Laboratory Manual for Basic Mechanical Engineering by Dr. Anil Singh Yadav & Prof. Sachin Kumar Nikam

Questions for Viva-Voce Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

MULTIPLE CHOICE QUESTIONS (✔)

Q1. Precision of micrometer screw gauge is
a) 0.1 cm
b) 0.01 mm
c) 0.1 mm
d) 0.01 m

Q2. Range of a micrometer screw gauge is
a) more than 1 cm
b) 2 cm
c) less than meter
d) less than cm

Q3. Ratchet stop in the micrometer helps to
a) hold the workpiece
b) adjust zero error
c) lock the spindle
d) control the pressure

Q4. Micrometer work on the principal of
a) screw
b) bolt
c) stud
d) nut & bolt

Q5. The diagram shows a micrometer scale.

What is the reading shown on the micrometer scale?
a) 5.64 mm
b) 7.16 mm
c) 7.14 mm
d) 7.64 mm

Q6. What is the reading as shown in the figure below?

a) 9.98 mm
b) 9.98 cm
c) 9.48 cm
d) 9.48 mm

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Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q7. What is the reading as shown in the figure below?

a) 9.98 mm
b) 9.48 cm
c) 9.48 mm
d) 9.98 cm

Questions for Viva-Voce Q8. The distance through which the screw advances when it is rotated
through one division of the head scale is
a) Zero error
b) Least count
c) Zero correction
d) pitch

Q9. The head scale of a screw gauge contains 100 divisions and its
pitch is 1 mm. What is the least count of the screw gauge?
a) 0.1mm
b) 0.05 mm
c) 0.001mm
d) 0.01mm

Q10. The part of the screw gauge which prevents it from undue
tightening.
a) Stud
b) Screw
c) Ratchet
d) Thimble

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 32

SSiinnee Baarr iiss a Precisionn Anguullaarr
mmeeaassuurriningg IInnssttrruummenetnt ttoo mmeeaassuurree
apanineggcleleess aaantndd tatoo lloroeccqaautteieretthdhee wwanoogrrklke oorrvJJeorobyb
apciceucreatealyt toa mraecqhuinirinegd. Itanisgluesedveirny
caocncjuurnactteiolyn twoimthasclhipinginaugg. eItbilsocukssedfoirn
pcroencjiusencatinognulawrithmesalsipuregmaeungte. blSoicnkes
bars are made from a high chromium
cfoorrrospiroenciseresaisntganutlar stemeel,asuarnedmenist.
hSairndeenbeda,rs parreecismioande gfrrooumnd,a haingdh
scthabroilmizeiudm. corrosion resistant steel,
and is hardened, precision ground,
and stabilized.

Sine Bar

Experiment# 4

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

4 EXPERIMENT NO. 4

Sine Bar Sine Bar

AIM
To measure the taper angle of a given taper specimen using Sine bar.

APPARATUS
Sine-bar, slip gauges, dial gauge, surface plate, tapered work piece.

THEORY
A measuring instrument is any device that may be used to obtain a
linear (dimension) or angular measurement. Measurement systems are
mainly used in industries for quality control management. Often quality
control engineers are applying some the measuring systems such as
linear and angular measurements. These measurements are very much
useful to compare the actual measurements with already existing
standard measurements.
Angular measurements represent an important aspect in metrology and
are generally concerned with measurement of angles on gauges, tools
as well as small changes and deflections. Angular measurements are
frequently necessary for the manufacture of interchangeable parts.
Angular measurement involves the measurement of angles of tapers
and similar surfaces. In workshop also, so often we come across
problems involving angular measurements. This is rather indispensable
in workshops for the manufacture of interchangeable parts, jigs, dies,
etc. The main difference between linear and angular measurement is
that no absolute standard is required for angular measurement. For
angular measurements, there are a wide variety of devices available in
metrology. But the measuring device can be preferred based on the type
of the component to be measured, and the accuracy and precession
required in the measurements.

(A) Non-precision instruments
• Protector
• Engineers square
• Adjustable bevel
• Combination set

(B) Precision instruments
• Bevel protector
• Angle gauges
• Sine bar
• Clinometers
• Autocollimators
• Sprit level

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 33

Sine Bar Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

SINE BAR
A sine bar along with its variants such as sine table and sine centre
are designed either to measure angles very accurately or for locating
any workpiece to a given angle within very close limits. The bar (Fig.
4.1) is essentially a hardened steel beam having a flat upper surface.
The bar is mounted on two equal accurate cylindrical rollers which
are located in the cylindrical grooves made for that purpose. The axes
of the two rollers are mutually parallel to each other and also parallel
to and at equal distance H from the upper surface of the sine bar. The
distance between the cylinder axes L is 100 mm, 200 mm and 300
mm in metric system and 5 inches or 10 inches in British system.
This distance plays an important role while manufacturing all the
parts of the sine bar. It can be used in conjunction with slip gauge set
and dial gauge for measurement of angles and tapers from horizontal
surface.

Figure 4.1 Sine Bar

The component whose angle is to measured is mounted on the sine
bar. One side of the sine bar is raised by means of slip gauges until
the upper surface of the workpiece is truly parallel to the datum
surface. The parallelism of the work surface is checked by moving
the dial gauge across the work surface.

Advantages of Sine Bar
• It provides precise and accurate angular measurement.
• Frequently available.
• Low cost.
• It is simple in design and construction.

