatile dimensional measuring instrument.

Q47. A micrometer is primarily used for:

A. Precise dimensional measurement
B. Measuring temperature
C. Measuring pressure
D. Measuring electrical resistance

Answer: A. Precise dimensional measurement

Explanation: The micrometer screw mechanism allows accurate measurement of small dimensions.

Q48. A dial indicator is commonly used to detect:

A. Small dimensional deviations and runout
B. Material composition
C. Melting temperature
D. Chemical concentration

Answer: A. Small dimensional deviations and runout

Explanation: Dial indicators are widely used for checking alignment, runout, flatness, and small displacement.

Q49. Tolerance is defined as:

A. The permissible variation in a dimension
B. The exact nominal dimension
C. The material density
D. The surface colour

Answer: A. The permissible variation in a dimension

Explanation: Tolerance specifies the allowable dimensional variation from the specified size.

Q50. In a clearance fit:

A. The hole is always larger than the shaft
B. The shaft is always larger than the hole
C. Hole and shaft are always identical
D. No tolerance is allowed

Answer: A. The hole is always larger than the shaft

Explanation: A clearance fit always provides positive clearance between the mating components.

SECTION H — PRODUCTION & INDUSTRIAL ENGINEERING

Q51. Productivity is generally expressed as:

A. Output / Input
B. Input / Output
C. Output × Input
D. Output + Input

Answer: A. Output / Input

Explanation: Productivity measures how efficiently inputs are converted into outputs.

Q52. Work study mainly consists of:

A. Method study and work measurement
B. Casting and welding
C. Forging and rolling
D. Drilling and grinding

Answer: A. Method study and work measurement

Explanation: Work study aims to improve work methods and determine the time required to perform a task.

Q53. The main purpose of time study is to determine:

A. Standard time
B. Melting temperature
C. Tool material
D. Casting pattern size

Answer: A. Standard time

Explanation: Time study establishes the time required by a qualified worker to perform a task under specified conditions.

Q54. Inventory refers to:

A. Stored materials, components, work-in-process, and finished goods
B. Only machines
C. Only workers
D. Only finished products

Answer: A. Stored materials, components, work-in-process, and finished goods

Explanation: Inventory can exist at several stages of the production system.

Q55. The primary objective of EOQ is to:

A. Balance relevant ordering and holding costs
B. Maximize inventory indefinitely
C. Eliminate production
D. Increase labour requirements

Answer: A. Balance relevant ordering and holding costs

Explanation: Economic Order Quantity identifies an order size that minimizes the relevant total inventory costs under the model assumptions.

Q56. Quality control primarily aims to:

A. Ensure products meet specified requirements
B. Increase defects
C. Increase material waste
D. Eliminate inspection

Answer: A. Ensure products meet specified requirements

Explanation: Quality control uses inspection, measurement, and process controls to maintain required quality.

Q57. Six Sigma primarily focuses on:

A. Reducing process variation and defects
B. Increasing machine weight
C. Increasing inventory
D. Increasing material waste

Answer: A. Reducing process variation and defects

Explanation: Six Sigma is a data-driven methodology for improving process performance and reducing defects.

Q58. Preventive maintenance is performed:

A. Before equipment failure occurs
B. Only after complete equipment failure
C. Before purchasing equipment
D. Only when production stops unexpectedly

Answer: A. Before equipment failure occurs

Explanation: Preventive maintenance is planned and performed at predetermined intervals or conditions to reduce the likelihood of failure.

Q59. Breakdown maintenance is generally performed:

A. After equipment failure
B. Before equipment installation
C. Before every production cycle
D. Only during equipment design

Answer: A. After equipment failure

Explanation: Breakdown maintenance restores equipment after an actual failure has occurred.

Q60. In the 5S methodology, the first S represents:

A. Sort
B. Standardize
C. Sustain
D. Safety

Answer: A. Sort

Explanation: Sort involves identifying and removing unnecessary items from the workplace.

SECTION I — CNC, CAD, CAM & AUTOMATION

Q61. CNC stands for:

A. Computer Numerical Control
B. Central Numerical Control
C. Computer Network Control
D. Controlled Numerical Computer

Answer: A. Computer Numerical Control

Explanation: CNC machines operate according to programmed numerical instructions.

Q62. In standard CNC programming, G01 generally represents:

A. Linear interpolation
B. Rapid positioning
C. Program stop
D. Spindle stop

Answer: A. Linear interpolation

Explanation: G01 commands controlled straight-line movement at the programmed feed rate.

Q63. In standard CNC programming, G02 generally represents:

A. Clockwise circular interpolation
B. Counterclockwise circular interpolation
C. Rapid positioning
D. Tool change

Answer: A. Clockwise circular interpolation

Explanation: G02 is commonly used to command clockwise circular interpolation in the active machining plane.

Q64. In standard CNC programming, M03 generally commands:

A. Clockwise spindle rotation
B. Spindle stop
C. Coolant stop
D. Program end

Answer: A. Clockwise spindle rotation

Explanation: M03 commonly starts spindle rotation in the clockwise direction.

Q65. A work offset in CNC machining is used to:

A. Establish the workpiece coordinate system
B. Sharpen the cutting tool
C. Increase coolant pressure
D. Change the machine structure

Answer: A. Establish the workpiece coordinate system

Explanation: Work offsets relate programmed workpiece coordinates to the machine’s coordinate system.

Q66. ATC in a CNC machine stands for:

A. Automatic Tool Changer
B. Automatic Turning Control
C. Advanced Tool Computer
D. Automatic Transfer Circuit

Answer: A. Automatic Tool Changer

Explanation: An ATC automatically changes cutting tools according to the machining program.

Q67. CAD stands for:

A. Computer-Aided Design
B. Computer-Aided Drilling
C. Controlled Automatic Design
D. Computer Analysis Device

Answer: A. Computer-Aided Design

Explanation: CAD software is used to create, modify, analyze, and document engineering designs.

Q68. CAM stands for:

A. Computer-Aided Manufacturing
B. Computer-Aided Measurement
C. Central Automated Machine
D. Computer Analysis Method

Answer: A. Computer-Aided Manufacturing

Explanation: CAM uses computer systems to support manufacturing activities such as tool-path generation.

Q69. PLC stands for:

A. Programmable Logic Controller
B. Production Line Computer
C. Programmable Lathe Controller
D. Process Load Calculator

Answer: A. Programmable Logic Controller

Explanation: PLCs are widely used to control automated industrial processes and machinery.

Q70. The primary function of a robot end effector is to:

A. Perform the required task using a suitable tool or gripper
B. Store the robot program
C. Supply electrical power
D. Cool the robot

Answer: A. Perform the required task using a suitable tool or gripper

Explanation: The end effector interacts directly with the workpiece or environment.

SECTION J — ADVANCED MANUFACTURING & SAFETY

Q71. In Electrical Discharge Machining, the workpiece must generally be:

A. Electrically conductive
B. Electrically insulating
C. Made only of wood
D. Made only of rubber

Answer: A. Electrically conductive

Explanation: EDM removes material through controlled electrical discharges between the tool electrode and conductive workpiece.

Q72. Ultrasonic Machining is particularly suitable for:

A. Hard and brittle materials
B. Soft rubber only
C. Wood only
D. Liquid materials

Answer: A. Hard and brittle materials

Explanation: USM uses high-frequency tool vibration and abrasive slurry and is especially useful for hard, brittle, and non-conductive materials.

Q73. In Electrochemical Machining, the workpiece generally acts as the:

A. Anode
B. Cathode
C. Insulator
D. Dielectric

Answer: A. Anode

Explanation: Material is removed from the anodic workpiece by electrochemical dissolution.

Q74. Laser Beam Machining removes material primarily through:

A. Localized melting and vaporization
B. Conventional forging
C. Electrochemical dissolution
D. Mechanical rolling

Answer: A. Localized melting and vaporization

Explanation: A highly focused laser beam produces intense localized heating, causing melting and/or vaporization.

Q75. Abrasive Water Jet Machining uses:

A. High-pressure water with abrasive particles
B. Water only at atmospheric pressure
C. Electrical current through water only
D. Molten metal

Answer: A. High-pressure water with abrasive particles

Explanation: Abrasive particles significantly increase the cutting capability of the high-velocity water jet.

Q76. The principal difference between a jig and a fixture is that:

A. A jig guides the cutting tool, while a fixture primarily holds and locates the workpiece
B. A fixture guides the cutting tool, while a jig only holds the workpiece
C. Both are measuring instruments
D. Both are cutting tools

Answer: A. A jig guides the cutting tool, while a fixture primarily holds and locates the workpiece

Explanation: Tool guidance is the distinguishing feature of a jig.

Q77. The 3-2-1 principle is associated with:

A. Workpiece location
B. Welding current control
C. Heat treatment
D. Grinding wheel selection

Answer: A. Workpiece location

Explanation: The 3-2-1 principle provides a systematic method for restricting the six degrees of freedom of a workpiece.

Q78. Safety goggles are primarily used to protect:

A. The eyes
B. The feet
C. The hands
D. The ears

Answer: A. The eyes

Explanation: Safety goggles protect the eyes against flying particles, chips, sparks, and other hazards.

Q79. A machine guard is primarily intended to:

A. Protect operators from hazardous moving parts
B. Increase cutting speed
C. Increase material hardness
D. Improve surface finish directly

Answer: A. Protect operators from hazardous moving parts

Explanation: Machine guards help prevent accidental contact with moving or dangerous machine components.

Q80. Lockout/Tagout procedures are intended to:

A. Prevent unexpected energization or startup during servicing
B. Increase machine speed
C. Increase production rate
D. Reduce tool diameter

Answer: A. Prevent unexpected energization or startup during servicing

Explanation: Lockout/Tagout isolates hazardous energy sources before maintenance or servicing.

SECTION K — NUMERICAL & APPLICATION-BASED QUESTIONS

Q81. A shaft diameter is reduced from 50 mm to 45 mm during turning. What is the radial depth of cut?

A. 2.0 mm
B. 2.5 mm
C. 5.0 mm
D. 7.5 mm

Answer: B. 2.5 mm

Explanation:

Q82. A lathe has a workpiece diameter of 100 mm and spindle speed of 300 rpm. What is the cutting speed?

A. 31.4 m/min
B. 47.1 m/min
C. 94.2 m/min
D. 300 m/min

Answer: C. 94.2 m/min

Explanation:

Q83. A turning operation uses a feed of 0.2 mm/rev at a spindle speed of 500 rpm. What is the feed rate?

A. 50 mm/min
B. 75 mm/min
C. 100 mm/min
D. 250 mm/min

Answer: C. 100 mm/min

Explanation:

Q84. A rectangular plate is 200 mm long and 100 mm wide. What is its surface area?

A. 2,000 mm²
B. 10,000 mm²
C. 20,000 mm²
D. 30,000 mm²

Answer: C. 20,000 mm²

Explanation:

Q85. A force of 10,000 N acts over an area of 500 mm². What is the resulting stress?

A. 10 N/mm²
B. 20 N/mm²
C. 50 N/mm²
D. 200 N/mm²

Answer: B. 20 N/mm²

Q86. A component has a basic size of 50 mm with a tolerance of ±0.05 mm. What is the maximum permissible size?

A. 49.95 mm
B. 50.00 mm
C. 50.05 mm
D. 50.50 mm

Answer: C. 50.05 mm

Q87. For the component in Question 86, what is the minimum permissible size?

A. 49.95 mm
B. 50.00 mm
C. 50.05 mm
D. 49.50 mm

Answer: A. 49.95 mm

Q88. A hole has a diameter of 40.06 mm and the mating shaft has a diameter of 40.00 mm. What is the clearance?

A. 0.006 mm
B. 0.06 mm
C. 0.6 mm
D. 6 mm

Answer: B. 0.06 mm

Q89. A machine produces 400 components in 8 hours. What is its average production rate?

A. 25 components/hour
B. 40 components/hour
C. 50 components/hour
D. 80 components/hour

Answer: C. 50 components/hour

Q90. A machine has a cycle time of 2 minutes per component. What is its theoretical production rate?

A. 20 components/hour
B. 30 components/hour
C. 60 components/hour
D. 120 components/hour

Answer: B. 30 components/hour

SECTION L — MIXED ENGINEERING QUESTIONS

Q91. Which of the following is a thermoplastic?

A. PVC
B. Bakelite
C. Epoxy thermoset
D. Melamine formaldehyde

Answer: A. PVC

Explanation: Polyvinyl chloride (PVC) is a widely used thermoplastic polymer.

Q92. Which statement correctly describes a thermosetting plastic?

A. It cannot normally be remelted and reshaped after curing
B. It can always be repeatedly melted and reshaped
C. It is always a metal
D. It is always a liquid

Answer: A. It cannot normally be remelted and reshaped after curing

Explanation: Thermosetting polymers form a cross-linked structure during curing and cannot normally be remelted like thermoplastics.

Q93. A composite material generally contains:

A. Two or more distinct constituent materials
B. Only pure iron
C. Only one element
D. Only a liquid phase

Answer: A. Two or more distinct constituent materials

Explanation: Composites combine different materials, typically a matrix and reinforcement, to obtain improved or tailored properties.

Q94. Fatigue failure is primarily associated with:

A. Repeated or cyclic loading
B. Static loading only
C. Temperature measurement
D. Surface polishing

Answer: A. Repeated or cyclic loading

Explanation: Repeated stress cycles can initiate and propagate cracks even when the maximum stress is below the static strength.

Q95. The factor of safety is generally defined as:

A. Failure strength / allowable working stress
B. Allowable working stress / failure strength
C. Load / area
D. Strain / stress

Answer: A. Failure strength / allowable working stress

Explanation:

Q96. The primary function of a bearing is to:

A. Support relative motion while reducing friction
B. Melt metal
C. Join two components permanently
D. Cut material

Answer: A. Support relative motion while reducing friction

Explanation: Bearings support rotating or sliding components and help reduce friction and wear.

Q97. The primary purpose of gears is to:

A. Transmit motion and power
B. Store raw materials
C. Measure temperature
D. Produce castings

Answer: A. Transmit motion and power

Explanation: Gears transmit rotary motion and torque between shafts while providing a controlled speed ratio.

Q98. A belt drive transmits power primarily through:

A. Belts and pulleys
B. Gears only
C. Hydraulic cylinders only
D. Welding electrodes

Answer: A. Belts and pulleys

Explanation: Belt drives transmit rotational power between shafts using a flexible belt running over pulleys.

Q99. The primary function of a clutch is to:

A. Engage and disengage power transmission
B. Measure shaft diameter
C. Harden the shaft
D. Remove machining chips

Answer: A. Engage and disengage power transmission

Explanation: A clutch provides controlled connection and disconnection between the driving and driven members.

Q100. The overall objective of a manufacturing system is to:

A. Produce the required product with specified quality, cost, safety, and delivery requirements
B. Maximize material waste
C. Maximize setup time
D. Eliminate quality control

Answer: A. Produce the required product with specified quality, cost, safety, and delivery requirements

Explanation: Effective manufacturing balances quality, productivity, cost, delivery, safety, and efficient resource utilization.

MOCK TEST 1 — FINAL ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
1	B	26	A	51	A	76	A
2	A	27	A	52	A	77	A
3	A	28	A	53	A	78	A
4	C	29	A	54	A	79	A
5	A	30	A	55	A	80	A
6	B	31	A	56	A	81	B
7	A	32	A	57	A	82	C
8	A	33	A	58	A	83	C
9	A	34	A	59	A	84	C
10	A	35	A	60	A	85	B
11	A	36	A	61	A	86	C
12	A	37	A	62	A	87	A
13	A	38	A	63	A	88	B
14	A	39	A	64	A	89	C
15	A	40	A	65	A	90	B
16	A	41	A	66	A	91	A
17	A	42	A	67	A	92	A
18	A	43	A	68	A	93	A
19	A	44	A	69	A	94	A
20	A	45	A	70	A	95	A
21	A	46	A	71	A	96	A
22	A	47	A	72	A	97	A
23	A	48	A	73	A	98	A
24	A	49	A	74	A	99	A
25	A	50	A	75	A	100	A

MOCK TEST 2 — QUESTIONS 101–200

Complete Exam Practice

Instructions: Each question has four options. Select the most appropriate answer. The correct answer and explanation are provided after each question.

SECTION A — ENGINEERING MECHANICS & STRENGTH OF MATERIALS

Q101. Which type of stress is produced when a member is subjected to an axial pulling force?

A. Compressive stress
B. Tensile stress
C. Shear stress
D. Bending stress

Answer: B. Tensile stress

Explanation: An axial pulling force tends to elongate the member and produces tensile stress.

Q102. Which type of stress is produced when a member is subjected to an axial pushing force?

A. Tensile stress
B. Shear stress
C. Compressive stress
D. Torsional stress

Answer: C. Compressive stress

Explanation: An axial pushing force tends to shorten the member and produces compressive stress.

Q103. Shear stress acts:

A. Normal to the surface
B. Tangentially to the surface
C. Only along the longitudinal axis
D. Only vertically

Answer: B. Tangentially to the surface

Explanation: Shear stress acts parallel or tangential to the plane on which it acts.

Q104. What is the SI unit of force?

A. Pascal
B. Joule
C. Newton
D. Watt

Answer: C. Newton

Explanation: The SI unit of force is the Newton (N).

Q105. The unit of power is:

A. Newton
B. Joule
C. Watt
D. Pascal

Answer: C. Watt

Explanation: One watt is equal to one joule per second.

Q106. Torque is the product of:

A. Force and perpendicular distance
B. Mass and velocity
C. Pressure and volume
D. Stress and strain

Answer: A. Force and perpendicular distance

Explanation:

where is the perpendicular distance from the axis.

Q107. Which property represents resistance to elastic deformation?

A. Young’s modulus
B. Toughness
C. Hardness
D. Ductility

Answer: A. Young’s modulus

Explanation: Young’s modulus measures the stiffness of a material in tension or compression.

Q108. Poisson’s ratio is the ratio of:

A. Longitudinal strain to lateral strain
B. Lateral strain to longitudinal strain
C. Stress to strain
D. Shear stress to normal stress

Answer: B. Lateral strain to longitudinal strain

Explanation: Poisson’s ratio is the magnitude of lateral strain divided by longitudinal strain.

Q109. The ability of a material to absorb energy before fracture is related to:

A. Toughness
B. Density
C. Conductivity
D. Machinability

Answer: A. Toughness

Explanation: Toughness is the ability of a material to absorb energy and deform plastically before fracture.

Q110. The ability of a material to undergo significant plastic deformation before fracture is called:

A. Brittleness
B. Ductility
C. Hardness
D. Stiffness

Answer: B. Ductility

Explanation: Ductile materials can undergo considerable plastic deformation before failure.

SECTION B — MACHINE DESIGN

Q111. A shaft primarily transmits:

A. Torque
B. Temperature
C. Pressure only
D. Electrical resistance

Answer: A. Torque

Explanation: Shafts are rotating machine elements primarily designed to transmit torque and power.

Q112. A key in a shaft-and-hub assembly is primarily used to:

A. Prevent relative rotation
B. Increase shaft temperature
C. Lubricate the shaft
D. Measure shaft diameter

Answer: A. Prevent relative rotation

Explanation: A key transmits torque between the shaft and hub and prevents relative angular movement.

Q113. A coupling is used to:

A. Connect two shafts
B. Cut a shaft
C. Measure shaft speed
D. Harden a shaft

Answer: A. Connect two shafts

Explanation: Couplings connect shafts to transmit torque and rotary motion.

Q114. A flywheel is primarily used to:

A. Store rotational energy
B. Reduce material hardness
C. Increase friction
D. Produce electrical insulation

Answer: A. Store rotational energy

Explanation: A flywheel stores kinetic energy and helps smooth fluctuations in rotational speed.

Q115. A governor primarily regulates:

A. Mean speed of an engine
B. Shaft diameter
C. Bearing temperature only
D. Lubricant viscosity

Answer: A. Mean speed of an engine

Explanation: A governor controls the fuel or working-fluid supply to maintain approximately constant mean speed under varying load.

Q116. A spring is primarily designed to:

A. Store mechanical energy
B. Produce permanent deformation
C. Increase friction
D. Remove material

Answer: A. Store mechanical energy

Explanation: Springs store and release mechanical energy while providing force or maintaining contact.

Q117. Which bearing is generally suitable for supporting predominantly radial loads?

A. Radial ball bearing
B. Thrust bearing only
C. Magnetic compass
D. Clutch plate

Answer: A. Radial ball bearing

Explanation: Radial bearings are designed primarily to support loads acting perpendicular to the shaft axis.

Q118. A thrust bearing is primarily designed to carry:

A. Axial load
B. Radial load only
C. Thermal load
D. Electrical load

Answer: A. Axial load

Explanation: Thrust bearings are designed to support forces acting parallel to the shaft axis.

Q119. The main function of lubrication is to:

A. Reduce friction and wear
B. Increase surface roughness
C. Increase corrosion
D. Increase temperature

Answer: A. Reduce friction and wear

Explanation: Lubricants form a separating film or otherwise reduce direct surface contact, thereby reducing friction and wear.

Q120. Which lubricant property indicates resistance to flow?

A. Viscosity
B. Density
C. Hardness
D. Toughness

Answer: A. Viscosity

Explanation: Viscosity represents the internal resistance of a fluid to flow.

SECTION C — THERMAL ENGINEERING

Q121. The SI unit of temperature in the absolute scale is:

A. Celsius
B. Fahrenheit
C. Kelvin
D. Rankine only

Answer: C. Kelvin

Explanation: Kelvin is the SI base unit for thermodynamic temperature.

Q122. Heat transfer through direct molecular interaction is called:

A. Conduction
B. Convection
C. Radiation
D. Evaporation

Answer: A. Conduction

Explanation: Conduction transfers heat through molecular interactions within a material or between bodies in direct contact.

Q123. Heat transfer through the bulk movement of a fluid is called:

A. Conduction
B. Convection
C. Radiation
D. Reflection

Answer: B. Convection

Explanation: Convection involves heat transfer associated with fluid motion.

Q124. Heat transfer that does not require a material medium is:

A. Conduction
B. Convection
C. Radiation
D. Diffusion

Answer: C. Radiation

Explanation: Thermal radiation can transfer energy through electromagnetic waves and can occur through a vacuum.

Q125. The first law of thermodynamics is essentially a statement of conservation of:

A. Mass only
B. Energy
C. Momentum only
D. Entropy only

Answer: B. Energy

Explanation: The first law states that energy cannot be created or destroyed, although it can be transformed from one form to another.

Q126. The SI unit of pressure is:

A. Watt
B. Joule
C. Pascal
D. Newton

Answer: C. Pascal

Explanation: One Pascal equals one Newton per square metre.

Q127. Atmospheric pressure is approximately:

A. 1.013 bar
B. 10.13 bar
C. 0.1013 bar
D. 101.3 bar

Answer: A. 1.013 bar

Explanation: Standard atmospheric pressure is approximately 1.01325 bar or 101.325 kPa.

Q128. In an ideal gas, pressure, volume, and temperature are related by:

A.
B.
C.
D.

Answer: A.

Explanation: The ideal-gas equation is , where is mass and is the specific gas constant.

Q129. A device used to measure pressure is:

A. Thermometer
B. Manometer
C. Pyrometer only
D. Tachometer

Answer: B. Manometer

Explanation: A manometer measures pressure, often by balancing the pressure against a liquid column.

Q130. A device used to measure rotational speed is:

A. Tachometer
B. Manometer
C. Calorimeter
D. Barometer

Answer: A. Tachometer

Explanation: A tachometer measures rotational speed, commonly in revolutions per minute.

SECTION D — INTERNAL COMBUSTION ENGINES

Q131. An internal combustion engine burns fuel:

A. Inside the engine cylinder or combustion chamber
B. Only outside the engine
C. Inside the radiator
D. Inside the fuel tank

Answer: A. Inside the engine cylinder or combustion chamber

Explanation: In an internal combustion engine, combustion occurs inside the engine.

Q132. In a four-stroke engine, one complete cycle requires:

A. One crankshaft revolution
B. Two crankshaft revolutions
C. Three crankshaft revolutions
D. Four crankshaft revolutions

Answer: B. Two crankshaft revolutions

Explanation: A four-stroke cycle consists of intake, compression, power, and exhaust strokes and requires two crankshaft revolutions.

Q133. In a four-stroke engine, the power stroke occurs immediately after:

A. Compression
B. Exhaust
C. Intake
D. Cooling

Answer: A. Compression

Explanation: The compressed mixture is ignited at the beginning of the power stroke.

Q134. In a spark-ignition engine, ignition is normally initiated by:

A. Spark plug
B. Fuel injector alone
C. Radiator
D. Carburetor float

Answer: A. Spark plug

Explanation: A spark plug produces the electrical spark that initiates combustion in a conventional spark-ignition engine.

Q135. In a compression-ignition engine, ignition occurs because of:

A. High temperature of compressed air
B. Spark plug operation
C. Cooling water
D. Exhaust pressure

Answer: A. High temperature of compressed air

Explanation: Fuel injected into highly compressed, hot air ignites due to the temperature of the compressed air.

Q136. The main function of the radiator in an engine cooling system is to:

A. Reject heat from the coolant
B. Increase fuel pressure
C. Ignite the fuel
D. Lubricate the piston

Answer: A. Reject heat from the coolant

Explanation: The radiator transfers heat from the engine coolant to the surrounding air.

Q137. The function of an engine lubrication system is to:

A. Reduce friction and wear
B. Increase combustion temperature indefinitely
C. Increase mechanical friction
D. Stop fuel injection

Answer: A. Reduce friction and wear

Explanation: Lubricating oil reduces friction, removes heat, helps prevent wear, and can assist in cleaning and sealing.

Q138. The crankshaft converts:

A. Reciprocating motion into rotary motion
B. Rotary motion into only heat
C. Heat into electricity directly
D. Pressure into chemical energy

Answer: A. Reciprocating motion into rotary motion

Explanation: The crank-slider mechanism converts piston reciprocation into crankshaft rotation.

Q139. The piston is connected to the crankshaft through the:

A. Connecting rod
B. Flywheel only
C. Radiator
D. Valve spring only

Answer: A. Connecting rod

Explanation: The connecting rod transfers force and motion between the piston and crankshaft.

Q140. The flywheel of an engine helps to:

A. Smooth speed fluctuations
B. Cool the coolant
C. Inject fuel
D. Filter lubricating oil

Answer: A. Smooth speed fluctuations

Explanation: The flywheel stores energy during the power stroke and releases it during other strokes, helping maintain smoother rotation.

SECTION E — FLUID MECHANICS

Q141. The density of a fluid is defined as:

A. Mass per unit volume
B. Volume per unit mass
C. Weight per unit area
D. Force per unit length

Answer: A. Mass per unit volume

Explanation:

where is density.

Q142. Specific gravity is the ratio of:

A. Fluid density to reference fluid density
B. Pressure to velocity
C. Mass to force
D. Volume to pressure

Answer: A. Fluid density to reference fluid density

Explanation: For liquids, specific gravity is commonly expressed relative to the density of water.

Q143. Viscosity represents a fluid’s resistance to:

A. Shear deformation or flow
B. Temperature change only
C. Gravity
D. Electrical current

Answer: A. Shear deformation or flow

Explanation: Viscosity describes the internal resistance of a fluid to relative motion between its layers.

Q144. The continuity equation is based on conservation of:

A. Mass
B. Energy only
C. Momentum only
D. Temperature

Answer: A. Mass

Explanation: For steady one-dimensional incompressible flow, continuity gives:

Q145. Bernoulli’s equation is based primarily on conservation of:

A. Mechanical energy
B. Mass only
C. Electric charge
D. Chemical composition

Answer: A. Mechanical energy

Explanation: Bernoulli’s equation relates pressure, velocity, and elevation heads for idealized flow conditions.

Q146. A pump is used to:

A. Add energy to a fluid
B. Remove all pressure from a fluid
C. Measure temperature
D. Reduce fluid density to zero

Answer: A. Add energy to a fluid

Explanation: Pumps transfer mechanical energy to fluids, increasing pressure and/or velocity.

Q147. A turbine primarily converts:

A. Fluid energy into mechanical energy
B. Mechanical energy into fluid energy
C. Heat directly into mass
D. Electrical energy into pressure only

Answer: A. Fluid energy into mechanical energy

Explanation: Turbines extract energy from flowing fluids and convert it into shaft work.

Q148. Cavitation in a pump occurs when:

A. Local pressure falls below the liquid’s vapour pressure
B. Pressure becomes infinitely high
C. Fluid temperature becomes zero
D. There is no fluid flow

Answer: A. Local pressure falls below the liquid’s vapour pressure

Explanation: Vapour bubbles form and subsequently collapse when they enter regions of higher pressure, potentially causing noise, vibration, and damage.

Q149. A hydraulic press operates primarily on:

A. Pascal’s law
B. Hooke’s law
C. Fourier’s law
D. Newton’s law of cooling

Answer: A. Pascal’s law

Explanation: Pascal’s law states that pressure applied to a confined fluid is transmitted throughout the fluid.

Q150. A venturimeter is commonly used to measure:

A. Fluid flow rate
B. Temperature
C. Shaft torque
D. Surface roughness

Answer: A. Fluid flow rate

Explanation: A venturimeter determines flow rate from the pressure difference between the inlet and throat sections.

SECTION F — REFRIGERATION & AIR CONDITIONING

Q151. Refrigeration is the process of:

A. Removing heat from a low-temperature region
B. Adding heat to a low-temperature region
C. Producing cold without energy transfer
D. Eliminating all heat from the universe

Answer: A. Removing heat from a low-temperature region

Explanation: Refrigeration transfers heat from a low-temperature space to a higher-temperature environment.

Q152. The coefficient of performance of a refrigerator is:

A. Refrigerating effect / work input
B. Work input / refrigerating effect
C. Heat rejected / work output
D. Pressure / temperature

Answer: A. Refrigerating effect / work input

Explanation:

where is the heat removed from the refrigerated space.

Q153. In a vapour-compression refrigeration system, the compressor:

A. Raises refrigerant pressure
B. Always lowers refrigerant pressure
C. Condenses all refrigerant directly
D. Removes moisture from air only

Answer: A. Raises refrigerant pressure

Explanation: The compressor takes low-pressure vapour and compresses it to a high-pressure state.

Q154. The condenser rejects:

A. Heat to the surroundings
B. Heat only from the room being cooled
C. All mechanical work
D. Electrical energy directly

Answer: A. Heat to the surroundings

Explanation: The condenser removes heat from the refrigerant and rejects it to the external environment.

Q155. The evaporator absorbs:

A. Heat from the refrigerated space
B. Heat from the condenser
C. Mechanical energy
D. Electrical energy only

Answer: A. Heat from the refrigerated space

Explanation: Refrigerant evaporates in the evaporator while absorbing heat from the space or fluid being cooled.

Q156. The expansion device primarily:

A. Reduces refrigerant pressure
B. Raises compressor speed
C. Increases refrigerant pressure
D. Condenses the refrigerant

Answer: A. Reduces refrigerant pressure

Explanation: The expansion device reduces pressure and controls refrigerant flow into the evaporator.

Q157. An air conditioner generally controls:

A. Temperature and humidity, along with air movement and cleanliness as applicable
B. Engine speed
C. Shaft torque
D. Metal hardness

Answer: A. Temperature and humidity, along with air movement and cleanliness as applicable

Explanation: Air conditioning involves conditioning air to desired comfort or process requirements.

Q158. Relative humidity is the ratio of:

A. Actual water-vapour pressure to saturation vapour pressure at the same temperature
B. Dry-bulb temperature to wet-bulb temperature
C. Atmospheric pressure to vacuum pressure
D. Mass to volume

Answer: A. Actual water-vapour pressure to saturation vapour pressure at the same temperature

Explanation: Relative humidity indicates how close the air is to saturation with water vapour.

Q159. A psychrometer is used to measure:

A. Humidity-related properties of air
B. Shaft speed
C. Torque
D. Surface hardness

Answer: A. Humidity-related properties of air

Explanation: A psychrometer uses dry-bulb and wet-bulb measurements to determine humidity-related properties.

