The document discusses various tools used for measurement and layout in workshops. It describes steel rules, calipers including vernier calipers, micrometers, and height gauges used for linear measurement. Layout tools covered include scribes, squares, dividers, trammels, calipers, bevels, combination sets, and punches for marking and transferring dimensions. Safety precautions for preventing accidents in the workshop are also briefly mentioned.

1. INTRODUCTION
Safety precaution
 Safety describes that it is the way of doing work
correctly to prevent accident.
 It can be defined as the way of prevention of
accidents.
The prevention of accident concerns
 The work man (operator) and his partner
 The work piece
 The working tool
 the work shop
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2. Causes of accidents
 Faulty attitude towards safety
 Emotions (anger, worry, excitements…)
 The other causes of accident are not to take safety as a
way of life.
General safety measures
 Dress correctly (wear apron, short sleeved beltless
coats).
 Remove rings, wrist watches, necklaces, bra- slates.
 Protect your eyes
 No horse play
 No scrap materials on the flour
 Take care of injuries 2
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3. MEASUREMENT
o Measurement is the process of determining or
finding the size, quantity or degree of something .
o The principle dimensional measurement is length;
secondary measurement is angle and curvature.
You can describe shape without describing size, but
not the reverse.
o Measurement science is vital for trade &commerce
,&the basis of modern science& technology.
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4. MEANS OF MEASUREMENT
The means of measurement could be classified as
follows:
I. Standards (reference masters or setting standards)-
these are used to reproduce one or several definite
values of a given quantity.
II. Fixed gauges-these are used to check the
dimensions, form, and position of product features.
III. Measuring instrument-these are used to determine
the values of the measured quantity.
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5. MEASUREMENT UNITS
SI UNITS
Symbol
Units
Measured Quantity
m
Meter
Length
Kg
Kilogram
Mass
s
Second
Time
K
Kelvin
Temperature
A
Ampere
Electrical Current
mol
Mole
Quantity of substance
Cd
Candela
Luminosity
rd
Radian
Plane angle
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6. ENGLISH UNITS
Equivalent value
in SI
Value
English unit
1 mile = 1.609 km
1mile=1760yard
Miles
1yd = 91.44 cm
1 yard = 3 ft
Yard
1 ft = 30.48 cm
1 ft = 12 in
Foot
1 in = 25.4 mm
in
Inch
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7. Use:- for linear measurement and
marking.
Material:- spring steel or stainless
steel.
Graduation:- in 10mm, 5mm, 1mm
and 0.5mm in metric system. The
reading accuracy of the steel rule is
0.5mm.
Size:- available in 150mm, 300mm
& 600mm.
STEEL RULE
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8.  Lengths can be measured by using the following
 metre/half-metre rule
 accuracy = 1 mm / 0.1 cm / 0.001 m
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9. calipers
Calipers are the very simple tools used together with a
steel rule for the measurement or comparison of linear
dimensions
Outside caliper
Outside calipers are used for measuring external
dimensions such as the length, diameter, or even the
thickness of a solid.
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10. the jaws are closed until
the points just touch the
object to be measured
remove the calipers and measure
the distance between the jaws
with a ruler 10
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11. Inside caliper
Inside calipers are used for measuring internal dimensions such as
the diameter of a hole, or the width of a slot etc.
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VERNIER CALIPER
 Function
 To measure smaller distances
 Can measure up to .001 inch or .01mm.
 Features
 Larger, lower jaws are designed to measure outer points e.g.
diameter of a rod.
 Top jaws are designed to measure inside points e.g. size of a hole.
 A rod extends from the rear of the caliper and can be used to
measure the depth.

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STRUCTURE OF VERNIER CALIPER

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STRUCTURE OF THE VERNIER CALIPER
 Main Scale
 Main scale is graduated in cm and mm.
 Vernier Scale
 It slides on the main scale.
 On Vernier scale 0.9cm is divided into 10 equal parts.
 Jaws
 Two inside jaws (Upper)
 Two outside jaws (Lower)

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LEAST COUNT
 Least count (L.C) is the smallest reading we can
measure with the instrument.
 L.C = one main scale division – one
vernier scale division
L.C = 1mm – 0.09mm
L.C = 0.1mm = 0.01cm
 Least Count = Value of the smallest division on MS/
Total number of division on VS
L.C = 1mm / 10 = 0.1 cm / 10 = 0.01cm

16. HOW TO USE VERNIER CALIPER?
 Close the jaws
 Calculate the least count
 Place the object between the
two jaws
 Record the position of zero
of Vernier scale on the Main
scale (3.2cm)
 Notice the reading of VS
which coincides with MS
reading (3rd division in this
case)
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READING OF THE INSTRUMENT
 Reading of the instrument = MS div +
(coinciding VS div x L.C)
 = 3.2 + (3 x 0.01)
 = 3.2 + 0.03
 = 3.23 cm