Limitations of Sine Bar
• Value of error increases for angle measurement more than
45°.
• Difficult to operate with combination of slip gauges.
• Fixed length between the cylinders limit the application of
sine bar.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 34

Sine Bar Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

• Small error in sine bar may leads to large error in
measurement.

Care of Sine Bar
• Sine bar should be used in dust and dirt-free environment.
• While measuring an angle with sine bar the clamping of job
should be proper.
• Selection of slip gauge should be proper.

Principle
The principle of operation of the sine bar is based on the
trigonometry. One of the rollers of sine bar is placed on the surface
plate and the combination of slip gauges is inserted under the second
roller for setting a given angle.
If 'H' is the height of combination of slip gauges and 'L' is the
distance between the rollers, then (refer Fig. 4.2.)

Taper angle θ = Sin-1(h/L)

Figure 4.2 Sine Bar
Sometimes, both the rollers are also placed on the combination of slip
gauges. If 'h1' and 'h2' are the height of slip gauges, then (refer Fig.
4.3.)

Taper angle θ = Sin-1[(h1-h2)/L)]

Figure 4.3 Sine Bar

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 35

Sine Bar Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Sources of Errors in Sine Bars
• The diameter of both the cylinders must be same, if it is not
then it will lead to error in angle measurement.
• Error in cylinder centre distance creates a progressive increase
in error with increases of angle.
• Cylinder roller setting.
• Flatness of the top surface of the sine bar.
• A constant angle error is introduced if the working surface
(top surface) and cylinder axes are- not parallel with each
other.
• Error in slip gauge combination used for angle setting.

PROCEDURE
• As shown in Fig. 4.2, the taper angle θ of the job WXYZ is to
be measured by the sine bar.
• The job is placed over the surface plate.
• The sine bar is placed over the job with plug or roller of one
end of the bar touching the surface plate. One end of the sine
bar is rested on the surface plate and the other end is rested on
the slip gauges.
• The angle of the job is then first measured by some non-
precision instrument, such as bevel protector. This angle gives
the idea of the approximate slip gauges required, at the other
end of sine bar. Finally, the exact number of slip gauges are
added equal to height h, such that, the top most slip gauges
touches the lower end of the roller.
• The height of the slip gauges required is then measured.
• Then the taper angle of the work piece is equal to the angle
between the sine bar and the surface plate. The angle can be
calculated as (Refer fig. 4.2)
Taper angle θ = Sin-1(h/L)
• When the size of the job is large having taper then we use slip
gauges for both the side to find the taper angle of the job as
shown in Fig. 1.3.
• Then the angle is calculated similar to previous method as,
Taper angle θ = Sin-1[(h1-h2)/L)]
• For a small component, the component or workpiece can be
placed over a sine bar as shown in Fig. 4.4.

Figure 4.4 Sine Bar

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 36

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

• The job is held on the sine bar with some suitable accessories.
• The dial indicator is provided at the top position and the

reading is taken at A position.
• The dial indicator is then moved to the right-hand side and the

reading is taken at position B.
• If there is a difference between reading at position A and B,

then the height of the slip gauges is adjusted until the dial
indicator shows the same reading at A and B.
• Then the angle is calculated similar to previous method as,

Taper angle θ = Sin-1(h/L)
• Take three-four sets of reading for all cases.

• Find out the arithmetic mean of readings taken for taper angle.

OBSERVATION
Length of sine bar, L=………… mm

OBSERVATION TABLE
• For small taper specimen:

Sine Bar S. No. Length Height Taper Angle
(L) (H) θ = Sin-1(h/L)
1
2
3
4

• For large taper specimen:

S. Length Height Height Taper Angle
No. (L) (h1) (h2) θ = Sin-1[(h1-h2)/L)]
1

2
3

4

CALCULATIONS
• For small taper specimen

Mean measured taper angle = [θ1+θ2+θ3+θ4]/4

=……….…………=….…..

• For large taper specimen

Mean measured taper angle = [θ1+θ2+θ3+θ4]/4

=……….…………=………

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 37

Sine Bar Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

RESULTS
• The angle of the given small taper specimen as measured by
sine bar is ……….............
• The angle of the given larger taper specimen as measured by
sine bar is ……….............

PRECAUTIONS
1. The surface plate, slip gauge set and sine bar should be
degreased properly.
2. The dial gauge should be clamped to the stand properly so
that the plunger is vertical to the base.
3. The dial gauge plunger should be handled gently and the
gauge was set to zero after giving slight initial compression to
the plunger.
4. The slip gauges should be placed gently under the roller of the
sine bar.
5. The sine bar should not be used for angle greater than 45°
because any possible error in construction is accentuated at
this limit.
6. As far as possible longer sine bar should be used since many
errors are reduced by using longer sine bars.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 38

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

REVIEW QUESTIONS

Questions for Viva-Voce Q1. What is sine centre?
Q2. Upto which inclination sine centres can be used.
Q3. Why is sine bar limited to 45 degrees?
Q4. Why there are holes in sine bar?
Q5. For what purpose a sine bar is used?
Q6. How sine bar is specified?
Q7. What is the accuracy of sine bar?
Q8. What are the advantages of sine bar?
Q9. What are the limitations of sine bar?
Q10. Draw free hand neat sketch of sine bar.