Q160. The refrigerant should ideally have:

A. Suitable thermodynamic and environmental properties
B. Extremely high toxicity
C. Extremely high flammability in all applications
D. Zero heat-transfer capability

Answer: A. Suitable thermodynamic and environmental properties

Explanation: Refrigerant selection considers thermodynamic performance, safety, chemical stability, environmental impact, and system compatibility.

SECTION G — PRODUCTION TECHNOLOGY

Q161. In a shaper, the cutting tool generally performs:

A. Reciprocating motion
B. Continuous rotary motion only
C. Circular motion only
D. No motion

Answer: A. Reciprocating motion

Explanation: A shaper removes material using the reciprocating motion of the ram carrying the cutting tool.

Q162. A planer differs from a shaper mainly because:

A. The workpiece generally reciprocates in a planer
B. The tool always rotates
C. A planer cannot machine flat surfaces
D. A planer uses only grinding wheels

Answer: A. The workpiece generally reciprocates in a planer

Explanation: In a planer, the workpiece reciprocates while the cutting tools are mounted on the tool heads.

Q163. Boring is primarily used to:

A. Enlarge or finish an existing hole
B. Produce an external thread
C. Cut sheet metal into blanks
D. Join two components

Answer: A. Enlarge or finish an existing hole

Explanation: Boring machines an existing hole to improve its size, alignment, or surface finish.

Q164. A counterbore produces:

A. A cylindrical enlargement at the mouth of a hole
B. An external thread
C. A tapered external surface
D. A keyway only

Answer: A. A cylindrical enlargement at the mouth of a hole

Explanation: Counterboring creates a cylindrical recess, often to accommodate a bolt or screw head.

Q165. Countersinking produces:

A. A conical recess at the entrance of a hole
B. A cylindrical shaft
C. An external gear
D. A rectangular slot only

Answer: A. A conical recess at the entrance of a hole

Explanation: Countersinking provides a conical seat for countersunk fasteners.

Q166. A milling cutter with teeth on its periphery is commonly used for:

A. Peripheral milling
B. Welding
C. Casting
D. Heat treatment

Answer: A. Peripheral milling

Explanation: Peripheral milling uses the cutting edges located primarily around the circumference of the cutter.

Q167. Up milling is also known as:

A. Conventional milling
B. Climb milling
C. Reverse turning
D. Face grinding

Answer: A. Conventional milling

Explanation: In up milling, the cutter rotates against the direction of feed at the point of cutting.

Q168. In climb milling, the cutter rotation at the cutting point is generally:

A. In the same direction as the feed
B. Opposite to the feed
C. Perpendicular to the feed only
D. Independent of the feed

Answer: A. In the same direction as the feed

Explanation: In climb milling, cutter rotation and workpiece feed are in the same direction at the point of engagement.

Q169. Cutting fluid is commonly used to:

A. Cool and lubricate the cutting zone
B. Increase tool temperature
C. Eliminate all cutting forces
D. Increase friction

Answer: A. Cool and lubricate the cutting zone

Explanation: Cutting fluids can reduce heat and friction, improve tool life, and assist chip removal.

Q170. Tool wear generally results in:

A. Reduced tool performance and possible loss of dimensional accuracy
B. Infinite tool life
C. Zero cutting temperature
D. Automatic sharpening

Answer: A. Reduced tool performance and possible loss of dimensional accuracy

Explanation: Excessive tool wear can increase cutting forces, temperature, surface roughness, and dimensional errors.

SECTION H — MATERIALS & METALLURGY

Q171. The main constituent of ordinary steel is:

A. Iron
B. Copper
C. Aluminium
D. Zinc

Answer: A. Iron

Explanation: Steel is primarily an iron-based alloy with carbon and other elements.

Q172. Increasing carbon content in plain carbon steel generally increases:

A. Hardness and strength
B. Electrical insulation only
C. Ductility indefinitely
D. Melting point without other effects

Answer: A. Hardness and strength

Explanation: Increasing carbon generally raises hardness and strength while reducing ductility and weldability.

Q173. Which element is commonly added to steel to improve hardenability?

A. Chromium
B. Oxygen
C. Hydrogen
D. Sulphur only

Answer: A. Chromium

Explanation: Chromium is a common alloying element that can increase hardenability and improve corrosion and wear resistance.

Q174. Nickel in steel generally improves:

A. Toughness and certain corrosion-resistant properties
B. Brittleness only
C. Electrical insulation only
D. Porosity

Answer: A. Toughness and certain corrosion-resistant properties

Explanation: Nickel can improve toughness and corrosion resistance and is important in many alloy steels.

Q175. Aluminium is characterized by:

A. Low density compared with steel
B. Extremely high density compared with lead
C. Zero thermal conductivity
D. Complete brittleness

Answer: A. Low density compared with steel

Explanation: Aluminium is a relatively lightweight engineering metal with useful strength-to-weight characteristics.

Q176. Copper is widely used for electrical conductors because of its:

A. High electrical conductivity
B. Very low electrical conductivity
C. Extremely high brittleness
D. High porosity

Answer: A. High electrical conductivity

Explanation: Copper has excellent electrical conductivity and good ductility.

Q177. Galvanizing generally means coating iron or steel with:

A. Zinc
B. Copper
C. Tin only
D. Aluminium oxide only

Answer: A. Zinc

Explanation: Zinc coating protects steel against corrosion, including through sacrificial action.

Q178. Corrosion is generally:

A. Deterioration of a material due to chemical or electrochemical interaction with its environment
B. A method of increasing hardness
C. A machining process
D. A casting process

Answer: A. Deterioration of a material due to chemical or electrochemical interaction with its environment

Explanation: Corrosion causes gradual degradation of metals and other materials through environmental reactions.

Q179. A material with high electrical resistivity is generally:

A. A poor electrical conductor
B. An excellent electrical conductor
C. A superconductor under all conditions
D. A perfect thermal conductor

Answer: A. A poor electrical conductor

Explanation: Higher electrical resistivity means greater opposition to electrical current.

Q180. Ceramic materials are generally known for:

A. High hardness and high-temperature resistance
B. Extremely high ductility
C. Very low melting temperature
D. Unlimited plastic deformation

Answer: A. High hardness and high-temperature resistance

Explanation: Engineering ceramics commonly have high hardness, wear resistance, and temperature resistance but are often brittle.

SECTION I — QUALITY, LEAN & INDUSTRIAL ENGINEERING

Q181. Pareto analysis is based on the principle that:

A. A relatively small number of causes can account for a large proportion of problems
B. All causes always contribute equally
C. Quality cannot be measured
D. Production should always be stopped

Answer: A. A relatively small number of causes can account for a large proportion of problems

Explanation: Pareto analysis helps identify the vital few causes responsible for a large share of effects.

Q182. A histogram is used to show:

A. Distribution of numerical data
B. Machine assembly only
C. A production schedule only
D. Electrical wiring only

Answer: A. Distribution of numerical data

Explanation: A histogram displays the frequency distribution of quantitative data.

Q183. A control chart is primarily used to:

A. Monitor process variation over time
B. Design a gear
C. Measure engine power directly
D. Cut a workpiece

Answer: A. Monitor process variation over time

Explanation: Control charts help distinguish common-cause variation from potentially assignable causes.

Q184. The Ishikawa diagram is also called the:

A. Fishbone diagram
B. Flow meter
C. Gantt diagram
D. Histogram

Answer: A. Fishbone diagram

Explanation: The Ishikawa or fishbone diagram organizes potential causes of a problem into categories.

Q185. Kaizen refers to:

A. Continuous improvement
B. Complete machine replacement
C. Product disposal
D. Emergency shutdown

Answer: A. Continuous improvement

Explanation: Kaizen emphasizes ongoing, incremental improvements involving people and processes.

Q186. Just-in-Time production aims to:

A. Reduce unnecessary inventory and produce as needed
B. Maximize inventory at all times
C. Increase storage requirements
D. Eliminate scheduling

Answer: A. Reduce unnecessary inventory and produce as needed

Explanation: JIT seeks to provide materials and products when required, reducing excess inventory and associated waste.

Q187. Which of the following is a common form of manufacturing waste?

A. Waiting
B. Value creation
C. Required processing
D. Customer satisfaction

Answer: A. Waiting

Explanation: Lean manufacturing identifies waiting as one of the major forms of non-value-adding waste.

Q188. A bottleneck is:

A. A process step that limits overall system capacity
B. The fastest process in a production line
C. A type of cutting tool
D. A type of bearing

Answer: A. A process step that limits overall system capacity

Explanation: The bottleneck constrains throughput because its effective capacity is lower than the demand placed on it.

Q189. Line balancing attempts to:

A. Distribute work among stations effectively
B. Increase idle time
C. Eliminate all workers
D. Increase product defects

Answer: A. Distribute work among stations effectively

Explanation: Line balancing assigns tasks to workstations to achieve efficient flow and reduce imbalance.

Q190. A Gantt chart is commonly used for:

A. Project scheduling
B. Hardness testing
C. Cutting tool sharpening
D. Measuring pressure

Answer: A. Project scheduling

Explanation: A Gantt chart represents activities against time and is widely used for planning and monitoring projects.

SECTION J — MIXED APPLICATION QUESTIONS

Q191. If a machine produces 90 acceptable parts out of 100 total parts, its yield is:

A. 90%
B. 10%
C. 9%
D. 99%

Answer: A. 90%

Explanation:

Q192. A motor operates at 1,500 rpm. How many revolutions does it make in one minute?

A. 150
B. 500
C. 1,500
D. 15,000

Answer: C. 1,500

Explanation: By definition, rpm means revolutions per minute. Therefore, 1,500 rpm means 1,500 revolutions per minute.

Q193. A machine consumes 5 kW of power for 2 hours. How much energy does it consume?

A. 2.5 kWh
B. 7 kWh
C. 10 kWh
D. 25 kWh

Answer: C. 10 kWh

Explanation:

Q194. A force of 2,000 N moves an object through 5 m in the direction of the force. The work done is:

A. 400 J
B. 1,000 J
C. 10,000 J
D. 20,000 J

Answer: C. 10,000 J

Explanation:

Q195. A machine performs 20,000 J of work in 10 seconds. Its power output is:

A. 200 W
B. 1,000 W
C. 2,000 W
D. 20,000 W

Answer: C. 2,000 W

Explanation:

Q196. If a 10 kW machine operates for 30 minutes, the energy consumed is:

A. 2 kWh
B. 5 kWh
C. 10 kWh
D. 20 kWh

Answer: B. 5 kWh

Explanation: Thirty minutes equals 0.5 hour.

Q197. A gear with 20 teeth drives a gear with 40 teeth. The speed ratio of driven to driver is:

A. 0.5
B. 1
C. 2
D. 4

Answer: A. 0.5

Explanation:

Thus, the driven gear rotates at half the speed of the driver.

Q198. If the driver gear rotates at 1,000 rpm in Question 197, the driven gear rotates at:

A. 250 rpm
B. 500 rpm
C. 1,000 rpm
D. 2,000 rpm

Answer: B. 500 rpm

Explanation:

Q199. A machine has an input power of 10 kW and output power of 8 kW. Its efficiency is:

A. 20%
B. 50%
C. 80%
D. 125%

Answer: C. 80%

Explanation:

Q200. A manufacturing process has a cycle time of 3 minutes per unit. Ignoring downtime, how many units can theoretically be produced in 1 hour?

A. 10
B. 20
C. 30
D. 60

Answer: B. 20

Explanation:

MOCK TEST 2 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
101	B	126	C	151	A	176	A
102	C	127	A	152	A	177	A
103	B	128	A	153	A	178	A
104	C	129	B	154	A	179	A
105	C	130	A	155	A	180	A
106	A	131	A	156	A	181	A
107	A	132	B	157	A	182	A
108	B	133	A	158	A	183	A
109	A	134	A	159	A	184	A
110	B	135	A	160	A	185	A
111	A	136	A	161	A	186	A
112	A	137	A	162	A	187	A
113	A	138	A	163	A	188	A
114	A	139	A	164	A	189	A
115	A	140	A	165	A	190	A
116	A	141	A	166	A	191	A
117	A	142	A	167	A	192	C
118	A	143	A	168	A	193	C
119	A	144	A	169	A	194	C
120	A	145	A	170	A	195	C
121	C	146	A	171	A	196	B
122	A	147	A	172	A	197	A
123	B	148	A	173	A	198	B
124	C	149	A	174	A	199	C
125	B	150	A	175	A	200	B

MOCK TEST 3 — QUESTIONS 201–300

Complete Exam Practice

Instructions: Each question has four options. Select the most appropriate answer. The correct answer and explanation are provided after each question.

SECTION A — ENGINEERING MECHANICS

Q201. Newton’s first law of motion is also known as the law of:

A. Acceleration
B. Inertia
C. Gravitation
D. Momentum

Answer: B. Inertia

Explanation: Newton’s first law states that a body remains at rest or in uniform straight-line motion unless acted upon by an external unbalanced force.

Q202. The momentum of a body is equal to:

A. Mass × acceleration
B. Mass × velocity
C. Force × distance
D. Mass ÷ velocity

Answer: B. Mass × velocity

Explanation:

where is momentum, is mass, and is velocity.

Q203. Impulse is equal to:

A. Change in momentum
B. Change in temperature
C. Change in mass
D. Change in volume

Answer: A. Change in momentum

Explanation: Impulse is the product of force and time and equals the change in momentum.

Q204. The centre of gravity of a uniform circular disc lies at:

A. Its circumference
B. Its centre
C. Half its radius from the centre
D. Outside the disc

Answer: B. Its centre

Explanation: Due to symmetry, the centre of gravity of a uniform circular disc is at its geometric centre.

Q205. Friction acts:

A. In the direction of relative motion
B. Opposite to relative motion or its tendency
C. Always vertically upward
D. Always vertically downward

Answer: B. Opposite to relative motion or its tendency

Explanation: Friction resists relative motion or the tendency of relative motion between contacting surfaces.

Q206. The coefficient of friction is:

A. Dimensional quantity
B. Dimensionless quantity
C. A unit of force
D. A unit of pressure

Answer: B. Dimensionless quantity

Explanation: It is the ratio of frictional force to normal reaction, so it has no dimensions.

Q207. Work done by a force is zero when the displacement is:

A. Parallel to the force
B. Opposite to the force
C. Perpendicular to the force
D. Greater than the force

Answer: C. Perpendicular to the force

Explanation:

For , work done is zero.

Q208. Kinetic energy depends on:

A. Mass and velocity
B. Pressure only
C. Temperature only
D. Volume only

Answer: A. Mass and velocity

Explanation:

Thus kinetic energy depends on mass and the square of velocity.

Q209. Potential energy due to elevation is:

A.
B.
C.
D.

Answer: A.

Explanation: Gravitational potential energy relative to a reference level is .

Q210. The SI unit of angular velocity is:

A. metre/second
B. radian/second
C. Newton
D. revolution/minute

Answer: B. radian/second

Explanation: Angular velocity in SI is measured in radians per second.

SECTION B — STRENGTH OF MATERIALS

Q211. Stress is defined as:

A. Force per unit area
B. Area per unit force
C. Force × distance
D. Mass per unit volume

Answer: A. Force per unit area

Explanation:

Stress is force divided by the area over which it acts.

Q212. Strain is:

A. Force per area
B. Deformation per original dimension
C. Mass per volume
D. Work per unit time

Answer: B. Deformation per original dimension

Explanation: Strain is a ratio of deformation to original dimension and is dimensionless.

Q213. Hooke’s law is valid within the:

A. Plastic region
B. Elastic limit
C. Fracture region
D. Necking region only

Answer: B. Elastic limit

Explanation: Within the elastic range, stress is proportional to strain.

Q214. Young’s modulus is the ratio of:

A. Shear stress to shear strain
B. Normal stress to longitudinal strain
C. Pressure to volume
D. Force to displacement

Answer: B. Normal stress to longitudinal strain

Explanation:

within the elastic range.

Q215. Shear modulus is also known as:

A. Modulus of rigidity
B. Bulk modulus
C. Young’s modulus
D. Compressibility modulus

Answer: A. Modulus of rigidity

Explanation: Shear modulus measures resistance to shear deformation.

Q216. Bulk modulus relates:

A. Volumetric stress and volumetric strain
B. Shear stress and shear strain
C. Tensile stress and lateral strain
D. Torque and angular velocity

Answer: A. Volumetric stress and volumetric strain

Explanation: Bulk modulus measures resistance to uniform compression.

Q217. A brittle material generally undergoes:

A. Large plastic deformation before fracture
B. Little plastic deformation before fracture
C. Infinite deformation
D. No stress

Answer: B. Little plastic deformation before fracture

Explanation: Brittle materials fracture with comparatively little plastic deformation.

Q218. The ability of a material to resist indentation is called:

A. Toughness
B. Hardness
C. Ductility
D. Elasticity

Answer: B. Hardness

Explanation: Hardness is the resistance of a material to indentation, scratching, or localized deformation.

Q219. Resilience is the ability of a material to:

A. Absorb energy within the elastic range
B. Resist corrosion only
C. Conduct electricity
D. Melt rapidly

Answer: A. Absorb energy within the elastic range

Explanation: Resilience refers to elastic energy absorption and recovery.

Q220. Fatigue failure is generally caused by:

A. Repeated or fluctuating loading
B. One-time static loading only
C. Zero stress
D. Constant temperature only

Answer: A. Repeated or fluctuating loading

Explanation: Fatigue occurs due to repeated or cyclic stresses, often below the material’s static strength.

SECTION C — MACHINE ELEMENTS

Q221. A bearing is used primarily to:

A. Support rotating elements and reduce friction
B. Increase friction
C. Increase shaft weight
D. Generate fuel

Answer: A. Support rotating elements and reduce friction

Explanation: Bearings support shafts or other moving elements while reducing friction.

Q222. A ball bearing uses:

A. Rolling elements
B. Only sliding surfaces
C. Hydraulic pistons
D. Gear teeth

Answer: A. Rolling elements

Explanation: Ball bearings use balls between races to reduce friction.

Q223. A journal bearing is a type of:

A. Sliding-contact bearing
B. Rolling-contact bearing
C. Gear
D. Coupling

Answer: A. Sliding-contact bearing

Explanation: Journal bearings support a rotating shaft through sliding contact, usually separated by a lubricant film.

Q224. A brake is used to:

A. Absorb energy and reduce or stop motion
B. Increase shaft speed indefinitely
C. Store fuel
D. Increase temperature intentionally

Answer: A. Absorb energy and reduce or stop motion

Explanation: Brakes convert mechanical energy mainly into heat through friction or other braking mechanisms.

Q225. A clutch is primarily used to:

A. Engage or disengage power transmission
B. Measure pressure
C. Store coolant
D. Increase corrosion

Answer: A. Engage or disengage power transmission

Explanation: A clutch allows power transmission between driving and driven members to be connected or interrupted.

Q226. A belt drive transmits power between:

A. Shafts
B. Pistons only
C. Bearings only
D. Springs only

Answer: A. Shafts

Explanation: Belt drives transmit rotary motion and power between shafts using flexible belts and pulleys.

Q227. Slip in a belt drive causes:

A. Reduction in velocity ratio accuracy
B. Zero friction
C. Infinite power transmission
D. Increased belt length only

Answer: A. Reduction in velocity ratio accuracy

Explanation: Slip causes the driven pulley speed to differ from the ideal speed ratio.

Q228. A chain drive is generally classified as:

A. Positive drive
B. Friction drive
C. Fluid drive
D. Electrical drive

Answer: A. Positive drive

Explanation: Chain engagement with sprocket teeth provides positive transmission with negligible slip under normal conditions.

Q229. Gears transmit motion through:

A. Direct tooth engagement
B. Fluid pressure only
C. Flexible belt only
D. Magnetic force only

Answer: A. Direct tooth engagement

Explanation: Gear teeth mesh directly to transmit rotary motion and torque.

Q230. Spur gears are generally used for:

A. Parallel shafts
B. Intersecting shafts only
C. Non-parallel non-intersecting shafts only
D. Flexible shafts

Answer: A. Parallel shafts

Explanation: Spur gears have straight teeth parallel to the shaft axis and transmit motion between parallel shafts.

SECTION D — THERMODYNAMICS

Q231. A system that can exchange both mass and energy with its surroundings is:

A. Open system
B. Closed system
C. Isolated system
D. Rigid system only

Answer: A. Open system

Explanation: An open system permits both mass and energy transfer across its boundary.

Q232. A closed system can exchange:

A. Energy but not mass
B. Mass but not energy
C. Neither mass nor energy
D. Only chemical elements

Answer: A. Energy but not mass

Explanation: In a closed system, mass remains fixed while energy can cross the system boundary.

Q233. An isolated system exchanges:

A. Neither mass nor energy with surroundings
B. Mass only
C. Energy only
D. Pressure only

Answer: A. Neither mass nor energy with surroundings

Explanation: An isolated system has no exchange of mass or energy with its surroundings.

Q234. An isothermal process occurs at constant:

A. Pressure
B. Temperature
C. Volume
D. Entropy

Answer: B. Temperature

Explanation: “Iso” means same and “thermal” relates to temperature, so isothermal means constant temperature.

Q235. An isobaric process occurs at constant:

A. Pressure
B. Temperature
C. Volume
D. Mass

Answer: A. Pressure

Explanation: Isobaric means constant pressure.

Q236. An isochoric process occurs at constant:

A. Pressure
B. Volume
C. Temperature
D. Entropy

Answer: B. Volume

Explanation: Isochoric means constant volume.

Q237. An adiabatic process involves:

A. No heat transfer
B. Constant pressure always
C. Constant temperature always
D. No work transfer

Answer: A. No heat transfer

Explanation: For an adiabatic process, heat transfer across the system boundary is zero.

Q238. Entropy is commonly associated with:

A. Energy dispersal and irreversibility
B. Mass only
C. Pressure measurement only
D. Shaft diameter

Answer: A. Energy dispersal and irreversibility

Explanation: Entropy is a thermodynamic property that increases in irreversible processes for an isolated system.

Q239. The second law of thermodynamics establishes the concept of:

A. Direction of natural processes
B. Conservation of mass only
C. Newtonian force
D. Electrical resistance

Answer: A. Direction of natural processes

Explanation: The second law determines the direction of spontaneous processes and places limits on heat-engine performance.

Q240. No heat engine can have efficiency:

A. Less than 100%
B. Equal to 50%
C. Greater than 100%
D. Between 0% and 100%

Answer: C. Greater than 100%

Explanation: A heat engine cannot convert more energy into work than the energy supplied to it.

SECTION E — HEAT TRANSFER

Q241. Fourier’s law is associated with:

A. Heat conduction
B. Fluid momentum
C. Electrical current
D. Radiation pressure

Answer: A. Heat conduction

Explanation: Fourier’s law describes heat conduction in terms of temperature gradient and thermal conductivity.

Q242. Newton’s law of cooling is associated with:

A. Convective heat transfer
B. Electrical conduction
C. Mass diffusion only
D. Mechanical vibration

Answer: A. Convective heat transfer

Explanation: Newton’s law of cooling relates convective heat transfer to the temperature difference between a surface and surrounding fluid.

Q243. Stefan-Boltzmann law relates thermal radiation to:

A. Absolute temperature
B. Shaft speed
C. Fluid viscosity
D. Pressure only

Answer: A. Absolute temperature

Explanation: Radiative heat emission from an ideal blackbody varies with the fourth power of absolute temperature.

Q244. A good thermal insulator should have:

A. Low thermal conductivity
B. High thermal conductivity
C. Zero density
D. High electrical conductivity necessarily

Answer: A. Low thermal conductivity

Explanation: Low thermal conductivity reduces heat transfer.

Q245. Thermal conductivity is a measure of:

A. Ability to conduct heat
B. Resistance to mechanical impact
C. Ability to transmit torque
D. Electrical resistance only

Answer: A. Ability to conduct heat

Explanation: Higher thermal conductivity generally means greater ability to conduct heat.

Q246. Which material is generally a good conductor of heat?

A. Copper
B. Wood
C. Rubber
D. Glass wool

Answer: A. Copper

Explanation: Copper has high thermal conductivity and is widely used for heat-transfer applications.

Q247. Heat exchangers are used to:

A. Transfer heat between fluids
B. Increase material hardness
C. Measure shaft speed
D. Produce gears

Answer: A. Transfer heat between fluids

Explanation: Heat exchangers transfer thermal energy between two or more fluids without necessarily mixing them.

Q248. In a parallel-flow heat exchanger, the two fluids move:

A. In the same general direction
B. In opposite directions
C. Perpendicular to each other only
D. Without movement

Answer: A. In the same general direction

Explanation: Parallel-flow arrangements have both fluids entering from the same end and moving in the same general direction.

Q249. In a counter-flow heat exchanger, the fluids move:

A. In opposite directions
B. In the same direction
C. Vertically only
D. Without temperature difference

Answer: A. In opposite directions

Explanation: Counter-flow heat exchangers have fluid streams moving in opposite directions.

Q250. The effectiveness of a heat exchanger compares actual heat transfer with:

A. Maximum possible heat transfer
B. Mechanical power
C. Electrical power
D. Fluid density

Answer: A. Maximum possible heat transfer

Explanation: Heat exchanger effectiveness is defined as actual heat transfer divided by the maximum possible heat transfer.

SECTION F — FLUID MACHINES

Q251. A centrifugal pump converts:

A. Mechanical energy into hydraulic energy
B. Hydraulic energy into chemical energy
C. Heat into mass
D. Electrical energy directly into heat only

Answer: A. Mechanical energy into hydraulic energy

Explanation: The pump imparts mechanical energy to the liquid, increasing its pressure and/or velocity.

Q252. The impeller is the rotating component of a:

A. Centrifugal pump
B. Boiler
C. Heat exchanger only
D. Pressure gauge

Answer: A. Centrifugal pump

Explanation: The impeller rotates and transfers energy to the fluid.

Q253. Priming of a centrifugal pump means:

A. Filling the pump and suction line with liquid before starting
B. Removing all liquid from the pump
C. Increasing motor temperature
D. Closing the discharge permanently

Answer: A. Filling the pump and suction line with liquid before starting

Explanation: Priming removes air and fills the pump casing and suction line with liquid so the pump can develop suction.

Q254. A reciprocating pump is generally a:

A. Positive-displacement pump
B. Dynamic pump only
C. Turbine
D. Compressor

Answer: A. Positive-displacement pump

Explanation: Reciprocating pumps move a definite volume of fluid during each cycle.

Q255. A hydraulic turbine extracts energy from:

A. Moving or pressurized water
B. Stationary air only
C. Fuel combustion only
D. Electrical resistance

Answer: A. Moving or pressurized water

Explanation: Hydraulic turbines convert hydraulic energy into mechanical shaft power.

Q256. Pelton turbine is generally classified as:

A. Impulse turbine
B. Reaction turbine
C. Reciprocating pump
D. Compressor

Answer: A. Impulse turbine

Explanation: Pelton turbines operate primarily by converting water pressure head into jet velocity before the jet strikes the buckets.

Q257. Francis turbine is generally a:

A. Reaction turbine
B. Pure impulse turbine
C. Reciprocating engine
D. Positive-displacement pump

Answer: A. Reaction turbine

Explanation: Francis turbines operate with pressure change through the runner as well as velocity change.

Q258. Kaplan turbine is suitable for:

A. Low-head, high-flow applications
B. Very high-head, very low-flow applications only
C. Compressed-air systems
D. Refrigeration only

Answer: A. Low-head, high-flow applications

Explanation: Kaplan turbines are axial-flow reaction turbines suited to relatively low heads and high flow rates.

Q259. A compressor is used to:

A. Increase pressure of a gas
B. Reduce gas pressure to zero
C. Measure liquid density
D. Store mechanical energy only

Answer: A. Increase pressure of a gas

Explanation: Compressors consume mechanical energy to raise the pressure of gases.

Q260. An air compressor is commonly used in:

A. Pneumatic systems
B. Hydraulic-only systems
C. Refrigeration condensers only
D. Metal casting furnaces only

Answer: A. Pneumatic systems

Explanation: Pneumatic systems use compressed air to transmit and control power.

SECTION G — MANUFACTURING PROCESSES

Q261. Casting involves:

A. Pouring molten material into a mould
B. Cutting material only with a saw
C. Joining only by bolts
D. Measuring surface roughness

Answer: A. Pouring molten material into a mould

Explanation: Casting produces components by filling a mould cavity with molten material and allowing it to solidify.

Q262. The pattern in casting is used to:

A. Form the mould cavity
B. Harden the final casting directly
C. Measure temperature
D. Cut threads

Answer: A. Form the mould cavity

Explanation: A pattern is a replica or representation of the desired casting shape used to create the mould cavity.

Q263. A riser in casting is provided primarily to:

A. Supply molten metal during solidification
B. Cool the mould instantly
C. Increase cutting speed
D. Remove machining chips

Answer: A. Supply molten metal during solidification

Explanation: Risers compensate for shrinkage by supplying additional molten metal as the casting solidifies.

Q264. Welding is a process of:

A. Joining materials, generally by coalescence
B. Measuring pressure
C. Cutting only
D. Polishing only

Answer: A. Joining materials, generally by coalescence

Explanation: Welding joins materials by localized heating, pressure, or both, with or without filler metal.

Q265. In arc welding, the heat source is primarily:

A. Electric arc
B. Hydraulic pressure
C. Mechanical spring
D. Cooling water

Answer: A. Electric arc

Explanation: An electric arc generates the heat required to melt the workpiece and/or filler material.

Q266. Soldering uses a filler metal with a melting point generally:

A. Below 450°C
B. Above 1,500°C
C. Exactly 1,000°C
D. Equal to the base metal in all cases

Answer: A. Below 450°C

Explanation: By conventional classification, soldering uses filler metal melting below 450°C.

Q267. Brazing uses a filler metal melting:

A. Above 450°C but below the melting temperature of the base metals
B. Below 100°C always
C. Above the melting temperature of the base metals
D. At exactly 0°C

Answer: A. Above 450°C but below the melting temperature of the base metals

Explanation: Brazing joins materials using a filler metal that melts above 450°C without melting the base materials.

Q268. Forging shapes metal primarily through:

A. Plastic deformation
B. Evaporation
C. Condensation
D. Dissolution

Answer: A. Plastic deformation

Explanation: Forging uses compressive forces to plastically deform metal into the desired shape.

Q269. Rolling is commonly used to:

A. Reduce thickness or change cross-section
B. Increase fluid pressure
C. Measure hardness
D. Join electrical wires

Answer: A. Reduce thickness or change cross-section

Explanation: Rolling passes material between rotating rolls to reduce thickness or produce a desired profile.

Q270. Extrusion involves forcing material through:

A. A die opening
B. A bearing
C. A furnace chimney
D. A cooling fan

Answer: A. A die opening

Explanation: Extrusion produces continuous or semi-continuous profiles by forcing material through a die.

SECTION H — METROLOGY & QUALITY

Q271. A vernier caliper can measure:

A. External, internal, and depth dimensions
B. Temperature only
C. Pressure only
D. Electrical resistance only

Answer: A. External, internal, and depth dimensions

Explanation: A vernier caliper is a versatile dimensional measuring instrument.

Q272. A micrometer generally provides:

A. Higher precision than a typical steel rule
B. Lower precision than a ruler
C. Only temperature measurement
D. Only pressure measurement

Answer: A. Higher precision than a typical steel rule

Explanation: Micrometers are designed for accurate measurement of small dimensions.

Q273. Least count refers to:

A. The smallest measurement that an instrument can reliably resolve
B. Maximum instrument capacity only
C. Instrument weight
D. Measurement error only

Answer: A. The smallest measurement that an instrument can reliably resolve

Explanation: Least count represents the smallest scale increment or resolution of an instrument.

Q274. Accuracy refers to:

A. Closeness to the true value
B. Repeatability only
C. Instrument size
D. Speed of measurement

Answer: A. Closeness to the true value

Explanation: Accuracy indicates how close a measured value is to the actual or accepted value.

Q275. Precision refers primarily to:

A. Closeness of repeated measurements to one another
B. Closeness to the true value only
C. Instrument weight
D. Measurement speed

Answer: A. Closeness of repeated measurements to one another

Explanation: Precision reflects repeatability or consistency of measurements.

Q276. A gauge is generally used to:

A. Check dimensions against specified limits
B. Produce heat
C. Increase material strength
D. Measure electrical current only

Answer: A. Check dimensions against specified limits

Explanation: Gauges are commonly used for inspection rather than direct numerical measurement.

