B.Tech. Petroleum,Mechanical Engineering Technology, Workshop Practices

1. Fitting Shop
and Fitting
Tools used in
Fitting shop

2. Introduction to Fitting Shop :
• Fitting is the assembling together of parts
and removing metals to secure the
necessary fit is called fitting. An operator
who does the fitting job is called fitter.
Fitting involves certain amount of bench
work using hand tools or power operated
tools. The various operations involved in
fitting are filing, marking, sawing, chipping,
drilling, reaming, tapping, etc.

3. Fitting shop tools are classified as below
• Clamping Tools.
• Measuring and Marking Tools.
• Cutting Tools.
• Striking Tools.
• Drilling Tools.
• Threading Tools.

4. Clamping
Tools
• The vice is the most common tool used for
clamping or holding work

5. Bench Vice
• It is firmly fixed to the bench with the help of
nuts and bolts. It consists of a cast iron and
cast iron jaws. Two jaw plates are fitted on
both the jaws. The holding surface of the
plates is knurled in order to increase the
gripping. Jaw plates are made up of carbon
steel are wear resistant. One jaw is fixed to
the body and the second slides on a square
threaded screw with the help of a handle.
• The jaws are opened up to required length,
job is placed in the two jaws and is fully
tightened with the help of handle. Handle is
used to move the movable jaw.

7. Precautions associated with the
use of vices
• Vices should be kept clean and free from
dust and metal chips, using a brush.
• The vice should never be used as an anvil.
• If should be occasionally oiled.
• The serrated jaws should be covered with
soft metal clamps when finished work is
held.
• Don't use hammer to move the handle.

8. Hand Vice
• For gripping very small work (objects) a
hand vice is gelidly employed. These are
made in different shapes and ides
depending upon the job. A commonly used
consists of the two steel legs hinged
together at the bottom. A spring provided
between two legs helps in opening out by
its pressure. The jaws are adjusted from a
flange nut. The vice s held in a one hand
and the other hand performs the required
operation.

10. Pin Vice
• It is used to hold wire or small diameter
rods. It consists Pivot of a self-centered
three jaw chuck made up of a tool steel.
The work is gripped between the jaw of
the chuck by rotating the handle.
Fig.3. Pin Vice.

11. Pipe Vice
• It is used to hold pipes,
shafts or round jobs. It
consists of a vertical screw
with square treads. A handle
is attached on the top of the
screw to move the movable
jaw, which is fixed, on the
lower end of the screw. It
grips the work at four points.

12. Block with U clamp
• In V Block, V grooves are provided to hold the
round objects longitudinally. The screw dl clamp
applies the holding pressure. When the handle
is rotated there is movement in the screw.

13. Measuring and
marking Tolls

14. Try Square
• It is used for checking
squareness of two surfaces.
It consists of a blade made
up of steel, which is attached
to a base at 90 degree. The
base is made up of cast iron
or steel. It is also used to
mark the right angles and
measuring straightness of
surfaces. Never use try
square as a hammer.
Fig. 6

15. Surface Plate
• It is used for testing the flatness, trueness of the
surfaces. It is made up of cast iron graphite. Its
upper face is planed to form a very smooth
surface. It is also used in scribing While not in
use, it should be covered with a wooden cover.

16. Angle Plate
• It is made up of cast iron
in different sizes. It has
two planed surfaces at
right angles to each other
and has various slots in
each surface to hold the
work by means of bolts
and clamps. Never do
hammering on the angle
plate to fasten (tighten)
the nuts and bolts.

17. Bevel Protractor
• It consists of a steel dial divided into 360
divisions. The dial can be rotated around
the centre. The value of any angle can be
marked or measured by the straight edge.
Straight edge can be slided along the
length.

18. Combination Set
• It is a multipurpose instrument that can be used as
protector, a level, a centre square and a try
square.

19. Centre Square
• It is used to find the centre of the round
jobs. It consists of a straight edge and two
arms. For finding out the centre, the round
job is placed between two arms.