WRITE YOUR ANSWERS HERE

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Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 39

Questions for Viva-Voce Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

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Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 40

Questions for Viva-Voce Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

MULTIPLE CHOICE QUESTIONS (✔)

Q1. Up to which angle sine bars can measure the angles?
a) 45 degree
b) 60 degree
c) 90 degree
d) 120 degree

Q2. Which of the following is not used in making of sine bars?
a) High carbon
b) High chromium
c) Corrosion resistant steel
d) Aluminium

Q3. Which of the following is incorrect regarding sine bars?
a) Sine bar is itself a complete measuring instrument
b) Some holes are drilled in the body
c) It can be used to locate any work to a given angle
d) It is capable of self generation

Q4. Sine bar is used for measuring
a) Surface roughness
b) Gear profiles
c) Internal tapers
d) External tapers

Q5. Which one the following is the angle measuring device
a) Vernier caliper
b) Slip gauge
c) Sine bar
d) Screw gauge

Q6. The principle of operation of the sine bar is based on the
a) Differential Calculus
b) Integral Calculus
c) Statistics
d) Trigonometry

Q7. Sine bar can be used in conjunction with
a) Vernier caliper
b) Screw gauge
c) Slip gauge set
d) Slip gauge set and dial gauge

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 41

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q8. What is sine centre?
a) Centre of sine bar
b) Sine bar with block holding centres
c) Sine bar with hole in centre
d) Sine bar with hollow rod in centre

Questions for Viva-Voce Q9. Which of the distance of the axes of two cylinders of sine bar?
a) 20 inches
b) 50 inches
c) 5 inches
d) 25 inches

Q10. Upto which inclination sine centres can be used?
a) 45 degree
b) 90 degree
c) 120 degree
d) 60 degree

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 42

STihne lBatahre iiss an Parneciesinotn toAonl.guTlahre
meaeralsiuesritngevidInesntcruemoenf t a tolathmeeadsautrees
apbniaegcclkeestoaantAdntacoielnoretcqaEuteigryetphdet awarnoogruklne dorv1Je3or0by0
aBcCcu.raTtehleyretoismaalcshointienngu. oIut siseuvsidedenicne
cfonrjuintcstioenxiwstietnhcselipatgauageMbylocceknsaefoarn
pGrerceieske saitneg,udlaartinmgebaasucrkemasenfat.r asSitnhee
bars are made from a high chromium
c1o3rtrhosoiorn14thresciesntatnutry BstCee.l,A laatnhde isisa
hmaradcehniende, tporoecl isiotnhat groruontda,tes anda
swtaobriklipzeiedc.e about an axis of rotation
to perform various operations such
as cutting, sanding, knurling,
drilling, deformation, facing, and
turning, with tools that are applied
to the workpiece to create an object
with symmetry about that axis.

Lathe Machine

Experiment# 5

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

EXPERIMENT NO. 5

5 Lathe Machine

AIM
To study of Lathe machine.
APPARATUS
Lathe Machine with various attachments.
THEORY
Machine tool is a power-driven machine used for making the components
of a desired shape, size, accuracy, and surface finish by removing the
material from the work pieces. The machine tools use cutting tools for
removing the material (Fig. 5.1).

Figure 5.1 Machine tool
Types of Machine tool (Fig. 5.2)

Figure 5.2 Types of Machine tool
Machining or metal cutting process is the process of removing the
material from the work piece, in the form of chips, by means of cutting
tools so as to give the desired shape and size to the component. The
commonly used machining or metal cutting processes are turning,
drilling, boring, milling, and shaping.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 43

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Surface finishing process is the process of imparting the good surface
finish and high dimensional accuracy to the already machined work piece,
with the negligible removal of the material. The commonly used surface
finishing processes are: grinding, honing, lapping, buffing, polishing and
electroplating.
LATHE MACHINE
Lathe machine is a machine tool basically used for removing the
undesirable material, in the form of the chips, from the cylindrical
surfaces. A Lathe machine is the oldest, simplest, versatile and commonly
used machine tool.
Principle of Operation of Lathe Machine
In lathe machine, the workpiece to be machined in held firmly and rotated
(turned) above its axis, while the cutting tool is moved relative to the
workpiece, as shown in Fig. 5.3. Because of this reason, the lathe
machine is also known as turning machine.
The cutting tool, which is made of the harder material than that of the
workpiece, is fed against the workpiece. It removes the undesirable
material from the workpiece in the form of the chips, so as to give the
desired shape and size to the workpiece.

Figure 5.3 Principle of operation of lathe machine
Types of surfaces machined
Basically, two types of surfaces can be produced by lathe machine:
(i) Cylindrical surface: If the cutting tool moves parallel to the axis

of rotation of the workpiece, the cylindrical surface is produced
[Fig. 5.3(a)].
(ii) Flat surface: If the cutting tool moves perpendicular to the axis of
rotation of the workpiece, the flat surface is produced [Fig. 5.3(b)].

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 44

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Types of Lathe Machine

Figure 5.4 Types of Lathe Machine
Basic Elements of Engine Lathe
The basic lathe used for turning and related operations is an engine lathe.
It is a versatile machine tool, manually operated, and widely used in low
and medium production. The term engine dates from the time when these
machines were driven by steam engines.
The lathe machine consists of following six basic elements [Fig. 5.5]:
1. Bed 2. Carriage 3. Headstock 4. Lead screw 5. Tailstock 6. Feed drive

Figure 5.5 Lathe Machine
Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 45

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

1. Bed:
• The bed is the base of the lathe.
• The top of the bed has two guideways to provide the support
and the sliding surfaces for the carriage and the tailstock.
• The bed is made of cast iron.
• The function of bed is to support all other elements of the
lathe.

