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DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
METROLOGY LABORATORY
MANUAL
iii-b.tECh i-sem-mechanical &
iv-b.tech i-sem-automobile
Prepared By:
S PRAVEEN KUMAR
Assistant Professor
DEPARTMENT OF MECHANICAL
ENGINEERING
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
SYLLABUS
(55604) MACHINE TOOLS AND METROLOGY LAB
Section A : METROLOGY LAB
S.NO: NAME OF THE EXPERIMENT NAME OF THE EQUIPMENT
1 Use Of Gear Teeth Vernier Calipers For
Checking The Chordal Addendum And
Chordal Height The Of Spur Gear
Gear Teeth Vernier Calipers
2 Machine Tool Alignment Of Test On
The Lathe
Lathe Machine and Dial Guage
3 Tool Makers Microscope And Its
Application
Tool Makers Microscope
4 (a) Angle And Taper Measurements By
Bevel Protractor
Bevel Protractor and Dial Guage
4 (b) Angle And Taper Measurements By
Sine Bars
Sine Bar and Slip Gauges
5 Use Of Spirit Level And Optical Flats In
Finding The Flatness Of Surface Plate
Spirit Level and Surface Plate
6 Thread Measurement By 2-Wire And 3-
Wire Methods
Micrometer and 2-Wire And 3-
Wire Threads
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No. 1
GEAR TOOTH MEASUREMENTUSING GEAR TOOTH CALIPER
AIM :-
Inspection of gear tooth using gear tooth caliper and
measurement of gear tooth thicknes
INTRODUCTION :-
Gears are mainly used for transmission of power and motion. For close
control over the accuracy of manufacture, precision measurement of gears plays
a vital role.
Various types of gears commonly used are:
Spur Gear :- It is cylindrical gear whose tooth traces are straight line.
Helical Gear:-It is cylindrical gear whose tooth traces are straight helical
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Spiral Gear :-A gear whose tooth traces are curved lines
Straight Bevel :-
A gear whose tooth traces are straight line generator of cone. It is conical in
form operating on intersecting axes usually at angles.
Worm Gear :- The worm and mating worm wheel have their axes nonintersecting.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Terminology Of Gear Tooth :-
Base Circle:- It is circle from which involutes form is generated. Only the hare on a gear is
fixed and unalterance.
Pitch Circle:-It is an imaginary
Pitch Circle Diameter:- It is the diameter of a circle which by pure rolling action would produce the
same motion as the tooth gear wheel. This is more important diameter of gear.
Module:- It is defined as length of pith circle diameter per tooth.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Addendum: This the radial distance from the pitch circles to the tooth.
Clearance :-
This is the radial distance from the tip of tooth to the bottom of a mating tooth
space, when the teeth are symmetrically engaged. Its STD value is 0.157 M .
Duodenum:-
This is radial distance from the pith circle to the bottom of tooth space.
Blank Diameter: - This is the diameter of blank from which gear is out
Blank Diameter = P.C.D + 2M
Tooth Thickness :-
This is the arc distance measured along the pitch circle from it’s intercept with
one flank to it’s intercept with the flank of same tooth.
The teeth thickness measurement is the more important measurement. Most of
gear manufacturer may not undergo checking of all other parameter but
thicknessmeasurement is must.
Gear tooth thickness is measured by using gear tooth vernier caliper. It is
applicable for gears where tooth traces are straight line.
Procedure: -
The gear tooth vernier has two vernier scales and they are set for width ‘W’ of
the tooth and depth‘d’ from the top at which ‘W’ occurs.
* Consider one gear tooth, the values of ‘W’ and‘d’ can be found by using
caliper.
It may be noted that ‘w’ is chord length but tooth thickness is specified by arc
distance. Also‘d’ found out by using caliper is slight greater than addendum.
Therefore ‘W’ and‘d’are called chordal thickness and chordal addendum
respectively.
* Take five readings of ‘W’ and‘d’ and calculate ‘Wavg’ and ‘davg’.
* With the help of ‘Wavg’ calculate the experimental value of module.
* Calculate theoretical value of the module.