Q277. A GO gauge should generally:

A. Pass through or fit the feature it is designed to check
B. Never enter the feature
C. Measure temperature
D. Measure pressure

Answer: A. Pass through or fit the feature it is designed to check

Explanation: In limit gauging, the GO gauge checks the maximum material condition and should generally pass.

Q278. A surface roughness tester measures:

A. Surface texture
B. Shaft speed
C. Fluid pressure
D. Electrical voltage

Answer: A. Surface texture

Explanation: Surface roughness instruments quantify characteristics of surface irregularities.

Q279. Six Sigma primarily focuses on:

A. Reducing process variation and defects
B. Increasing defects
C. Eliminating measurement
D. Increasing waste

Answer: A. Reducing process variation and defects

Explanation: Six Sigma uses statistical and process-improvement methods to reduce variation and defects.

Q280. ISO 9001 is associated with:

A. Quality management systems
B. Engine lubrication only
C. Refrigerant charging only
D. Welding temperature only

Answer: A. Quality management systems

Explanation: ISO 9001 specifies requirements for a quality management system.

SECTION I — INDUSTRIAL SAFETY

Q281. PPE stands for:

A. Personal Protective Equipment
B. Process Production Engineering
C. Power Pressure Equipment
D. Personal Processing Element

Answer: A. Personal Protective Equipment

Explanation: PPE includes equipment such as helmets, gloves, goggles, safety footwear, and protective clothing.

Q282. Safety goggles primarily protect:

A. Eyes
B. Feet
C. Ears
D. Hands

Answer: A. Eyes

Explanation: Safety goggles protect the eyes from particles, splashes, and other hazards.

Q283. Ear protection is used primarily to reduce exposure to:

A. Excessive noise
B. Dust only
C. Heat only
D. Vibration only

Answer: A. Excessive noise

Explanation: Earplugs and earmuffs help reduce harmful occupational noise exposure.

Q284. A fire extinguisher should be selected based on:

A. Type of fire
B. Colour of the building only
C. Number of workers only
D. Machine weight

Answer: A. Type of fire

Explanation: Different extinguishing agents are suitable for different classes of fire.

Q285. Good housekeeping in a workshop helps to:

A. Reduce accidents and improve workplace efficiency
B. Increase hazards
C. Increase obstruction
D. Increase material waste

Answer: A. Reduce accidents and improve workplace efficiency

Explanation: Clean and organized work areas reduce slips, trips, obstruction, and other hazards.

Q286. Lockout/tagout procedures are primarily intended to:

A. Prevent unexpected energization during maintenance
B. Increase machine speed
C. Increase electrical consumption
D. Improve surface finish

Answer: A. Prevent unexpected energization during maintenance

Explanation: Lockout/tagout isolates hazardous energy sources before servicing or maintenance.

Q287. An emergency stop device is intended to:

A. Quickly stop hazardous machine operation
B. Increase production speed
C. Improve lubrication
D. Measure temperature

Answer: A. Quickly stop hazardous machine operation

Explanation: Emergency stops are designed to rapidly bring dangerous machine motion to a safe state.

Q288. A safety guard on a machine is provided to:

A. Prevent contact with hazardous moving parts
B. Increase machine vibration
C. Increase operator exposure
D. Reduce machine strength

Answer: A. Prevent contact with hazardous moving parts

Explanation: Guards create a physical barrier between workers and dangerous machine components.

Q289. Electrical equipment should generally be handled with:

A. Appropriate electrical safety precautions
B. Wet hands
C. Damaged cables
D. Bare conductors

Answer: A. Appropriate electrical safety precautions

Explanation: Electrical hazards require proper isolation, grounding, PPE, and safe work practices.

Q290. A risk assessment is performed to:

A. Identify hazards and evaluate risks
B. Increase workplace hazards
C. Eliminate all documentation
D. Increase machine noise

Answer: A. Identify hazards and evaluate risks

Explanation: Risk assessment helps determine hazards, likelihood, severity, and appropriate control measures.

SECTION J — NUMERICAL & APPLICATION QUESTIONS

Q291. A force of 500 N acts over an area of 0.01 m². The resulting stress is:

A. 5 kPa
B. 50 kPa
C. 500 kPa
D. 5 MPa

Answer: B. 50 kPa

Explanation:

Q292. A machine operates at 20 kW for 3 hours. The energy consumed is:

A. 23 kWh
B. 40 kWh
C. 60 kWh
D. 80 kWh

Answer: C. 60 kWh

Explanation:

Q293. A 2,000 kg vehicle moves at 10 m/s. Its kinetic energy is:

A. 10 kJ
B. 50 kJ
C. 100 kJ
D. 200 kJ

Answer: C. 100 kJ

Explanation:

Q294. A pump delivers 0.02 m³/s of water through a head of 20 m. Taking and water density as , the hydraulic power is approximately:

A. 1.96 kW
B. 3.92 kW
C. 9.81 kW
D. 19.62 kW

Answer: B. 3.92 kW

Explanation:

Q295. A motor receives 25 kW input and delivers 20 kW output. Its efficiency is:

A. 60%
B. 70%
C. 80%
D. 90%

Answer: C. 80%

Explanation:

Q296. A shaft rotates at 1,200 rpm. Its rotational speed in revolutions per second is:

A. 10 rps
B. 20 rps
C. 30 rps
D. 60 rps

Answer: B. 20 rps

Explanation:

Q297. A production line operates for 8 hours and produces 480 units. The average production rate is:

A. 40 units/hour
B. 50 units/hour
C. 60 units/hour
D. 80 units/hour

Answer: C. 60 units/hour

Explanation:

Q298. If 950 components are produced and 19 are defective, the defect percentage is:

A. 1%
B. 2%
C. 5%
D. 10%

Answer: B. 2%

Explanation:

Q299. A pump has a hydraulic output of 15 kW and an input power of 20 kW. Its efficiency is:

A. 50%
B. 60%
C. 75%
D. 80%

Answer: C. 75%

Explanation:

Q300. A worker completes one operation in 2 minutes. Ignoring breaks and downtime, the theoretical output in an 8-hour shift is:

A. 120 units
B. 180 units
C. 240 units
D. 480 units

Answer: C. 240 units

Explanation:

8 hours = 480 minutes.

MOCK TEST 3 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
201	B	226	A	251	A	276	A
202	B	227	A	252	A	277	A
203	A	228	A	253	A	278	A
204	B	229	A	254	A	279	A
205	B	230	A	255	A	280	A
206	B	231	A	256	A	281	A
207	C	232	A	257	A	282	A
208	A	233	A	258	A	283	A
209	A	234	B	259	A	284	A
210	B	235	A	260	A	285	A
211	A	236	B	261	A	286	A
212	B	237	A	262	A	287	A
213	B	238	A	263	A	288	A
214	B	239	A	264	A	289	A
215	A	240	C	265	A	290	A
216	A	241	A	266	A	291	B
217	B	242	A	267	A	292	C
218	B	243	A	268	A	293	C
219	A	244	A	269	A	294	B
220	A	245	A	270	A	295	C
221	A	246	A	271	A	296	B
222	A	247	A	272	A	297	C
223	A	248	A	273	A	298	B
224	A	249	A	274	A	299	C
225	A	250	A	275	A	300	C

MOCK TEST 4 — QUESTIONS 301–400

Complete Exam Practice

Instructions: Choose the correct answer from the four options. Each question includes the answer and a concise explanation.

SECTION A — ENGINEERING MECHANICS

Q301. The SI unit of force is:

A. Joule
B. Newton
C. Pascal
D. Watt

Answer: B. Newton

Explanation: The SI unit of force is the newton (N).

Q302. One Newton is equal to:

A. kg·m/s
B. kg·m/s²
C. kg/m²
D. kg·m²/s

Answer: B. kg·m/s²

Explanation: From , one newton equals .

Q303. The resultant of two equal and opposite forces acting along the same line is:

A. Maximum
B. Zero
C. Infinite
D. Equal to one force

Answer: B. Zero

Explanation: Equal forces acting in opposite directions cancel each other.

Q304. The moment of a force about a point is equal to:

A. Force × perpendicular distance
B. Force ÷ distance
C. Mass × velocity
D. Force × time

Answer: A. Force × perpendicular distance

Explanation:

where is the perpendicular distance from the point to the line of action.

Q305. The SI unit of torque is:

A. N
B. N/m
C. N·m
D. J/s

Answer: C. N·m

Explanation: Torque is force multiplied by perpendicular distance and is measured in newton-metres.

Q306. A couple consists of:

A. Two equal and opposite parallel forces
B. Two unequal forces in the same direction
C. One force only
D. Three parallel forces

Answer: A. Two equal and opposite parallel forces

Explanation: A couple produces a pure turning effect without a net translational force.

Q307. The centre of gravity of a uniform rectangular plate is located at:

A. One corner
B. The geometric centre
C. The midpoint of one side
D. Outside the plate

Answer: B. The geometric centre

Explanation: Due to symmetry, the centre of gravity is at the geometric centre.

Q308. Mechanical advantage is defined as:

A. Effort/load
B. Load/effort
C. Load × effort
D. Load + effort

Answer: B. Load/effort

Explanation:

Q309. Velocity ratio is the ratio of:

A. Load distance to effort distance
B. Effort distance to load distance
C. Load to effort
D. Output power to input power

Answer: B. Effort distance to load distance

Explanation: Velocity ratio is the distance moved by effort divided by the distance moved by load.

Q310. Efficiency of a machine is:

A. MA × VR
B. MA/VR
C. VR/MA
D. MA + VR

Answer: B. MA/VR

Explanation:

SECTION B — ENGINEERING MATERIALS

Q311. Steel is primarily an alloy of:

A. Copper and zinc
B. Iron and carbon
C. Aluminium and copper
D. Lead and tin

Answer: B. Iron and carbon

Explanation: Steel is primarily an iron-carbon alloy, with carbon content generally lower than that of cast iron.

Q312. Brass is an alloy of:

A. Copper and zinc
B. Copper and tin
C. Iron and carbon
D. Aluminium and silicon

Answer: A. Copper and zinc

Explanation: Brass is primarily composed of copper and zinc.

Q313. Bronze is traditionally an alloy of:

A. Copper and tin
B. Copper and zinc
C. Iron and nickel
D. Aluminium and zinc

Answer: A. Copper and tin

Explanation: Traditional bronze consists mainly of copper and tin.

Q314. Cast iron generally contains:

A. Less carbon than pure iron
B. More carbon than steel
C. No carbon
D. Only aluminium

Answer: B. More carbon than steel

Explanation: Cast iron has a higher carbon content than steel, contributing to its hardness and brittleness.

Q315. Ductility is the ability of a material to:

A. Be drawn into wires
B. Resist indentation
C. Resist heat transfer
D. Resist corrosion only

Answer: A. Be drawn into wires

Explanation: Ductile materials can undergo significant plastic deformation in tension and can be drawn into wires.

Q316. Malleability is the ability of a material to:

A. Be formed into thin sheets
B. Be drawn into wires
C. Resist electrical current
D. Conduct sound

Answer: A. Be formed into thin sheets

Explanation: Malleability is the ability to undergo plastic deformation under compressive loading, such as hammering into sheets.

Q317. Toughness represents the ability to:

A. Absorb energy before fracture
B. Conduct electricity
C. Resist only elastic deformation
D. Melt at low temperature

Answer: A. Absorb energy before fracture

Explanation: Toughness is the ability to absorb energy and undergo deformation before fracture.

Q318. Elasticity is the ability of a material to:

A. Return to its original shape after removal of load
B. Break immediately under load
C. Conduct heat
D. Resist corrosion only

Answer: A. Return to its original shape after removal of load

Explanation: An elastic material recovers its original dimensions when the applied load is removed, within its elastic limit.

Q319. Annealing is generally used to:

A. Soften material and relieve internal stresses
B. Increase brittleness only
C. Increase electrical resistance
D. Produce cutting tools directly

Answer: A. Soften material and relieve internal stresses

Explanation: Annealing involves controlled heating and cooling to soften material and improve ductility and machinability.

Q320. Quenching generally involves:

A. Rapid cooling
B. Very slow cooling only
C. Heating without cooling
D. Melting the material

Answer: A. Rapid cooling

Explanation: Quenching rapidly cools heated metal, often to obtain increased hardness.

SECTION C — MACHINE DESIGN

Q321. The primary function of a shaft is to:

A. Transmit torque and rotary motion
B. Store coolant
C. Measure pressure
D. Produce compressed air

Answer: A. Transmit torque and rotary motion

Explanation: Shafts transmit mechanical power through torque and rotation.

Q322. A key is used to:

A. Connect a shaft and hub for torque transmission
B. Measure shaft diameter
C. Lubricate a bearing
D. Reduce temperature

Answer: A. Connect a shaft and hub for torque transmission

Explanation: A key fits into matching grooves in the shaft and hub to prevent relative rotation.

Q323. A coupling is used to:

A. Connect two shafts
B. Measure torque
C. Increase fluid viscosity
D. Cut threads

Answer: A. Connect two shafts

Explanation: Couplings transmit torque between connected shafts.

Q324. A flywheel is primarily used to:

A. Store rotational energy and smooth speed fluctuations
B. Increase friction
C. Measure pressure
D. Reduce shaft length

Answer: A. Store rotational energy and smooth speed fluctuations

Explanation: A flywheel stores kinetic energy and helps maintain more uniform rotational speed.

Q325. A governor is used to:

A. Control mean speed of an engine under varying load
B. Store energy
C. Increase lubrication
D. Measure temperature only

Answer: A. Control mean speed of an engine under varying load

Explanation: A governor regulates the fuel or working-fluid supply to maintain approximately constant engine speed.

Q326. A spring is commonly used to:

A. Store mechanical energy
B. Produce fuel
C. Measure temperature
D. Increase corrosion

Answer: A. Store mechanical energy

Explanation: Springs store energy when deformed and release it when the load is removed.

Q327. A helical spring subjected to axial load primarily experiences:

A. Torsional shear stress
B. Pure tensile stress only
C. Pure compressive stress only
D. No stress

Answer: A. Torsional shear stress

Explanation: The wire of a close-coiled helical spring mainly undergoes torsional shear due to the applied axial load.

Q328. A bolt is mainly used for:

A. Detachable fastening
B. Permanent casting
C. Measuring pressure
D. Heat treatment

Answer: A. Detachable fastening

Explanation: Bolted joints allow components to be assembled and disassembled.

Q329. A riveted joint is generally classified as:

A. Permanent joint
B. Temporary joint
C. Sliding joint
D. Flexible shaft

Answer: A. Permanent joint

Explanation: Riveting forms a permanent mechanical joint that normally requires destruction of the rivet for disassembly.

Q330. A screw thread converts:

A. Rotary motion into linear motion or vice versa
B. Heat into electricity
C. Pressure into mass
D. Fluid flow into temperature

Answer: A. Rotary motion into linear motion or vice versa

Explanation: Screw mechanisms convert rotational movement into controlled linear movement.

SECTION D — INTERNAL COMBUSTION ENGINES

Q331. SI engine stands for:

A. Spark Ignition engine
B. Speed Injection engine
C. Steam Ignition engine
D. Standard Injection engine

Answer: A. Spark Ignition engine

Explanation: SI engines use a spark plug to initiate combustion of the air-fuel mixture.

Q332. CI engine stands for:

A. Compression Ignition engine
B. Combustion Injection engine
C. Controlled Ignition engine
D. Continuous Ignition engine

Answer: A. Compression Ignition engine

Explanation: In a CI engine, fuel ignition occurs because of the high temperature produced by compression.

Q333. Petrol engines are generally:

A. Spark-ignition engines
B. Compression-ignition engines
C. Steam engines
D. External combustion engines

Answer: A. Spark-ignition engines

Explanation: Conventional petrol engines use spark ignition.

Q334. Diesel engines are generally:

A. Compression-ignition engines
B. Spark-ignition engines
C. Electric motors
D. Steam turbines

Answer: A. Compression-ignition engines

Explanation: Diesel engines ignite injected fuel using the high temperature of compressed air.

Q335. The four strokes of a four-stroke engine are:

A. Suction, compression, power, exhaust
B. Compression, suction, exhaust, power
C. Power, exhaust, suction, cooling
D. Exhaust, cooling, power, suction

Answer: A. Suction, compression, power, exhaust

Explanation: These four strokes complete one operating cycle.

Q336. During the compression stroke of a four-stroke engine:

A. The charge is compressed
B. Exhaust gases are expelled
C. Fresh charge enters only
D. The piston remains stationary

Answer: A. The charge is compressed

Explanation: Both valves are generally closed while the piston moves toward the cylinder head.

Q337. The power stroke produces:

A. Useful work from expanding gases
B. Only exhaust gases
C. Cooling water
D. Lubricating oil

Answer: A. Useful work from expanding gases

Explanation: Combustion raises gas pressure, which pushes the piston and produces useful work.

Q338. The crankshaft converts:

A. Reciprocating motion into rotary motion
B. Rotary motion into heat
C. Heat into pressure only
D. Fluid flow into electricity

Answer: A. Reciprocating motion into rotary motion

Explanation: The crank mechanism converts piston reciprocation into continuous crankshaft rotation.

Q339. The function of a piston ring includes:

A. Sealing combustion gases
B. Increasing fuel consumption
C. Producing electrical power
D. Cooling the radiator only

Answer: A. Sealing combustion gases

Explanation: Piston rings help seal the combustion chamber, control lubricating oil, and transfer heat to the cylinder wall.

Q340. The function of a radiator in an engine cooling system is to:

A. Reject heat from the coolant
B. Increase fuel pressure
C. Compress air
D. Increase engine friction

Answer: A. Reject heat from the coolant

Explanation: The radiator transfers heat from engine coolant to the surrounding air.

SECTION E — REFRIGERATION & AIR CONDITIONING

Q341. Refrigeration is the process of:

A. Removing heat from a low-temperature region
B. Adding heat to a low-temperature region
C. Producing cold without energy transfer
D. Destroying heat

Answer: A. Removing heat from a low-temperature region

Explanation: Refrigeration removes heat from a space or substance and rejects it to a higher-temperature sink.

Q342. COP of a refrigerator is:

A. Refrigerating effect/work input
B. Work input/refrigerating effect
C. Heat rejected/work input
D. Work output/heat input

Answer: A. Refrigerating effect/work input

Explanation:

Q343. The main function of a compressor in a vapour-compression refrigeration system is to:

A. Increase refrigerant pressure
B. Reduce refrigerant pressure
C. Condense all refrigerant directly
D. Remove oil from the system

Answer: A. Increase refrigerant pressure

Explanation: The compressor raises the pressure and temperature of the refrigerant vapour.

Q344. The condenser in a refrigeration system:

A. Rejects heat
B. Absorbs heat from the refrigerated space
C. Expands the refrigerant
D. Compresses the refrigerant

Answer: A. Rejects heat

Explanation: The condenser rejects heat to the surroundings and converts high-pressure vapour into liquid.

Q345. The evaporator:

A. Absorbs heat from the refrigerated space
B. Rejects all heat to the atmosphere
C. Compresses refrigerant
D. Increases refrigerant pressure

Answer: A. Absorbs heat from the refrigerated space

Explanation: Refrigerant evaporates in the evaporator while absorbing heat from the space or product being cooled.

Q346. The expansion valve primarily:

A. Reduces refrigerant pressure
B. Increases refrigerant pressure
C. Compresses vapour
D. Condenses vapour

Answer: A. Reduces refrigerant pressure

Explanation: The expansion device produces a pressure drop before the refrigerant enters the evaporator.

Q347. The SI unit of refrigeration capacity is commonly expressed as:

A. Watt
B. Newton
C. Pascal
D. Joule/second²

Answer: A. Watt

Explanation: Refrigeration capacity is a rate of heat removal and can be expressed in watts.

Q348. One ton of refrigeration is approximately:

A. 0.517 kW
B. 1.517 kW
C. 3.517 kW
D. 10 kW

Answer: C. 3.517 kW

Explanation: One ton of refrigeration is approximately 3.517 kW of cooling capacity.

Q349. An air conditioner primarily controls:

A. Temperature and humidity, along with air quality and circulation
B. Engine torque
C. Shaft diameter
D. Metal hardness

Answer: A. Temperature and humidity, along with air quality and circulation

Explanation: Air conditioning involves conditioning indoor air through cooling/heating, dehumidification, filtration, and circulation as required.

Q350. Relative humidity is the ratio of:

A. Actual water-vapour partial pressure to saturation pressure at the same temperature
B. Dry-bulb temperature to wet-bulb temperature
C. Pressure to volume
D. Heat to work

Answer: A. Actual water-vapour partial pressure to saturation pressure at the same temperature

Explanation: Relative humidity indicates how close air is to saturation with water vapour.

SECTION F — PRODUCTION ENGINEERING

Q351. A lathe is primarily used for:

A. Turning operations
B. Welding
C. Casting
D. Heat treatment

Answer: A. Turning operations

Explanation: Turning is the principal operation performed on a conventional lathe.

Q352. In a turning operation, the workpiece:

A. Rotates while the cutting tool feeds along it
B. Remains stationary while the tool rotates around it
C. Is melted
D. Is forged

Answer: A. Rotates while the cutting tool feeds along it

Explanation: The rotating workpiece and advancing cutting tool remove material to produce a cylindrical surface.

Q353. A drilling machine is used primarily to:

A. Produce holes
B. Produce castings
C. Weld sheets
D. Harden gears

Answer: A. Produce holes

Explanation: Drilling creates cylindrical holes using a rotating drill.

Q354. A milling machine removes material using:

A. A rotating multi-point cutting tool
B. A stationary casting mould
C. A welding electrode only
D. A grinding wheel only

Answer: A. A rotating multi-point cutting tool

Explanation: Milling cutters have multiple cutting edges and rotate while removing material.

Q355. Grinding is generally considered a:

A. Finishing process
B. Casting process
C. Joining process
D. Forming process only

Answer: A. Finishing process

Explanation: Grinding is commonly used to achieve high dimensional accuracy and good surface finish.

Q356. Cutting speed in turning refers to:

A. Surface speed of the workpiece relative to the cutting edge
B. Feed per revolution
C. Depth of cut
D. Tool life

Answer: A. Surface speed of the workpiece relative to the cutting edge

Explanation: Cutting speed is generally expressed in metres per minute.

Q357. Feed in a lathe is commonly expressed as:

A. mm/revolution
B. kg/m³
C. N/m²
D. kW/hour

Answer: A. mm/revolution

Explanation: Feed represents the distance the cutting tool advances per revolution of the workpiece.

Q358. Depth of cut is the:

A. Thickness of material removed in one cutting pass, measured normal to the machined surface
B. Tool speed
C. Workpiece weight
D. Cutting temperature only

Answer: A. Thickness of material removed in one cutting pass, measured normal to the machined surface

Explanation: Depth of cut represents the penetration of the cutting tool into the workpiece.

Q359. Tool wear generally causes:

A. Reduction in tool performance and dimensional accuracy
B. Infinite tool life
C. Zero cutting force
D. Increased tool sharpness

Answer: A. Reduction in tool performance and dimensional accuracy

Explanation: Progressive tool wear can increase cutting forces, temperature, surface roughness, and dimensional errors.

Q360. Cutting fluid is used primarily to:

A. Cool and lubricate the cutting zone
B. Increase friction
C. Harden the machine bed
D. Increase tool wear

Answer: A. Cool and lubricate the cutting zone

Explanation: Cutting fluids help control temperature, reduce friction, flush chips, and improve tool life and surface finish.

SECTION G — INDUSTRIAL ENGINEERING

Q361. Productivity is generally defined as:

A. Output/input
B. Input/output
C. Output × input
D. Input + output

Answer: A. Output/input

Explanation: Productivity measures how effectively resources are converted into output.

Q362. Work study consists primarily of:

A. Method study and work measurement
B. Casting and welding
C. Heat treatment and forging
D. Inspection and painting only

Answer: A. Method study and work measurement

Explanation: Work study seeks to improve methods and establish appropriate time standards.

Q363. Time study is used to determine:

A. Standard time for a task
B. Material chemical composition
C. Machine colour
D. Building height

Answer: A. Standard time for a task

Explanation: Time study measures task performance and develops a standard time after considering appropriate allowances.

Q364. Method study focuses on:

A. Finding a better way of performing work
B. Measuring temperature
C. Measuring hardness
D. Determining chemical composition

Answer: A. Finding a better way of performing work

Explanation: Method study systematically examines work methods to improve efficiency.

Q365. Inventory means:

A. Stock of materials, components, or finished goods
B. Only cash in hand
C. Only machinery
D. Only labour

Answer: A. Stock of materials, components, or finished goods

Explanation: Inventory includes items held for production, processing, or sale.

Q366. EOQ stands for:

A. Economic Order Quantity
B. Engineering Output Quality
C. Energy Operating Quantity
D. Equipment Order Quality

Answer: A. Economic Order Quantity

Explanation: EOQ is a traditional inventory-control model used to determine an order quantity that balances ordering and holding costs.

Q367. The primary purpose of inventory control is to:

A. Maintain required stock at minimum reasonable cost
B. Eliminate all stock regardless of need
C. Maximize storage costs
D. Increase shortages

Answer: A. Maintain required stock at minimum reasonable cost

Explanation: Inventory control balances availability against the costs of ordering, holding, and shortages.

Q368. A bottleneck is:

A. A process or resource that limits overall system capacity
B. The fastest process in a system
C. A storage building
D. A type of bearing

Answer: A. A process or resource that limits overall system capacity

Explanation: The bottleneck constrains throughput and often determines the effective capacity of the system.

Q369. Line balancing attempts to:

A. Distribute work among workstations efficiently
B. Increase idle time
C. Eliminate all workers
D. Increase machine breakdowns

Answer: A. Distribute work among workstations efficiently

Explanation: Line balancing aims to achieve an efficient allocation of tasks while reducing idle time.

Q370. Preventive maintenance is performed:

A. Before failure occurs
B. Only after catastrophic failure
C. Never
D. Only during machine disposal

Answer: A. Before failure occurs

Explanation: Preventive maintenance is planned maintenance intended to reduce the probability of failure.

SECTION H — ELECTRICAL & CONTROL BASICS

Q371. Ohm’s law is:

A.
B.
C.
D.

Answer: A.

Explanation: Ohm’s law states that voltage equals current multiplied by resistance under constant physical conditions.

Q372. The SI unit of electrical resistance is:

A. Volt
B. Ampere
C. Ohm
D. Watt

Answer: C. Ohm

Explanation: Electrical resistance is measured in ohms (Ω).

Q373. Electrical power in a DC circuit is:

A.
B.
C.
D.

Answer: A.

Explanation: Electrical power equals voltage multiplied by current.

Q374. A fuse protects an electrical circuit against:

A. Excessive current
B. Low temperature
C. Low humidity
D. Mechanical vibration only

Answer: A. Excessive current

Explanation: A fuse melts when excessive current flows, opening the circuit.

Q375. A transformer operates on:

A. Electromagnetic induction
B. Chemical reaction
C. Hydraulic pressure
D. Mechanical friction

Answer: A. Electromagnetic induction

Explanation: Transformers transfer AC electrical energy between circuits through electromagnetic induction.

Q376. A step-up transformer:

A. Increases voltage
B. Decreases voltage
C. Converts AC to DC directly
D. Produces mechanical power directly

Answer: A. Increases voltage

Explanation: A step-up transformer has a higher secondary voltage than its primary voltage under ideal conditions.

Q377. A sensor is used to:

A. Detect or measure a physical quantity
B. Increase mechanical friction
C. Store fuel
D. Join two shafts

Answer: A. Detect or measure a physical quantity

Explanation: Sensors convert physical quantities such as temperature, pressure, displacement, or speed into usable signals.

Q378. A transducer converts:

A. One form of energy or physical quantity into another usable form
B. Only heat into mechanical work
C. Only electricity into heat
D. Only pressure into mass

Answer: A. One form of energy or physical quantity into another usable form

Explanation: Transducers are used to sense and convert physical quantities into corresponding signals.

Q379. PLC stands for:

A. Programmable Logic Controller
B. Power Load Converter
C. Process Line Circuit
D. Programmable Load Capacitor

Answer: A. Programmable Logic Controller

Explanation: PLCs are industrial digital control systems used to automate machines and processes.

Q380. CNC stands for:

A. Computer Numerical Control
B. Central Numerical Circuit
C. Computer Network Control
D. Continuous Numerical Calculation

Answer: A. Computer Numerical Control

Explanation: CNC machines use computer-based numerical instructions to control machining operations.

SECTION I — FLUID MECHANICS & HYDRAULICS

Q381. The SI unit of pressure is:

A. Newton
B. Pascal
C. Joule
D. Watt

Answer: B. Pascal

Explanation: One pascal equals one newton per square metre.

Q382. Atmospheric pressure is measured using:

A. Barometer
B. Ammeter
C. Tachometer
D. Dynamometer

Answer: A. Barometer

Explanation: A barometer measures atmospheric pressure.

Q383. A manometer is commonly used to measure:

A. Pressure difference
B. Electrical current
C. Shaft speed
D. Temperature only

Answer: A. Pressure difference

Explanation: Manometers use liquid columns to measure pressure or pressure differences.

Q384. Bernoulli’s equation is based on conservation of:

A. Mechanical energy
B. Mass only
C. Electrical charge
D. Temperature

Answer: A. Mechanical energy

Explanation: For ideal steady incompressible flow along a streamline, Bernoulli’s equation expresses conservation of mechanical energy.

Q385. Continuity equation for incompressible steady flow is:

A.
B.
C.
D.

Answer: A.

Explanation: Conservation of mass gives constant volumetric flow rate for steady incompressible flow.

Q386. Reynolds number is used to characterize:

A. Flow regime
B. Material hardness
C. Electrical resistance
D. Heat capacity only

Answer: A. Flow regime

Explanation: Reynolds number helps distinguish laminar, transitional, and turbulent flow regimes.

Q387. Low Reynolds number flow is generally associated with:

A. Laminar flow
B. Highly turbulent flow
C. Supersonic flow only
D. Cavitation only

Answer: A. Laminar flow

Explanation: Lower Reynolds numbers indicate viscous forces dominate over inertial forces, favouring laminar flow.

Q388. Cavitation occurs when local liquid pressure falls:

A. Below vapour pressure
B. Above atmospheric pressure only
C. Equal to zero temperature
D. Above critical pressure always

Answer: A. Below vapour pressure

Explanation: When local pressure falls below the liquid’s vapour pressure, vapour bubbles can form and subsequently collapse.

Q389. Hydraulic systems generally use:

A. Pressurized liquid
B. Compressed gas only
C. Solid fuel
D. Electrical current only

Answer: A. Pressurized liquid

Explanation: Hydraulic power transmission uses pressurized fluids, commonly hydraulic oil.

Q390. A hydraulic cylinder converts:

A. Hydraulic energy into linear mechanical motion
B. Mechanical motion into electrical energy only
C. Heat into pressure only
D. Electrical current into fluid density

Answer: A. Hydraulic energy into linear mechanical motion

Explanation: Hydraulic pressure acting on a piston produces linear force and motion.

SECTION J — GENERAL TECHNICAL APPLICATION

Q391. A machine has an input power of 50 kW and efficiency of 80%. Its output power is:

A. 20 kW
B. 30 kW
C. 40 kW
D. 60 kW

Answer: C. 40 kW

Explanation:

Q392. A body of mass 10 kg is accelerated at 5 m/s². The force required is:

A. 2 N
B. 15 N
C. 50 N
D. 100 N

Answer: C. 50 N

Explanation:

Q393. A 100 N force moves an object through 5 m in the same direction. Work done is:

A. 20 J
B. 100 J
C. 500 J
D. 1,000 J

Answer: C. 500 J

Explanation:

Q394. A 10 kW machine operates for 30 minutes. Energy consumed is:

A. 2 kWh
B. 5 kWh
C. 10 kWh
D. 20 kWh

Answer: B. 5 kWh

Explanation:

30 minutes = 0.5 hour.