Figure 5.6 Lathe Machine
2. Headstock:

• The headstock is permanently fastened to the left-hand end of
the lathe bed.

• Functions of headstock are (i) To support the spindle; and (ii)
To house the main drive.
(i) Spindle: Spindle is the hollow rotating shaft used for
holding the workpiece. The work holding device such
as chuck is mounted on the spindle.
(ii) Main drive: The function of the main drive is to drive
the spindle and to change the spindle speed. The main
drive is powered by an electric motor.

3. Tailstock:
• The tailstock is located at the right-hand end of the lathe bed.
• It can be moved along the guideways on the lathe bed and can
be clamped in any position on the lathe bed.
• Functions of tailstock are
(i) To hold the dead center which can support the long
workpieces during machining; and
(ii) To hold the tools like drill, reamer, or tap for carrying
out operations like: drilling, reaming, or taping
respectively.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 46

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Lathe Machine Figure 5.7 Lathe Machine

4. Carriage:
• The carriage is located between the headstock and the
tailstock of the lathe bed.
• It slides along the guideways on the lathe bed.
• Functions of carriage are
(i) To hold the cutting tool; and
(ii) To give longitudinal and/ or cross feed to the cutting tool.
• Parts of carriage:

• The carriage has following five major parts:

Saddle It is the part of the carriage which slides along the
guideways of the lathe bed.
Apron
It is the mechanism of the carriage used for manual and
Cross-slide mechanized movements of the carriage along the
longitudinal axis of the lathe.
Compound It is the part of the carriage which is mounted on the
rest saddle. It gives cross-feed (motion perpendicular to the
Tool post longitudinal axis of the lathe) to the cutting tool.

It is mounted on top of the cross-slide. It can be swiveled
to any angle in the horizontal plane to facilitate the taper
turning.
It is mounted on the compound rest. Its function is to hold
the cutting tool.

5. Lead screw:

• Lead screw is the long-threaded shaft driven by the feed drive.

• Function of lead screw: It is used for giving the mechanized
motion to the carriage for cutting threads on the workpiece.
The split nut in the apron mechanism engages with the lead
screw. The rotary motion of the lead screw is converted into
the linear motion of the split nut and the carriage.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 47

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

6. Feed drive:
• Feed drive is the unit used for transmitting the power and
motion from the main drive to the lead screw with required
reduction ratio.

Figure 5.8 Lathe Machine

Figure 5.9 Lathe Machine Carriage
Specifications of Lathe Machine

• Overall length of bed: It is the total length of the lathe bed.
• Swing: It is the maximum diameter of the workpiece that can

revolve between the centers without touching the bed. It is also
the maximum diameter of the workpiece that can be machined.
Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 48

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

• Distance between centers: It is the distance between the live
center and the dead center. It is also the maximum length of the
workpiece that can be mounted between the centers.

• Maximum and minimum spindle speeds: It gives the maximum
speed and minimum speed at which spindle rotates.

Figure 5.10 Specifications of Lathe Machine
Types of Operations Performed on Lathe Machine
The various operations performed on lathe machine are as follows:
1. Turning:

• Turning is the process of removing the material from the
cylindrical surface of the workpiece to reduce its diameter [Fig.
5.11].

• In turning operation, the tool motion is longitudinal i.e. parallel to
the axis of the lathe spindle.

• The tool used for the turning operation is called turning tool.

Figure 5.11 Turning

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 49

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

2. Eccentric turning:
• Eccentric turning is the process of removing the material from the
cylindrical surface of the workpiece to reduce its diameter about
an axis offset from the axis of the workpiece [Fig. 5.12].
• In eccentric turning, the turned part is eccentric to the remaining
part of the original workpiece. This can be achieved by holding
the workpiece in four-jaw chuck with the axis of workpiece offset
from the axis of the lathe spindle.
• For eccentric turning, the workpiece is hold in four-jaw chuck.

Figure 5.12 Eccentric turning
3. Taper turning:

• Taper turning is the process of uniformly reducing the diameter of
the workpiece along its length [Fig. 5.13].

• In taper turning, the cutting tool is moved at an angle to the axis of
the workpiece by using compound slide.

Figure 5.13 Taper turning
4. Contour turning:

• Instead of feeding the tool along a straight line parallel to the axis
of rotation as in turning, the tool follows a contour that is other
than straight, thus creating a contoured form in the turned part
[Fig. 5.14].

Figure 5.14 Contour turning

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Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

5. Form turning:
• In this operation, sometimes called forming, the tool has a shape
that is imparted to the work by plunging the tool radially into the
work [Fig. 5.15].

Figure 5.15 Form turning
6. Facing:

• Facing is the process of removing the material from the end
surface or face of workpiece [Fig. 5.16].

• The facing operation produces a flat surface.
• The facing operation is used for reducing the length of the

workpiece.
• In facing operation, the tool motion is perpendicular to the axis of

the lathe spindle.
• The tool used for the facing operation is called facing tool.

Figure 5.16 Facing
7. Chamfering:

• Chamfering is the process of beveling the sharp ends of a
workpiece [Fig. 5.17].

• Chamfering is provided:
1. for avoiding the injuries to the persons handling the finished
products; and
2. for aesthetic look to the finished product.

• The tool used for chamfering operation is called chamfering tool.

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Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Figure 5.17 Chamfering
8. Grooving:

• Grooving is the process of providing a narrow groove on the
cylindrical surface of the workpiece [Fig. 5.18].