20. Scriber and Surface Gauge
• It consists of a cast iron base on the centre of
which a steel rod is fixed vertically. Scriber is
made up of high carbon steel and is hardened
from the front edge. It is used for locating the
centres round bars or for marking of the lines.

21. Universal Marking Surface
Gauge
• It consists of a cast
iron base, a spindle
and a scriber. The
spindle can be set at
any angle. Scriber can
also be set at any
angle and at any height
from the base
maximum upto the
length of spindle. It is
used for marking
purposes.

22. Punches
• Punches are used for marking purposes. Dot punches
are used for marking dotted line and centre punch is
used to mark the centre of hole before drilling. Punches
are made up of high carbon steel or high speed steels.
One end is sharpened. Hammering is done on the
second end while working. For dot punch, angle of the
punching end is 60 degree while in centre punch, angle
d punching end is 900 degree.

23. Steel Rule
• These are made up of stainless steel and
are available in many sizes ranging from
½ ft to 2 ft. These are marked in inches or
millimetres. All the faces are machined
true. The edges of rule should be
protected from rough handling.

24. Vernier Caliper
• It is a precision instrument used for measuring heights, diameters
and depths. It cat used for measuring external and internal
dimensions.
• It consist of a beam, carrying the main scale, inside and outside
measuring jaws, a depth gauge bar and an adjustable Vernier
head which can be moved along the beam. Fine adjustment done
with the help of a screw. Both the heads are provided with locking
screw to lock at any desired position. The dimension is measured
by the main scale reading and by the vernier scale division.
• Dimension = Main scale reading + Least count x Vernier scale
reading
• Least count. It is the minimum reading that an instrument can
measure.

25. Vernier Caliper

26. Micrometer
• It is used for measuring diameter or thickness of
any job. It is more precise than Vernier Caliper. It
consists of a hook type frame. A hard anvil is
screwed on one end. On the second arid, a
spindle moves to and fro carrying another small
anvil on its end. The sleeve on the spindle
graduated and is called main scale. The Vernier
scale is provided on the thimble that is around the
spindle. The gap between the two anvils is
adjusted by moving (rotating) the thimble. Ratchet
is provided on the side of the spindle to apply fine
pressure. Lock nut is provided to lock any desired
position.

27. Micrometer

28. Least count
• In one complete turn of the thimble distance covered on main scale
• = 0.5 mm = pitch
• Divisions on Vernier scale (i.e. on thimble) = 50
• Pitch = 0.5 mm
• Least count = Pitch/Division on Vernier scale
• = 0.5/50 = 0.01 mm
• Final reading = Main divisions x 1 mm + sub division on main scale
x 0.5 mm + least
• Count x division on Vernier scale.
• Example : If there are 8 mm division crossed, one 0.5 mm sub
division on main scale
• also crossed and the 15th division of the thimble coincides with the
datum line then
• 8 main divisions = 8.00 mm
• 1 sub division on sleeve = 0.50 mm
• 15 divisions on thimble = 0.15 mm (15 x 0.01)
• The final reading = 8.65 mm
• (Provided zero of the thimble coincides with the datum line i.e. no
zero error)

29. Dial Indicator
• It is a round gauge in which a pointer moves
over a graduated scale. The movemerd
magnified through links. When there is
movement in plunger pin, this movement is
magnified various mechanical links and
shown by the rotatory motion of the pointer. A
nut is also prove on the head for zero
adjustment. End of the plunger touches with
the job while measuring. Complete revolution
of the main pointer corresponds to 1 mm that
is divided into 100 parts. Total no. of
revolution of main pointer is indicated by
small pointer. It is used to check the run out
modality of jobs.

30. Dial Indicator

31. Dividers
• These are made up of
steel. Dividers have two
legs having sharp feet.
These are hinged at the
top. It is used for marking
arcs, dividing a line or
transferring a dimension.