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TO MEASURE THE DEPTH
 A rod extends from the rear of the caliper and can be used to
measure the depth.
 Open the jaws of caliper and place the rod inside hole of the
object, such as the rod reaches the inner most portion of the
object.
 Read the Vernier caliper. (same procedure as described in
previous slides)

19. MEASURING EXTERNAL DIAMETER
Use the outside jaws of the
caliper as shown
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20. MEASURING DEPTH OF A HOLE
Use the depth gauge of
the caliper as shown
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21. READING THE VERNIER SCALE
 Read the “0” position of the vernier scale on the main scale to
get a rough reading. Rough reading = 18mm
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Look along the veriner
scale until one of the
veriner division
coincides with the
mail scale.
Accurate reading
=18.46mm ±0.01

22. EXAMPLE 1: The external measurement (diameter) of a round section piece of steel is
measured using a vernier caliper, metric scale.
A. The main metric scale is read first and this shows that there are 13 whole divisions
before the 0 on the hundredths scale. Therefore, the first number is 13.
B. The’ hundredths of mm’ scale is then read. Only one division on the main metric
scale lines up with a division on the hundredths scale below it, whilst others do not. In
the example below, the 41st division on the hundredths scale lines up exactly with a
division on the metric scale above.
C. This 41 is multiplied by 0.02 giving 0.82 as the answer (each division on the
hundredths scale is equivalent to 0.02mm).
D. The 13 and the 0.82 are added together to give the final measurement of 13.82mm
(the diameter of the piece of round section steel).
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23. 23
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26. EXERCISE
What is the reading in the caliper shown?
Please click on one of the following answer.
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A. 3.51cm
B. 3.57cm
C. 3.62cm
D. 3.642cm
E. 3.67cm
3.5
0 5 10
3 4
overlap

27. 0 5 10
3 4
overlap
SOLUTION
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Read the “0” position of the
vernier scale on the main scale
to get a rough reading.
Rough reading = 3.6cm
Look along the vernier scale
until one of the vernier division
coincides with the main scale
Accurate reading =
3.67cm±0.005cm