• In grooving operation, the shape of the tool is reproduced on the
workpiece; hence, this process is also known as form turning
operation

Figure 5.18 Grooving
9. Parting/ Cutting-off:

• Parting is the process of cutting a workpiece into two parts [Fig.
5.19].

• The tool used for parting operation is called parting tool.

Figure 5.19 Parting/ Cut-off

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Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

10. Knurling:
• Knurling is the process of embossing a diamond shaped regular
pattern on the surface of the workpiece using a tool called
knurling tool [Fig. 5.20].
• Knurling is not a metal cutting process. It is a process of
squeezing the metal into peaks and troughs with the help of plastic
deformation.
• Knurling serves the following two purposes:
1. It provides a non-slip grip on the surface; and
2. It gives decorative look.

Figure 5.20 Knurling
11. Drilling:

• Drilling is the process producing a cylindrical hole in the
workpiece [Fig. 5.21].

• In a drilling operation, the workpiece is held in a chuck of while
the drill is held in the tailstock. The drill is then fed against the
rotating workpiece by rotating the handle of the tailstock in
clockwise direction. Once the hole is drilled, the drill is
withdrawn by rotating the handle of the tailstock in the anti-
clockwise direction.

• The tool used for drilling operation is called the drill bit. The drill
bit is a multipoint cutting tool.

Figure 5.21 Drilling
12. Boring:

• Boring is the process of enlarging the already existing hole in the
workpiece [Fig. 5.22].

• Boring is used for machining the larger diameter holes, since the
drills of larger diameter are expensive.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 53

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

• The tool used for boring operation is called the boring tool. The
boring tool is a single point tool mounted on a boring bar.

Figure 5.22 Boring
13. Reaming:

• Reaming is the process of finishing and accurately sizing the
previously drilled hole in the workpiece [Fig. 5.23].

• A reamed hole is of good surface finish and accurate size. When a
smooth and very accurate hole is required, the hole is first drilled
a little undersize and then it is reamed to a correct size.

• In reaming operation, the material removal is negligible.
• The Tool used for reaming operation is called reamer. The reamer

is a multipoint cutting tool.

Figure 5.23 Reaming
14. External Thread Cutting:

• Thread cutting is the process of producing a helical groove of 'V'
or 'square' shape on a cylindrical surface [Fig. 5.24].

• The tool used for threading operation is called thread cutting tool.
• In threading operation, the tool motion is longitudinal i.e. parallel

to the axis of the lathe spindle. For one rotation of workpiece, the
tool automatically travels by a distance equal to the pitch of the
threads
• The definite relation between the rotary motion of the workpiece
and the linear motion of the tool is achieved by engaging the
carriage with the lead screw.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 54

Lathe Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Figure 5.24 Thread Cutting
15. Internal Thread Cutting (Tapping):

• It is the operation of cutting internal threads by using a tool called
a tap. A tap is similar to a bolt with accurate threads cut on it. To
perform the tapping operation, a tap is screwed into the hole by
hand or by machine. The tap removes metal and cuts internal
threads, which will fit into external threads of the same size. [Fig.
5.25].

• The tool used for internal threading operation is called tap.

Figure 5.25 Internal Thread Cutting (Tapping)
In addition to it, with the help of special attachments, operations like
1. Keyway cutting
2. Cam and gear cutting
3. Shaping
4. Milling
5. Fluting,
6. Grinding can also be performed on lathe machine.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 55

Questions for Viva-Voce Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

REVIEW QUESTIONS
Q1. Draw the neat sketch of Lathe machine.
A1.

Q2. State any four specification of lathe?
Q3. Which type of lathe is also known as centre lathe.
Q4. What is the function of chuck?

WRITE YOUR ANSWERS HERE
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Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 56

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q5. Draw the diagram of following Lathe operations:

S. Diagram of the operations
Lathe operations

No.

1 Turning

Questions for Viva-Voce 2 Facing

3 Chamfering

4 Knurling

5 Contour Turning

6 Tapping

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 57

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q6. Which type of feed is needed in turning operation?
Q7. Which type of feed is needed in facing operation?
Q8. Which type of surface is produced by turning operation in lathe
machine?
Q9. Which machine tool is known as the mother machine tool?
Q10. What is an apron?

WRITE YOUR ANSWERS HERE

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Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 58

Questions for Viva-Voce Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

MULTIPLE CHOICE QUESTIONS (✔)

Q1. Lathe bed is usually made of
a) Structural steel
b) Stainless steel
c) Cast iron
d) Mild steel
e) All of the above

Q2. Lathe spindle has got
a) Internal threads
b) External threads
c) Taper threads
d) No threads
e) None of the above

Q3. Which of the following lathe operations requires that the cutting
edge of a tool bit be placed exactly on the work centre line?
a) Boring
b) Drilling
c) Facing
d) Turning
e) Chamfering

Q4. In lathe, the carriage and tail stock are guided on
a) Same guideways
b) Different guideways
c) Any of the above
d) Not guided on guideways
e) None of the above

Q5. In lathe work, when the tool is fed parallel to the rotation of job
work, it will produce
a) Cylindrical surface
b) Spherical surface
c) Tapered surface
d) All of the above

Q6. The following part of Lathe serves as housing for the driving
pulleys and back gears
a) Head stock
b) Tail stock
c) Bed
d) Carriage

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 59

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q7. A desired speed of …….. can be obtained by selecting the suitable
change gears having proper number of teeth
a) Lead screw
b) Countershaft
c) Spindle
d) Feed gear box