32. Caliper
• These are generally used to measure the inside or
outside diameters. Different types are :
• Outside Caliper. It is used to measure the outside
dimensions.
• Inside Caliper, it is used to measure the inside
dimensions. Spring Caliper. Spring is provided to
apply the pressure and lock nut is provided to lock
any desired position.
• Hermaphrodite, Jenny or Oddleg Caliper. One leg
is bent at the tip inwardly and the other has a
straight pointed end. It is used to scribe lines
parallel to the straight edges.

33. Caliper

34. Gauges
• Depth Gauge. It consists of a stainless steel head and a beam. The head slides the
beam and can be tightened with the help of a screw. The beam is graduated in' or
millimetres.
• Feeler Gauge. It is used to check the gap between two mating parts. It consists
number of metal leaves. These have different thickness (marked on each leave
fastened together in a small holder. The material of the leaves is stainless steel.
• Radius Gauge. It is just like a feeler gauge. Every leaf has different radius. It is of
two types—internal or external. It is used to check the radius of outer and inner
surfaces. The radius is marked on each leave and is fastened together in a small
holder.
• Thread Gauge. It is used to check the pitch of threads. It consists of a number of
leaves. On every leaf cuts art provided to check the threads on the job. The thread on
the leave should be properly fit on the thread to be measured. The material of the leaf
is stainless steel and is assembled in a holder.
• Wire Gauge. This gauge is used to check the diameter of wires. It is made up of a
steel sheet disc.
• Vernier Height Gauge. It is used for measuring the height of the parts or scribing
lines at height or for marking purposes. It consists of a vertical bar mounted on a
base. A sliding head with pointer is carried on the vertical rectangular part (bar). The
bar and head are graduated. The scale on the bar is called main scale and on the
called vernier scale. It is always used by placing it on the surface plate. The base of
height gauge is made up of cast iron and the beam is made up of stainless steel.

35. Gauges

36. Gauges

37. Method of Marking
• Marking means setting out dimensions with the help of a
working drawing or the transferring them from a similar part.
The procedure of marking is as follows
• The surface to be marked is coated with the paste of chalk or
red lead and allowed dry.
• Then the work is held in a holding device depending upon
shape and size. if it is use surface plate, if it is round use V
block and clamp, else use angle plate etc.
• Lines in horizontal direction are scribed by means of a surface
gauge. Lines at n angles can be drawn by turning the work
through 90 degree and then using the sat% If true surface is
available, try square can also be used.
• The centre on the end of a round bar can be located by using
an odd leg caliper, swim gauge etc.
• The circles and arcs on a flat surface are marked by means of
a divider.
• After the scribing work is over, indentations on the surface are
made using dot punch arid hammer.

38. Cutting Tools
• The tools, which are used to remove the
material from the work piece, are known
as cutting tools. The cutting tools used in
fitting are hacksaws, files and chisels.
These are described below in detail.

39. Hacksaw
• Hacksaw is used for cutting of rods, bars,
pipes, flats etc. it consists of a frame, which
is made from mild steel. The blade is placed
inside the frame and is tightened with the
help of a flange nut. The blade is made up of
high carbon steel or high speed steel. The
points of the teeth are bent in a zig-zag
fashion, to cut a wide groove and prevents
the body of the blade from rubbing or
jamming in the saw cut. The teeth of the
blades are generally forward cut so in that
case, pressure is applied in the forward
direction only.

40. Hacksaw
Depending upon the direction of cut, blades are classified as :
• Forward cut
• Backward cut.
Depending upon the pitch of the teeth (Distance between the two
consecutive teeth) blades are classified as :
• Coarse (8-14 teeth per inch)
• Medium (16-20 teeth per inch)
• Fine (24-32 teeth per inch)