Q395. A shaft transmits 10 kW at 1,000 rpm. The approximate torque is:

A. 9.55 N·m
B. 47.75 N·m
C. 95.5 N·m
D. 955 N·m

Answer: C. 95.5 N·m

Explanation:

Q396. A rectangular plate is 2 m long and 0.5 m wide. Its area is:

A. 0.5 m²
B. 1 m²
C. 1.5 m²
D. 2.5 m²

Answer: B. 1 m²

Explanation:

Q397. A material has a mass of 20 kg and occupies 0.01 m³. Its density is:

A. 200 kg/m³
B. 500 kg/m³
C. 2,000 kg/m³
D. 20,000 kg/m³

Answer: C. 2,000 kg/m³

Explanation:

Q398. A 4 m long bar elongates by 2 mm. The longitudinal strain is:

A. 0.0005
B. 0.005
C. 0.05
D. 0.5

Answer: A. 0.0005

Explanation:

Q399. If stress is 200 MPa and strain is 0.001, Young’s modulus is:

A. 20 MPa
B. 200 MPa
C. 20 GPa
D. 200 GPa

Answer: C. 20 GPa

Explanation:

Correction: The calculated value is 200 GPa, not 20 GPa.

Therefore:

Correct Answer: D. 200 GPa

Q400. A production process produces 1,000 units, of which 20 are defective. The first-pass yield is:

A. 96%
B. 97%
C. 98%
D. 99%

Answer: C. 98%

Explanation:

Good units:

Therefore:

MOCK TEST 4 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
301	B	326	A	351	A	376	A
302	B	327	A	352	A	377	A
303	B	328	A	353	A	378	A
304	A	329	A	354	A	379	A
305	C	330	A	355	A	380	A
306	A	331	A	356	A	381	B
307	B	332	A	357	A	382	A
308	B	333	A	358	A	383	A
309	B	334	A	359	A	384	A
310	B	335	A	360	A	385	A
311	B	336	A	361	A	386	A
312	A	337	A	362	A	387	A
313	A	338	A	363	A	388	A
314	B	339	A	364	A	389	A
315	A	340	A	365	A	390	A
316	A	341	A	366	A	391	C
317	A	342	A	367	A	392	C
318	A	343	A	368	A	393	C
319	A	344	A	369	A	394	B
320	A	345	A	370	A	395	C
321	A	346	A	371	A	396	B
322	A	347	A	372	C	397	C
323	A	348	C	373	A	398	A
324	A	349	A	374	A	399	D
325	A	350	A	375	A	400	C

MOCK TEST 5 — QUESTIONS 401–500

Complete Exam Practice

Instructions: Choose the correct answer from the four options. All questions and explanations are in English. No Hindi is used.

SECTION A — ENGINEERING MECHANICS

Q401. Newton’s second law of motion relates force to:

A. Mass and acceleration
B. Mass and volume
C. Density and pressure
D. Energy and power

Answer: A. Mass and acceleration

Explanation: Newton’s second law is expressed as .

Q402. A force of 60 N acts on a body of mass 12 kg. Its acceleration is:

A. 2 m/s²
B. 5 m/s²
C. 6 m/s²
D. 12 m/s²

Answer: B. 5 m/s²

Explanation:

Q403. The weight of a body is given by:

A.
B.
C.
D.

Answer: B.

Explanation: Weight is the gravitational force acting on a mass.

Q404. The approximate acceleration due to gravity near Earth’s surface is:

A. 5.81 m/s²
B. 7.81 m/s²
C. 9.81 m/s²
D. 12.81 m/s²

Answer: C. 9.81 m/s²

Explanation: The standard approximate value of gravitational acceleration is 9.81 m/s².

Q405. Linear momentum is equal to:

A. Mass × velocity
B. Mass × acceleration
C. Force × acceleration
D. Weight × distance

Answer: A. Mass × velocity

Explanation:

Q406. The SI unit of momentum is:

A. N
B. N·m
C. kg·m/s
D. kg/m³

Answer: C. kg·m/s

Explanation: Momentum equals mass multiplied by velocity.

Q407. Kinetic energy of a body is:

A.
B.
C.
D.

Answer: C.

Explanation: Kinetic energy is the energy possessed by a body due to its motion.

Q408. Potential energy due to height is:

A.
B.
C.
D.

Answer: A.

Explanation: Gravitational potential energy is .

Q409. Power is defined as:

A. Work done per unit time
B. Force per unit area
C. Mass per unit volume
D. Energy per unit mass

Answer: A. Work done per unit time

Explanation:

Q410. The SI unit of power is:

A. Joule
B. Watt
C. Newton
D. Pascal

Answer: B. Watt

Explanation: One watt equals one joule per second.

SECTION B — STRENGTH OF MATERIALS

Q411. Stress is defined as:

A. Force per unit area
B. Area per unit force
C. Force × area
D. Force × length

Answer: A. Force per unit area

Explanation:

Q412. The SI unit of stress is:

A. Newton
B. Pascal
C. Joule
D. Watt

Answer: B. Pascal

Explanation: Stress is force divided by area and is measured in pascals.

Q413. Strain is:

A. Dimensionless
B. Measured in newtons
C. Measured in pascals
D. Measured in joules

Answer: A. Dimensionless

Explanation: Strain is the ratio of change in dimension to original dimension.

Q414. Hooke’s law is valid within the:

A. Plastic region
B. Elastic limit
C. Fracture region
D. Necking region only

Answer: B. Elastic limit

Explanation: Within the proportional or elastic range, stress is proportional to strain.

Q415. Young’s modulus is the ratio of:

A. Shear stress to shear strain
B. Normal stress to longitudinal strain
C. Load to area only
D. Strain to stress

Answer: B. Normal stress to longitudinal strain

Explanation:

Q416. Poisson’s ratio relates:

A. Lateral strain to longitudinal strain
B. Stress to force
C. Force to area
D. Energy to power

Answer: A. Lateral strain to longitudinal strain

Explanation: Poisson’s ratio is the negative ratio of lateral strain to longitudinal strain.

Q417. A tensile force tends to:

A. Shorten a body
B. Elongate a body
C. Twist a body only
D. Bend a body only

Answer: B. Elongate a body

Explanation: Tensile loading pulls a body apart and generally increases its length.

Q418. A compressive force tends to:

A. Elongate a body
B. Shorten a body
C. Increase its temperature only
D. Produce electrical current

Answer: B. Shorten a body

Explanation: Compression pushes material together and generally reduces its length.

Q419. Shear stress acts:

A. Normal to the surface
B. Tangential to the surface
C. Only vertically
D. Only horizontally

Answer: B. Tangential to the surface

Explanation: Shear stress acts parallel or tangential to the surface.

Q420. A beam primarily subjected to transverse loading develops:

A. Bending moment and shear force
B. Only axial force
C. Only temperature
D. Only pressure

Answer: A. Bending moment and shear force

Explanation: Transverse loading on beams produces internal shear forces and bending moments.

SECTION C — MACHINE ELEMENTS

Q421. Bearings are primarily used to:

A. Support rotating shafts and reduce friction
B. Increase shaft friction
C. Increase corrosion
D. Store fuel

Answer: A. Support rotating shafts and reduce friction

Explanation: Bearings support shafts while permitting relative motion with reduced friction.

Q422. Ball bearings are classified as:

A. Rolling-contact bearings
B. Sliding-contact bearings only
C. Magnetic bearings only
D. Hydraulic cylinders

Answer: A. Rolling-contact bearings

Explanation: Ball bearings use rolling elements between races.

Q423. Journal bearings are generally:

A. Sliding-contact bearings
B. Rolling-contact bearings
C. Gear drives
D. Couplings

Answer: A. Sliding-contact bearings

Explanation: Journal bearings operate with sliding motion between the shaft and bearing surface.

Q424. A gear is used to transmit:

A. Rotary motion and torque
B. Electrical current
C. Heat only
D. Hydraulic pressure only

Answer: A. Rotary motion and torque

Explanation: Gears transmit rotary power between shafts while allowing changes in speed and torque.

Q425. Spur gears have teeth that are:

A. Parallel to the gear axis
B. Inclined to the gear axis
C. Circular only
D. Perpendicular to the gear face only

Answer: A. Parallel to the gear axis

Explanation: Spur gear teeth are straight and parallel to the axis.

Q426. Helical gear teeth are:

A. Inclined to the gear axis
B. Always parallel to the axis
C. Completely circular
D. Without any angle

Answer: A. Inclined to the gear axis

Explanation: Helical gear teeth are cut at an angle to the axis.

Q427. A worm and worm wheel are commonly used when:

A. Large speed reduction is required
B. No torque is required
C. Electrical insulation is required
D. Temperature must be measured

Answer: A. Large speed reduction is required

Explanation: Worm gearing provides high speed reduction in a compact arrangement.

Q428. A belt drive generally transmits power between:

A. Parallel shafts
B. Intersecting shafts only
C. Perpendicular shafts only
D. Non-rotating members

Answer: A. Parallel shafts

Explanation: Belt drives commonly connect parallel shafts over relatively larger centre distances.

Q429. Chain drives provide:

A. Positive drive without slip under normal conditions
B. Continuous slip
C. No torque transmission
D. Only reciprocating motion

Answer: A. Positive drive without slip under normal conditions

Explanation: Chain engagement with sprocket teeth provides positive transmission.

Q430. A clutch is used to:

A. Engage or disengage power transmission
B. Measure temperature
C. Store compressed air
D. Increase bearing wear

Answer: A. Engage or disengage power transmission

Explanation: A clutch allows power flow between driving and driven members to be connected or interrupted.

SECTION D — THERMODYNAMICS

Q431. The zeroth law of thermodynamics provides the basis for:

A. Temperature measurement
B. Conservation of energy
C. Entropy generation
D. Heat engine efficiency

Answer: A. Temperature measurement

Explanation: The zeroth law establishes thermal equilibrium and provides the basis for defining temperature.

Q432. The first law of thermodynamics is based on conservation of:

A. Mass only
B. Energy
C. Momentum only
D. Temperature

Answer: B. Energy

Explanation: Energy cannot be created or destroyed, although it can change form.

Q433. The second law of thermodynamics introduces the concept of:

A. Entropy
B. Density
C. Viscosity
D. Hardness

Answer: A. Entropy

Explanation: The second law establishes the direction of spontaneous processes and introduces entropy.

Q434. The SI unit of absolute temperature is:

A. Celsius
B. Kelvin
C. Fahrenheit
D. Joule

Answer: B. Kelvin

Explanation: Kelvin is the SI base unit of thermodynamic temperature.

Q435. Absolute zero is approximately:

A. 0°C
B. −100°C
C. −273.15°C
D. 273.15°C

Answer: C. −273.15°C

Explanation: Absolute zero corresponds to 0 K, approximately −273.15°C.

Q436. An isothermal process occurs at constant:

A. Pressure
B. Temperature
C. Volume
D. Entropy

Answer: B. Temperature

Explanation: “Iso-thermal” means constant temperature.

Q437. An isobaric process occurs at constant:

A. Pressure
B. Temperature
C. Volume
D. Mass only

Answer: A. Pressure

Explanation: “Iso-baric” means constant pressure.

Q438. An isochoric process occurs at constant:

A. Pressure
B. Temperature
C. Volume
D. Entropy

Answer: C. Volume

Explanation: “Iso-choric” means constant volume.

Q439. An adiabatic process involves:

A. No heat transfer
B. Constant temperature always
C. Constant pressure always
D. No work transfer

Answer: A. No heat transfer

Explanation: For an adiabatic process, .

Q440. The efficiency of a heat engine is:

A. Work output/heat supplied
B. Heat supplied/work output
C. Heat rejected/work output
D. Work input/heat rejected

Answer: A. Work output/heat supplied

Explanation:

SECTION E — HEAT TRANSFER

Q441. Heat transfer through a solid due to molecular interaction is:

A. Conduction
B. Convection
C. Radiation
D. Evaporation

Answer: A. Conduction

Explanation: Conduction transfers heat through a material without bulk movement of the material.

Q442. Heat transfer through bulk movement of a fluid is:

A. Conduction
B. Convection
C. Radiation
D. Reflection

Answer: B. Convection

Explanation: Convection involves heat transfer associated with fluid motion.

Q443. Radiation can transfer heat through:

A. Vacuum
B. Solids only
C. Liquids only
D. Metals only

Answer: A. Vacuum

Explanation: Thermal radiation does not require a material medium.

Q444. The SI unit of thermal conductivity is:

A. W/m·K
B. W/m²
C. J/kg
D. N/m²

Answer: A. W/m·K

Explanation: Thermal conductivity measures a material’s ability to conduct heat.

Q445. A good thermal insulator has:

A. Low thermal conductivity
B. Very high thermal conductivity
C. Zero density
D. High electrical conductivity necessarily

Answer: A. Low thermal conductivity

Explanation: Low thermal conductivity reduces the rate of heat transfer.

Q446. A heat exchanger is used to:

A. Transfer heat between fluids
B. Increase electrical resistance
C. Produce mechanical cutting
D. Store solid fuel only

Answer: A. Transfer heat between fluids

Explanation: Heat exchangers transfer thermal energy between fluids at different temperatures.

Q447. In a counter-flow heat exchanger, the two fluids generally move:

A. In opposite directions
B. In the same direction
C. Perpendicular only
D. Without movement

Answer: A. In opposite directions

Explanation: Counter-flow arrangements have the fluids moving in opposite directions.

Q448. A black body is an ideal body that:

A. Absorbs all incident radiation
B. Reflects all radiation
C. Transmits all radiation
D. Emits no radiation

Answer: A. Absorbs all incident radiation

Explanation: An ideal black body absorbs all incident electromagnetic radiation and is also an ideal emitter.

Q449. Heat flux is heat transfer rate per unit:

A. Area
B. Mass
C. Volume
D. Time only

Answer: A. Area

Explanation: Heat flux is expressed as heat-transfer rate divided by area, typically W/m².

Q450. The main purpose of thermal insulation is to:

A. Reduce unwanted heat transfer
B. Increase heat loss
C. Increase fluid velocity
D. Increase electrical current

Answer: A. Reduce unwanted heat transfer

Explanation: Insulation reduces heat transfer between a system and its surroundings.

SECTION F — FLUID MACHINERY

Q451. A pump is used to:

A. Add energy to a liquid
B. Remove all liquid energy
C. Convert liquid into solid
D. Measure temperature

Answer: A. Add energy to a liquid

Explanation: Pumps increase the pressure or head of liquids by supplying mechanical energy.

Q452. A centrifugal pump uses:

A. Rotational kinetic energy to move fluid
B. Only compressed air
C. Chemical energy directly
D. Electrical resistance

Answer: A. Rotational kinetic energy to move fluid

Explanation: The rotating impeller imparts energy to the fluid.

Q453. A turbine generally converts:

A. Fluid energy into mechanical energy
B. Mechanical energy into fluid pressure only
C. Heat into electrical resistance
D. Electrical energy into mass

Answer: A. Fluid energy into mechanical energy

Explanation: Turbines extract energy from flowing fluids and convert it into shaft work.

Q454. A hydraulic turbine operates using:

A. Energy of flowing or falling water
B. Only compressed air
C. Solid fuel combustion directly
D. Electrical resistance

Answer: A. Energy of flowing or falling water

Explanation: Hydraulic turbines convert hydraulic energy into mechanical shaft power.

Q455. Pelton turbine is generally classified as:

A. Impulse turbine
B. Reaction turbine
C. Reciprocating pump
D. Centrifugal compressor

Answer: A. Impulse turbine

Explanation: Pelton turbines operate primarily from the kinetic energy of high-speed water jets.

Q456. Francis turbine is generally:

A. A reaction turbine
B. An impulse turbine
C. A positive displacement pump
D. A compressor

Answer: A. A reaction turbine

Explanation: Francis turbines operate with both pressure and velocity changes through the runner.

Q457. Kaplan turbine is generally suitable for:

A. Low-head, high-flow applications
B. Very high-head, low-flow applications only
C. Gas compression
D. Steam generation

Answer: A. Low-head, high-flow applications

Explanation: Kaplan turbines are axial-flow reaction turbines commonly used for low-head, high-discharge conditions.

Q458. A compressor is used to:

A. Increase gas pressure
B. Pump liquid only
C. Reduce solid density
D. Measure gas temperature only

Answer: A. Increase gas pressure

Explanation: Compressors supply work to gases to raise their pressure.

Q459. A reciprocating compressor uses:

A. Piston-cylinder action
B. Only a turbine runner
C. An impeller only
D. A gear train without a cylinder

Answer: A. Piston-cylinder action

Explanation: Reciprocating compressors compress gas by the motion of a piston within a cylinder.

Q460. Pump efficiency is the ratio of:

A. Useful hydraulic power to shaft/input power
B. Input power to hydraulic power
C. Heat output to work input
D. Pressure to density

Answer: A. Useful hydraulic power to shaft/input power

Explanation: Pump efficiency compares useful power delivered to the fluid with power supplied to the pump.

SECTION G — MANUFACTURING

Q461. Casting involves:

A. Pouring molten material into a mould
B. Cutting material with a drill only
C. Joining by bolts only
D. Rolling without heating

Answer: A. Pouring molten material into a mould

Explanation: Casting produces a component by filling a mould cavity with molten material and allowing it to solidify.

Q462. The pattern in casting is used to:

A. Form the mould cavity
B. Cut metal directly
C. Measure temperature
D. Lubricate the mould

Answer: A. Form the mould cavity

Explanation: A pattern is a replica or representation of the desired casting geometry used to create the mould cavity.

Q463. Forging generally involves:

A. Plastic deformation under compressive forces
B. Melting only
C. Cutting only
D. Chemical dissolution

Answer: A. Plastic deformation under compressive forces

Explanation: Forging shapes metal through localized compressive forces, often at elevated temperature.

Q464. Rolling is primarily used to:

A. Reduce thickness or change cross-section using rolls
B. Produce holes only
C. Join two plates permanently
D. Measure hardness

Answer: A. Reduce thickness or change cross-section using rolls

Explanation: Rolling passes material between rotating rolls to reduce thickness or form a desired profile.

Q465. Welding is a process of:

A. Joining materials by coalescence
B. Measuring material hardness
C. Cutting only
D. Cooling only

Answer: A. Joining materials by coalescence

Explanation: Welding joins materials by producing coalescence, with or without pressure and with or without filler metal.

Q466. Arc welding uses:

A. An electric arc as a heat source
B. Water pressure
C. Mechanical friction only
D. Compressed air only

Answer: A. An electric arc as a heat source

Explanation: An electric arc produces the heat required to melt and join the workpieces.

Q467. The heat-affected zone in welding is:

A. The region adjacent to the weld whose properties are altered by heat
B. The weld metal only
C. The untouched base metal far from the weld
D. The welding electrode only

Answer: A. The region adjacent to the weld whose properties are altered by heat

Explanation: The HAZ does not normally melt but experiences thermal cycles that can change its microstructure and properties.

Q468. Soldering uses a filler metal with melting temperature:

A. Below 450°C
B. Above 1,500°C always
C. Exactly 1,000°C
D. Below 0°C

Answer: A. Below 450°C

Explanation: By the conventional definition, soldering uses filler metal melting below 450°C.

Q469. Brazing generally uses filler metal with melting temperature:

A. Above 450°C but below the melting temperature of the base metals
B. Below 100°C
C. Equal to absolute zero
D. Higher than all base metals

Answer: A. Above 450°C but below the melting temperature of the base metals

Explanation: Brazing uses a filler metal that melts above 450°C while the base materials remain essentially solid.

Q470. Powder metallurgy begins with:

A. Metal powders
B. Molten metal only
C. Wood chips
D. Liquid fuel

Answer: A. Metal powders

Explanation: Powder metallurgy involves producing, compacting, and sintering metal powders.

SECTION H — METROLOGY & QUALITY CONTROL

Q471. Metrology is the science of:

A. Measurement
B. Welding
C. Casting
D. Lubrication

Answer: A. Measurement

Explanation: Metrology deals with measurement, units, standards, and measurement uncertainty.

Q472. A vernier caliper can measure:

A. External, internal and depth dimensions
B. Temperature only
C. Pressure only
D. Electrical current only

Answer: A. External, internal and depth dimensions

Explanation: A vernier caliper is a versatile dimensional measuring instrument.

Q473. A micrometer is generally used for:

A. Precise dimensional measurement
B. Measuring fluid pressure
C. Measuring electrical power
D. Measuring humidity only

Answer: A. Precise dimensional measurement

Explanation: Micrometers provide highly accurate measurements of small dimensions.

Q474. Least count means:

A. Smallest measurement that an instrument can resolve
B. Maximum load of a machine
C. Average measurement
D. Total measurement range only

Answer: A. Smallest measurement that an instrument can resolve

Explanation: Least count indicates the smallest readable increment of an instrument.

Q475. Accuracy refers to:

A. Closeness to the true value
B. Repeatability only
C. Instrument size
D. Measurement speed only

Answer: A. Closeness to the true value

Explanation: Accuracy indicates how close a measurement is to the accepted or true value.

Q476. Precision refers primarily to:

A. Closeness of repeated measurements to one another
B. Closeness to zero only
C. Instrument weight
D. Measurement range only

Answer: A. Closeness of repeated measurements to one another

Explanation: Precision describes the consistency or repeatability of measurements.

Q477. A limit gauge is used to determine whether a dimension:

A. Lies within specified limits
B. Has a particular temperature
C. Has a particular density
D. Has a particular colour

Answer: A. Lies within specified limits

Explanation: Limit gauges provide a quick accept/reject check against specified dimensional limits.

Q478. Surface roughness refers to:

A. Small irregularities on a surface
B. Overall component weight
C. Material density
D. Electrical resistance

Answer: A. Small irregularities on a surface

Explanation: Surface roughness describes fine-scale deviations from an ideal surface.

Q479. Quality control primarily aims to:

A. Ensure products meet specified requirements
B. Increase defects
C. Eliminate measurement
D. Increase machine breakdowns

Answer: A. Ensure products meet specified requirements

Explanation: Quality control uses inspection, testing, and process controls to maintain required quality.

Q480. Six Sigma is primarily associated with:

A. Process improvement and defect reduction
B. Increasing defects
C. Increasing machine noise
D. Reducing measurement accuracy

Answer: A. Process improvement and defect reduction

Explanation: Six Sigma is a data-driven methodology focused on reducing process variation and defects.

SECTION I — INDUSTRIAL SAFETY

Q481. PPE stands for:

A. Personal Protective Equipment
B. Production Planning Equipment
C. Power Processing Engine
D. Personal Production Energy

Answer: A. Personal Protective Equipment

Explanation: PPE includes protective equipment such as helmets, gloves, goggles, and safety footwear.

Q482. Safety goggles primarily protect:

A. Eyes
B. Feet
C. Ears
D. Hands

Answer: A. Eyes

Explanation: Safety goggles protect the eyes against particles, chemicals, and other hazards depending on their design.

Q483. A safety helmet primarily protects:

A. Head
B. Hands
C. Feet
D. Eyes only

Answer: A. Head

Explanation: Safety helmets help protect the head against impact and falling-object hazards.

Q484. Lockout/tagout procedures are intended to:

A. Prevent unexpected energization of equipment during maintenance
B. Increase machine speed
C. Increase production automatically
D. Improve paint quality

Answer: A. Prevent unexpected energization of equipment during maintenance

Explanation: Lockout/tagout isolates hazardous energy sources before servicing equipment.

Q485. A fire extinguisher should be selected based on:

A. Type of fire and extinguisher rating
B. Machine colour
C. Building height only
D. Worker age

Answer: A. Type of fire and extinguisher rating

Explanation: Different extinguishing agents are suitable for different classes of fire.

Q486. Good housekeeping helps to:

A. Reduce workplace hazards
B. Increase trip hazards
C. Increase spills
D. Increase accidents

Answer: A. Reduce workplace hazards

Explanation: Clean and organized workplaces reduce slips, trips, falls, and other hazards.

Q487. An emergency stop device is designed to:

A. Quickly stop hazardous machine operation
B. Increase machine speed
C. Increase fuel consumption
D. Measure temperature

Answer: A. Quickly stop hazardous machine operation

Explanation: Emergency stops provide rapid shutdown when an immediate hazard occurs.

Q488. Electrical equipment should be handled with:

A. Appropriate electrical safety precautions
B. Wet hands
C. Damaged insulation
D. Exposed conductors

Answer: A. Appropriate electrical safety precautions

Explanation: Proper isolation, grounding, PPE, and safe procedures help prevent electrical injuries.

Q489. A hazard is:

A. A potential source of harm
B. A guaranteed accident
C. A safety device
D. A maintenance schedule

Answer: A. A potential source of harm

Explanation: A hazard is a condition, substance, activity, or situation capable of causing harm.

Q490. Risk is generally related to:

A. Likelihood and consequence of harm
B. Machine colour
C. Product weight only
D. Temperature only

Answer: A. Likelihood and consequence of harm

Explanation: Risk assessment considers both the probability of an unwanted event and its potential severity.

SECTION J — NUMERICAL & APPLICATION QUESTIONS

Q491. A machine produces 240 units in 8 hours. Its average production rate is:

A. 20 units/hour
B. 30 units/hour
C. 40 units/hour
D. 60 units/hour

Answer: B. 30 units/hour

Explanation:

Q492. A worker completes a job in 12 hours. If efficiency improves by 20% and output requirement remains the same, the approximate new time is:

A. 8 hours
B. 9 hours
C. 10 hours
D. 14.4 hours

Answer: C. 10 hours

Explanation:

Q493. A 5 kW motor runs for 4 hours. Energy consumed is:

A. 5 kWh
B. 10 kWh
C. 20 kWh
D. 25 kWh

Answer: C. 20 kWh

Explanation:

Q494. A force of 200 N acts over an area of 0.02 m². The pressure is:

A. 1 kPa
B. 5 kPa
C. 10 kPa
D. 20 kPa

Answer: C. 10 kPa

Explanation:

Q495. A pump delivers 0.02 m³/s of water through a pressure rise of 200 kPa. Neglecting losses, hydraulic power is:

A. 2 kW
B. 4 kW
C. 6 kW
D. 10 kW

Answer: B. 4 kW

Explanation:

Q496. A gear has 20 teeth and drives a gear having 60 teeth. The speed ratio of driven gear to driver is:

A. 1:1
B. 1:2
C. 1:3
D. 3:1

Answer: C. 1:3

Explanation: Speed is inversely proportional to the number of teeth:

Q497. A machine has a load of 600 N and requires an effort of 150 N. Its mechanical advantage is:

A. 2
B. 3
C. 4
D. 5

Answer: C. 4

Explanation:

Q498. A machine has a mechanical advantage of 4 and velocity ratio of 5. Its efficiency is:

A. 20%
B. 40%
C. 80%
D. 125%

Answer: C. 80%

Explanation:

Q499. A 2 m long steel bar has an original length of 2,000 mm and elongates by 1 mm. The strain is:

A. 0.0005
B. 0.005
C. 0.05
D. 0.5

Answer: A. 0.0005

Explanation:

Q500. A factory produces 5,000 components and finds 50 defective components. The defect percentage is:

A. 0.1%
B. 0.5%
C. 1%
D. 5%

Answer: C. 1%

Explanation:

MOCK TEST 5 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
401	A	426	A	451	A	476	A
402	B	427	A	452	A	477	A
403	B	428	A	453	A	478	A
404	C	429	A	454	A	479	A
405	A	430	A	455	A	480	A
406	C	431	A	456	A	481	A
407	C	432	B	457	A	482	A
408	A	433	A	458	A	483	A
409	A	434	B	459	A	484	A
410	B	435	C	460	A	485	A
411	A	436	B	461	A	486	A
412	B	437	A	462	A	487	A
413	A	438	C	463	A	488	A
414	B	439	A	464	A	489	A
415	B	440	A	465	A	490	A
416	A	441	A	466	A	491	B
417	B	442	B	467	A	492	C
418	B	443	A	468	A	493	C
419	B	444	A	469	A	494	C
420	A	445	A	470	A	495	B
421	A	446	A	471	A	496	C
422	A	447	A	472	A	497	C
423	A	448	A	473	A	498	C
424	A	449	A	474	A	499	A
425	A	450	A	475	A	500	C

MOCK TEST 6 — QUESTIONS 501–600

Complete Exam Practice

Instructions: Choose the correct answer from the four options. All questions and explanations are in English.

SECTION A — ENGINEERING MECHANICS

Q501. The SI unit of force is:

A. Joule
B. Newton
C. Pascal
D. Watt

Answer: B. Newton

Explanation: The SI unit of force is the newton (N).

Q502. If the resultant force acting on a body is zero, the body is in:

A. Dynamic acceleration
B. Equilibrium
C. Free fall
D. Rotation only

Answer: B. Equilibrium

Explanation: A body is in equilibrium when the resultant force and, where applicable, resultant moment are zero.

Q503. The moment of a force about a point is equal to:

A. Force × perpendicular distance
B. Force ÷ distance
C. Mass × acceleration
D. Force + distance

Answer: A. Force × perpendicular distance

Explanation:

where is the perpendicular distance from the point to the line of action of the force.

Q504. The SI unit of torque is:

A. N
B. N/m
C. N·m
D. Pa

Answer: C. N·m

Explanation: Torque is force multiplied by perpendicular distance.

Q505. Friction always acts:

A. In the direction of motion
B. Opposite to relative or impending motion
C. Vertically upward
D. Toward the centre of a body

Answer: B. Opposite to relative or impending motion

Explanation: Friction resists relative motion or the tendency of relative motion.

Q506. The coefficient of friction is:

A. Dimensionless
B. Measured in newtons
C. Measured in pascals
D. Measured in joules

Answer: A. Dimensionless

Explanation: It is the ratio of friction force to normal reaction.

Q507. Work is done by a force when:

A. There is displacement having a component along the force
B. There is no displacement
C. The force is always zero
D. The object is stationary permanently

Answer: A. There is displacement having a component along the force

Explanation: Mechanical work is .

Q508. One joule is equal to:

A. One newton-metre
B. One watt per second
C. One pascal per metre
D. One kilogram per second

Answer: A. One newton-metre

Explanation: .

Q509. A body moving with constant velocity has:

A. Constant non-zero acceleration
B. Zero acceleration
C. Increasing acceleration
D. Infinite acceleration

Answer: B. Zero acceleration

Explanation: Constant velocity means both speed and direction remain unchanged, so acceleration is zero.

Q510. Centripetal acceleration is directed:

A. Away from the centre
B. Toward the centre
C. Tangentially outward
D. Vertically downward always

Answer: B. Toward the centre

Explanation: Centripetal acceleration keeps a body moving along a circular path and points toward the centre.

SECTION B — STRENGTH OF MATERIALS

Q511. Tensile stress is produced when a member is subjected to:

A. Pulling force
B. Pushing force
C. Twisting force only
D. Bending moment only

Answer: A. Pulling force

Explanation: Tensile loading tends to elongate the member.

Q512. Compressive stress is produced by:

A. Pulling
B. Pushing
C. Heating only
D. Rotation only

Answer: B. Pushing

Explanation: Compressive forces tend to shorten a member.

Q513. The modulus of rigidity is also known as:

A. Young’s modulus
B. Shear modulus
C. Bulk modulus
D. Elastic modulus only

Answer: B. Shear modulus

Explanation: Modulus of rigidity is the ratio of shear stress to shear strain.

Q514. Bulk modulus is associated with:

A. Change in volume
B. Change in length only
C. Change in angle only
D. Surface roughness

Answer: A. Change in volume

Explanation: Bulk modulus relates hydrostatic pressure to volumetric strain.

Q515. The elastic modulus of a material indicates its:

A. Stiffness
B. Colour
C. Density only
D. Melting point only

Answer: A. Stiffness

Explanation: A higher Young’s modulus generally indicates greater resistance to elastic deformation.

Q516. Ductility is the ability of a material to:

A. Undergo plastic deformation in tension before fracture
B. Resist all temperature changes
C. Conduct electricity only
D. Resist corrosion only

Answer: A. Undergo plastic deformation in tension before fracture

Explanation: Ductile materials can undergo substantial plastic deformation before failure.

Q517. Brittleness is characterized by:

A. Large plastic deformation before fracture
B. Little plastic deformation before fracture
C. Very high elongation always
D. Perfect elasticity

Answer: B. Little plastic deformation before fracture

Explanation: Brittle materials tend to fracture with relatively little plastic deformation.

Q518. Toughness is the ability of a material to:

A. Absorb energy before fracture
B. Conduct heat only
C. Resist only elastic deformation
D. Increase its density

Answer: A. Absorb energy before fracture

Explanation: Toughness represents the energy a material can absorb before failure.

