1. Precision Measurement
Principles of EngineeringTM
Lesson 6.4 – Quality Assurance
Forging new generations of engineers
Project Lead The Way, Inc.
Copyright 2007

2. PRECISION MEASUREMENT
HELP !

3. Precision Instruments Explained
MICROMETERS
CALIPERS
DIAL INDICATORS
GAGE BLOCKS
FEELER GAGE

4. How Precise Do I Need To Be ?
We need to be able to accurately measure parts to 1/1000 of an inch or as a decimal
.001
Tenths
Thousands
Hundreds

5. Decimal to Fraction Conversions
.0625 – 1/ 16”
.1875 – 3/ 16”
.3125 – 5/ 16”
.4375 – 7/ 16”
.5625 – 9/ 16”
.6875 – 11/ 16”
.8125 – 13/ 16”
.9375 – 15/ 16”
.125 – 1/ 8”
.250 – 1/ 4”
.375 – 3/ 8”
.500 – 1/ 2”
.625 – 5/ 8”
.750 – 3/ 4”
.875 – 7/ 8”
1.00 – 1”

6. Micrometers

7. Micrometer Set 1” To 6”

8. Micrometer Parts Ratchet Screw Thimble Thimble Scale Barrel
Barrel Scale
Frame
Spindle
Anvil

9. Micrometer Standards

10. Zeroing A Micrometer
To zero micrometer scale use spanner wrench, place it in small hole as shown and turn

11. Divisions 0.001” Division 1 2 3 0.025” Division 0.100” Division Barrel
Scale
Thimble
Scale 1 2 3
0.025” Division
0.100” Division

12. Reading a Micrometer
Observe the greatest inch division on the barrel scale.
Observe the number of inch divisions on the barrel scale.
Add the thimble scale reading (0.001-inch division) that coincides with the horizontal line on the barrel scale.

13. Reading a Micrometer
Observe the greatest inch division on the barrel scale. (three 0.100” = 0.300”) 1 2 3 10 5

14. Reading a Micrometer
Observe the number of inch divisions between the inch mark and the thimble. (two x 0.025” = 0.050”) 1 2 3 10 5

15. Reading a Micrometer
Add the thimble scale reading that coincides with the horizontal line on the barrel scale. (eight 0.001” = 0.008”) 1 2 3 10 5
Micrometer reading
0.300”
0.050”
0.008”
0.358” +

16. Types Of Calipers
Venier
Dial
Digital

17. Parts Of A Caliper Inside Measuring Jaws Depth Gage Dial .001
Bar Scale
Outside Measuring Jaws

18. Reading Calipers Divisions 0.001” 1.000” 0.100” 0.010” 1 90 10 20 801 10 20 30 40 50 60 70 80 90

19. Reading Calipers Observe the greatest 1.000” division 1.000” 1 90 101 10 20 30 40 50 60 70 80 90
1.000”

20. Reading Calipers Observe the greatest 0.100” (0.100” = 0.600”) 0.600”1 10 20 30 40 50 60 70 80 90
1.000”
0.600”

21. Observe the greatest 0.010” (0.010” = 0.000”)
Reading Calipers
Observe the greatest 0.010” (0.010” = 0.000”)
0.000” 1 10 20 30 40 50 60 70 80 90
1.000”
0.600”
0.000”

22. Observe the greatest 0.001” (0.001” = 0.005”)
Reading Calipers
Observe the greatest 0.001” (0.001” = 0.005”) 1 10 20 30 40 50 60 70 80 90
0.005”
1.000”
0.600”
0.000”
0.005” +
1.605”

23. Dial Indicators
1/2”, 1”, AND 2” TRAVEL

24. Dial Indicator Parts
Bezel
Pointer
Dial
Graduations
Shank
Stem
Contact

25. Dial Indicator Scale
EACH DIVISION = 1\1000 =.001 INCH

26. Dial Indicator
Mounted On Magnetic Base

27. Dial Indicator Mounted on a support
Size range from 1 inch to 4 1/2 inches in diameter
Balanced scale (read plus or minus)
Continuous scale (dimensions)
Scales range from .002” to 1.000”
This setup is used to check for
end play on a crankshaft.

28. Gage Blocks
Gage blocks are very accurate measuring standards to 1\1,000,000 in.

29. Gage Blocks
Five Individual Gage Blocks From Set

30. Ringing Blocks Together
Ringing Two Blocks Together So They Attach

31. Gage Blocks
Gage Blocks Rung Together To Give An Accurate Size

32. Feeler Gage Thin strips of steel or brass
Available in various thickness
Measured in thousandths of an inch
Millimeter

33. Here a feeler gauge is checking the valve adjustment
Feeler Gage
Here a feeler gauge is checking the valve adjustment

34. Measuring Tools Summary
MICROMETERS
CALIPERS
DIAL INDICATORS
GAGE BLOCKS
FEELER GAGES

35. Measuring Questions NAME 5 TYPES OF MEASURING TOOLS.
NAME THE TWO SYSTEMS USED TO MEASURE.
WHAT 3 MEASURING JOBS CAN A CALIPER DO?
HOW IS A FRACTION CHANGED TO A DECIMAL?
WHAT ARE GAGE BLOCKS AND HOW ARE THEY USED?
WHAT IS A DIAL INDICATOR AND ITS USES?
NAME THE PARTS OF A MICROMETER.
LIST 5 PRECAUTIONS TO PRACTICE WHEN USING PRECISION MEASURING TOOLS.