41. Hacksaw
Precautions while using Hacksaw :
• Always move the hacksaw in perfect straight and horizontal direction.
• Never tilt the frame while sawing.
• Work should be held firmly in the vice.
• Blade must be properly strained in the frame.
• Don't apply too much pressure.
• Don't use a new blade in the cut made by another blade.
• Entire length of the blade should be used in the sawing. Don't allow wing nut to strike
the workpiece.
• For forward stroke blades, the teeth should be in forward direction.
• Don't use hacksaw as a hammer.
• While cutting thin sections wooden piece must be clamped along with the workpiece
Sawing. It is the cutting operation and is performed as follow :
• The work is held tightly in the vice.
• Blade is fixed with its teeth facing forward so that cutting stroke is forward stroke. The
blade is tensioned sufficiently by a wing nut.
• The desired cut is marked and a notch is made with a file.
• The frame is held by one hand just above the wing nut and hold the handle by the
second hand.
• Cutting is started by keeping the blade slightly inclined.
• Pressure is applied during the forward stroke only and it should be relieved during the

42. Files
• Files are multi points cutting tools. It is used to remove the material by rubbing
it on the metals. Files are available in a number of sizes, shapes and degree
of coarseness.
Classification of files
• On the basis of grade :
• Rough (20 teeth per inch)
• Bastard (30 teeth per inch)
• Second cut (40 teeth per inch)
• Smooth file (50 teeth per inch)
Dead smooth (100 teeth per inch)
Rough and bastard files are the big cut files. When the material removal is more,
these file are used. These files have bigger cut but the surface produced is
rough.
Dead smooth and smooth files have smaller teeth and used for finishing work.
Second cut file has degree of finish in between bastard and smooth file.

43. On the basis of shape and size
• The length of the files varies from 4" to
14". The various shapes of cross-section
available are hand file, flat file, triangular,
round, square, half round, knife-edge,
pillar, needle and mill file.

44. On the basis of number of cuts
 Single cut files.
 Double cut files.
 Rasp files.

45. On the basis of number of cuts

46. Precautions for files
• Files should be stored in wooden racks.
• Files should not be used without handle or with
loose fitting handle.
• The file should not be allowed to rust. To prevent
it, it should be coated with machine oil. The oil
should be removed before using the file.
• File cleaner should be used for cleaning the files.
Use file card or hard wire brush for cleaning.
• The new file should be used first on copper, brass
and then on wrought iron or mild steel.
• Never use files as a hammer.

47. Filing
Filing is required after chipping, cutting or to finish the shape
of the work piece. The operation consists of the following
steps
1. The work should be held tightly in the vice. The amount of
projection of the workspace from the vice should be
minimum to reduce the noise.
2. The file handle is hold by the right hand. Left-hand palm
is pressed against the end the file.
3. The file must remain horizontal throughout the stroke.
The stroke should be long, and steady. Pressure should
be applied only in the forward direction.
4. The pressure is relieved during the return stroke but file
should remain in contact the workpiece.
5. When quantity of material removal is more, use rough
files and for finishing cut smooth files. Surface
smoothness is generated progressively,

48. Chisels
• These are used for chipping away the material from the
work piece. These are made up high carbon steel. The
top is flattened and a sharp cutting edge is ground to an
angle suited the material being worked upon. The most
commonly used cutting angle is 60 degrees, but varies
according to the type of material cut.

49. • Commonly used forms of chisels are flat,
cross cut, half round and diamond point.
Flat chisel is used for general work. Cross
cut chisel and half round chisels are used
for grooving and diamond point chisels are
used for precision work.

50. Care for chisels. (Precautions associated
with chipping)
 The same cutting angle of the chisel must be maintained
during the chipping operation.
 Use proper cutting angle for proper metal.
 When removing large amount of metal, it is necessary to
lubricate the cutting edge frequently. This increases the life of
the chisel and the chipping operation becomes easy and
smooth.
 Wear glasses on the eyes while doing chipping.
 While doing hammering on the chisel heads, keep your
fingers away.
 Never use chisel as a hammer.
 If the surface to be chipped is very large, it is advisable to cut
grooves along the whole surface by means of a cross cut
chisel and then chip off the remaining metal.

51. Chipping
• The removal of thick layers of metal by chisel
is known as chipping. This is carried out as
follows.
• The work is properly held in a vice.
• The chisel is properly gripped in the left hand.
The fingers are kept below the head of the
chisel.
• The hammer is grasped in the right hand
near the end of the hammer handle. Then
apply the blow on the chisel.
• Lubricate the surface if needed.