* Finally find out % error in module.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Observation Table:-
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No. 2
LATHE MACHINE ALIGNMENT
AIM :-
To perform the alignment test on the lathe machine
APPARATUS:
Dial gauge with stand
PROCEDURE:
1) Clamp the job in universal chuck.
2) Place the dial gauge stand on the compound slide and turn on magnetic
lock
3) Adjust the stylus of the dial gauge so that it touches the surface of the job
with pressure.
4) Rotate the chuck by ha
5) nd.
6) If there is change in the reading of the dial gauge adjust the job to
compensate the deflection
7) Rotate the chuck by hand
8) See if there is any deflections do the same as in step number 5
9) Repeat the procedure till there is no deflection in the reading of the dial
gauge during complete revolution.
RESULT:
Using the above procedure the alignment of the chuck is done.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No. 03
TOOL MAKERS MICROSCOPE AND ITS APPPLICATION
AIM:- Measurement of threads parameters using tool maker's microscope.
APPARATUS :- Tool maker's microscope, threading job.
TOOL MAKER'S MICROSCOPE :-
Tool maker's microscope is versatile instrument that measures by optical means
with no pressure being involved it is thus a very useful instrument for making
measurements on small and delicates parts. The tool maker's microscope is
designed for the following measurements; measurements on parts of complex
form for example, the profile of external thread as well as for the tools,
templates and gauges, measuring centre to centre distance of holes in any plane
and other wide variety of linear measurements and accurate angular
measurements A tool maker's microscope is as shown in fig. The optical head can be moved up or
down the vertical column and can e clamped at any height by means of a clamping
screws. The table which is mounted n the base of the instrument can be moved in two
mutually perpendicular horizontal directions (longitudinal and lateral) by means of
accurate micromeres screws having thimble scale and venires.
A ray of light from light source is reflected by mirror through 90. It is then passes
through a transparent glass plate (on which flat parts may be placed). A shadow image
of the outline or contour of the work piece passes through the objective of the optical
head and is projected by a system of three prisms to ground glass screen. Observations
are made through an eyepiece. Measurements are made by means of crosslines
engraved on the ground glass screen. The screen can be rotated trough 360 the angle
of rotation is read through an auxiliary eyepiece.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
TOOL MAKERS MICROSCOPE
PROCEDURE:-
The use of - tool maker's microscope for the taking the various measurements is
explained below-
1) For taking linear measurements, the work piece is placed over the table. The
microscope is focused and one end of the work piece is made to coincide
with cross line in the microscope (by operating micrometers screws). The
table is again moved until the other end of the work piece coincide with the
cross line on the screen and the final reading taken. From the final reading,
the desired measurement can be taken.
2) To measure the screw pitch, the screw is mounted on the table. The
microscope is focused (by adjusting the height of the optical head) until a
sharp image of the projected contour of the screw is seen of the ground glass
screen. The contour is set so that some point on the contour coincides with
the cross line on the screen. The reading on the thimble of the longitudinal
micrometer screw is noted. Then the table is moved by then same screw until
a corresponding point on the contour (profile) of the next thread coincides
with the cross line. The reading is again noted and the difference in two
reading gives the screw pitch.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
3) To determine pitch diameter the lateral movement to the table is given
4) To determine the thread handle, the screen is rotated until a line on the angle
of screen rotation is noted. The screen is further rotated until the same line
coincides with the other flank of the threads. The angle of thread on the
screen will be difference in two angular readings.
Different types of gradated and engraved screens and corresponding eye piece
are used for measuring different elements.
RESULTS:- 1) External diameter = R2 - R1 = -------------- mm.
2) Internal diameter = R2 - R1 = -------------- mm.
3) Pitch of threads = R2 - R1 = --------------- mm.
4) Threads angle = R2 - R1 = --------------- mm.
PRECAUTION:-
1) Obtain clean picture of cross line and the cross thread seen through the eye
piece.
2) For angular measurements lines must remain parallel to flank edge to the
tooth.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No. 04[a]
MEASUREMENT OF ANGLE USING VERNIER BEVEL PROTRACTOR
AIM:- To measure the angles o f given specimen using bevel protractor
APPARATUS REQUIR ED
1. Surface P late,
2. Dial Gauge,
3. Slip Gauge,
4. Bevel protractor,
5. Specimen
FORMULA
×100
BEVEL PROTRACTOR
A bevel protractor is a graduated circular protractor with one pivoted
arm; used for measuring or marking off angles. It is attached with an acute
angle attachment. The body is designed such that its back is flat and no
projection is beyond its back. The base plate is attached to the main body
and an adjustable blade is attached to the circular plate containing vernier
scale. The main scale is graduated in degrees from 0o-90o in both the
direction. The adjustable blade can be made to rotate freely about the centre.
