Metrology is the science of measurement and involves establishing measurement units, developing measurement methods, analyzing measurement errors, and ensuring accuracy. Key aspects of metrology include linear and angular measurements using various instruments ranging from simple rules and calipers to high-precision gauges, comparators, and microscopes. Metrology allows for planning, commercial exchange, and quality control through precise quantification.

1. WHAT IS METROLOGY
SCIENCE OF MEASUREMENTS
Everything
has to do with
measurement
Designing
Conducting
Analyzing
Results
Experiment
or test
within the Metrology realm
Allowing people to
plan their lives
and make
commercial
exchange with
confidence
CAN BE SEEN
EVERYWHERE

2.  Metrology is mainly concerned with:
(1) Establishing the units of measurements, ensuring
the uniformity of measurements.
(2) Developing methods of measurement.
(3) Errors of measurement.
(4) Accuracy of measuring instruments and their care.
(5) Industrial inspection and its various techniques.

3. Linear and Angular MeasurementLinear and Angular Measurement
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4. Linear and AngularLinear and Angular
MeasurementMeasurement
The Linear Measurement includes
measurements of length, diameters,
heights and thickness
The Angular measurement includes the
measurement of angles or tapers
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5. DimensionsDimensions
A very common measurement is that of
dimensions, i.e., length, width, height of
an object
Dimensions of the measuring instruments
are classified as follows
◦ Low resolution devices (up to 0.25mm)
◦ Medium resolution devices (up to
0.0025mm)
◦ High resolution devices (less than microns)
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6. Low resolution devicesLow resolution devices
Steel rule
Steel rule with assistance of
◦ Calipers
◦ Dividers &
◦ Surface gauges
Thickness gauges
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7. Medium resolution devicesMedium resolution devices
Micrometer
Micrometer with assistance of
◦ Telescoping
◦ Extendable ball gauges
Vernier calipers
Dial indicators
Microscope
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8. High resolution devicesHigh resolution devices
Gauge blocks
Gauge block with assistance of
◦ Mechanical comparator
◦ Electronic comparator
◦ Pneumatic comparator
◦ Optical flats
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9. Linear Measuring InstrumentsLinear Measuring Instruments
Vernier caliper
Micrometer
Slip gauge or gauge blocks
Optical flats
Interferometer
Comparators
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10. Vernier caliperVernier caliper
Components of vernier calipers are
◦ Main scale
◦ Vernier scale
◦ Fixed jaw
◦ Movable jaw
Types of vernier calipers
◦ Type A vernier caliper
◦ Type B vernier caliper
◦ Type C vernier caliper
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11. Type A Vernier CaliperType A Vernier Caliper
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12. Type B Vernier CaliperType B Vernier Caliper
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13. Type C Vernier CaliperType C Vernier Caliper
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14. Vernier caliperVernier caliper
VERIER CALIPER WITH 0.02MM LEAST COUNT IS GENERLY USED
IM WORK SHOP.
In this Vernier caliper main scale division (49mm) are divided in to 50
equal part in the Vernier scale.
i.e. 1 main scale division =1 mm
(MSD)
1. Vernier scale division =4950 mm
(VSD)
Least count is 1mm – 4950 =150 mm
THE DIFFERENCE BETWEEN 1.MSD and 1. VSD=0.02MM
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15. ExampleExample
Main scale reading =35mm
The vernier division coinciding with the main scale is the 20th division.
Value=20 multiplied by 0.02=0.40mm.
Total reading is 35mm+0.40= 35.40mm
35.40 mm
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16. Vernier Depth GaugeVernier Depth Gauge
A vernier depth is very commonly used
precision instrument for measuring depth of
holes recesses, slot and step.
Its construction and method of reading
are similar to those of a vernier caliper.
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17. VERNIER DEPTH GAUGEVERNIER DEPTH GAUGE
Base
Graduated beam
Clamping screw
Fine adjustment
mechanism
Vernier scale
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18. VERNIER HEIGHT GAUGEVERNIER HEIGHT GAUGE
The main parts of a vernier height
gauge and their function are given.
1.base
2. beam
3.vernier slide
4. fine setting device
5. vernier plate
6. locking screws
7. scriber