28. vernier depth gauge
A vernier depth gauge is
used for measuring depth
of hole, slots and
recesses.
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29. Vernier Height Gauge
A vernier height gauge is used for
measuring height of an object or
for marking lines onto an object of
given distance from a datum base.
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30. LAYING OUT
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31.  Laying out is the process of scribing lines, points and arcs on to
the metal to indicate the shape and size of the object or it is
transforming the drawing of the object to be made on to the metal.
 Accuracy of a layout is very important to the accuracy of the
finished product.
 Good layout will entail the proper and careful use of all layout
tools.
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32. SCRIBER
Use:- scribe lines to indicate the dimensions of the work
piece to be filed or machined.
Material:- They are made of high carbon steel.
Types:- 1. Single ended 2. Double ended
3. Knife edge 4. Off-set.
1. Single ended:- This scriber is also
known as Hand scriber. Point is
made on one side only. Knurling is
made on the body of this scriber. It
is used for general marking
purposes.
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33. Grip
Bent
Point
Straight
Point
2. Double ended:- This scriber has
one point each at both ends. One of
which is bent at 90º, another point
is kept straight. Centre portion of
body is knurled for better gripping.
This scriber is used mainly in
accordance with scribing block.
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34. 3. Knife edge:- This scriber has one
point each at both ends. One of
which is knife edge, another point
is kept straight. Centre portion of
body is knurled for better gripping.
This scriber is used mainly for
plastic and wood working
4. Off-set:- Point of this scriber is made
offset to facilitate the marking of
minimum height and to set zero when
used with Vernier Height Gauge.
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35. TRY SQUARE
Stock
Blade
90º
Use:- to check the squareness of
machined surface, flatness of
surface, make lines at 90º to the edge
of work pieces & to set work piece at
right angle on work holding device.
Material:- hardened steel.
Size:- available in 100mm, 150mm
& 200mm.
Types:- 1. Fixed try square
2. Adjustable try square
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37. DIVIDER
Use:- for scribing circles, arcs
and transferring and stepping
of distances.
Material:- tool steel or high
carbon steel.
Size:- 50mm to 200mm.
Spring
Type
Wing
Type
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38. • For the correct location and setting of the
divider legs, prick punch marks of 30º are
used.
• Both the legs of the divider should always
be of equal length.
• Dividers are specified by the type of their
joints and length.
• The divider point should be kept sharp in
order to produce fine lines. Frequent
sharpening with an oil stone is better than
sharpening by grinding. Sharpening by
grinding will make the points soft.
Firm Joint
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39. TRAMMEL
Used to scribe larger circles and arcs that are not within
the capacity of dividers
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40. CALIPER:- Calipers are simple measuring intstrument
used to transfer measurement from steel rule to objects
and vice versa. They are made from tools steel or high
carbon steel.
CALIPER
1. Firm joint caliper:- In the case of firm joint
caliper, both legs are pivoted at one end.
To take measurement of a work piece, the
caliper is opened roughly to the required
size. Fine setting is done by tapping the
caliper lightly on a wooden surface.
Outside Caliper
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41. 2. Spring joint caliper:- For this type of
caliper, the legs are assembled by means of
a pivot loaded with a spring. For opening
and closing the caliper legs, a screw and nut
are provided.
Spring joint caliper have the advantage
of quick setting. The setting made will not
change unless the nut is turned. The size of
caliper is specified by its length, which is
the distance between the pivot centre and
the tip of the leg.
Spring
Pivot
Adjusting
Unit
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42. 3. Inside Caliper:- This caliper is used to measure the inside
dimensions like the width of slots, diameter of holes, etc.
Legs of this caliper are bent in outward direction as shown
in figure beside.
Inside Caliper
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43. 4. Odd leg Caliper:- This caliper is also known as Jenny
caliper or Hermaphrodite caliper or leg and point
caliper.They are used for marking lines parallel to inside
and outside edges, locating the centre of round bars,
drawing parallel lines along outer edges, scribing lines
along curved edges.
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44. Engineer’s bevel:- is a tool that is used for transferring
angles and testing angular surfaces for accuracy. This
tool not used for measuring angles.
Bevel Protractor:- is used to check the angles of
inclined surfaces, marking out, and for transferring
angles. Graduated in degrees from 0-1800
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45. Combination set:- is a versatile too used in laying out that
consists of a steel rule, square head, bevel protractor and
center head.
bevel protractor
center head
steel rule,
square head
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46. Blade
The blade is designed to allow the different heads to slide along the blade
and be clamped at any desired location. The groove in the blade is
concave to eliminate dirt buildup and permit a free and easy slide for the
heads. By removing all the heads, the blade may be used alone as a rule.
Square Head
The square head is designed with a 45° and 90° edge, which makes it
possible to be used as a try square and miter square. By extending the
blade below the square, it can be used as a depth rule. The square head
can also be used as a level.
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47. Bevel Protractor
The protractor head is equipped
with a revolving turret graduated in
degrees from 0 to 180 or to 90 in
either direction. It is used to
measure or lay out angles to an
accuracy of 0.5°.
Center Head
The center head, when inserted on
the blade, is used to locate and lay
out the center of cylindrical work
pieces.
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48. PUNCH
Use:- Punches are used in order to make certain
dimensional feature of the layout permanent.
Material:- They are made of high carbon steel.
Types:- 1. Centre punch(90º)
2. Dot punch(60º)
3. Prick punch(30º)
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49. 1. Centre Punch:- The angle of
the point is 90º. The punch
mark made by this is wide and
not very deep. This punch is
used for locating hole. The
wide punch mark gives a good
seating for starting the drill.
2. Dot Punch:- The angle of the
point is 60º. This punch is used
for marking witness marks.
Dot Punch
Centre Punch
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50. 3. Prick Punch:- The angle of the
point is 30º. The 30º point
punch is used for making light
punch marks needed to position
dividers. The divider leg will
get a proper seating in the
punch mark.
Prick Punch
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51. Use:- Surface plates are used most widely as a datum
surface in machine shop work.
SURFACE PLATE
Material:- Gray cast iron and Granite.
Specification:- Cast iron surface plates are designated by
their length, breadth, grade and the Indian Standard
number. i.e. C.I. Surface plate 2000 X 1000 Gr1. I.S.
2285.
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52. 3 Point suspension
TOP
Heavy
Ribs
BOTTOM
SURFACE PLATE
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53. Use:- To support the job and to provide a vertical or
angular plane for marking.
Material:- Angle plates are made from Cast iron or
Steel.
Types:-
1. Solid Angle plate
2. Adjustable Angle Plate
3. Box Angle plate.
ANGLE PLATE
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54. Solid Angle Plate:- This angle
plate is most common. It has the
two plane surfaces perfectly
machined at 90º to each other.
Such angle plates are suitable for
supporting work pieces during
layout work. They are
comparatively smaller in size.
Slots are provided to clamp the
work piece and to reduce the
weight.
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55. Vee Block
Vee blocks usually in a couple are made
of cast iron or steel in case-hardening.
They are generally used for holding
circular work piece for marking out or
machining.
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