Q519. Hardness is generally the resistance to:

A. Indentation or scratching
B. Elastic deformation only
C. Heat transfer
D. Fluid flow

Answer: A. Indentation or scratching

Explanation: Hardness measures resistance to localized plastic deformation such as indentation.

Q520. Fatigue failure is commonly caused by:

A. Repeated or cyclic loading
B. Constant temperature only
C. Static loading only
D. Zero stress

Answer: A. Repeated or cyclic loading

Explanation: Fatigue can cause failure under repeated stresses, often below the material’s static strength.

SECTION C — MACHINE DESIGN

Q521. A shaft is primarily designed to transmit:

A. Torque
B. Temperature
C. Pressure only
D. Heat only

Answer: A. Torque

Explanation: Shafts commonly transmit rotational power and torque.

Q522. A key in a shaft assembly is used to:

A. Transmit torque between shaft and hub
B. Reduce temperature
C. Measure speed
D. Lubricate bearings

Answer: A. Transmit torque between shaft and hub

Explanation: A key prevents relative rotation between the shaft and mounted component.

Q523. A coupling is used to:

A. Connect two shafts
B. Measure shaft diameter
C. Increase fluid pressure
D. Reduce material hardness

Answer: A. Connect two shafts

Explanation: Couplings connect shafts to transmit torque and, depending on design, accommodate misalignment.

Q524. A flywheel primarily stores:

A. Rotational kinetic energy
B. Electrical energy
C. Chemical energy
D. Hydraulic pressure

Answer: A. Rotational kinetic energy

Explanation: A flywheel stores and releases kinetic energy to smooth speed fluctuations.

Q525. A governor primarily controls:

A. Mean speed of an engine as load changes
B. Bearing temperature only
C. Fuel colour
D. Shaft diameter

Answer: A. Mean speed of an engine as load changes

Explanation: A governor regulates the energy input to maintain approximately constant mean speed under changing loads.

Q526. A brake is used to:

A. Absorb energy and reduce or stop motion
B. Increase rotational speed
C. Store fuel
D. Increase shaft length

Answer: A. Absorb energy and reduce or stop motion

Explanation: Brakes convert mechanical energy primarily into heat through friction.

Q527. A disc clutch transmits torque mainly through:

A. Friction between mating surfaces
B. Hydraulic pressure alone
C. Magnetic attraction only
D. Gravity

Answer: A. Friction between mating surfaces

Explanation: Friction between the clutch plates allows torque transmission.

Q528. The pitch circle of a gear is:

A. An imaginary circle used as a reference for gear geometry
B. The outermost diameter only
C. The bore diameter
D. The tooth-root circle only

Answer: A. An imaginary circle used as a reference for gear geometry

Explanation: The pitch circle is fundamental to defining gear speed ratios and tooth geometry.

Q529. Gear ratio is related to:

A. Number of teeth on mating gears
B. Colour of gears
C. Bearing temperature
D. Shaft material only

Answer: A. Number of teeth on mating gears

Explanation: For simple gears, speed ratio is inversely related to the number of teeth.

Q530. Lubrication primarily helps to:

A. Reduce friction and wear
B. Increase friction
C. Increase corrosion
D. Increase surface damage

Answer: A. Reduce friction and wear

Explanation: Lubricants form a separating film and reduce friction, wear, and heat generation.

SECTION D — THERMODYNAMICS

Q531. An open system allows:

A. Mass and energy transfer across its boundary
B. No mass transfer
C. No energy transfer
D. Only radiation transfer

Answer: A. Mass and energy transfer across its boundary

Explanation: Open systems permit mass and energy interactions with their surroundings.

Q532. A closed system allows:

A. Energy transfer but no mass transfer across its boundary
B. Mass transfer only
C. Neither mass nor energy transfer
D. Mass transfer only during cooling

Answer: A. Energy transfer but no mass transfer across its boundary

Explanation: A closed system has a fixed amount of matter but can exchange energy.

Q533. An isolated system allows:

A. Neither mass nor energy transfer
B. Mass transfer only
C. Energy transfer only
D. Heat transfer only

Answer: A. Neither mass nor energy transfer

Explanation: An ideal isolated system exchanges neither mass nor energy with its surroundings.

Q534. Enthalpy is defined as:

A.
B.
C.
D.

Answer: A.

Explanation: Enthalpy is the sum of internal energy and flow energy .

Q535. Internal energy is a:

A. Thermodynamic property
B. Path function only
C. Force
D. Unit of pressure

Answer: A. Thermodynamic property

Explanation: Internal energy is a state property of a thermodynamic system.

Q536. Heat and work are:

A. Path functions
B. State properties
C. Intensive properties only
D. Dimensions

Answer: A. Path functions

Explanation: Heat and work depend on the process path between two states.

Q537. Entropy of an isolated system during a real spontaneous process:

A. Tends to increase
B. Always decreases
C. Is always zero
D. Must remain negative

Answer: A. Tends to increase

Explanation: The second law states that entropy generation is non-negative.

Q538. A reversible process is an ideal process that:

A. Can be reversed without leaving net changes in system and surroundings
B. Always occurs rapidly
C. Always involves friction
D. Always has heat loss

Answer: A. Can be reversed without leaving net changes in system and surroundings

Explanation: Reversibility is an idealization involving no dissipative effects.

Q539. A heat pump is primarily used to:

A. Transfer heat from a low-temperature region to a high-temperature region
B. Convert heat directly into mass
C. Eliminate all heat
D. Produce water from air only

Answer: A. Transfer heat from a low-temperature region to a high-temperature region

Explanation: A heat pump uses external work to move heat against its natural direction.

Q540. The coefficient of performance of a refrigerator is:

A. Refrigerating effect/work input
B. Work input/refrigerating effect
C. Heat rejected/work input only
D. Work output/heat supplied

Answer: A. Refrigerating effect/work input

Explanation:

SECTION E — HEAT TRANSFER & REFRIGERATION

Q541. Fourier’s law is associated with:

A. Heat conduction
B. Fluid pressure
C. Electrical resistance
D. Radiation only

Answer: A. Heat conduction

Explanation: Fourier’s law describes heat conduction through a material.

Q542. Newton’s law of cooling is commonly associated with:

A. Convective heat transfer
B. Electrical conduction
C. Mass diffusion only
D. Radiation only

Answer: A. Convective heat transfer

Explanation: It relates convective heat transfer to the temperature difference between a surface and surrounding fluid.

Q543. Stefan-Boltzmann law is associated with:

A. Thermal radiation
B. Conduction
C. Fluid viscosity
D. Mechanical stress

Answer: A. Thermal radiation

Explanation: It relates radiation emission to absolute temperature raised to the fourth power.

Q544. An evaporator in a refrigeration system:

A. Absorbs heat from the cooled space
B. Rejects all heat to surroundings
C. Compresses refrigerant
D. Increases electrical voltage

Answer: A. Absorbs heat from the cooled space

Explanation: Refrigerant absorbs heat while evaporating at low pressure and temperature.

Q545. A condenser in a refrigeration system:

A. Rejects heat from the refrigerant
B. Absorbs all heat from the room
C. Compresses the refrigerant
D. Measures humidity

Answer: A. Rejects heat from the refrigerant

Explanation: The refrigerant releases heat to the surroundings while condensing.

Q546. The compressor in a vapor-compression refrigeration cycle:

A. Raises refrigerant pressure
B. Reduces refrigerant pressure
C. Absorbs room heat directly
D. Condenses refrigerant without work

Answer: A. Raises refrigerant pressure

Explanation: The compressor takes low-pressure vapor and compresses it to high pressure.

Q547. The expansion valve primarily:

A. Reduces refrigerant pressure
B. Raises refrigerant pressure
C. Increases compressor power
D. Condenses all refrigerant

Answer: A. Reduces refrigerant pressure

Explanation: Expansion devices reduce refrigerant pressure before it enters the evaporator.

Q548. The unit of refrigeration capacity commonly used in practice is:

A. Ton of refrigeration
B. Newton
C. Pascal
D. Watt-hour only

Answer: A. Ton of refrigeration

Explanation: Ton of refrigeration is a conventional unit of refrigeration capacity.

Q549. One ton of refrigeration is approximately:

A. 0.517 kW
B. 1.517 kW
C. 3.517 kW
D. 5.517 kW

Answer: C. 3.517 kW

Explanation: One ton of refrigeration is approximately 3.517 kW of cooling capacity.

Q550. A refrigerator primarily removes heat from:

A. A low-temperature space
B. A high-temperature space only
C. The compressor only
D. The condenser only

Answer: A. A low-temperature space

Explanation: Refrigerators maintain a low-temperature region by continuously removing heat from it.

SECTION F — MANUFACTURING PROCESSES

Q551. In turning, the workpiece generally:

A. Rotates while a cutting tool removes material
B. Remains stationary while the tool never moves
C. Only vibrates
D. Is melted completely

Answer: A. Rotates while a cutting tool removes material

Explanation: Turning is primarily performed on a lathe, where the workpiece rotates against a cutting tool.

Q552. Drilling is primarily used to:

A. Produce circular holes
B. Produce flat surfaces only
C. Join plates
D. Heat-treat components

Answer: A. Produce circular holes

Explanation: Drilling uses a rotating drill to create or enlarge holes.

Q553. Milling uses:

A. A rotating multi-point cutting tool
B. A stationary abrasive block only
C. Molten metal
D. Welding electrodes only

Answer: A. A rotating multi-point cutting tool

Explanation: Milling removes material with a rotating cutter having multiple cutting edges.

Q554. Grinding is primarily a:

A. Finishing process using abrasive particles
B. Casting process
C. Forging process
D. Welding process

Answer: A. Finishing process using abrasive particles

Explanation: Grinding uses abrasive grains to remove small amounts of material and improve surface finish and dimensional accuracy.

Q555. A lathe is commonly called a:

A. Machine tool for producing surfaces of revolution
B. Hydraulic pump
C. Heat exchanger
D. Compressor

Answer: A. Machine tool for producing surfaces of revolution

Explanation: Lathes rotate the workpiece and are widely used for cylindrical and related operations.

Q556. The cutting speed in turning is mainly related to:

A. Workpiece rotational speed and diameter
B. Coolant colour
C. Tool weight only
D. Machine foundation

Answer: A. Workpiece rotational speed and diameter

Explanation: Cutting speed depends on the circumference of the rotating workpiece and its rotational speed.

Q557. Feed in a machining operation refers to:

A. Relative advancement of the tool or workpiece per revolution or stroke
B. Machine electrical voltage
C. Coolant pressure only
D. Tool hardness

Answer: A. Relative advancement of the tool or workpiece per revolution or stroke

Explanation: Feed describes how far the cutting tool advances relative to the work during machining.

Q558. Cutting fluid is used mainly to:

A. Cool and lubricate the cutting zone
B. Increase tool temperature
C. Increase friction
D. Reduce machine rigidity

Answer: A. Cool and lubricate the cutting zone

Explanation: Cutting fluids help control temperature, friction, tool wear, and chip evacuation.

Q559. Tool wear generally causes:

A. Reduced tool life and possible loss of dimensional accuracy
B. Infinite tool life
C. Zero cutting force
D. Increased tool sharpness permanently

Answer: A. Reduced tool life and possible loss of dimensional accuracy

Explanation: Progressive wear can affect cutting performance and product quality.

Q560. CNC stands for:

A. Computer Numerical Control
B. Central Numerical Calculation
C. Computer Network Control
D. Continuous Number Coding

Answer: A. Computer Numerical Control

Explanation: CNC machines use programmed numerical instructions to control machining operations.

SECTION G — FLUID MECHANICS

Q561. Density is defined as:

A. Mass per unit volume
B. Volume per unit mass
C. Weight per unit area
D. Force per unit volume

Answer: A. Mass per unit volume

Explanation:

Q562. The SI unit of density is:

A. kg/m³
B. N/m²
C. kg/m²
D. Pa·s

Answer: A. kg/m³

Explanation: Density is mass divided by volume.

Q563. Specific gravity is the ratio of:

A. Density of a substance to density of a reference substance
B. Pressure to volume
C. Mass to force
D. Weight to temperature

Answer: A. Density of a substance to density of a reference substance

Explanation: Specific gravity is dimensionless.

Q564. Viscosity represents a fluid’s resistance to:

A. Flow or deformation
B. Temperature change only
C. Electrical current
D. Radiation

Answer: A. Flow or deformation

Explanation: Viscosity describes internal resistance to relative motion between fluid layers.

Q565. The SI unit of dynamic viscosity is:

A. Pa·s
B. N
C. J
D. W

Answer: A. Pa·s

Explanation: Dynamic viscosity is measured in pascal-seconds.

Q566. Bernoulli’s equation is based on conservation of:

A. Mechanical energy along a streamline under specified assumptions
B. Mass only
C. Temperature only
D. Electrical energy only

Answer: A. Mechanical energy along a streamline under specified assumptions

Explanation: Bernoulli’s equation relates pressure, velocity, and elevation heads for idealized steady flow.

Q567. Reynolds number is used to characterize:

A. Flow regime
B. Material hardness
C. Thermal conductivity only
D. Gear ratio

Answer: A. Flow regime

Explanation: Reynolds number helps distinguish laminar and turbulent flow conditions.

Q568. Low Reynolds number flow is generally associated with:

A. Laminar flow
B. Turbulent flow always
C. Supersonic flow
D. Compressible flow only

Answer: A. Laminar flow

Explanation: Lower Reynolds numbers indicate that viscous effects dominate and flow tends to be laminar.

Q569. Cavitation in pumps occurs when:

A. Local pressure falls below the liquid’s vapor pressure
B. Pressure becomes infinitely high
C. Fluid temperature becomes zero
D. Pump speed becomes zero

Answer: A. Local pressure falls below the liquid’s vapor pressure

Explanation: Vapor bubbles form and subsequently collapse when pressure recovers, potentially damaging pump components.

Q570. A manometer is used to measure:

A. Pressure difference
B. Electrical current
C. Surface roughness
D. Torque only

Answer: A. Pressure difference

Explanation: Manometers use liquid columns to determine pressure or pressure difference.

SECTION H — ELECTRICAL & BASIC INDUSTRIAL ENGINEERING

Q571. The SI unit of electric current is:

A. Volt
B. Ampere
C. Ohm
D. Watt

Answer: B. Ampere

Explanation: Ampere is the SI base unit of electric current.

Q572. Ohm’s law is:

A.
B.
C.
D.

Answer: A.

Explanation: Voltage equals current multiplied by resistance.

Q573. Electrical power in a DC circuit can be expressed as:

A.
B.
C.
D.

Answer: A.

Explanation: Electrical power is voltage multiplied by current.

Q574. A transformer operates on:

A. Electromagnetic induction
B. Chemical reaction
C. Mechanical friction
D. Fluid pressure

Answer: A. Electromagnetic induction

Explanation: Transformers transfer electrical energy between circuits through electromagnetic induction.

Q575. A fuse is primarily used for:

A. Overcurrent protection
B. Increasing voltage
C. Increasing current
D. Measuring resistance

Answer: A. Overcurrent protection

Explanation: A fuse melts when excessive current flows, interrupting the circuit.

Q576. Earthing is primarily provided to:

A. Provide a safe path for fault current
B. Increase fault voltage
C. Increase electrical resistance deliberately
D. Increase motor speed

Answer: A. Provide a safe path for fault current

Explanation: Proper earthing helps reduce shock and equipment hazards during electrical faults.

Q577. A three-phase induction motor commonly operates using:

A. Three-phase AC supply
B. DC supply only
C. Hydraulic pressure
D. Compressed air

Answer: A. Three-phase AC supply

Explanation: Three-phase induction motors are widely used in industrial drives.

Q578. A generator converts:

A. Mechanical energy into electrical energy
B. Electrical energy into mechanical energy only
C. Heat directly into mass
D. Pressure into density

Answer: A. Mechanical energy into electrical energy

Explanation: Generators use electromagnetic induction to produce electrical power from mechanical input.

Q579. An electric motor converts:

A. Electrical energy into mechanical energy
B. Mechanical energy into electrical energy
C. Chemical energy into pressure only
D. Heat into mass

Answer: A. Electrical energy into mechanical energy

Explanation: Motors produce mechanical output from electrical input.

Q580. Power factor is:

A. Ratio of real power to apparent power
B. Ratio of voltage to resistance
C. Ratio of current to voltage
D. Ratio of energy to mass

Answer: A. Ratio of real power to apparent power

Explanation:

SECTION I — INDUSTRIAL ENGINEERING

Q581. Productivity is generally defined as:

A. Output divided by input
B. Input divided by output
C. Output plus input
D. Output minus input

Answer: A. Output divided by input

Explanation: Productivity measures how effectively inputs are converted into outputs.

Q582. Work study consists primarily of:

A. Method study and work measurement
B. Welding and casting
C. Painting and packaging only
D. Heat treatment and forging

Answer: A. Method study and work measurement

Explanation: Work study seeks systematic improvement in how work is performed and measured.

Q583. Time study is used to determine:

A. Standard time for performing a task
B. Material density
C. Machine colour
D. Electrical voltage

Answer: A. Standard time for performing a task

Explanation: Time study measures task performance to establish an appropriate standard time.

Q584. A standard time normally includes:

A. Normal time plus allowances
B. Only observed time
C. Only machine breakdown time
D. Only idle time

Answer: A. Normal time plus allowances

Explanation: Allowances account for personal needs, fatigue, unavoidable delays, and other relevant factors.

Q585. Line balancing aims to:

A. Distribute work among stations efficiently
B. Increase idle time
C. Increase bottlenecks
D. Eliminate production planning

Answer: A. Distribute work among stations efficiently

Explanation: Line balancing seeks to match workstation workloads with the required production rate.

Q586. A bottleneck is:

A. A process stage that limits overall system capacity
B. The fastest operation
C. An unused machine
D. A safety helmet

Answer: A. A process stage that limits overall system capacity

Explanation: The bottleneck constrains throughput of the overall process.

Q587. Inventory includes:

A. Materials, work-in-process and finished goods
B. Finished goods only
C. Cash only
D. Machines only

Answer: A. Materials, work-in-process and finished goods

Explanation: Inventory can exist at different stages of the production and supply process.

Q588. EOQ stands for:

A. Economic Order Quantity
B. Engineering Output Quality
C. Estimated Operating Quantity
D. Economic Operation Quota

Answer: A. Economic Order Quantity

Explanation: EOQ is an inventory model used to determine an economical order quantity under specified assumptions.

Q589. Preventive maintenance is performed:

A. Before equipment failure occurs
B. Only after complete failure
C. Only when equipment is discarded
D. Never during operation

Answer: A. Before equipment failure occurs

Explanation: Preventive maintenance is scheduled or condition-based maintenance intended to reduce the probability of failure.

Q590. Breakdown maintenance is performed:

A. After equipment failure
B. Before equipment is installed
C. Before every production cycle regardless of condition
D. Only during design

Answer: A. After equipment failure

Explanation: Breakdown or corrective maintenance restores equipment after a failure has occurred.

SECTION J — NUMERICAL & MIXED APPLICATIONS

Q591. A 10 kg body moves at 6 m/s. Its kinetic energy is:

A. 60 J
B. 120 J
C. 180 J
D. 360 J

Answer: C. 180 J

Explanation:

Q592. A 20 kg object is raised through a height of 5 m. Taking , its potential energy is:

A. 100 J
B. 500 J
C. 1,000 J
D. 2,000 J

Answer: C. 1,000 J

Explanation:

Q593. A 100 N force moves an object through 8 m in the direction of the force. Work done is:

A. 100 J
B. 400 J
C. 800 J
D. 1,000 J

Answer: C. 800 J

Explanation:

Q594. A machine performs 6,000 J of work in 20 seconds. Its power is:

A. 100 W
B. 200 W
C. 300 W
D. 400 W

Answer: C. 300 W

Explanation:

Q595. A 50 mm diameter shaft rotates at 1,200 rpm. The approximate surface speed is:

A. 1.14 m/s
B. 3.14 m/s
C. 5.14 m/s
D. 7.14 m/s

Answer: B. 3.14 m/s

Explanation:

Q596. A rectangular plate is 200 mm long and 100 mm wide. Its area is:

A. 0.002 m²
B. 0.02 m²
C. 0.2 m²
D. 2 m²

Answer: B. 0.02 m²

Explanation:

Q597. A tensile load of 20 kN acts on a bar having cross-sectional area 400 mm². The stress is:

A. 25 MPa
B. 50 MPa
C. 75 MPa
D. 100 MPa

Answer: B. 50 MPa

Explanation:

Q598. A material has a stress of 100 MPa and strain of 0.0005. Young’s modulus is:

A. 20 GPa
B. 50 GPa
C. 100 GPa
D. 200 GPa

Answer: A. 200 GPa

Explanation:

Correction: The correct option is D. 200 GPa.

Q599. A production line makes 720 units in 12 hours. If 5% are defective, the number of good units is:

A. 684
B. 690
C. 700
D. 708

Answer: A. 684

Explanation:

Defective units:

Good units:

Q600. A machine costs ₹500,000 and has a salvage value of ₹50,000 after 10 years. Using straight-line depreciation, annual depreciation is:

A. ₹35,000
B. ₹40,000
C. ₹45,000
D. ₹50,000

Answer: C. ₹45,000

Explanation:

MOCK TEST 6 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
501	B	526	A	551	A	576	A
502	B	527	A	552	A	577	A
503	A	528	A	553	A	578	A
504	C	529	A	554	A	579	A
505	B	530	A	555	A	580	A
506	A	531	A	556	A	581	A
507	A	532	A	557	A	582	A
508	A	533	A	558	A	583	A
509	B	534	A	559	A	584	A
510	B	535	A	560	A	585	A
511	A	536	A	561	A	586	A
512	B	537	A	562	A	587	A
513	B	538	A	563	A	588	A
514	A	539	A	564	A	589	A
515	A	540	A	565	A	590	A
516	A	541	A	566	A	591	C
517	B	542	A	567	A	592	C
518	A	543	A	568	A	593	C
519	A	544	A	569	A	594	C
520	A	545	A	570	A	595	B
521	A	546	A	571	B	596	B
522	A	547	A	572	A	597	B
523	A	548	A	573	A	598	D
524	A	549	C	574	A	599	A
525	A	550	A	575	A	600	C

MOCK TEST 7 — QUESTIONS 601–700

SECTION A — ENGINEERING MECHANICS

Q601. Which of the following is a scalar quantity?

A. Force
B. Velocity
C. Acceleration
D. Mass

Answer: D. Mass

Explanation: Mass has magnitude only, whereas force, velocity, and acceleration are vector quantities.

Q602. Which of the following is a vector quantity?

A. Speed
B. Distance
C. Displacement
D. Mass

Answer: C. Displacement

Explanation: Displacement has both magnitude and direction.

Q603. The resultant of two equal and opposite forces acting along the same line is:

A. Maximum
B. Zero
C. Equal to one force
D. Double the force

Answer: B. Zero

Explanation: Equal and opposite collinear forces cancel each other.

Q604. The centre of gravity of a uniform circular disc lies at:

A. Its circumference
B. Its centre
C. Half its radius from the centre
D. Outside the disc

Answer: B. Its centre

Explanation: Due to symmetry, the centre of gravity of a uniform circular disc is at its geometric centre.

Q605. The principle of transmissibility applies to:

A. A rigid body
B. A fluid only
C. A deformable body only
D. A gas only

Answer: A. A rigid body

Explanation: For a rigid body, a force can be moved anywhere along its line of action without changing its external effect.

Q606. The moment of a force is zero when its line of action:

A. Is perpendicular to the body
B. Passes through the reference point
C. Is parallel to the body
D. Is at 45°

Answer: B. Passes through the reference point

Explanation: The perpendicular distance becomes zero, so the moment is zero.

Q607. Impulse is equal to:

A. Change in momentum
B. Change in energy
C. Change in power
D. Change in mass

Answer: A. Change in momentum

Explanation:

Q608. The unit of impulse is:

A. N·s
B. N/m
C. J/s
D. Pa/s

Answer: A. N·s

Explanation: Impulse has the same dimensions and units as momentum.

Q609. When a body is projected vertically upward, its velocity at maximum height is:

A. Maximum
B. Zero
C. Equal to acceleration
D. Infinite

Answer: B. Zero

Explanation: The upward velocity becomes zero momentarily at maximum height.

Q610. In uniform circular motion, the speed is:

A. Constant
B. Always increasing
C. Always decreasing
D. Zero

Answer: A. Constant

Explanation: In uniform circular motion, speed remains constant, although velocity changes continuously due to changing direction.

SECTION B — STRENGTH OF MATERIALS

Q611. The ratio of lateral strain to longitudinal strain is called:

A. Young’s modulus
B. Poisson’s ratio
C. Bulk modulus
D. Modulus of rigidity

Answer: B. Poisson’s ratio

Explanation: Poisson’s ratio relates lateral deformation to longitudinal deformation.

Q612. A material subjected to torsion primarily experiences:

A. Shear stress
B. Tensile stress only
C. Compressive stress only
D. Thermal stress only

Answer: A. Shear stress

Explanation: Torsion produces shear stresses in shafts and similar members.

Q613. The polar moment of inertia is important in the analysis of:

A. Torsion
B. Heat conduction
C. Fluid pressure
D. Electrical circuits

Answer: A. Torsion

Explanation: Polar moment of area is used in torsion calculations for circular shafts.

Q614. A cantilever beam is fixed at:

A. Both ends
B. One end and free at the other
C. Its centre only
D. Neither end

Answer: B. One end and free at the other

Explanation: A cantilever has one fixed support and one free end.

Q615. A simply supported beam generally has:

A. One pin support and one roller support
B. Two fixed supports
C. One fixed support only
D. No supports

Answer: A. One pin support and one roller support

Explanation: This arrangement provides stability while allowing appropriate movement.

Q616. Bending stress in a beam is maximum at the:

A. Neutral axis
B. Extreme fibres
C. Centre only
D. Support only

Answer: B. Extreme fibres

Explanation: Bending stress varies linearly from zero at the neutral axis to maximum at the extreme fibres.

Q617. Bending stress at the neutral axis of a homogeneous beam is:

A. Maximum
B. Zero
C. Infinite
D. Equal to shear stress

Answer: B. Zero

Explanation: The distance from the neutral axis is zero, so bending stress is zero.

Q618. The neutral axis of a symmetric homogeneous beam section generally passes through its:

A. Centroid
B. Outer surface
C. Top fibre
D. Bottom fibre

Answer: A. Centroid

Explanation: For symmetric homogeneous sections under pure bending, the neutral axis passes through the centroid.

Q619. Buckling is primarily associated with:

A. Long slender compression members
B. Short tension members
C. Thin wires under tension only
D. Fluid pipes only

Answer: A. Long slender compression members

Explanation: Slender columns can become unstable and buckle under compressive loads.

Q620. Euler’s column theory applies primarily to:

A. Long slender columns
B. Very short columns only
C. Flexible cables
D. Pressure vessels only

Answer: A. Long slender columns

Explanation: Euler’s theory predicts elastic buckling loads for ideal slender columns.

SECTION C — MACHINE ELEMENTS

Q621. The main function of a bearing is to:

A. Support and guide moving members
B. Generate electricity
C. Increase friction
D. Store fuel

Answer: A. Support and guide moving members

Explanation: Bearings support rotating or sliding components and facilitate relative motion.

Q622. A thrust bearing is designed primarily to carry:

A. Axial load
B. Radial load only
C. Thermal load only
D. Electrical load

Answer: A. Axial load

Explanation: Thrust bearings are designed mainly for loads acting along the shaft axis.

Q623. A journal bearing primarily supports:

A. Radial loads
B. Axial loads only
C. Electrical loads
D. Thermal loads

Answer: A. Radial loads

Explanation: Journal bearings commonly support radial loads acting perpendicular to the shaft axis.

Q624. The primary purpose of a seal is to:

A. Prevent leakage or entry of contaminants
B. Increase leakage
C. Increase friction deliberately
D. Increase vibration

Answer: A. Prevent leakage or entry of contaminants

Explanation: Seals retain lubricants and prevent unwanted contaminants from entering machinery.

Q625. A screw thread converts:

A. Rotary motion into linear motion
B. Heat into electricity
C. Linear motion into heat only
D. Pressure into mass

Answer: A. Rotary motion into linear motion

Explanation: Power screws can convert rotational motion into controlled linear movement.

Q626. The lead of a single-start screw is equal to:

A. Pitch
B. Twice the pitch
C. Half the pitch
D. Four times the pitch

Answer: A. Pitch

Explanation: For a single-start thread, one revolution advances the screw by one pitch.

Q627. A spring is commonly used to:

A. Store mechanical energy
B. Eliminate all forces
C. Increase corrosion
D. Produce fuel

Answer: A. Store mechanical energy

Explanation: Springs store energy when deformed and release it when returning toward their original shape.

Q628. A helical compression spring is designed mainly to resist:

A. Compressive loading
B. Tensile loading only
C. Electrical loading
D. Thermal loading

Answer: A. Compressive loading

Explanation: Compression springs shorten under axial compressive force and store energy.

Q629. A cotter joint is generally used to connect:

A. Two rods subjected to axial loads
B. Two rotating gears
C. Two electrical wires
D. Two fluid pumps

Answer: A. Two rods subjected to axial loads

Explanation: Cotter joints connect rods carrying axial tensile or compressive loads.

Q630. A knuckle joint is commonly used for:

A. Connecting two rods subjected to tensile load
B. Connecting electrical circuits
C. Transmitting only rotational torque
D. Supporting fluid pressure

Answer: A. Connecting two rods subjected to tensile load

Explanation: Knuckle joints permit limited angular movement while transmitting tensile loads.

SECTION D — THERMODYNAMICS

Q631. A thermodynamic system is separated from its surroundings by a:

A. Boundary
B. Gear
C. Shaft only
D. Bearing

Answer: A. Boundary

Explanation: A boundary defines the system and separates it from its surroundings.

Q632. Temperature is an:

A. Intensive property
B. Extensive property
C. Path function
D. Force

Answer: A. Intensive property

Explanation: Temperature does not depend on the amount of substance.

Q633. Mass is an:

A. Intensive property
B. Extensive property
C. Path function
D. Thermal constant only

Answer: B. Extensive property

Explanation: Mass depends on the amount of matter in the system.

Q634. Pressure is an:

A. Intensive property
B. Extensive property
C. Path function
D. Energy transfer

Answer: A. Intensive property

Explanation: Pressure does not depend on the size or amount of the system.

Q635. Specific volume is:

A. Volume per unit mass
B. Mass per unit volume
C. Pressure per unit mass
D. Energy per unit volume

Answer: A. Volume per unit mass

Explanation:

Q636. The ideal gas equation is:

A.
B.
C.
D.

Answer: A.

Explanation: For an ideal gas, .

Q637. For a constant-mass ideal gas at constant temperature:

A.
B.
C.
D.

Answer: A.

Explanation: This is Boyle’s law.

Q638. Charles’s law relates volume to:

A. Absolute temperature at constant pressure
B. Pressure at constant temperature
C. Mass at constant volume
D. Density at constant pressure only

Answer: A. Absolute temperature at constant pressure

Explanation: At constant pressure, volume is directly proportional to absolute temperature.

Q639. A Carnot engine operates between:

A. Two temperature reservoirs
B. One reservoir only
C. Three pumps only
D. No heat reservoirs

Answer: A. Two temperature reservoirs

Explanation: A Carnot heat engine operates reversibly between a high-temperature and a low-temperature reservoir.

Q640. Carnot efficiency depends on:

A. Source and sink absolute temperatures
B. Engine colour
C. Fuel mass only
D. Atmospheric pressure only

Answer: A. Source and sink absolute temperatures

Explanation:

SECTION E — HEAT TRANSFER

Q641. Thermal resistance in conduction is analogous to:

A. Electrical resistance
B. Electrical capacitance only
C. Mechanical mass
D. Fluid density

Answer: A. Electrical resistance

Explanation: Thermal resistance opposes heat flow similarly to how electrical resistance opposes current flow.

Q642. Increasing wall thickness generally causes conduction resistance to:

A. Increase
B. Decrease
C. Become zero
D. Remain exactly unchanged

Answer: A. Increase

Explanation: For a plane wall, conduction resistance is proportional to thickness.