Questions for Viva-Voce Q8. The Lathe carriage serves the following purpose of the tool
a) Guiding
b) Feeding
c) Supporting
d) All of the above

Q9. The following is used for holding bored parts for machining their
outside surfaces on Lathe
a) Mandrel
b) Dogs
c) Driving plate
d) Angle plate

Q10. The following is taper turning method on lathe
a) Tail stock set-over method
b) By swivelling the compound rest
c) Using a broad nose tool
d) All of the above

Q11. External threads can be produced by means of
a) Taps
b) Dies
c) Lathe machine
d) All of the above

Q12. A Turret (square) tool post can accommodate ……… tool(s)
a) One
b) Two
c) Three
d) Four

Q13. In which of the following type of lathe, a square tool post can be
provided?
a) Centre
b) Turret
c) Capstan
d) All of the above

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 60

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Drilling Machine

Experiment# 6

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

6 EXPERIMENT NO. 6

Drilling Machine

AIM
To study of Drilling machine.

APPARATUS
Drilling Machine.

Drilling Machine THEORY
If the two components are to be connected to each other with the help of
nuts and bolts, the cylindrical holes need to be made in the components.
The cylindrical holes are required to be made in the components for many
other purposes. Therefore, most of the components have one or more
cylindrical holes in them.

Drilling: The process of making the cylindrical hole in the workpiece is
called as drilling.

Drilling machine: The machine tool used for making the hole in the
workpiece by forcing the rotating tool into the stationary workpiece is
called as drilling machine.

Drill or drill bit: The tool used for making the cylindrical hole in the
workpiece is called drill bit. The most common drill bit is the twist drill.

Principle of Operation of Drill Machine
• In a drilling machine, the workpiece is firmly clamped on the
worktable or base. The workpiece is stationary.

• The multipoint cutting tool, called drill, is press fitted into the
spindle of the drilling machine.

• The spindle and drill rotate at the desired speed.

• The rotating drill, which is made of the harder material than that
of the workpiece, is fed against the stationary workpiece by hand
feed or by power feed. It removes the material from the workpiece
in the form of the chips; so as to produce the cylindrical hole, as
shown in Fig. 6.1.

Basic Elements of Drilling Machine

The drilling machine consists of following five base elements [Fig. 6.2]:

1. Base 2. Column 3. Work table 4. Drilling head

5. Spindle

1. Base:
• Base is the lower most part of the drilling machine which supports
the entire structure.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 61

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Figure 6.1 Principle of operation of drilling
2. Column:

• Column is the vertical part fixed on the base.
• It supports all other elements of the drilling machine.
3. Work table:
• The work table is mounted on the column. It has two types of

motions:
(i) up and down motion along the column; and
(ii) swing about the axis of the column.
• The work table supports the workpiece and facilitates the
positioning of workpiece for drilling operation.
• The top surface of the work table has T-slots for clamping the
workpiece.

Figure 6.2 Drilling machine
Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 62

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

4. Drilling head:
• The drilling head is mounted on the top of the column.
It contains:
(i) The drive mechanism; and (ii) The feed mechanism.
• The drive mechanism is used for driving the spindle (drill). It
consists of an electric motor and a gear box.
• The feed mechanism is used for feeding the spindle (drill) against
the workpiece. The feed can be either power feed or manual feed.

5. Spindle:
• Spindle is a hollow part, which is provided with a rotary motion.
• It supports the drill and imparts the rotary motion to it.

Types of Drilling Machines
The drilling machines are classified into the following types:

1. Portable drilling machine
2. Sensitive or bench drilling machine
3. Pillar or upright drilling machine
4. Radial drilling machine
5. Multi-spindle drilling machine
6. Gang drilling machine
7. Vertical turret type drilling machine
8. Automotive drilling machine
9. Deep hole drilling machine
1. Portable drilling machine
• The portable drilling machine, shown in Fig. 6.3, is the small

sized, compact drilling machine.
• It consists 01 a spindle driven by an electric motor.
• The example of a portable drilling machine is a hand drill.

Figure 6.3 Portable drilling machine

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 63

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

2. Sensitive or bench drilling machine
• The sensitive or bench drilling machine is the simplest type of
drilling machine used for light duty works. It is used for drilling
holes up to 12.5 mm diameter.
• The sensitive or bench drilling machine, shown in Fig. 6.4,
consists of five basic elements: base, column, work table, drilling,
head and spindle
• The drilling head is fixed to the column.
• The spindle is driven by an electric motor through the cone pulley
drive. The cone pulley drive provides different spindle speeds.
• The manual feed mechanism is used for feeding the spindle (drill)
against the workpiece.
• This manual feed mechanism, which essentially consists of rack
and pinion, is operated by the hand liver. This arrangement helps
the operator to feel the force acting on the drill, and hence it is
called as sensitive drilling machine.
• The work table is mounted on the column. It has two types of
motions:
(i) up and down motion along the column; and
(ii) swing about the axis of the column.

Figure 6.4 Sensitive or bench drilling machine

3. Pillar or upright drilling machine
• The pillar or upright drilling machine, shown in Fig. 6.5, is similar
to the sensitive or bench drilling machine except the following
differences:
1. The pillar or upright drilling machine has more rigid column
and hence it is used for medium duty works.
2. It can be used for drilling holes up to 75 mm in diameter.
3. The spindle is driven by an electric motor through the gear
drive. The gear drive provides the wide range of spindle
speeds.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 64

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

4. The spindle feed is automatic or power feed.
5. The up and down motion of the work table along the column

is controlled by lead screw. Therefore, the table motion is
more precise.