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19. Gear Tooth VernierGear Tooth Vernier
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20. Profile ProjectorProfile Projector
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21. MICRO METERMICRO METER
A micro meter is a precision instrument
used to measure a job, generally within an
accuracy of 0.01mm.Micrometer used to take
the outside measurements are know as outside
micrometer.
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22. PARTS OF MICROMETERPARTS OF MICROMETER
Frame
Anvil and spindle
Screwed spindle
Graduated sleeve or barrel
Ratchet or friction stop
Spindle clamp
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23. Interval measurementsInterval measurements
Slip gauges
Interferometer
Optical flats and limit gauges
Comparators
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24. SLIP GAUGESLIP GAUGE
Slip gauges are rectangular blocks of steel
having a cross-section of about 30 by 10
mm
Normal set
Range Step Pieces
1.001 to 1.009 0.001 9
1.01 to 1.09 0.01 9
1.1 to 1.9 0.1 9
1 to 9 1 9
10 to 90 10 9
Total 45
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25. Special Set
Range Step Pieces
1.001 to 1.009 0.001 9
1.01 to 1.49 0.01 49
1.5 to 9.5 0.5 19
10 to 90 10 9
Total 86
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26. Limit gaugesLimit gauges
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27. GaugesGauges
Basic dimension: exact size of part from
which all limiting variations made
Limits: maximum and minimum
dimensions
Tolerance: permissible variation of part
◦ unilateral: one direction only
◦ Bilateral: both plus and minus (two directions)
Allowance: intentional difference in
dimensions of mating parts
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28. Cylindrical Plug GaugesCylindrical Plug Gauges
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29. Cylindrical Plug gaugeCylindrical Plug gauge
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30. Taper Plug GaugesTaper Plug Gauges
Used to check size of hole and taper
accuracy
Made with standard or special tapers
Some have "go" and "no-go" rings scribed
◦ gauge fits into hole between two rings means
within required tolerance
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31. Taper Plug and Ring GaugesTaper Plug and Ring Gauges
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32. Thread Plug GaugesThread Plug Gauges
Used for checking internal threads of the
"go" and "no-go" variety
Based on same principle as cylindrical plug
gauges
"go" end (longer end)
◦ Should be turned in flush to bottom of hole
"no-go" end
◦ Should just start into hole and become snug
before third thread enters
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33. Thread Plug GaugesThread Plug Gauges
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34. Thread Ring GaugesThread Ring Gauges
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35. FEELER GAUGEFEELER GAUGE
A feeler gauge (also
known as a thickness
gauge) is an accurately
manufactured strip of
metal that is used to
determine the gap or
clearance between two
components.

36. FEELER GAUGEFEELER GAUGE
 A feeler gauge can be
used to check the
following:
◦ Piston ring gap
◦ Piston ring side clearance
◦ Connecting rod side
clearance

37. Radius GaugeRadius Gauge
A radius gauge is a tool used to
measure the radius of an object.
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38. Thread Pitch GaugeThread Pitch Gauge
It used to quickly determine the pitch of
various threads by matching the teeth on
the leaves with teeth on the work.
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39. ComparatorsComparators
Mechanical comparators
Electrical comparators
Optical comparators
Pneumatic comparators
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40. Mechanical comparatorsMechanical comparators
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41. It is a precision instrument employed to
compare the dimension of a given
component with a working standard
It does not measure the actual dimension
but indicates how much it differs from
the basic dimension
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42. Electrical comparatorsElectrical comparators
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43. Tool Makers MicroscopeTool Makers Microscope
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44. Telescopic GaugeTelescopic Gauge
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45. Bore diameter measurement using micrometer
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46. CMMCMM
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