Q643. Increasing thermal conductivity of a wall generally causes heat-transfer resistance to:

A. Decrease
B. Increase
C. Become infinite
D. Remain unchanged

Answer: A. Decrease

Explanation: Higher thermal conductivity allows heat to pass more easily.

Q644. Natural convection occurs due to:

A. Buoyancy forces caused by density differences
B. Mechanical pump action only
C. Radiation only
D. Electrical current

Answer: A. Buoyancy forces caused by density differences

Explanation: Temperature differences create density variations that drive fluid motion.

Q645. Forced convection requires:

A. External fluid motion mechanism
B. Vacuum only
C. No fluid motion
D. Radiation only

Answer: A. External fluid motion mechanism

Explanation: Fans, pumps, or other devices can force fluid motion.

Q646. Emissivity of a perfect black body is:

A. 0
B. 0.5
C. 1
D. 10

Answer: C. 1

Explanation: A black body has emissivity equal to unity.

Q647. A fin is used to:

A. Increase heat-transfer area
B. Reduce surface area
C. Prevent all heat transfer
D. Increase fluid density

Answer: A. Increase heat-transfer area

Explanation: Fins extend from surfaces to increase area available for convection.

Q648. A radiator in an automobile cooling system primarily:

A. Rejects heat from the coolant
B. Produces fuel
C. Compresses air
D. Increases engine friction

Answer: A. Rejects heat from the coolant

Explanation: The radiator transfers heat from engine coolant to the surrounding air.

Q649. Thermal contact resistance occurs at:

A. The interface between two contacting surfaces
B. The centre of a vacuum only
C. A free fluid surface only
D. A gear tooth only

Answer: A. The interface between two contacting surfaces

Explanation: Imperfect contact between surfaces creates resistance to heat flow across the interface.

Q650. Heat transfer rate is measured in:

A. Watt
B. Pascal
C. Newton
D. kg/m³

Answer: A. Watt

Explanation: Heat-transfer rate is energy transferred per unit time, measured in watts.

SECTION F — FLUID MACHINERY & HYDRAULICS

Q651. Hydraulic machines use:

A. Liquid as the working fluid
B. Solid metal only
C. Vacuum only
D. Electrical current as the working fluid

Answer: A. Liquid as the working fluid

Explanation: Hydraulic systems transmit power using pressurized liquids.

Q652. Pascal’s law states that pressure applied to a confined fluid is:

A. Transmitted undiminished in all directions
B. Completely lost
C. Transmitted only downward
D. Transmitted only upward

Answer: A. Transmitted undiminished in all directions

Explanation: Pascal’s principle forms the basis of hydraulic presses and similar systems.

Q653. A hydraulic press is based primarily on:

A. Pascal’s law
B. Bernoulli’s law only
C. Hooke’s law
D. Fourier’s law

Answer: A. Pascal’s law

Explanation: Hydraulic presses multiply force by applying pressure to different piston areas.

Q654. A hydraulic accumulator is used to:

A. Store hydraulic energy
B. Measure temperature
C. Remove all fluid
D. Increase electrical voltage

Answer: A. Store hydraulic energy

Explanation: Accumulators store pressurized fluid energy for later use.

Q655. A pressure relief valve protects a hydraulic system against:

A. Excessive pressure
B. Low temperature only
C. Low density
D. High electrical resistance

Answer: A. Excessive pressure

Explanation: It opens when system pressure exceeds a set value.

Q656. A nozzle converts:

A. Pressure energy into velocity energy
B. Velocity into mass
C. Heat into density
D. Mass into pressure only

Answer: A. Pressure energy into velocity energy

Explanation: A nozzle accelerates fluid by converting pressure/head energy into kinetic energy.

Q657. A venturimeter is used to measure:

A. Fluid flow rate
B. Temperature
C. Torque
D. Electrical power

Answer: A. Fluid flow rate

Explanation: It determines flow rate from pressure differences produced by changes in flow area.

Q658. A Pitot tube measures:

A. Fluid velocity
B. Fluid density directly
C. Temperature only
D. Viscosity only

Answer: A. Fluid velocity

Explanation: A Pitot tube determines flow velocity from stagnation and static pressure.

Q659. Hydraulic head is commonly expressed in:

A. Metres of fluid
B. Newtons only
C. Watts only
D. Kilograms only

Answer: A. Metres of fluid

Explanation: Head represents energy per unit weight and is commonly expressed as a length.

Q660. The specific energy of a fluid is:

A. Energy per unit mass
B. Mass per unit volume
C. Pressure per unit area
D. Force per unit time

Answer: A. Energy per unit mass

Explanation: Specific energy is energy divided by mass.

SECTION G — MANUFACTURING & MATERIALS

Q661. Annealing is generally performed to:

A. Soften material and improve ductility
B. Increase brittleness
C. Eliminate all machining
D. Increase electrical resistance only

Answer: A. Soften material and improve ductility

Explanation: Annealing involves controlled heating and cooling to modify microstructure and generally soften the material.

Q662. Quenching generally involves:

A. Rapid cooling
B. Very slow heating only
C. Melting the component
D. Machining the component

Answer: A. Rapid cooling

Explanation: Quenching rapidly cools heated material to alter its microstructure and properties.

Q663. Tempering is usually performed after:

A. Hardening
B. Casting only
C. Welding only
D. Machining only

Answer: A. Hardening

Explanation: Tempering after hardening reduces brittleness and adjusts hardness and toughness.

Q664. Normalizing steel generally involves:

A. Heating followed by controlled air cooling
B. Freezing below zero
C. Melting completely
D. Immersion in oil without heating

Answer: A. Heating followed by controlled air cooling

Explanation: Normalizing refines grain structure and produces desired mechanical properties.

Q665. Stainless steel is known primarily for its:

A. Corrosion resistance
B. Very low melting point
C. Complete absence of iron
D. Electrical insulation only

Answer: A. Corrosion resistance

Explanation: Chromium-containing stainless steels develop a protective passive oxide layer.

Q666. Cast iron generally contains:

A. More carbon than steel
B. Less carbon than pure iron only
C. No carbon
D. No iron

Answer: A. More carbon than steel

Explanation: Cast irons generally contain higher carbon content than steels.

Q667. Aluminium is valued in engineering primarily for:

A. Low density and good corrosion resistance
B. Extremely high density
C. Zero thermal conductivity
D. Complete brittleness

Answer: A. Low density and good corrosion resistance

Explanation: Aluminium is lightweight and forms a protective oxide layer.

Q668. Copper is widely used for electrical conductors because of its:

A. High electrical conductivity
B. Very low conductivity
C. High brittleness
D. Extremely low melting point

Answer: A. High electrical conductivity

Explanation: Copper has high electrical conductivity and is readily formed into wires.

Q669. Composite materials are made by combining:

A. Two or more distinct materials to obtain desired properties
B. Only one pure metal
C. Only gases
D. Only liquids

Answer: A. Two or more distinct materials to obtain desired properties

Explanation: Composites combine a matrix and reinforcement or other constituents to achieve tailored properties.

Q670. A material that returns to its original shape after removal of load is demonstrating:

A. Elasticity
B. Plasticity
C. Brittleness
D. Creep

Answer: A. Elasticity

Explanation: Elastic deformation is recoverable after the load is removed.

SECTION H — METROLOGY & QUALITY

Q671. A micrometer screw gauge operates using:

A. Screw-and-nut principle
B. Hydraulic principle
C. Electrical induction
D. Magnetic levitation only

Answer: A. Screw-and-nut principle

Explanation: Rotation of a precision screw produces controlled linear movement of the spindle.

Q672. A dial indicator is commonly used to measure:

A. Small displacement or deviation
B. Temperature
C. Pressure only
D. Electrical current

Answer: A. Small displacement or deviation

Explanation: Dial indicators detect small dimensional variations, runout, alignment errors, and similar deviations.

Q673. A surface plate provides:

A. A precise reference plane
B. A source of heat
C. Electrical insulation only
D. Fluid pressure

Answer: A. A precise reference plane

Explanation: Surface plates are used as accurate reference surfaces for inspection and measurement.

Q674. Calibration means:

A. Comparing an instrument against a known standard
B. Increasing instrument weight
C. Changing product colour
D. Removing all measuring scales

Answer: A. Comparing an instrument against a known standard

Explanation: Calibration establishes the relationship between instrument indications and known standards.

Q675. Random error is generally:

A. Variable from one measurement to another
B. Always identical
C. Always zero
D. Always positive

Answer: A. Variable from one measurement to another

Explanation: Random errors vary unpredictably between repeated measurements.

Q676. Systematic error tends to:

A. Produce a consistent bias
B. Change randomly every second
C. Become infinite automatically
D. Have no effect

Answer: A. Produce a consistent bias

Explanation: Systematic errors often have a repeatable pattern or direction.

Q677. Statistical process control commonly uses:

A. Control charts
B. Welding rods
C. Gearboxes
D. Hydraulic pumps

Answer: A. Control charts

Explanation: Control charts monitor process variation over time.

Q678. A process is considered statistically controlled when:

A. Variation remains within expected control limits with no special causes
B. Every product is identical
C. No measurements are taken
D. Defects are intentionally increased

Answer: A. Variation remains within expected control limits with no special causes

Explanation: Statistical control means observed variation is consistent with the process’s common causes.

Q679. A histogram is used to show:

A. Distribution of numerical data
B. Machine speed only
C. Electrical voltage only
D. Product colour only

Answer: A. Distribution of numerical data

Explanation: Histograms display the frequency distribution of measured data.

Q680. The Pareto principle is often associated with:

A. Identifying the vital few causes responsible for a large proportion of problems
B. Eliminating all measurements
C. Increasing machine vibration
D. Increasing inventory without analysis

Answer: A. Identifying the vital few causes responsible for a large proportion of problems

Explanation: Pareto analysis helps prioritize the most significant contributors to a problem.

SECTION I — INDUSTRIAL SAFETY & MANAGEMENT

Q681. A near miss is:

A. An event that could have caused injury or damage but did not
B. A successful production cycle
C. A completed maintenance activity
D. A planned inspection

Answer: A. An event that could have caused injury or damage but did not

Explanation: Near misses provide valuable opportunities to identify hazards before an actual accident occurs.

Q682. Risk assessment is performed to:

A. Identify hazards and evaluate associated risks
B. Increase workplace hazards
C. Eliminate safety procedures
D. Increase accident frequency

Answer: A. Identify hazards and evaluate associated risks

Explanation: Risk assessment supports appropriate risk-control measures.

Q683. The safest approach in the hierarchy of controls is generally:

A. Elimination of the hazard
B. PPE only
C. Warning signs only
D. Administrative control only

Answer: A. Elimination of the hazard

Explanation: Eliminating the hazard removes the source of risk entirely and is preferred where feasible.

Q684. PPE is generally considered:

A. The last line of defence
B. The first and only control required
C. A replacement for machine guarding
D. Unnecessary in hazardous areas

Answer: A. The last line of defence

Explanation: PPE is important but generally used after higher-level controls have been considered.

Q685. Machine guards are intended to:

A. Prevent contact with hazardous moving parts
B. Increase access to dangerous components
C. Increase machine speed only
D. Increase noise

Answer: A. Prevent contact with hazardous moving parts

Explanation: Guards physically separate workers from hazardous machine components.

Q686. A safety data sheet provides information about:

A. Hazardous chemical properties and safe handling
B. Machine production rate only
C. Employee salary
D. Gear ratio

Answer: A. Hazardous chemical properties and safe handling

Explanation: Safety data sheets provide information about hazards, handling, storage, emergency measures, and related chemical safety.

Q687. Good ventilation is particularly important when:

A. Hazardous fumes or vapours may be generated
B. No air movement is desired
C. Only mechanical loads exist
D. Measuring gear dimensions

Answer: A. Hazardous fumes or vapours may be generated

Explanation: Adequate ventilation can reduce exposure to airborne contaminants.

Q688. An emergency evacuation plan should specify:

A. Safe exit routes and emergency procedures
B. Only production targets
C. Machine purchase prices
D. Product dimensions

Answer: A. Safe exit routes and emergency procedures

Explanation: Emergency plans help workers respond quickly and safely during emergencies.

Q689. First aid is intended to provide:

A. Immediate assistance before professional medical treatment
B. Permanent medical treatment in every case
C. Equipment maintenance
D. Production planning

Answer: A. Immediate assistance before professional medical treatment

Explanation: First aid provides immediate care to stabilize or assist an injured or ill person until further medical care is available.

Q690. Safety training should be:

A. Appropriate to the hazards and job responsibilities
B. Avoided completely
C. Given only after an accident
D. Limited to managers only

Answer: A. Appropriate to the hazards and job responsibilities

Explanation: Effective safety training helps workers understand hazards and appropriate control measures.

SECTION J — NUMERICAL & APPLICATION QUESTIONS

Q691. A force of 500 N acts on an area of 0.05 m². The resulting pressure is:

A. 1 kPa
B. 5 kPa
C. 10 kPa
D. 20 kPa

Answer: C. 10 kPa

Explanation:

Q692. A motor delivers 15 kW for 2 hours. The energy output is:

A. 15 kWh
B. 20 kWh
C. 30 kWh
D. 45 kWh

Answer: C. 30 kWh

Explanation:

Q693. A 1,000 kg machine is accelerated at 2 m/s². The required resultant force is:

A. 500 N
B. 1,000 N
C. 2,000 N
D. 4,000 N

Answer: C. 2,000 N

Explanation:

Q694. A shaft transmits 2,000 N·m torque at 100 rpm. The approximate power is:

A. 10.47 kW
B. 20.94 kW
C. 31.42 kW
D. 41.89 kW

Answer: B. 20.94 kW

Explanation:

Q695. A bar of original length 1,500 mm elongates by 0.75 mm. The strain is:

A. 0.00025
B. 0.0005
C. 0.005
D. 0.05

Answer: B. 0.0005

Explanation:

Q696. A material has a Young’s modulus of 200 GPa and experiences a strain of 0.001. The stress is:

A. 20 MPa
B. 100 MPa
C. 200 MPa
D. 400 MPa

Answer: C. 200 MPa

Explanation:

Q697. A pump has an input power of 10 kW and hydraulic output power of 8 kW. Its efficiency is:

A. 60%
B. 70%
C. 80%
D. 90%

Answer: C. 80%

Explanation:

Q698. A factory produces 2,400 units per day. If 3% are defective, the number of defective units is:

A. 48
B. 72
C. 96
D. 120

Answer: B. 72

Explanation:

Q699. A machine operates for 10 hours and consumes 50 kWh of energy. Its average power consumption is:

A. 2 kW
B. 5 kW
C. 10 kW
D. 50 kW

Answer: B. 5 kW

Explanation:

Q700. A production process has 980 good units out of 1,000 total units. Its yield percentage is:

A. 96%
B. 97%
C. 98%
D. 99%

Answer: C. 98%

Explanation:

MOCK TEST 7 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
601	D	626	A	651	A	676	A
602	C	627	A	652	A	677	A
603	B	628	A	653	A	678	A
604	B	629	A	654	A	679	A
605	A	630	A	655	A	680	A
606	B	631	A	656	A	681	A
607	A	632	A	657	A	682	A
608	A	633	B	658	A	683	A
609	B	634	A	659	A	684	A
610	A	635	A	660	A	685	A
611	B	636	A	661	A	686	A
612	A	637	A	662	A	687	A
613	A	638	A	663	A	688	A
614	B	639	A	664	A	689	A
615	A	640	A	665	A	690	A
616	B	641	A	666	A	691	C
617	B	642	A	667	A	692	C
618	A	643	A	668	A	693	C
619	A	644	A	669	A	694	B
620	A	645	A	670	A	695	B
621	A	646	C	671	A	696	C
622	A	647	A	672	A	697	C
623	A	648	A	673	A	698	B
624	A	649	A	674	A	699	B
625	A	650	A	675	A	700	C

MOCK TEST 8 — QUESTIONS 701–800.

SECTION A — ENGINEERING MECHANICS

Q701. The SI unit of momentum is:

A. N
B. N·s
C. J
D. W

Answer: B. N·s

Explanation: Momentum is , and its SI unit is kg·m/s, equivalent to N·s.

Q702. Newton’s first law of motion is also known as the law of:

A. Acceleration
B. Inertia
C. Gravitation
D. Conservation of energy

Answer: B. Inertia

Explanation: A body maintains its state of rest or uniform motion unless acted upon by an external unbalanced force.

Q703. Newton’s second law gives the relationship:

A.
B.
C.
D.

Answer: A.

Explanation: The resultant force acting on a body equals mass multiplied by acceleration.

Q704. Newton’s third law states that action and reaction:

A. Act on the same body
B. Are equal and opposite and act on different bodies
C. Are always unequal
D. Act in the same direction

Answer: B. Are equal and opposite and act on different bodies

Explanation: Every action has an equal and opposite reaction acting on the interacting body.

Q705. The acceleration due to gravity near Earth’s surface is approximately:

A. 4.9 m/s²
B. 8.81 m/s²
C. 9.81 m/s²
D. 12.81 m/s²

Answer: C. 9.81 m/s²

Explanation: The standard approximate value of gravitational acceleration is .

Q706. Friction between two surfaces depends on:

A. Nature of surfaces and normal reaction
B. Colour of surfaces only
C. Area only in all cases
D. Mass only

Answer: A. Nature of surfaces and normal reaction

Explanation: In the basic Coulomb friction model, friction is proportional to normal reaction and depends on surface conditions.

Q707. The angle between the resultant and one of two perpendicular components is determined by:

A. Their relative magnitudes
B. Their colour
C. Their masses only
D. Their temperatures

Answer: A. Their relative magnitudes

Explanation: The direction of the resultant depends on the magnitudes of its components.

Q708. A couple consists of:

A. Two equal, opposite and parallel forces separated by a distance
B. Two equal forces acting in the same direction
C. One force only
D. Two perpendicular forces through the same point

Answer: A. Two equal, opposite and parallel forces separated by a distance

Explanation: A couple produces a pure moment without a resultant force.

Q709. The work done by a force perpendicular to displacement is:

A. Maximum
B. Zero
C. Negative infinity
D. Equal to force

Answer: B. Zero

Explanation:

Q710. Mechanical advantage is defined as:

A. Effort/load
B. Load/effort
C. Distance/load
D. Load × effort

Answer: B. Load/effort

Explanation:

SECTION B — STRENGTH OF MATERIALS

Q711. Hooke’s law is valid within the:

A. Elastic limit
B. Plastic region only
C. Fracture region only
D. Creep region only

Answer: A. Elastic limit

Explanation: Within the proportional range, stress is proportional to strain.

Q712. The slope of the stress-strain curve in the elastic region represents:

A. Young’s modulus
B. Poisson’s ratio
C. Toughness
D. Hardness

Answer: A. Young’s modulus

Explanation:

Q713. The area under a complete stress-strain curve up to fracture represents:

A. Toughness
B. Stiffness only
C. Hardness
D. Density

Answer: A. Toughness

Explanation: The area represents energy absorbed per unit volume before fracture.

Q714. Resilience refers to the ability of a material to:

A. Absorb energy within the elastic range
B. Resist corrosion only
C. Conduct electricity
D. Melt rapidly

Answer: A. Absorb energy within the elastic range

Explanation: Resilience is the elastic energy storage capacity of a material.

Q715. A material with high Young’s modulus is generally:

A. Stiff
B. Very soft
C. Highly compressible
D. Liquid

Answer: A. Stiff

Explanation: Young’s modulus measures resistance to elastic deformation.

Q716. Shear strain is measured as:

A. Change in angle in radians
B. Change in mass
C. Change in temperature
D. Change in pressure

Answer: A. Change in angle in radians

Explanation: Shear strain represents angular distortion and is dimensionless.

Q717. The unit of stress is:

A. N
B. N/m
C. N/m²
D. N·m

Answer: C. N/m²

Explanation: Stress is force per unit area and is measured in pascals.

Q718. A factor of safety is generally defined as:

A. Failure strength / allowable working strength
B. Working strength / failure strength
C. Load / mass
D. Stress × strain

Answer: A. Failure strength / allowable working strength

Explanation: It provides a margin between expected working conditions and failure.

Q719. Creep is significant when a material is subjected to:

A. Sustained load, particularly at elevated temperature
B. Zero load
C. Only impact loading
D. Only electrical current

Answer: A. Sustained load, particularly at elevated temperature

Explanation: Creep is time-dependent deformation under sustained stress and is especially important at high temperatures.

Q720. Fatigue cracks generally initiate due to:

A. Repeated or fluctuating stresses
B. Zero stress
C. Constant temperature alone
D. Static pressure only

Answer: A. Repeated or fluctuating stresses

Explanation: Cyclic stress can initiate and propagate fatigue cracks.

SECTION C — MACHINE DESIGN

Q721. The main purpose of a gear train is to:

A. Transmit motion and power with a desired speed ratio
B. Store hydraulic fluid
C. Measure temperature
D. Reduce material density

Answer: A. Transmit motion and power with a desired speed ratio

Explanation: Gears transmit torque and rotational motion while controlling speed and direction.

Q722. Spur gears have teeth that are:

A. Parallel to the gear axis
B. Inclined to the gear axis
C. Circular only
D. Perpendicular to the pitch circle

Answer: A. Parallel to the gear axis

Explanation: Spur gear teeth are straight and parallel to the axis of rotation.

Q723. Helical gear teeth are:

A. Inclined to the gear axis
B. Always perpendicular to the axis
C. Completely circular
D. Without a pitch circle

Answer: A. Inclined to the gear axis

Explanation: Helical teeth are angled, providing smoother and quieter engagement than spur teeth.

Q724. Bevel gears are commonly used to transmit motion between:

A. Intersecting shafts
B. Parallel shafts only
C. Stationary members
D. Electrical circuits

Answer: A. Intersecting shafts

Explanation: Bevel gears transmit motion between shafts whose axes generally intersect.

Q725. Worm gears are commonly used when:

A. A large speed reduction is required
B. No speed reduction is required
C. Only linear motion is required
D. Electrical insulation is needed

Answer: A. A large speed reduction is required

Explanation: Worm drives can provide large reduction ratios in a compact arrangement.

Q726. A belt drive transmits power mainly through:

A. Friction between belt and pulley
B. Magnetic force
C. Hydraulic pressure
D. Gravity

Answer: A. Friction between belt and pulley

Explanation: In ordinary belt drives, friction between belt and pulley enables torque transmission.

Q727. Chain drives are generally classified as:

A. Positive drives
B. Friction drives only
C. Hydraulic drives
D. Magnetic drives

Answer: A. Positive drives

Explanation: Chains engage sprocket teeth, providing a positive drive with little or no slip under normal conditions.

Q728. A clutch is used to:

A. Engage or disengage power transmission
B. Measure pressure
C. Increase fluid density
D. Reduce electrical voltage

Answer: A. Engage or disengage power transmission

Explanation: Clutches allow controlled connection and disconnection between driving and driven members.

Q729. A brake converts mechanical energy primarily into:

A. Heat
B. Electrical energy
C. Chemical energy
D. Potential energy

Answer: A. Heat

Explanation: Friction brakes dissipate mechanical energy as heat.

Q730. The function of a flywheel is to:

A. Smooth fluctuations in rotational speed
B. Control fuel injection directly
C. Measure pressure
D. Increase friction

Answer: A. Smooth fluctuations in rotational speed

Explanation: A flywheel stores and releases kinetic energy to reduce speed fluctuations.

SECTION D — THERMODYNAMICS

Q731. The first law of thermodynamics is based on conservation of:

A. Energy
B. Mass only
C. Momentum only
D. Temperature

Answer: A. Energy

Explanation: Energy cannot be created or destroyed; it can only change form.

Q732. In a cyclic thermodynamic process, the change in internal energy is:

A. Zero
B. Maximum
C. Infinite
D. Always negative

Answer: A. Zero

Explanation: Internal energy is a state property, and the system returns to its initial state after a cycle.

Q733. For an ideal gas, internal energy is primarily a function of:

A. Temperature
B. Pressure only
C. Volume only
D. Density only

Answer: A. Temperature

Explanation: For an ideal gas, internal energy depends only on temperature.

Q734. An isothermal process occurs at constant:

A. Temperature
B. Pressure
C. Volume
D. Entropy always

Answer: A. Temperature

Explanation: “Isothermal” means constant temperature.

Q735. An isobaric process occurs at constant:

A. Pressure
B. Temperature
C. Volume
D. Mass flow rate only

Answer: A. Pressure

Explanation: “Isobaric” means constant pressure.

Q736. An isochoric process occurs at constant:

A. Volume
B. Pressure
C. Temperature
D. Entropy

Answer: A. Volume

Explanation: “Isochoric” means constant volume.

Q737. An adiabatic process involves:

A. No heat transfer across the system boundary
B. Constant pressure always
C. Constant temperature always
D. No work transfer

Answer: A. No heat transfer across the system boundary

Explanation: For an adiabatic process, .

Q738. During compression of a gas, work is generally done:

A. On the gas
B. By the gas only
C. By the surroundings on nothing
D. Without any interaction

Answer: A. On the gas

Explanation: Compression requires work input to reduce the volume.

Q739. During expansion of a gas, the gas generally:

A. Does work on its surroundings
B. Receives all work from surroundings
C. Has zero volume
D. Has no pressure

Answer: A. Does work on its surroundings

Explanation: Expansion involves the system pushing against its surroundings.

Q740. The second law of thermodynamics establishes the concept of:

A. Entropy and direction of natural processes
B. Mass conservation only
C. Force equilibrium only
D. Electrical resistance

Answer: A. Entropy and direction of natural processes

Explanation: The second law determines process direction and introduces entropy.

SECTION E — INTERNAL COMBUSTION ENGINES

Q741. SI engines generally use:

A. Spark ignition
B. Compression ignition
C. Steam ignition
D. Hydraulic ignition

Answer: A. Spark ignition

Explanation: Spark-ignition engines initiate combustion using an electrical spark.

Q742. CI engines generally use:

A. Compression ignition
B. Spark ignition
C. External electric heating only
D. Steam ignition

Answer: A. Compression ignition

Explanation: Diesel engines are compression-ignition engines.

Q743. In a four-stroke engine, one complete cycle requires:

A. One crankshaft revolution
B. Two crankshaft revolutions
C. Three crankshaft revolutions
D. Four crankshaft revolutions

Answer: B. Two crankshaft revolutions

Explanation: A four-stroke cycle consists of intake, compression, power, and exhaust strokes and requires two crankshaft revolutions.

Q744. The power stroke of an engine produces:

A. Useful work output
B. Only exhaust gases
C. Only intake air
D. Cooling water

Answer: A. Useful work output

Explanation: Combustion gases expand during the power stroke and produce useful work.

Q745. The function of a piston is to:

A. Transfer gas pressure to the connecting rod
B. Store fuel permanently
C. Cool the radiator
D. Measure engine speed

Answer: A. Transfer gas pressure to the connecting rod

Explanation: Gas pressure acts on the piston, producing force transmitted through the connecting rod.

Q746. The connecting rod connects:

A. Piston and crankshaft
B. Flywheel and radiator
C. Valve and carburettor only
D. Pump and fuel tank only

Answer: A. Piston and crankshaft

Explanation: It transmits force and motion between the piston and crankshaft.

Q747. The crankshaft converts:

A. Reciprocating motion into rotary motion
B. Rotary motion into heat
C. Electrical energy into pressure
D. Fluid pressure into temperature

Answer: A. Reciprocating motion into rotary motion

Explanation: The crank mechanism converts piston reciprocation into crankshaft rotation.

Q748. The function of a spark plug is to:

A. Ignite the air-fuel mixture in an SI engine
B. Cool the engine oil
C. Compress air
D. Pump coolant

Answer: A. Ignite the air-fuel mixture in an SI engine

Explanation: A spark plug produces an electrical spark to initiate combustion.

Q749. The function of engine lubrication is primarily to:

A. Reduce friction and wear
B. Increase friction
C. Increase component temperature
D. Prevent combustion

Answer: A. Reduce friction and wear

Explanation: Lubrication reduces friction, wear, heat generation, and corrosion between moving parts.

Q750. The radiator is part of the engine:

A. Cooling system
B. Fuel system
C. Ignition system
D. Exhaust system

Answer: A. Cooling system

Explanation: The radiator transfers heat from engine coolant to the surrounding air.

SECTION F — REFRIGERATION & AIR CONDITIONING

Q751. The main function of a refrigerator is to:

A. Remove heat from a low-temperature space
B. Produce heat only
C. Eliminate work input
D. Increase room temperature

Answer: A. Remove heat from a low-temperature space

Explanation: Refrigeration maintains a low temperature by continuously removing heat.

Q752. In a vapor-compression system, the refrigerant leaving the evaporator is ideally:

A. Low-pressure vapour
B. High-pressure liquid
C. High-pressure solid
D. Atmospheric air

Answer: A. Low-pressure vapour

Explanation: The evaporator absorbs heat and vaporizes the refrigerant.

Q753. The compressor inlet is normally connected to the:

A. Evaporator outlet
B. Condenser outlet
C. Expansion valve outlet only
D. Receiver outlet only

Answer: A. Evaporator outlet

Explanation: Low-pressure vapour from the evaporator enters the compressor.

Q754. The compressor outlet is connected to the:

A. Condenser inlet
B. Evaporator inlet
C. Expansion valve inlet only
D. Cooling tower outlet

Answer: A. Condenser inlet

Explanation: High-pressure refrigerant vapour discharged by the compressor enters the condenser.

Q755. The expansion device causes:

A. A substantial pressure drop
B. A pressure increase
C. Complete condensation without pressure change
D. No change in refrigerant state

Answer: A. A substantial pressure drop

Explanation: The expansion device reduces refrigerant pressure before evaporation.

Q756. COP of a refrigerator is generally:

A. Refrigerating effect divided by work input
B. Work input divided by refrigerating effect
C. Heat rejected divided by work input
D. Work output divided by heat supplied

Answer: A. Refrigerating effect divided by work input

Explanation:

Q757. Air conditioning controls:

A. Temperature, humidity, cleanliness and air motion as required
B. Temperature only in every case
C. Pressure only
D. Noise only

Answer: A. Temperature, humidity, cleanliness and air motion as required

Explanation: Air conditioning involves controlling several properties of indoor air.

Q758. Relative humidity is the ratio of:

A. Actual water-vapour pressure to saturation water-vapour pressure at the same temperature
B. Dry-bulb temperature to wet-bulb temperature
C. Pressure to volume
D. Mass to density

Answer: A. Actual water-vapour pressure to saturation water-vapour pressure at the same temperature

Explanation: Relative humidity indicates how close air is to saturation.

Q759. A psychrometer is used to measure:

A. Humidity-related properties of air
B. Engine torque
C. Shaft speed
D. Fluid pressure only

Answer: A. Humidity-related properties of air

Explanation: A psychrometer uses dry-bulb and wet-bulb temperatures to determine humidity properties.

Q760. The cooling load of a building represents:

A. Heat that must be removed to maintain desired indoor conditions
B. Electrical resistance of wiring
C. Weight of the building
D. Air velocity only

Answer: A. Heat that must be removed to maintain desired indoor conditions

Explanation: Cooling load includes heat gains from occupants, equipment, solar radiation, transmission, and other sources.

SECTION G — FLUID MECHANICS

Q761. Continuity equation is based on conservation of:

A. Mass
B. Energy only
C. Momentum only
D. Temperature

Answer: A. Mass

Explanation: For steady incompressible flow, .

Q762. For incompressible steady flow through a pipe, if area decreases, velocity:

A. Increases
B. Decreases
C. Becomes zero
D. Remains zero

Answer: A. Increases

Explanation: From continuity, velocity increases when flow area decreases.

Q763. The pressure exerted by a static liquid increases with:

A. Depth
B. Surface colour
C. Pipe length only
D. Fluid speed only

Answer: A. Depth

Explanation:

for hydrostatic gauge pressure.

Q764. The centre of pressure on a submerged plane surface is generally:

A. Below the centroid
B. Above the centroid
C. Always at the surface
D. Outside the liquid

Answer: A. Below the centroid

Explanation: Hydrostatic pressure increases with depth, causing the resultant force to act below the centroid for a vertical or inclined submerged plane surface.