Figure 6.5 Pillar or upright drilling machine
4. Radial drilling machine

• The radial drilling machine, shown in Fig. 6.6, is the largest and
most versatile of all the drilling machines. It is suitable for heavy
duty works.

• The radial drilling machine consists of six basic elements:
(i) Base (iv) Radial arm (ii) Work table (v) Drilling head (iii)
Column (vi) Spindle
1. Base: Base is the lowermost part of the drilling machine
which supports the entire structure.
2. Work table: The worktable, which is mounted on the base, is
stationary. It can support heavy and bulky workpieces.
3. Column: The column is the vertical part fixed on the base. It
supports the radial arm.
4. Radial arm: A large arm is supported on the column. It can
be raised or lowered along the column, with the help of the
motor driven lead screw. It also swings around the column
through an arc of 180° or more.
5. Drilling head: The drilling head, which is mounted on the
radial arm, can move along the arm. The movement of the
drilling head along the radial arm can be power driven as well
as the manually operated.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 65

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Figure 6.6 Radial drilling machine
6. Spindle: The spindle is driven by an electric motor through

the gear drive. The gear drive provides the number of spindle
speeds. The spindle is provided with manual feed as well as
power feed.
• Due to the movement of the drilling head along the radial arm and
the swinging motion of the radial arm around the column, the
holes can be drilled in different locations without moving the
workpiece.
Types of Operations Performed on Drilling Machine
Several operations are related to drilling. These are illustrated and
described in this section. Most of the operations follow drilling; a hole
must be made first by drilling, and then the hole is modified by one of the
other operations. All of the operations use rotating tools. The various
operations performed on drilling machine are as follows:
1. Drilling
• Drilling is the process of making the cylindrical hole in the
workpiece [Fig. 6.7].
• The tool used for drilling operation is called drill. The drill is a
multipoint cutting tool.
2. Boring:
• Boring is the process of enlarging the already existing hole in the
workpiece [Fig. 6.8].
• Boring is used for machining the larger diameter holes, since the
drills of larger diameter are expensive.
• The tool used for boring operation is called the boring tool. The
boring tool is a single point tool mounted on a boring bar.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 66

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Figure 6.7 Drilling
Figure 6.8 Boring

Figure 6.9 Reaming
Figure 6.10 Counter-boring
Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 67

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

3. Reaming
• Reaming is the process of finishing and accurately sizing the
previously drilled hole in the workpiece [Fig. 6.9].
• A reamed hole is of good surface finish and accurate size. When a
smooth and very accurate hole is required, the hole is first drilled
a little undersize and then it is reamed to a correct size.
• In reaming operation, the material removal is negligible.
• The Tool used for reaming operation is called reamer. The reamer
is a multipoint cutting tool.

4. Counter-boring:
• Counter-boring is the process of enlarging the existing hole to a
larger diameter and making the surface at the bottom of the larger
diameter flat [Fig. 6.10].
• The tool used for counter-boring operation is called counter-bore.
• The counter-boring is essential for providing a recess for bolt
heads or nuts.

5. Spot-facing:
• Spot-Facing is the process of enlarging the existing hole to a
larger diameter and making the surface at the bottom of the larger
diameter flat such that the depth of the enlarged hole is sufficient
to provide a seat for the washer [Fig. 6.11].
• Spot-facing is similar to the counter-boring except in spot-facing
the depth of the enlarged hole is very small

6. Counter-sinking:
• Counter-sinking is the process of chamfering the entrance of a
drilled hole [Fig. 6.12].
• The tool used for the counter-sinking operation is called counter-
sink.
• The counter-sinking is necessary for providing a recess for a
counter-sink flat head screw or a counter-sink rivet to be fitted
into the hole.

7. Tapping:
• Tapping is the process of making the internal threads in a drilled
hole [Fig. 6.13].
• The tool used for the tapping operation is called tap.

8. Trepanning:
• Trepanning is the process of making a large hole by removing the
metal along the circumference of the hole with the help of a
multipoint hollow tool [Fig. 6.14].
• This process is used for making the large size holes.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 68

Drilling Machine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Figure 6.11 Spot-facing
Figure 6.12 Counter-sinking

Figure 6.13 Tapping
Figure 6.14 Trepanning

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 69

Questions for Viva-Voce Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

REVIEW QUESTIONS
Q1. Draw neat sketch of Drilling machine.
A1.

Q2. What is the tool used for drilling?
Q3. What is the use of drill?
Q4. What are the different types of drilling operations?

WRITE YOUR ANSWERS HERE
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Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 70

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q5. Draw the diagram of following drilling operations:

S. Drilling Diagram of the operations
No. operations

1 Boring

Questions for Viva-Voce 2 Reaming

3 Counter-boring

4 Spot-facing

5 Counter-sinking

6 Trepanning

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 71

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q6. What is difference between drilling and boring?
Q7. What is tapping operation?
Q8. What is counter boring operation?
Q9. What is reaming operation?
Q10. What is trepanning operation?