52. Chipping

53. Striking Tools
• Hammers are the only toots used for striking in fitting
shop. A hammer consists of a heavy iron body with a
wooden handle. The weight of the hammer ranges from
0.25 to 2 kg. The parts of a hammer are pean, eye neck,
face and a handle as shown in Fig. 31 below :

54. The main types of hammer are
shown in fig.

55. Care while doing hammering :
(Precautions)
1. The handle of the hammer should have
proper strength. It should be tightly fitted,
2. Use proper size hammer for proper work.
3. Wipe off any oil, if there, from handle or
face of the hammer.
4. Replace the worn out handles. Don't take
risk.
5. While doing hammering, keep mind in
job.

56. Drill
• The tool used for making round holes is
called drill. It is a multipoint cutting tool. It
is made up of high speed steel. The parts
of a twist drill are shown as below :

57. Reamer
• Reamer is used to finish the drilled hole and the
operation is called reaming. So the reaming is a
process of imparting necessary smoothness,
parallelism, roundness and accuracy in size, to
the previously drilled hole by using a reamer. The
commonly used reamer is shown below:

58. Counter Sunk
• Counter sunk are
taper cutters used
to make the hole
cone-shaped from
the upper end. It is
made for fitting
screws and nails.

59. Taps
• Taps are used for making internal threads.
The tap is provided with cutting edges
hardened, so that when it is screwed into a
hole, it cuts an internal thread to fit an
external of the same size. The taps are
made of high carbon or high speed steel
These are made insets of three. First use
taper tap then use medium tap and then
use bottoming or plug tap.

60. Taps

61. Die and die stock
• Die and die stock are used for cutting
internal threads. Dies are made from tool
steel have internal treads. By holding the
die into die stock, the handle is rotated by
hand.

62. Drilling
The drilling operation is carried out as below :
The work is marked with a centre punch at the centre of the hole
to be drilled.
1. Hold the job properly in a vice or in other suitable holding
device.
2. The drill is fitted in the chuck.
3. The hand lever lowers the spindle with the chuck and it is
ensured that the point of the drill is in exact alignment with
the previously marked centre of the hole.
4. The motor is now started and the rotating drill is gradually
pressed into the work to produce desired hole.
5. The pressure should be frequently relieved during the drilling
operation, otherwise the cutting edges of the drill will be
damaged. A coolant should be used constantly during the
drilling operation. Coolant is not used for drilling in brass and
cast iron. For drilling large size hole, first produce the small
sized holes then produce large holes.

63. Drilling

64. Tapping
The process of cutting internal threads into a drilled hole by using a tap is known as Tapping.
The procedure is described below :
First of all, a hole is drilled to a diameter smaller than the outside diameter of the thread on the tap. The
diameter of the hole to be drilled is called tapping size.
1. Tapping size = outside diameter 2 x depth of thread.
2. Where depth of thread = 0.64 x pitch of thread.
3. After drilling, the taper tap is fixed in the tap wrench and screwed in the hole. The tap is held with its
axis vertical.
4. For all materials except cast iron, a little lubricate oil is applied to improve the action.
5. The tap is not turned continuously, but after every half turn, it should be reversed slightly to clear the
threads.
6. When a blind hole is being tapped, the tap should be withdrawn from time to time the metal is
cleared from the bottom of the hole.
7. When the hole is through, the reduction of resistance on the tap indicates the cutting of a full thread
by taper tap.
8. Then use intermediate tap and follow the same procedure and after intermediate tap bottom or plug
tap to finish the threads.
9. When large no. of holes are to be tapped, in that case tapping is done by drilling machine with slow
speed.
10. If the tap is broken during the operation. it creates the problem. .
11. If the piece is project out of the hole, use pliers to unscrew it. For removing the piece, which does
not pr out of the hole, two pins or four pins tool is used. The tool used is called tap extractor.