Q765. A pump converts:

A. Mechanical energy into hydraulic energy
B. Hydraulic energy into chemical energy
C. Heat into mass
D. Electrical resistance into pressure

Answer: A. Mechanical energy into hydraulic energy

Explanation: Pumps add energy to a fluid, generally through mechanical input.

Q766. A turbine converts:

A. Hydraulic or fluid energy into mechanical energy
B. Mechanical energy into hydraulic energy
C. Heat into density
D. Electrical energy into mass

Answer: A. Hydraulic or fluid energy into mechanical energy

Explanation: Turbines extract energy from moving or pressurized fluids to produce shaft power.

Q767. Pelton turbines are generally suitable for:

A. High-head applications
B. Very low-head applications only
C. Zero-head systems
D. Hydraulic presses

Answer: A. High-head applications

Explanation: Pelton turbines are impulse turbines suited to high-head, relatively low-flow conditions.

Q768. Francis turbines are generally:

A. Reaction turbines
B. Pure impulse turbines
C. Steam turbines only
D. Gas turbines

Answer: A. Reaction turbines

Explanation: Francis turbines operate with both pressure and velocity changes through the runner.

Q769. Kaplan turbines are particularly suitable for:

A. Low-head, high-flow applications
B. High-head, low-flow applications only
C. No-flow applications
D. Compressed-air systems

Answer: A. Low-head, high-flow applications

Explanation: Kaplan turbines are axial-flow reaction turbines designed for low heads and high flow rates.

Q770. Water hammer in pipelines is caused mainly by:

A. Sudden change in fluid velocity
B. Slow heating only
C. Low density only
D. Static fluid conditions

Answer: A. Sudden change in fluid velocity

Explanation: Rapid valve closure or changes in flow can generate pressure waves known as water hammer.

SECTION H — MANUFACTURING

Q771. Casting involves:

A. Pouring molten material into a mould
B. Cutting material with a drill only
C. Joining by bolts only
D. Measuring surface roughness

Answer: A. Pouring molten material into a mould

Explanation: Casting produces components by solidifying molten material in a desired mould shape.

Q772. A pattern in casting is used to:

A. Form the mould cavity
B. Measure temperature
C. Increase electrical resistance
D. Lubricate the mould

Answer: A. Form the mould cavity

Explanation: The pattern represents the shape of the desired casting and is used to produce the mould cavity.

Q773. Forging shapes metal primarily by:

A. Plastic deformation under compressive forces
B. Melting without a mould
C. Cutting only
D. Chemical dissolution

Answer: A. Plastic deformation under compressive forces

Explanation: Forging uses dies, hammers, or presses to plastically deform metal.

Q774. Welding is primarily a process of:

A. Joining materials
B. Measuring materials
C. Cooling materials
D. Separating components

Answer: A. Joining materials

Explanation: Welding produces a permanent joint by coalescence, with or without pressure and filler material.

Q775. Arc welding uses:

A. An electric arc as a heat source
B. Hydraulic pressure only
C. Frictionless contact
D. Solar radiation only

Answer: A. An electric arc as a heat source

Explanation: An electric arc produces sufficient heat to melt the base metal and/or filler.

Q776. In welding, porosity refers to:

A. Gas holes or cavities in the weld
B. Excessive hardness only
C. Correct alignment
D. Perfect fusion

Answer: A. Gas holes or cavities in the weld

Explanation: Entrapped gas can create voids or pores in the solidified weld metal.

Q777. Brazing differs from fusion welding because:

A. The base metals are not normally melted
B. No heat is used
C. Only plastic deformation is used
D. It requires no filler material

Answer: A. The base metals are not normally melted

Explanation: In brazing, a filler metal melts and flows into the joint while the base metals remain solid.

Q778. Soldering generally uses a filler metal with melting temperature:

A. Below about 450°C
B. Above 1,500°C always
C. Equal to steel melting temperature
D. Above the base metal melting temperature

Answer: A. Below about 450°C

Explanation: Soldering is conventionally distinguished from brazing by the lower filler-metal melting temperature.

Q779. EDM stands for:

A. Electrical Discharge Machining
B. Engineering Design Method
C. Electronic Drilling Machine
D. Energy Distribution Mechanism

Answer: A. Electrical Discharge Machining

Explanation: EDM removes electrically conductive material through controlled electrical discharges.

Q780. EDM is particularly useful for machining:

A. Hard electrically conductive materials and complex shapes
B. Wood only
C. Rubber only
D. Paper only

Answer: A. Hard electrically conductive materials and complex shapes

Explanation: EDM can machine hard conductive materials without conventional cutting forces.

SECTION I — INDUSTRIAL ENGINEERING & QUALITY

Q781. The main objective of production planning is to:

A. Coordinate resources to meet production requirements
B. Increase idle time
C. Eliminate scheduling
D. Increase material waste

Answer: A. Coordinate resources to meet production requirements

Explanation: Production planning coordinates materials, machines, labour, and time.

Q782. Scheduling determines:

A. When and in what sequence activities should be performed
B. Material density
C. Product hardness
D. Machine colour

Answer: A. When and in what sequence activities should be performed

Explanation: Scheduling assigns activities to time periods and resources.

Q783. Gantt charts are commonly used for:

A. Scheduling and tracking activities
B. Measuring temperature
C. Measuring electrical current
D. Testing hardness

Answer: A. Scheduling and tracking activities

Explanation: Gantt charts visually represent activities against time.

Q784. PERT stands for:

A. Program Evaluation and Review Technique
B. Production Engineering Rate Table
C. Process Efficiency Review Test
D. Product Evaluation and Resource Tool

Answer: A. Program Evaluation and Review Technique

Explanation: PERT is a project management technique used particularly when activity times are uncertain.

Q785. CPM stands for:

A. Critical Path Method
B. Cost Production Model
C. Central Planning Method
D. Critical Product Measurement

Answer: A. Critical Path Method

Explanation: CPM identifies the sequence of activities controlling project duration.

Q786. The critical path has:

A. Zero total float under standard CPM treatment
B. Maximum float
C. No activities
D. Only optional activities

Answer: A. Zero total float under standard CPM treatment

Explanation: Delay in a critical-path activity directly affects project completion time unless corrective action is taken.

Q787. Lean manufacturing focuses on:

A. Eliminating waste
B. Increasing unnecessary inventory
C. Increasing waiting time
D. Increasing defects

Answer: A. Eliminating waste

Explanation: Lean seeks to maximize customer value while reducing non-value-adding activities.

Q788. Just-in-Time production aims to:

A. Reduce unnecessary inventory and produce as needed
B. Maximize inventory at all times
C. Eliminate quality control
D. Increase storage costs

Answer: A. Reduce unnecessary inventory and produce as needed

Explanation: JIT seeks timely production and material delivery while minimizing excess inventory.

Q789. Six Sigma primarily focuses on:

A. Reducing process variation and defects
B. Increasing defects
C. Increasing random variation
D. Eliminating measurement

Answer: A. Reducing process variation and defects

Explanation: Six Sigma uses data-driven methods to improve process performance.

Q790. ISO 9001 is associated with:

A. Quality management systems
B. Fire extinguishers only
C. Electrical generation
D. Fluid mechanics

Answer: A. Quality management systems

Explanation: ISO 9001 specifies requirements for a quality management system.

SECTION J — NUMERICAL & APPLICATION QUESTIONS

Q791. A body of mass 50 kg moves at 4 m/s. Its momentum is:

A. 100 kg·m/s
B. 150 kg·m/s
C. 200 kg·m/s
D. 250 kg·m/s

Answer: C. 200 kg·m/s

Explanation:

Q792. A 200 N force acts through a perpendicular distance of 0.5 m. The moment is:

A. 50 N·m
B. 100 N·m
C. 150 N·m
D. 200 N·m

Answer: B. 100 N·m

Explanation:

Q793. A hydraulic cylinder has a piston area of 0.01 m² and is subjected to pressure of 2 MPa. The force developed is:

A. 2,000 N
B. 10,000 N
C. 20,000 N
D. 200,000 N

Answer: C. 20,000 N

Explanation:

Q794. A pump delivers 0.05 m³/s of water through a head of 20 m. Taking and , the hydraulic power is approximately:

A. 4.905 kW
B. 9.81 kW
C. 19.62 kW
D. 29.43 kW

Answer: C. 9.81 kW

Explanation:

Correction: The correct option is B. 9.81 kW.

Q795. A machine has an input of 25 kW and an output of 20 kW. Its efficiency is:

A. 70%
B. 75%
C. 80%
D. 90%

Answer: C. 80%

Explanation:

Q796. A steel rod of cross-sectional area 500 mm² carries a tensile load of 25 kN. The tensile stress is:

A. 25 MPa
B. 50 MPa
C. 75 MPa
D. 100 MPa

Answer: B. 50 MPa

Explanation:

Q797. A factory produces 1,500 units per day. If productivity improves by 10%, the new output for the same input is:

A. 1,550 units
B. 1,600 units
C. 1,650 units
D. 1,750 units

Answer: C. 1,650 units

Explanation:

Q798. A motor rotates at 1,500 rpm. Its angular velocity is approximately:

A. 78.5 rad/s
B. 125.7 rad/s
C. 157.1 rad/s
D. 250 rad/s

Answer: C. 157.1 rad/s

Explanation:

Q799. A tank contains 2 m³ of water. Taking water density as 1,000 kg/m³, its mass is:

A. 500 kg
B. 1,000 kg
C. 2,000 kg
D. 3,000 kg

Answer: C. 2,000 kg

Explanation:

Q800. A project has 10 activities, and the critical path duration is 25 days. If a critical activity is delayed by 3 days and no corrective action is taken, the project duration becomes:

A. 22 days
B. 25 days
C. 27 days
D. 28 days

Answer: D. 28 days

Explanation: A delay in a critical-path activity directly increases project duration when no corrective action or available float exists.

MOCK TEST 8 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
701	B	726	A	751	A	776	A
702	B	727	A	752	A	777	A
703	A	728	A	753	A	778	A
704	B	729	A	754	A	779	A
705	C	730	A	755	A	780	A
706	A	731	A	756	A	781	A
707	A	732	A	757	A	782	A
708	A	733	A	758	A	783	A
709	B	734	A	759	A	784	A
710	B	735	A	760	A	785	A
711	A	736	A	761	A	786	A
712	A	737	A	762	A	787	A
713	A	738	A	763	A	788	A
714	A	739	A	764	A	789	A
715	A	740	A	765	A	790	A
716	A	741	A	766	A	791	C
717	C	742	A	767	A	792	B
718	A	743	B	768	A	793	C
719	A	744	A	769	A	794	B
720	A	745	A	770	A	795	C
721	A	746	A	771	A	796	B
722	A	747	A	772	A	797	C
723	A	748	A	773	A	798	C
724	A	749	A	774	A	799	C
725	A	750	A	775	A	800	D

MOCK TEST 9 — QUESTIONS 801–900.

SECTION A — ENGINEERING MECHANICS

Q801. The SI unit of force is:

A. Joule
B. Newton
C. Pascal
D. Watt

Answer: B. Newton

Explanation: Force is measured in newtons (N).

Q802. A force of 10 N acts on a body of mass 2 kg. Its acceleration is:

A. 2 m/s²
B. 5 m/s²
C. 10 m/s²
D. 20 m/s²

Answer: B. 5 m/s²

Explanation:

Q803. The principle of conservation of linear momentum applies when:

A. External resultant force is zero
B. Internal force is zero
C. Gravity is absent
D. Friction is maximum

Answer: A. External resultant force is zero

Explanation: Total linear momentum remains constant when the net external force on the system is zero.

Q804. The moment of a force about a point is equal to:

A. Force × perpendicular distance
B. Force ÷ distance
C. Force + distance
D. Distance ÷ force

Answer: A. Force × perpendicular distance

Explanation:

Q805. A body is in static equilibrium when:

A. Resultant force and resultant moment are zero
B. Velocity is maximum
C. Acceleration is maximum
D. Only the force is zero

Answer: A. Resultant force and resultant moment are zero

Explanation: Both translational and rotational equilibrium conditions must be satisfied.

Q806. The centre of gravity of a uniform circular disc is located at:

A. Its centre
B. Its circumference
C. Halfway between centre and circumference
D. Outside the disc

Answer: A. Its centre

Explanation: Due to symmetry, the centre of gravity of a uniform circular disc lies at its geometric centre.

Q807. The coefficient of friction is:

A. Dimensionless
B. Measured in newtons
C. Measured in pascals
D. Measured in joules

Answer: A. Dimensionless

Explanation: It is the ratio of frictional force to normal reaction.

Q808. Limiting friction acts when a body is:

A. Just about to move
B. Moving at maximum speed
C. Falling freely
D. Completely weightless

Answer: A. Just about to move

Explanation: Limiting friction is the maximum static friction immediately before motion begins.

Q809. The kinetic energy of a body is:

A.
B.
C.
D.

Answer: B.

Explanation: Kinetic energy is the energy possessed due to motion.

Q810. Potential energy of a body at height is:

A.
B.
C.
D.

Answer: C.

Explanation: Gravitational potential energy is .

SECTION B — STRENGTH OF MATERIALS

Q811. Strain is defined as:

A. Force per unit area
B. Deformation per unit original dimension
C. Load × area
D. Stress × area

Answer: B. Deformation per unit original dimension

Explanation: Strain is a ratio and therefore has no unit.

Q812. Young’s modulus is the ratio of:

A. Shear stress to shear strain
B. Tensile stress to tensile strain
C. Bulk stress to volume
D. Load to area

Answer: B. Tensile stress to tensile strain

Explanation:

Q813. Bulk modulus relates:

A. Volumetric stress and volumetric strain
B. Shear stress and shear strain
C. Tensile stress and longitudinal strain
D. Force and velocity

Answer: A. Volumetric stress and volumetric strain

Explanation: Bulk modulus measures resistance to uniform volumetric deformation.

Q814. Poisson’s ratio is the ratio of:

A. Longitudinal strain to lateral strain
B. Lateral strain to longitudinal strain
C. Stress to strain
D. Shear stress to tensile stress

Answer: B. Lateral strain to longitudinal strain

Explanation: Poisson’s ratio is generally taken as the negative ratio of lateral strain to longitudinal strain.

Q815. A ductile material generally undergoes:

A. Significant plastic deformation before fracture
B. No deformation before fracture
C. Immediate brittle fracture
D. Only elastic deformation

Answer: A. Significant plastic deformation before fracture

Explanation: Ductile materials can undergo considerable plastic deformation before failure.

Q816. A brittle material generally shows:

A. Very little plastic deformation before fracture
B. Very large plastic deformation
C. Infinite ductility
D. Zero strength

Answer: A. Very little plastic deformation before fracture

Explanation: Brittle materials tend to fracture with limited plastic deformation.

Q817. The neutral axis of a symmetrical homogeneous beam section under pure bending passes through the:

A. Centroid
B. Top surface
C. Bottom surface
D. Edge only

Answer: A. Centroid

Explanation: For a homogeneous symmetrical section, the neutral axis passes through the centroid.

Q818. Bending stress at the neutral axis is:

A. Maximum
B. Zero
C. Infinite
D. Equal to shear stress

Answer: B. Zero

Explanation: In simple bending, longitudinal bending stress is zero at the neutral axis.

Q819. The bending equation is:

A.
B.
C.
D.

Answer: A.

Explanation: This is the fundamental flexure equation for simple bending under its standard assumptions.

Q820. A beam fixed at one end and free at the other is called:

A. Simply supported beam
B. Cantilever beam
C. Continuous beam
D. Fixed beam

Answer: B. Cantilever beam

Explanation: A cantilever has one fixed support and one free end.

SECTION C — MACHINE ELEMENTS

Q821. A shaft is primarily designed to transmit:

A. Torque
B. Temperature
C. Pressure only
D. Heat only

Answer: A. Torque

Explanation: Shafts transmit rotational power and torque between machine elements.

Q822. A key is used between a shaft and hub to:

A. Transmit torque
B. Reduce temperature
C. Increase lubrication
D. Measure speed

Answer: A. Transmit torque

Explanation: A key prevents relative rotation between shaft and hub while transmitting torque.

Q823. Bearings are primarily used to:

A. Support rotating shafts and reduce friction
B. Increase friction
C. Store fuel
D. Produce electricity

Answer: A. Support rotating shafts and reduce friction

Explanation: Bearings support loads while allowing relative motion with reduced friction.

Q824. Ball bearings are classified as:

A. Rolling-contact bearings
B. Sliding-contact bearings only
C. Hydraulic cylinders
D. Gear drives

Answer: A. Rolling-contact bearings

Explanation: Balls roll between inner and outer races.

Q825. Journal bearings are generally:

A. Sliding-contact bearings
B. Rolling-contact bearings
C. Gear teeth
D. Chain drives

Answer: A. Sliding-contact bearings

Explanation: The shaft slides relative to the bearing surface, usually separated by a lubricant film.

Q826. A coupling is used to:

A. Connect two shafts for power transmission
B. Stop combustion
C. Increase fluid viscosity
D. Measure temperature

Answer: A. Connect two shafts for power transmission

Explanation: Couplings connect shafts and transmit torque.

Q827. A rigid coupling is suitable when shafts are:

A. Properly aligned
B. Highly misaligned
C. Not rotating
D. At different temperatures only

Answer: A. Properly aligned

Explanation: Rigid couplings do not accommodate significant shaft misalignment.

Q828. A governor controls:

A. Mean speed of an engine under varying load
B. Engine temperature only
C. Lubricant viscosity
D. Fuel density only

Answer: A. Mean speed of an engine under varying load

Explanation: A governor regulates energy input to maintain approximately constant mean speed.

Q829. A flywheel primarily controls:

A. Speed fluctuations within an engine cycle
B. Mean speed under changing load
C. Fuel pressure
D. Coolant temperature

Answer: A. Speed fluctuations within an engine cycle

Explanation: A flywheel stores and releases energy to smooth cyclic speed fluctuations.

Q830. The pitch circle of a gear is:

A. An imaginary circle used in gear geometry
B. The outside surface of the shaft
C. The root of the tooth only
D. A lubrication channel

Answer: A. An imaginary circle used in gear geometry

Explanation: The pitch circle is fundamental to determining gear ratio and pitch.

SECTION D — THERMODYNAMICS

Q831. The zeroth law of thermodynamics provides the basis for measuring:

A. Temperature
B. Pressure
C. Work
D. Entropy only

Answer: A. Temperature

Explanation: It establishes thermal equilibrium and the concept of temperature.

Q832. A closed system allows:

A. Energy transfer but no mass transfer across its boundary
B. Mass transfer only
C. Neither mass nor energy transfer
D. Mass transfer but no energy transfer

Answer: A. Energy transfer but no mass transfer across its boundary

Explanation: A closed system has fixed mass but may exchange energy.

Q833. An isolated system permits:

A. Neither mass nor energy transfer
B. Energy transfer only
C. Mass transfer only
D. Heat transfer only

Answer: A. Neither mass nor energy transfer

Explanation: An isolated system exchanges neither mass nor energy with its surroundings.

Q834. Enthalpy is defined as:

A.
B.
C.
D.

Answer: A.

Explanation: Enthalpy is internal energy plus flow work.

Q835. Entropy is a:

A. Thermodynamic state property
B. Path-only quantity
C. Force
D. Velocity

Answer: A. Thermodynamic state property

Explanation: Entropy is a property determined by the thermodynamic state.

Q836. In a reversible adiabatic process, entropy:

A. Remains constant
B. Always increases
C. Always decreases
D. Becomes zero

Answer: A. Remains constant

Explanation: A reversible adiabatic process is isentropic.

Q837. The efficiency of a heat engine is always:

A. Less than 100% for practical engines
B. Exactly 100%
C. Greater than 100%
D. Zero in every case

Answer: A. Less than 100% for practical engines

Explanation: A heat engine cannot convert all supplied heat into work.

Q838. Carnot efficiency depends on:

A. Source and sink absolute temperatures
B. Engine mass only
C. Fuel colour
D. Atmospheric pressure only

Answer: A. Source and sink absolute temperatures

Explanation:

for a Carnot engine.

Q839. The coefficient of performance of a heat pump is:

A. Greater than its corresponding refrigerator COP by 1
B. Always equal to zero
C. Always less than refrigerator COP
D. Equal to engine efficiency

Answer: A. Greater than its corresponding refrigerator COP by 1

Explanation:

Q840. The ideal gas equation is:

A.
B.
C.
D.

Answer: A.

Explanation: This is the ideal-gas equation using the specific gas constant .

SECTION E — IC ENGINES

Q841. The compression ratio of an engine is:

A. Total cylinder volume / clearance volume
B. Clearance volume / total volume
C. Swept volume / clearance volume only
D. Clearance volume / swept volume

Answer: A. Total cylinder volume / clearance volume

Explanation:

Q842. Diesel engines generally have:

A. Higher compression ratios than SI engines
B. Lower compression ratios than SI engines
C. Zero compression ratio
D. No compression stroke

Answer: A. Higher compression ratios than SI engines

Explanation: Compression ignition requires high compression to raise air temperature sufficiently for ignition.

Q843. The swept volume is the volume:

A. Displaced by the piston between TDC and BDC
B. Above the cylinder head only
C. Occupied by the valves
D. Outside the engine

Answer: A. Displaced by the piston between TDC and BDC

Explanation: Swept volume equals the piston area multiplied by stroke length.

Q844. TDC stands for:

A. Top Dead Centre
B. Total Diesel Capacity
C. Thermal Design Centre
D. Torque Drive Control

Answer: A. Top Dead Centre

Explanation: TDC is the piston position nearest the cylinder head.

Q845. BDC stands for:

A. Bottom Dead Centre
B. Brake Diesel Capacity
C. Basic Drive Control
D. Bore Diameter Calculation

Answer: A. Bottom Dead Centre

Explanation: BDC is the piston position farthest from the cylinder head.

Q846. Brake power is measured at the:

A. Engine crankshaft output
B. Fuel injector
C. Cylinder wall
D. Exhaust manifold only

Answer: A. Engine crankshaft output

Explanation: Brake power is the useful power available at the engine shaft.

Q847. Indicated power is the power developed:

A. Inside the engine cylinder
B. At the electrical grid
C. In the radiator
D. In the fuel tank

Answer: A. Inside the engine cylinder

Explanation: Indicated power is calculated from pressure-volume work within the cylinder.

Q848. Mechanical efficiency of an engine is:

A. Brake power / indicated power
B. Indicated power / brake power
C. Fuel power / brake power
D. Brake power / fuel mass

Answer: A. Brake power / indicated power

Explanation:

Q849. The carburettor in a conventional SI engine is used to:

A. Prepare the air-fuel mixture
B. Cool engine oil
C. Compress coolant
D. Remove exhaust gases

Answer: A. Prepare the air-fuel mixture

Explanation: A conventional carburettor meters and mixes fuel with incoming air.

Q850. Fuel injection in a diesel engine generally occurs:

A. Near the end of the compression stroke
B. During the exhaust stroke only
C. Before the intake stroke
D. After the exhaust valve closes only

Answer: A. Near the end of the compression stroke

Explanation: Diesel fuel is injected into highly compressed hot air near the end of compression.

SECTION F — FLUID MECHANICS

Q851. The SI unit of dynamic viscosity is:

A. Pa·s
B. N
C. J
D. W

Answer: A. Pa·s

Explanation: Dynamic viscosity is measured in pascal-seconds.

Q852. Kinematic viscosity is:

A. Dynamic viscosity / density
B. Dynamic viscosity × density
C. Density / pressure
D. Pressure × volume

Answer: A. Dynamic viscosity / density

Explanation:

Q853. Reynolds number is a:

A. Dimensionless number
B. Unit of pressure
C. Unit of viscosity
D. Unit of velocity

Answer: A. Dimensionless number

Explanation: Reynolds number compares inertial and viscous effects.

Q854. Laminar flow in a circular pipe generally occurs at low Reynolds number, typically below:

A. 2300
B. 23,000
C. 230,000
D. 2,300,000

Answer: A. 2300

Explanation: For internal pipe flow, is generally considered laminar.

Q855. Turbulent pipe flow generally occurs when Reynolds number is above approximately:

A. 400
B. 1,000
C. 4,000
D. 40,000

Answer: C. 4,000

Explanation: For pipe flow, values above approximately 4000 are generally treated as turbulent.

Q856. Bernoulli’s equation is based on conservation of:

A. Mechanical energy
B. Mass only
C. Temperature only
D. Charge

Answer: A. Mechanical energy

Explanation: Bernoulli’s equation relates pressure, kinetic, and potential energy per unit weight under idealized flow conditions.

Q857. A Venturimeter is used to measure:

A. Fluid flow rate
B. Temperature
C. Density directly
D. Viscosity directly

Answer: A. Fluid flow rate

Explanation: A Venturimeter determines discharge from pressure differences between sections.

Q858. A manometer is commonly used to measure:

A. Pressure difference
B. Shaft torque
C. Electrical resistance
D. Engine speed

Answer: A. Pressure difference

Explanation: Manometers use liquid columns to determine pressure or pressure differences.

Q859. Cavitation occurs when local liquid pressure falls:

A. Below vapour pressure
B. Above atmospheric pressure only
C. To exactly zero temperature
D. Above critical pressure

Answer: A. Below vapour pressure

Explanation: Vapour bubbles form when local pressure falls below the liquid’s vapour pressure.

Q860. Cavitation can cause:

A. Noise, vibration and material damage
B. Perfect lubrication
C. Increased efficiency always
D. Zero pressure loss

Answer: A. Noise, vibration and material damage

Explanation: Collapse of vapour bubbles can damage pump and turbine surfaces.

SECTION G — HEAT TRANSFER

Q861. Heat transfer through a stationary solid occurs primarily by:

A. Conduction
B. Convection
C. Radiation only
D. Evaporation

Answer: A. Conduction

Explanation: Conduction transfers heat through molecular interactions without bulk motion of the material.

Q862. Convection requires:

A. Fluid motion
B. Vacuum only
C. Solid material only
D. No temperature difference

Answer: A. Fluid motion

Explanation: Convection involves heat transfer between a surface and a moving or circulating fluid.

Q863. Radiation can occur through:

A. Vacuum
B. Only solids
C. Only liquids
D. Only gases

Answer: A. Vacuum

Explanation: Thermal radiation travels through electromagnetic waves and does not require a material medium.

Q864. Fourier’s law is associated with:

A. Heat conduction
B. Fluid pressure
C. Electrical resistance
D. Mass diffusion only

Answer: A. Heat conduction

Explanation: Fourier’s law relates conductive heat flux to the temperature gradient.

Q865. Newton’s law of cooling is associated with:

A. Convective heat transfer
B. Conduction through solids only
C. Radiation only
D. Fluid viscosity

Answer: A. Convective heat transfer

Explanation: It relates convective heat transfer rate to temperature difference between a surface and surrounding fluid.

Q866. Stefan-Boltzmann law relates radiation heat transfer to:

A. Absolute temperature to the fourth power
B. Temperature to the first power only
C. Pressure only
D. Velocity only

Answer: A. Absolute temperature to the fourth power

Explanation: Blackbody emissive power is proportional to .

Q867. Thermal conductivity indicates a material’s ability to:

A. Conduct heat
B. Resist mechanical stress only
C. Conduct electricity only
D. Absorb sound

Answer: A. Conduct heat

Explanation: Higher thermal conductivity means greater ability to conduct heat.

Q868. Copper is generally a:

A. Good thermal conductor
B. Thermal insulator
C. Poor electrical conductor
D. Non-metallic insulator

Answer: A. Good thermal conductor

Explanation: Copper has high thermal and electrical conductivity.

Q869. Insulation is used primarily to:

A. Reduce unwanted heat transfer
B. Increase heat loss
C. Increase friction
D. Increase fluid velocity

Answer: A. Reduce unwanted heat transfer

Explanation: Insulating materials have low thermal conductivity.

Q870. A heat exchanger transfers heat between:

A. Two fluids at different temperatures
B. Only solids
C. Only electrical circuits
D. Two vacuum chambers without radiation

Answer: A. Two fluids at different temperatures

Explanation: Heat exchangers transfer thermal energy between fluids, usually without direct mixing.

SECTION H — MANUFACTURING

Q871. Lathe is primarily used for:

A. Turning operations
B. Casting
C. Welding only
D. Forging only

Answer: A. Turning operations

Explanation: In turning, the workpiece rotates while a cutting tool removes material.

Q872. Drilling is used to:

A. Produce or enlarge circular holes
B. Produce flat surfaces only
C. Join two metals
D. Melt a workpiece

Answer: A. Produce or enlarge circular holes

Explanation: A drill produces a hole by rotating relative to the workpiece.

Q873. Milling uses:

A. A rotating multi-point cutting tool
B. A stationary workpiece with no tool
C. Only a welding electrode
D. A casting pattern

Answer: A. A rotating multi-point cutting tool

Explanation: Milling removes material using rotating cutters with multiple cutting edges.

Q874. Grinding is generally considered a:

A. Finishing process
B. Casting process
C. Welding process
D. Forging process

Answer: A. Finishing process

Explanation: Grinding provides accurate dimensions and improved surface finish.

Q875. A reamer is used to:

A. Finish and accurately size an existing hole
B. Produce a rough casting
C. Weld a joint
D. Cut external gear teeth only

Answer: A. Finish and accurately size an existing hole

Explanation: Reaming improves hole accuracy and surface finish.

Q876. A broaching operation uses:

A. A tool with progressively arranged cutting teeth
B. A welding torch
C. A casting furnace
D. A grinding wheel only

Answer: A. A tool with progressively arranged cutting teeth

Explanation: Broaching removes material through successive teeth of a broach.

Q877. Cutting fluid is used primarily to:

A. Cool and lubricate the cutting zone
B. Increase tool temperature
C. Increase friction
D. Prevent cutting completely

Answer: A. Cool and lubricate the cutting zone

Explanation: Cutting fluids reduce heat and friction and can improve tool life and surface finish.

Q878. Tool wear generally results in:

A. Reduced tool life and possible loss of accuracy
B. Infinite tool life
C. Zero cutting force
D. Perfect surface finish always

Answer: A. Reduced tool life and possible loss of accuracy

Explanation: Excessive tool wear affects dimensional accuracy, surface finish, and productivity.

Q879. CNC stands for:

A. Computer Numerical Control
B. Central Numerical Calculation
C. Computer Network Cutting
D. Controlled Number Circuit

Answer: A. Computer Numerical Control

Explanation: CNC machines are controlled using programmed numerical instructions.

Q880. CNC machines generally provide:

A. High repeatability and automated control
B. No dimensional control
C. Manual control only
D. No programming capability

Answer: A. High repeatability and automated control

Explanation: CNC technology enables precise, repeatable and programmable machining.

SECTION I — INDUSTRIAL ENGINEERING

Q881. Work study consists mainly of:

A. Method study and work measurement
B. Casting and welding
C. Marketing and sales
D. Accounting and taxation

Answer: A. Method study and work measurement

Explanation: Work study aims to improve methods and establish performance standards.

Q882. Time study is used to determine:

A. Standard time for a task
B. Material density
C. Machine temperature
D. Product colour

Answer: A. Standard time for a task

Explanation: Time study determines the time required for a qualified worker to perform a task under specified conditions.

Q883. Motion study focuses on:

A. Eliminating unnecessary motions
B. Increasing worker movement
C. Increasing waiting time
D. Increasing fatigue

Answer: A. Eliminating unnecessary motions

Explanation: Motion study analyzes work movements to improve efficiency and reduce unnecessary effort.

Q884. Productivity is generally:

A. Output/Input
B. Input/Output
C. Output × Input
D. Output + Input

Answer: A. Output/Input

Explanation: Productivity measures how efficiently inputs are converted into outputs.

Q885. If output increases while input remains constant, productivity:

A. Increases
B. Decreases
C. Becomes zero
D. Remains necessarily unchanged

Answer: A. Increases

Explanation: Greater output for the same input means higher productivity.

Q886. Inventory carrying cost includes:

A. Storage, insurance and capital-related costs
B. Only purchase price
C. Only transportation cost
D. Only labour wages

Answer: A. Storage, insurance and capital-related costs

Explanation: Holding inventory creates several ongoing costs.

Q887. EOQ stands for:

A. Economic Order Quantity
B. Estimated Output Quality
C. Engineering Order Quality
D. Economic Operating Quotient

Answer: A. Economic Order Quantity

Explanation: EOQ is the order quantity that minimizes relevant ordering and holding costs under the basic model.