The base plate is made flat for measuring angles and can be moved
throughtout it‘s length.
Uses:-
It has wide application in architectural and mechanical drawing, although its use is decreasing with the availability of modern drawing software or CAD.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
PROCEDURE
1. Initially bevel protractor is adjusted as per requirements.
2. Specimen is placed between the blades.
3. Reading noted directly from main scale and Vernier scale
4. For measuring, taper angle of sine bar, protractor is fixed to height gauge
5. The protractor is corresponding adjusted.
6. Noted reading is tabulated
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
TABULATIONS
RESULT:
Thus angle of the given specimens was determined by using bevel protractor
Angle of the given specimen 1 =
Angle of the given specimen 2=
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No. 04[b]
MEASUREMENT OF TAPER ANGLE USING SINE BAR
AIM:-
To determine unknown angle using sine bar.
APPARATUS:- Sine bar, surface plate, dial indicator, slip gauges.
INTRODUCTION:-
Sine bar is used in conjunction with slip gauges for precise angular
measurement. Sine bar is used either to measure angle very accurately or face
locating any work to a given angle. Sine bars are made from high chromium,
corrosion resistant steel, hardened, ground and stabilized.
Two cylinders of equal dia. are attached at ends. The axes of these two cylinders
are mutually parallel to each other and also parallel to and at equal distance
from the upper surfaces of the sine bar. Accuracy up to 0.01mm /m length of
sine bar can be obtain.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Application of sine bar :-
A] Checking of unknown angles of small workpiece
B] Checking of unknown angles of heavy component.
Figure. Checking of unknown angles of heavy component.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
SLIP GAUGES:-
Introduction:- Slip gauges are rectangular blocks of steel having a cross-section of about 30 by
10mm. These gauges are used to provide end standard of specific length by
temporarily combining a number of individual gauge by ‘wringing’, each
representing a dimension (standard) into a single gauge bar. Here the basic
requirements are formation of a bar in reasonable cohesion between individual
element and its dimension truly within specific limits representing the desired
nominal dimensions.
Accuracy:-
Accuracy up to 10 millionth of an inch for flatness and parallelism can be
obtained in slip gauges
Grading:-
Grading according to accuracy and application.
AA - for master slip gauges.
A - for reference purpose.
B - for working slip gauges.
Grade 2 - Workshop grade
Grade 1 - Tool-room grade (More precise work)
Grade 0 - Inspection grade
Grade 00 - Standard-room grade
Calibration grade - Special grade (Prepared on chart)
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Precaution in use of sine bar :- 1) The sine bar should not be used for angle greater than 60
0.
2) A compound angle should not be formed by mis-aligning the component
with sine bar.
3) Accuracy of sine bar should be ensured.
4) As far as possible longer sine bar should be used since many errors are
reduced by using longer sine bars.
Wringing:-
The term ‘wringing’ refers to condition of intimate and complete contact and of
permanent adhesion between measuring faces. Wringing is done by hand
though sliding and twisting motions. One gauge is placed perpendicular to other
using standard gauging pressure and rotary motion is then applied until the
blocks are lined up. In this way air is expelled from between the gauge faces
causing the blocks to adhere. This adherence is caused partly by molecular
attraction and partly by atmospheric pressure. Similarly, for separating two
wring slip gauges, combined sliding and twisting motion should be used.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
PROCEDURE:- 1) Surface plate is placed on a horizontal surface.
2) Build up slip gauges of a proper height by wringing.
3) Place one of the cylinders of sine bar on surface plate and other on slip
gauges.
4) Dial indicator is set at one end of the component and moved to the other
end.
5) Note the deviation in dial reading.
6) Again slip gauges are so adjusted that dial indicator reads zero deviation
across the
7) work surface if deviation is ‘δh’ over length ‘l1’, change slip gauge height
by (δh x L / l1)
8) Where L is standard sine bar length
9) Again take dial indicator reading to assure zero deviation.