Questions for Viva-Voce WRITE YOUR ANSWERS HERE

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Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 72

Questions for Viva-Voce Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

MULTIPLE CHOICE QUESTIONS (✔)

Q1. On drilling machine, which process is known as reaming?
a) Enlargement of existing hole
b) Hole made by removal of metal along the hole circumference
c) Smoothly finishing and accurately sizing a drilled hole
d) All of the above

Q2. The process of chamfering the entrance of a drilled hole is known
as
a) counter-boring
b) counter-sinking
c) counter-fillet
d) trepanning

Q3. Which one of the following processing sequences will give the
best accuracy as well as surface finish?
a) Drilling, Reaming, Grinding
b) Drilling, Boring, Grinding
c) Drilling, Reaming, Lapping
d) Drilling, Reaming, Electroplating

Q4. A twist drill is specified by its
a) Shank, material and diameter
b) Shank, lip angle and size of flute
c) Material, length of body and helix angle
d) Any one of these

Q5. Twist drills are made of
a) High speed steel
b) Carbon steel
c) Stainless steel
d) Either (a) or (b)

Q6. In a drilling operation
a) Torque is equal to the axial force
b) Torque is more than the axial force
c) Torque is less than the axial force
d) Torque is half the axial force
e) None of above

Q7. In drilling operation if the drill point is outside the drill axis, the
effect on the drilled hole will be
a) The hole will become too large
b) The hole will become elliptical
c) The hole will be rough
d) The drilled hole will be normal

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 73

Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

Q8. If a drill does not cut; the probable cause would be
a) Drill blunt
b) Material difficult to drill
c) Absence of coolant
d) Speed low

Questions for Viva-Voce Q9. A 12 mm drilling machine means
a) It can drill holes in 12 mm thick plates
b) It can drill holes maximum 12 mm in diameter
c) All of the above
d) It can be used for drilling holes having cross-sectional area of
12 sq mm

Q10. In following operations are to be performed on a job, which one
would be performed first
a) Drilling
b) Boring
c) Tapping
d) Counter sinking
e) Sport facing

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 74

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The four-stroke cycle engine is the
most common type of small engine.
A four-stroke cycle engine completes
five processes in one operating cycle,
including intake, compression,
ignition, power and exhaust Strokes.

Four Stroke Engine

Experiment# 7

Four Stroke Engine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

7 EXPERIMENT NO. 7

Four Stroke Engine

AIM
To study of four stroke engines.
APPARATUS
Models of four stroke petrol and diesel engine.
THEORY
All operations are carried out in four strokes of the piston, i.e., two
revolutions of the crank shaft. Therefore, the engine is called a four-
stroke engine. A large number of internal combustion engines, both petrol
and diesel, operate on a four-stroke cycle.
FOUR STROKE SPARK IGNITION (SI)/PETROL ENGINE
Constructional Details
Petrol engine (spark ignition engine) consist of a cylinder, cylinder head
attached with spark plug, piston attached with piston ring, connecting rod,
crank, crank shaft, etc., as shown in Fig. 7.1. In a four-stroke engine,
valves are used instead of ports. There are inlet and exhaust valves. These
valves are operated by cams attached on a separate shaft, called a cam
shaft. It is rotated at half the speed of a crank shaft.

Figure 7.1 Four Stroke Petrol Engine
Operations
The travel of the piston from one dead centre to another is called piston
stroke and a four-stroke cycle consists of four strokes as suction,
compression, expansion and exhaust strokes. The sequence of four
strokes is as follows: -

1. Intake or suction stroke,
2. Compression stroke,
3. Working or expansion or power stroke and,
4. Exhaust stroke.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 75

Four Stroke Engine Lakshmi Narain College of Technology (LNCT) Bhopal (MP)

1. Suction Stroke Suppose that the piston is very near to the top dead
centre position (T.D.C.) [Fig 7.2 (a)]. During suction stroke the inlet
valve is opened and the discharge valve is closed and the piston moves
down (i.e. outward) due to rotation of the crankshaft either getting energy
from the flywheel or a motor starter. As the piston move, vacuum is
created between the piston and cylinder and the pressure in the cylinder
drops below atmospheric pressure. The piston moves from the top dead
centre to the bottom dead centre, the charge (mixture of fuel and air
prepared in the carburettor) rushes inside the cylinder through inlet
manifold and valve which is cam operated. The suction process continues
till the piston reaches the bottom dead centre position (B.D.C.).

Figure 7.2 Operations of a Four Stroke Petrol Engine

2. Compression Stroke During a compression stroke [Fig 7.2 (b)], both
the valves are closed and the piston moves from bottom to top dead centre
position. The charge or air is compressed up to a compression ratio which
depends upon the type and need of the engine. Since both the valves are
closed and the piston moves inwards, there is a reduction in volume of the
charge which results in an increase of pressure and temperate of the
cylinder contents. In petrol engines, the compression ratio varies from 6
to 12 and pressure and temperature at the end of compression are 7 to 14
bar and 250°C to 300° C respectively.

3. Expansion Stroke During power stroke [Fig 7.2 (c)], both the valves
are closed. The power stroke includes combustion of fuel and expansion
of the products of combustion. The combustion starts at the end of the
compression stroke when the piston is approaching the T.D.C. position.
In S.I. Engine a spark plug initiates the combustion. During combustion
the chemical energy of the fuel is released and there is a rise in
temperature and pressure of the gas. The temperature of the gases is
increased to between 1800-2300°C and the pressure to 30–40 bar. The
volume of the gas however remains constant during combustion. The
high pressure and the high temperature of the products of combustion,
thus obtained, pushes the piston outward from T.D.C. to B.D.C. position
for expansion stroke. This reciprocating motion of the piston is converted
into rotary motion by the crankshaft, connecting rod and crank
mechanism.

Mechanical Engineering Department | Lab Manual | Basic Mechanical Engineering [BT-203] 76