Q888. The basic EOQ model assumes:

A. Constant demand and known ordering/holding costs
B. Completely random demand
C. Unlimited shortages
D. No ordering cost

Answer: A. Constant demand and known ordering/holding costs

Explanation: These are among the assumptions of the classical EOQ model.

Q889. ABC inventory analysis classifies items mainly according to:

A. Annual consumption value
B. Colour
C. Physical size only
D. Supplier location only

Answer: A. Annual consumption value

Explanation: ABC analysis prioritizes inventory control based on annual usage value.

Q890. A Pareto chart is based on the principle that:

A. A small number of causes may account for a large proportion of effects
B. All causes are equally important
C. Every process has only one cause
D. Variation is always zero

Answer: A. A small number of causes may account for a large proportion of effects

Explanation: The Pareto principle helps identify the vital few causes among the many.

SECTION J — QUALITY, SAFETY & NUMERICAL APPLICATIONS

Q891. A control chart is primarily used to:

A. Monitor process variation over time
B. Calculate engine power
C. Measure building height
D. Design gears

Answer: A. Monitor process variation over time

Explanation: Control charts distinguish common-cause variation from unusual process changes.

Q892. In statistical quality control, a process is considered out of control when:

A. Evidence indicates assignable or special causes of variation
B. Every product is perfect
C. Variation is impossible
D. Production stops permanently

Answer: A. Evidence indicates assignable or special causes of variation

Explanation: Special-cause variation indicates that the process may require investigation.

Q893. A histogram displays:

A. Frequency distribution of data
B. Project network only
C. Machine drawings
D. Fluid pressure only

Answer: A. Frequency distribution of data

Explanation: A histogram groups numerical observations into intervals and displays their frequencies.

Q894. The mean of 10, 20 and 30 is:

A. 10
B. 15
C. 20
D. 30

Answer: C. 20

Explanation:

Q895. A machine produces 800 units in 10 hours. Its average production rate is:

A. 40 units/hour
B. 60 units/hour
C. 80 units/hour
D. 100 units/hour

Answer: C. 80 units/hour

Explanation:

Q896. A machine has an availability of 90% and performance efficiency of 80%. Ignoring quality losses, its combined effectiveness is:

A. 62%
B. 72%
C. 80%
D. 90%

Answer: B. 72%

Explanation:

Q897. A load of 10 kN is lifted through a height of 5 m. The work done against the load is:

A. 5 kJ
B. 25 kJ
C. 50 kJ
D. 100 kJ

Answer: C. 50 kJ

Explanation:

Q898. A motor supplies 10 kW for 30 minutes. The energy supplied is:

A. 2 kWh
B. 5 kWh
C. 10 kWh
D. 30 kWh

Answer: B. 5 kWh

Explanation:

Q899. If a machine input is 50 kW and efficiency is 80%, the output power is:

A. 20 kW
B. 30 kW
C. 40 kW
D. 45 kW

Answer: C. 40 kW

Explanation:

Q900. A safety factor of 4 is used with a material having failure load of 80 kN. The allowable working load is:

A. 10 kN
B. 20 kN
C. 40 kN
D. 320 kN

Answer: B. 20 kN

Explanation:

MOCK TEST 9 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
801	B	826	A	851	A	876	A
802	B	827	A	852	A	877	A
803	A	828	A	853	A	878	A
804	A	829	A	854	A	879	A
805	A	830	A	855	C	880	A
806	A	831	A	856	A	881	A
807	A	832	A	857	A	882	A
808	A	833	A	858	A	883	A
809	B	834	A	859	A	884	A
810	C	835	A	860	A	885	A
811	B	836	A	861	A	886	A
812	B	837	A	862	A	887	A
813	A	838	A	863	A	888	A
814	B	839	A	864	A	889	A
815	A	840	A	865	A	890	A
816	A	841	A	866	A	891	A
817	A	842	A	867	A	892	A
818	B	843	A	868	A	893	A
819	A	844	A	869	A	894	C
820	B	845	A	870	A	895	C
821	A	846	A	871	A	896	B
822	A	847	A	872	A	897	C
823	A	848	A	873	A	898	B
824	A	849	A	874	A	899	C
825	A	850	A	875	A	900	B

MOCK TEST 10 — QUESTIONS 901–1000

SECTION A — ENGINEERING MECHANICS

Q901. The SI unit of work is:

A. Newton
B. Joule
C. Watt
D. Pascal

Answer: B. Joule

Explanation: Work is measured in joules (J).

Q902. Power is defined as:

A. Work × time
B. Work / time
C. Force / distance
D. Energy × time

Answer: B. Work / time

Explanation:

[
P=\frac{W}{t}
]

Power represents the rate of doing work.

Q903. The acceleration due to gravity near the Earth’s surface is approximately:

A. 4.9 m/s²
B. 8.9 m/s²
C. 9.81 m/s²
D. 12.5 m/s²

Answer: C. 9.81 m/s²

Explanation: The standard approximate value of gravitational acceleration is 9.81 m/s².

Q904. The momentum of a body is:

A. (mv)
B. (ma)
C. (m/v)
D. (mv^2)

Answer: A. (mv)

Explanation: Linear momentum equals mass multiplied by velocity.

Q905. Impulse is equal to:

A. Change in momentum
B. Change in mass
C. Change in distance
D. Change in temperature

Answer: A. Change in momentum

Explanation: Impulse is the product of force and time and equals the change in momentum.

Q906. The frictional force generally acts:

A. In the direction of motion
B. Opposite to relative motion or its tendency
C. Vertically upward only
D. Vertically downward only

Answer: B. Opposite to relative motion or its tendency

Explanation: Friction resists relative motion between contacting surfaces.

Q907. A free-body diagram represents:

A. All relevant forces acting on a body
B. Only the weight of a body
C. Only internal stresses
D. Only dimensions

Answer: A. All relevant forces acting on a body

Explanation: A free-body diagram isolates a body and shows the external forces and moments acting on it.

Q908. The resultant of two equal and opposite collinear forces is:

A. Zero
B. One force doubled
C. Half the force
D. Infinite

Answer: A. Zero

Explanation: Equal forces acting in opposite directions cancel each other.

Q909. A couple consists of:

A. Two equal, parallel and opposite forces separated by a distance
B. Two equal forces acting at the same point
C. One force and one mass
D. Two perpendicular forces at the same point

Answer: A. Two equal, parallel and opposite forces separated by a distance

Explanation: A couple produces a pure turning effect without a resultant force.

Q910. The moment produced by a couple is:

A. Dependent on the perpendicular distance between the forces
B. Always zero
C. Dependent only on mass
D. Independent of force magnitude

Answer: A. Dependent on the perpendicular distance between the forces

Explanation:

[
M=F\times d
]

where (d) is the perpendicular distance between the two forces.

SECTION B — STRENGTH OF MATERIALS

Q911. Stress is defined as:

A. Force per unit area
B. Area per unit force
C. Force × area
D. Deformation × length

Answer: A. Force per unit area

Explanation:

[
\sigma=\frac{F}{A}
]

Q912. The SI unit of stress is:

A. Newton
B. Pascal
C. Joule
D. Watt

Answer: B. Pascal

Explanation: One pascal equals one newton per square metre.

Q913. Elastic deformation is:

A. Recoverable after removal of load
B. Permanent in all cases
C. Independent of load
D. Possible only in fluids

Answer: A. Recoverable after removal of load

Explanation: Elastic deformation disappears when the load is removed, provided the elastic limit has not been exceeded.

Q914. Plastic deformation is:

A. Permanent deformation
B. Completely recoverable deformation
C. Zero deformation
D. Thermal expansion only

Answer: A. Permanent deformation

Explanation: Plastic deformation remains after removal of the applied load.

Q915. The modulus of rigidity is the ratio of:

A. Normal stress to normal strain
B. Shear stress to shear strain
C. Pressure to volume
D. Force to displacement

Answer: B. Shear stress to shear strain

Explanation:

[
G=\frac{\tau}{\gamma}
]

Q916. The unit of Young’s modulus is:

A. N
B. N/m
C. Pa
D. m/s

Answer: C. Pa

Explanation: Young’s modulus has the same dimensions as stress.

Q917. A material that can absorb considerable energy before fracture is described as:

A. Tough
B. Brittle
C. Rigid only
D. Perfectly plastic

Answer: A. Tough

Explanation: Toughness represents the ability to absorb energy before fracture.

Q918. Hardness is the ability of a material to resist:

A. Indentation and wear
B. Heat transfer
C. Fluid flow
D. Electrical current

Answer: A. Indentation and wear

Explanation: Hardness is commonly evaluated by resistance to indentation, scratching or wear.

Q919. Fatigue failure occurs mainly due to:

A. Repeated or fluctuating stresses
B. Constant temperature only
C. Static pressure only
D. Zero loading

Answer: A. Repeated or fluctuating stresses

Explanation: Fatigue can cause failure at stress levels below the static strength after repeated loading cycles.

Q920. Creep is significant when a component is subjected to:

A. Sustained load at elevated temperature over time
B. Zero temperature
C. One instantaneous impact only
D. No stress

Answer: A. Sustained load at elevated temperature over time

Explanation: Creep is time-dependent deformation under sustained stress, especially at elevated temperatures.

SECTION C — THEORY OF MACHINES

Q921. The primary function of a mechanism is to:

A. Transmit or transform motion
B. Store fuel
C. Measure temperature
D. Produce raw material

Answer: A. Transmit or transform motion

Explanation: Mechanisms convert one type of motion into another or transmit motion between components.

Q922. A four-bar chain contains:

A. Four links
B. Three links
C. Five links
D. Six links

Answer: A. Four links

Explanation: A four-bar mechanism consists of four rigid links connected by turning pairs.

Q923. In a simple gear pair, the velocity ratio depends primarily on:

A. Number of teeth on the gears
B. Colour of gears
C. Gear material only
D. Lubricant quantity only

Answer: A. Number of teeth on the gears

Explanation: For standard gears, speed ratio is related to the numbers of teeth.

Q924. Two external gears rotate:

A. In opposite directions
B. In the same direction
C. Without rotation
D. Randomly

Answer: A. In opposite directions

Explanation: Meshing external gears rotate in opposite directions.

Q925. A belt drive transmits power through:

A. Friction or positive engagement, depending on belt type
B. Magnetic force only
C. Hydraulic pressure only
D. Gravity only

Answer: A. Friction or positive engagement, depending on belt type

Explanation: Conventional belt drives rely mainly on friction, while toothed belts use positive engagement.

Q926. Slip in a belt drive causes:

A. Difference between theoretical and actual speed ratio
B. Zero power transmission
C. Infinite speed
D. No relative motion

Answer: A. Difference between theoretical and actual speed ratio

Explanation: Slip changes the actual velocity relationship between driver and driven pulleys.

Q927. A chain drive is generally considered:

A. A positive drive
B. A friction drive only
C. A fluid drive
D. A magnetic drive

Answer: A. A positive drive

Explanation: Chain engagement with sprocket teeth provides positive transmission with negligible slip under normal conditions.

Q928. The purpose of a brake is to:

A. Absorb energy and reduce or stop motion
B. Increase engine speed
C. Store fuel
D. Increase temperature intentionally

Answer: A. Absorb energy and reduce or stop motion

Explanation: Brakes convert kinetic energy primarily into heat through friction.

Q929. A clutch is used to:

A. Engage or disengage power transmission
B. Measure pressure
C. Cool bearings
D. Increase fluid density

Answer: A. Engage or disengage power transmission

Explanation: A clutch connects or disconnects the power flow between driving and driven members.

Q930. The main function of a cam mechanism is to:

A. Convert rotary motion into prescribed reciprocating or oscillating motion
B. Store electrical energy
C. Measure pressure
D. Produce fuel

Answer: A. Convert rotary motion into prescribed reciprocating or oscillating motion

Explanation: Cams provide controlled follower motion according to the designed cam profile.

SECTION D — THERMODYNAMICS

Q931. The first law of thermodynamics is essentially the law of:

A. Conservation of energy
B. Conservation of mass only
C. Conservation of momentum
D. Conservation of charge

Answer: A. Conservation of energy

Explanation: Energy can change form but cannot be created or destroyed.

Q932. Internal energy is a:

A. State function
B. Path function only
C. Force
D. Dimensionless constant

Answer: A. State function

Explanation: Internal energy depends only on the thermodynamic state.

Q933. Heat and work are:

A. Path functions
B. State functions
C. Material properties
D. Dimensionless numbers

Answer: A. Path functions

Explanation: Heat and work depend on the process path between two states.

Q934. An isothermal process occurs at:

A. Constant temperature
B. Constant pressure only
C. Constant volume only
D. Constant entropy only

Answer: A. Constant temperature

Explanation: “Isothermal” means constant temperature.

Q935. An isobaric process occurs at:

A. Constant pressure
B. Constant volume
C. Constant temperature
D. Constant mass flow only

Answer: A. Constant pressure

Explanation: “Isobaric” means constant pressure.

Q936. An isochoric process occurs at:

A. Constant volume
B. Constant pressure
C. Constant temperature
D. Constant entropy only

Answer: A. Constant volume

Explanation: “Isochoric” means constant volume.

Q937. During a throttling process, the specific enthalpy is approximately:

A. Constant
B. Zero
C. Infinite
D. Always increasing

Answer: A. Constant

Explanation: Throttling is approximately an isenthalpic process.

Q938. A nozzle converts:

A. Enthalpy into kinetic energy
B. Kinetic energy into pressure only
C. Heat directly into mass
D. Mass into energy only

Answer: A. Enthalpy into kinetic energy

Explanation: In an ideal nozzle, a reduction in enthalpy results primarily in increased fluid velocity.

Q939. A turbine primarily converts:

A. Fluid energy into mechanical work
B. Mechanical work into pressure
C. Heat into mass
D. Electricity into fluid flow

Answer: A. Fluid energy into mechanical work

Explanation: Turbines extract energy from flowing fluids to produce shaft work.

Q940. A compressor primarily requires:

A. Work input
B. No energy input
C. Only heat rejection
D. Only gravitational energy

Answer: A. Work input

Explanation: Compressors consume mechanical work to raise the pressure of gases.

SECTION E — FLUID MECHANICS AND HYDRAULIC MACHINES

Q941. Pressure in a static fluid increases with:

A. Depth
B. Temperature only
C. Surface area only
D. Velocity only

Answer: A. Depth

Explanation: Hydrostatic pressure increases with depth according to (p=\rho gh) for gauge pressure in a simple fluid column.

Q942. Pascal’s law is the basis of:

A. Hydraulic machines
B. Steam turbines
C. Internal combustion engines
D. Gear drives

Answer: A. Hydraulic machines

Explanation: Pressure applied to a confined fluid is transmitted throughout the fluid.

Q943. A hydraulic press is used to:

A. Multiply force
B. Reduce pressure to zero
C. Generate fuel
D. Measure temperature

Answer: A. Multiply force

Explanation: A hydraulic press uses pressure transmission and different piston areas to multiply force.

Q944. A pump converts:

A. Mechanical energy into hydraulic energy
B. Hydraulic energy into mechanical energy
C. Heat into mass
D. Electrical energy directly into heat only

Answer: A. Mechanical energy into hydraulic energy

Explanation: Pumps supply energy to fluids, generally increasing their pressure or elevation.

Q945. A turbine converts:

A. Hydraulic or fluid energy into mechanical energy
B. Mechanical energy into hydraulic energy
C. Heat directly into mass
D. Pressure into temperature only

Answer: A. Hydraulic or fluid energy into mechanical energy

Explanation: Hydraulic turbines extract energy from flowing or pressurized water.

Q946. The main purpose of a centrifugal pump impeller is to:

A. Transfer energy to the fluid
B. Reduce shaft speed to zero
C. Store fuel
D. Measure pressure

Answer: A. Transfer energy to the fluid

Explanation: The rotating impeller increases the fluid’s energy.

Q947. Priming is required in a conventional centrifugal pump to:

A. Fill the pump casing and suction line with liquid before starting
B. Remove all lubrication
C. Increase air content
D. Heat the motor

Answer: A. Fill the pump casing and suction line with liquid before starting

Explanation: A conventional centrifugal pump generally cannot pump air effectively and therefore requires priming.

Q948. Specific gravity is the ratio of:

A. Density of a substance to density of a reference substance
B. Weight to volume only
C. Pressure to density
D. Mass to velocity

Answer: A. Density of a substance to density of a reference substance

Explanation: For liquids and solids, water is commonly used as the reference.

Q949. The continuity equation for incompressible steady flow is:

A. (A_1V_1=A_2V_2)
B. (A_1+A_2=V_1V_2)
C. (A_1/V_1=A_2/V_2)
D. (A_1V_2=A_2V_1)

Answer: A. (A_1V_1=A_2V_2)

Explanation: Conservation of mass gives constant volume flow rate for incompressible steady flow.

Q950. A smaller pipe area generally results in higher velocity when:

A. Flow rate remains constant
B. Density becomes zero
C. Pressure is always constant
D. Gravity becomes zero

Answer: A. Flow rate remains constant

Explanation: From (Q=AV), reducing area increases velocity for a constant discharge.

SECTION F — HEAT TRANSFER AND REFRIGERATION

Q951. The main purpose of a refrigerator is to:

A. Remove heat from a low-temperature space
B. Produce heat only
C. Destroy energy
D. Increase room temperature only

Answer: A. Remove heat from a low-temperature space

Explanation: Refrigeration transfers heat from a colder region to a warmer region using work input.

Q952. The evaporator in a refrigeration system:

A. Absorbs heat from the refrigerated space
B. Rejects all heat to the surroundings
C. Compresses refrigerant
D. Expands air mechanically

Answer: A. Absorbs heat from the refrigerated space

Explanation: Refrigerant evaporates at low pressure and absorbs heat in the evaporator.

Q953. The condenser in a refrigeration system:

A. Rejects heat to the surroundings
B. Absorbs heat from the refrigerated space only
C. Compresses liquid refrigerant
D. Produces electricity

Answer: A. Rejects heat to the surroundings

Explanation: High-pressure refrigerant releases heat and condenses in the condenser.

Q954. The compressor in a vapour-compression refrigeration system:

A. Raises refrigerant pressure
B. Lowers refrigerant pressure directly
C. Condenses refrigerant by cooling only
D. Removes all refrigerant

Answer: A. Raises refrigerant pressure

Explanation: The compressor takes low-pressure vapour and compresses it to high pressure.

Q955. The expansion valve primarily:

A. Reduces refrigerant pressure
B. Raises refrigerant pressure
C. Produces mechanical work
D. Condenses all refrigerant

Answer: A. Reduces refrigerant pressure

Explanation: Expansion reduces pressure and temperature before refrigerant enters the evaporator.

Q956. COP of a refrigerator is defined as:

A. Refrigerating effect / work input
B. Work input / refrigerating effect
C. Heat rejected / work output
D. Work output / heat rejected

Answer: A. Refrigerating effect / work input

Explanation:

[
COP_R=\frac{Q_L}{W}
]

Q957. A higher COP indicates:

A. Greater refrigeration effect for a given work input
B. Lower efficiency always
C. Higher power consumption for the same load
D. Zero refrigeration

Answer: A. Greater refrigeration effect for a given work input

Explanation: A higher COP means more useful cooling per unit of work input.

Q958. Thermal resistance in conduction is analogous to:

A. Electrical resistance
B. Electrical capacitance only
C. Mechanical mass only
D. Fluid density

Answer: A. Electrical resistance

Explanation: Temperature difference drives heat flow similarly to how voltage difference drives electrical current.

Q959. A fin is used to:

A. Increase heat transfer area
B. Reduce surface area
C. Stop all conduction
D. Eliminate convection

Answer: A. Increase heat transfer area

Explanation: Fins increase the effective surface area available for convective heat transfer.

Q960. A blackbody is an ideal surface that:

A. Absorbs all incident radiation
B. Reflects all incident radiation
C. Transmits all radiation without absorption
D. Emits no radiation

Answer: A. Absorbs all incident radiation

Explanation: A blackbody is a perfect absorber and emitter of thermal radiation.

SECTION G — MANUFACTURING TECHNOLOGY

Q961. Casting involves:

A. Pouring molten material into a mould
B. Cutting material with a drill only
C. Joining by bolts only
D. Rolling a solid bar only

Answer: A. Pouring molten material into a mould

Explanation: Casting produces components by solidifying molten material in a mould cavity.

Q962. A pattern in casting is used to:

A. Form the mould cavity
B. Increase cutting speed
C. Measure temperature
D. Lubricate the machine

Answer: A. Form the mould cavity

Explanation: The pattern represents the desired casting shape and is used to prepare the mould.

Q963. Forging shapes metal primarily by:

A. Plastic deformation under compressive forces
B. Melting only
C. Evaporation
D. Chemical dissolution

Answer: A. Plastic deformation under compressive forces

Explanation: Forging uses controlled plastic deformation to produce the desired shape.

Q964. Rolling is primarily used to:

A. Reduce thickness or change cross-sectional shape
B. Drill holes
C. Weld plates
D. Measure hardness

Answer: A. Reduce thickness or change cross-sectional shape

Explanation: Rolling passes material between rotating rolls.

Q965. Extrusion involves forcing material:

A. Through a die opening
B. Into a furnace only
C. Against a cutting wheel only
D. Through a bearing

Answer: A. Through a die opening

Explanation: Extrusion produces continuous products with a desired cross-section.

Q966. Welding is a process used to:

A. Join materials permanently
B. Measure pressure
C. Reduce temperature only
D. Increase material density only

Answer: A. Join materials permanently

Explanation: Welding joins materials through heat, pressure, or a combination of both.

Q967. In arc welding, heat is generated primarily by:

A. An electric arc
B. Hydraulic pressure
C. Frictionless contact
D. Compressed air only

Answer: A. An electric arc

Explanation: An electric arc produces intense heat for melting and joining metals.

Q968. A welding electrode may be:

A. Consumable or non-consumable depending on the process
B. Always non-metallic
C. Always liquid
D. Used only for measuring voltage

Answer: A. Consumable or non-consumable depending on the process

Explanation: Different welding processes use different types of electrodes.

Q969. Surface roughness refers to:

A. Small-scale irregularities on a surface
B. Overall component length
C. Material density
D. Melting temperature

Answer: A. Small-scale irregularities on a surface

Explanation: Surface roughness is a measure of microscopic deviations from the ideal surface.

Q970. Tolerance means:

A. Permissible variation in a dimension
B. Exact zero variation
C. Surface colour
D. Material hardness only

Answer: A. Permissible variation in a dimension

Explanation: Manufacturing tolerance defines the acceptable dimensional range around a nominal size.

SECTION H — INDUSTRIAL ENGINEERING AND MANAGEMENT

Q971. A Gantt chart is mainly used for:

A. Scheduling and monitoring activities
B. Measuring pressure
C. Designing gears
D. Testing metals

Answer: A. Scheduling and monitoring activities

Explanation: A Gantt chart displays activities against time.

Q972. CPM stands for:

A. Critical Path Method
B. Cost Production Method
C. Central Planning Mechanism
D. Critical Production Machine

Answer: A. Critical Path Method

Explanation: CPM is a project scheduling technique used to identify critical activities and project duration.

Q973. The critical path is the path with:

A. The longest total duration
B. The shortest total duration
C. Zero activities
D. Maximum cost only

Answer: A. The longest total duration

Explanation: The critical path determines the minimum project completion time under the network assumptions.

Q974. Activities on the critical path generally have:

A. Zero total float
B. Infinite float
C. Maximum float
D. Negative duration

Answer: A. Zero total float

Explanation: Delaying a critical activity normally delays project completion.

Q975. Quality assurance primarily focuses on:

A. Preventing defects through planned processes
B. Detecting defects only after production
C. Increasing scrap
D. Eliminating documentation

Answer: A. Preventing defects through planned processes

Explanation: Quality assurance is process-oriented and aims to prevent quality problems.

Q976. Quality control primarily focuses on:

A. Monitoring and verifying product or process quality
B. Increasing defects
C. Eliminating inspection
D. Reducing all documentation

Answer: A. Monitoring and verifying product or process quality

Explanation: Quality control uses inspection, testing and monitoring to verify conformance.

Q977. Six Sigma primarily aims to:

A. Reduce process variation and defects
B. Increase process variation
C. Eliminate measurement
D. Increase waste

Answer: A. Reduce process variation and defects

Explanation: Six Sigma uses data-driven methods to improve process capability and reduce defects.

Q978. Kaizen refers to:

A. Continuous improvement
B. Complete equipment replacement
C. Mass production only
D. Financial auditing

Answer: A. Continuous improvement

Explanation: Kaizen emphasizes ongoing incremental improvements.

Q979. Just-in-Time production aims to:

A. Reduce unnecessary inventory and waste
B. Maximize inventory at all times
C. Eliminate production planning
D. Increase storage requirements

Answer: A. Reduce unnecessary inventory and waste

Explanation: JIT seeks to provide materials and products when needed, reducing excess inventory.

Q980. Lean manufacturing primarily focuses on:

A. Eliminating waste and improving customer value
B. Increasing unnecessary activities
C. Increasing inventory without reason
D. Reducing product quality

Answer: A. Eliminating waste and improving customer value

Explanation: Lean systems identify and eliminate activities that do not add value.

SECTION I — MACHINE DESIGN AND MATERIALS

Q981. The primary function of a spring is to:

A. Store and release mechanical energy
B. Produce fuel
C. Measure temperature only
D. Increase fluid density

Answer: A. Store and release mechanical energy

Explanation: Springs store elastic potential energy and release it when required.

Q982. A helical compression spring is designed mainly to resist:

A. Compressive loading
B. Fluid pressure only
C. Thermal radiation
D. Electrical current

Answer: A. Compressive loading

Explanation: Compression springs are commonly used to resist compressive forces.

Q983. A bolt is primarily used for:

A. Detachable fastening
B. Permanent casting
C. Heat transfer
D. Fluid filtration

Answer: A. Detachable fastening

Explanation: Bolted joints allow components to be assembled and disassembled.

Q984. A riveted joint is generally considered:

A. A permanent joint
B. A temporary joint
C. A sliding joint
D. A fluid joint

Answer: A. A permanent joint

Explanation: Rivets normally need to be destroyed or removed to separate the joined components.

Q985. A welded joint is generally:

A. Permanent
B. Easily detachable
C. A rolling joint
D. A temporary fastening

Answer: A. Permanent

Explanation: Welding creates a permanent material joint.

Q986. Factor of safety is generally defined as:

A. Failure strength / allowable working strength
B. Allowable strength / failure strength
C. Load / area
D. Stress × strain

Answer: A. Failure strength / allowable working strength

Explanation: The factor of safety provides a margin between expected failure and allowable operating conditions.

Q987. Stainless steel is characterized primarily by:

A. Good resistance to corrosion
B. Zero strength
C. Extremely low melting point
D. Complete absence of iron in all grades

Answer: A. Good resistance to corrosion

Explanation: Chromium-containing stainless steels develop a protective passive oxide layer.

Q988. Cast iron generally has:

A. Good compressive strength and relatively low ductility
B. Very high ductility
C. No carbon
D. No strength

Answer: A. Good compressive strength and relatively low ductility

Explanation: Many cast irons are strong in compression but relatively brittle compared with ductile steels.

Q989. Aluminium is valued in engineering applications primarily because of its:

A. Low density and good corrosion resistance
B. Extremely high density
C. Complete brittleness
D. Very low electrical conductivity

Answer: A. Low density and good corrosion resistance

Explanation: Aluminium alloys provide useful strength-to-weight ratios and corrosion resistance.

Q990. Brass is primarily an alloy of:

A. Copper and zinc
B. Copper and tin
C. Iron and carbon
D. Aluminium and magnesium

Answer: A. Copper and zinc

Explanation: Brass is mainly a copper-zinc alloy.

SECTION J — FINAL NUMERICAL AND CONCEPTUAL QUESTIONS

Q991. A force of 200 N acts through a distance of 10 m in its direction. The work done is:

A. 200 J
B. 1,000 J
C. 2,000 J
D. 20,000 J

Answer: C. 2,000 J

Explanation:

[
W=Fs=200\times10=2000J
]

Q992. A 5 kg body moves at 4 m/s. Its kinetic energy is:

A. 10 J
B. 20 J
C. 40 J
D. 80 J

Answer: C. 40 J

Explanation:

[
KE=\frac12mv^2
=\frac12(5)(4^2)
=40J
]

Q993. A body of mass 10 kg is raised by 5 m. Taking (g=10m/s^2), its potential energy is:

A. 50 J
B. 100 J
C. 500 J
D. 1,000 J

Answer: C. 500 J

Explanation:

[
PE=mgh=10\times10\times5=500J
]

Q994. A shaft transmits a torque of 100 N·m at 1,000 rpm. Its approximate power is:

A. 1.05 kW
B. 5.24 kW
C. 10.47 kW
D. 20.94 kW

Answer: C. 10.47 kW

Explanation:

[
P=\frac{2\pi NT}{60}
]

[
P=\frac{2\pi(1000)(100)}{60}
\approx10472W
]

[
P\approx10.47kW
]

Q995. A machine has an input power of 25 kW and an efficiency of 80%. Its output power is:

A. 5 kW
B. 15 kW
C. 20 kW
D. 31.25 kW

Answer: C. 20 kW

Explanation:

[
P_{out}=0.8\times25=20kW
]

Q996. Water flows through a pipe at a discharge of 0.02 m³/s. If the cross-sectional area is 0.01 m², the average velocity is:

A. 0.2 m/s
B. 1 m/s
C. 2 m/s
D. 20 m/s

Answer: C. 2 m/s

Explanation:

[
Q=AV
]

[
V=\frac{Q}{A}=\frac{0.02}{0.01}=2m/s
]

Q997. If a material has a stress of 200 MPa and a strain of 0.001, its Young’s modulus is:

A. 20 MPa
B. 200 MPa
C. 20,000 MPa
D. 200,000 MPa

Answer: C. 20,000 MPa

Explanation:

[
E=\frac{\sigma}{\epsilon}
=\frac{200}{0.001}
=200,000MPa
]

Correction: The numerical result is 200,000 MPa, so the correct option is D, not C.

Q998. A refrigerator removes 4 kW of heat while consuming 1 kW of work. Its COP is:

A. 0.25
B. 2
C. 4
D. 5

Answer: C. 4

Explanation:

[
COP_R=\frac{Q_L}{W}
=\frac{4}{1}=4
]

Q999. A pump delivers 0.1 m³/s of water through a head of 20 m. Taking (\rho=1000kg/m^3) and (g=10m/s^2), the hydraulic power is:

A. 2 kW
B. 10 kW
C. 20 kW
D. 200 kW

Answer: C. 20 kW

Explanation:

[
P=\rho gQH
]

[
P=1000\times10\times0.1\times20
=20,000W
=20kW
]

Q1000. A component has a failure load of 120 kN and a factor of safety of 3. The allowable load is:

A. 20 kN
B. 30 kN
C. 40 kN
D. 360 kN

Answer: C. 40 kN

Explanation:

[
\text{Allowable load}=
\frac{120}{3}
=40kN
]

MOCK TEST 10 — ANSWER KEY

Q	Ans.	Q	Ans.	Q	Ans.	Q	Ans.
901	B	926	A	951	A	976	A
902	B	927	A	952	A	977	A
903	C	928	A	953	A	978	A
904	A	929	A	954	A	979	A
905	A	930	A	955	A	980	A
906	B	931	A	956	A	981	A
907	A	932	A	957	A	982	A
908	A	933	A	958	A	983	A
909	A	934	A	959	A	984	A
910	A	935	A	960	A	985	A
911	A	936	A	961	A	986	A
912	B	937	A	962	A	987	A
913	A	938	A	963	A	988	A
914	A	939	A	964	A	989	A
915	B	940	A	965	A	990	A
916	C	941	A	966	A	991	C
917	A	942	A	967	A	992	C
918	A	943	A	968	A	993	C
919	A	944	A	969	A	994	C
920	A	945	A	970	A	995	C
921	A	946	A	971	A	996	C
922	A	947	A	972	A	997	D
923	A	948	A	973	A	998	C
924	A	949	A	974	A	999	C
925	A	950	A	975	A	1000	C

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