Read slip gauge height and perform calculation
RESULT:-
The unknown angle of component is
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No.05[a]
USE OF SPIRIT LEVEL FINDING THE FLATNESS OF SURFACE
PLATES
SPIRIT LEVEL:
Spirit level is one of the most commonly used instruments for inspecting
the horizontal position of surfaces and for evaluating the direction and
magnitude of minor deviation from that nominal condition. It essentially
consists of a close glass tube of accurate form. It is called as the vial. It is filled
almost entirely with a liquid, leaving a small space for the formation of an air or
gas bubble. Generally, low viscosity fluids, such as ether, alcohol or benzol, are
preferred for filling the vial. The liquid due to its greater specific weight tends
to fill the lower portion of the closed space.
Upper side of the vial is graduated in linear units. Inclination of a surface
can be known from the deviation of the bubble from its position when the spirit
level is kept in a horizontal plane. Temperature variations in the ambient
condition cause both liquid and vial to expand or contract. Therefore, selection
of proper liquid and material for the spirit level is very important for accurate
result. To reduce the effect of heat transfer in handling spirit levels are made of
a relatively stable casting and are equipped with thermally insulated handles.
Figure shows a schematic diagram of a spirit level.
Spirit Level
Sensitivity of the vial used in spirit level is commonly expressed in the
following two ways.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Each graduation line representing a specific slope is defined by a tangent
relationship, e.g. 0.01 cm per meter.
An angular value is assigned to the vial length covered by the distance of two
adjacent graduation lines, i.e. the distance moved by the bubble from the zero
will correspond the angle directly.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No.05 [b]
USE OF OPTICAL FLATS FINDING THE FLATNESS OF SURFACE
PLATES
AIM :- Use Of Optical Flat And Monochromatic Light
APPRATUS :- Optical Flat And Monochromatic Light Source
OPTICAL FLAT
Optical flats are cylindrical in form with the working surfaces flat and are of
two types: Type A-It has only one surface flat. The working surface of this
type of flat is indecently by an arrow head on the cylindrical surface pointing
towards the working surfaces. Type B-It has both the surfaces flat and parallel
to each other. Type A are used for testing the flatness of precision measuring
surface of flats, slip gauges, measuring tables, etc.
Type B are used for testing measuring surfaces of micrometers,
measuring anvils and simila length measuring devices for testing flatness and
parallelism These are generally made of either fused quartz or borosilicate
glass. This glass is clear and colorless and free from inclusions and defect like
bubbles, internal strains and extraneous matter. The cylindrical surface of
the optical flat are finished by grinding and the working surfaces are
finished by lapping and the polishing process. The finishing is done to such
an extent that straight and parallel interference b fringes are produced when
the optical flat is viewed under a monochromatic source of light by
placing it in contact with reference flat surface. Their edges are
generally beveled to45 degree by a suitable grinding or polishing process
so that the edges are free from any chips.
Out measurement of length variation when reference plane of the
measurement is established and both indicator and object are located in a
definite relation to the common reference plane. These are achieved by means
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
of appropriate gauging set-ups.when dial indicator united with member which
serve
PROCEDURE :-
1. Start the optical flat m/c and place w/p on platform whose curvature is
to be measured.
2. Now the Optical flat is placed on it and observed the types of fringes
appear on the optical flat.
3. To take a current reading applying the finger tip at a center of optical
flat and observed the behavior of fringes made on optical flat.
4. By comparing behavior on the fringes with std-one & decided whether the
surface is convex concave or flat etc.
RESULT: - Thus we are studying the different types of flat or curvature
of surface.
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
Experiment No.06
THREAD MEASUREMENT BY 3-WIRE AND 2-WIRE METHODS
AIM:- Measurement Of Thread By 3-Wire Method
The pitch diameter of a threaded object can’t be measured directly except
with specialized thread micrometers. But using three wires of the same known
diameter, the thread pitch can be measured with a standard micrometer.
PROCEDURE:
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor
DEPARTMENT OF MECHANICAL ENGINEERING NRIH
S PRAVEEN KUMAR Assistant Professor