1. Chapter 5
Measurement

2. Objectives Measure to 1/64″ (0.5 mm) with a steel rule
Measure to ″ (0.002 mm) using a vernier micrometer caliper
Measure to 0.001″ (0.02 mm) using vernier measuring tools
Measure angles to 0°5′ using a universal vernier bevel
Identify and use various types of gages found in a machine shop
Use a dial indicator
Use the various helper measuring tools found in a machine shop

3. Introduction to Measurement
Metrology
Science that deals with system of measurement
US Conventional units of measure
Inch and foot
Metric units of measure
International System of Units (SI)
Micrometer/micron is one-millionth of a meter

4. Compare Different Rules
Goodheart-Willcox Publisher

5. The Rule Steel rule Incorrectly called a scale
Simplest of the measuring tools found in a shop
Many different types of rules are used to make measuring quicker and more accurate

6. Reading the Rule (US Conventional)
Graduations
Lines representing the divisions
Become familiar with the rule
Fractional measurements are always reduced to the lowest term
Goodheart-Willcox Publisher

7. Reading the Rule (Metric)
Most are divided into millimeter or half-millimeter graduations
Goodheart-Willcox Publisher

8. Care of the Rule Use for measurements only
Avoid laying other tools on rule
Wipe steel rules with oily cloth to prevent rust
Clean with steel wool to keep legible
Make measurements from 1″ (10 mm) line
Store separately
Use with care

9. The Micrometer Caliper
Systeme Palmer basis for modern tool
Micrometer caliper – also known as a “mike”
Precision tool capable of measuring to 0.001″ or 0.01 mm
With vernier scale will read ″ or mm

10. Outside Micrometer Measures external diameters and thickness
Mitutoyo/MTI Corp.

11. Inside Micrometer
Measures internal diameter of cylinders, rings, and slots
Conventional
Range can be extended
Jaw-type
Range limited to 1″ or 25 mm
Scale graduated from right to left
L.S. Starrett Co.

12. Depth Gage Measure the depths of holes, slots, and projections
Measuring range changed by using longer spindles
Measurements read from right to left
Goodheart-Willcox Publisher

13. Screw Thread Measures pitch diameter of thread
A set of thread micrometers is necessary to measure the full range of thread pitches
L.S. Starrett Co.

14. Other Micrometers Chamfer
Accurately measure countersunk holes and other chamfer-type measurements
Other special micrometers are available for other applications
Devised to handle nonstandard measurement tasks

15. Reading an Inch-Based Micrometer
Each revolution of thimble moves spindle 1/40″ (0.025″)
Lines engraved lengthwise on sleeve divided into 40 equal parts per inch
Each line equals 1/40″ (0.025″)
Beveled edge of thimble divided into 25 equal parts around circumference
Each division equals 1/1000″ (0.001″)

16. Example of Reading Mircometer
Add readings from the sleeve to the thimble
4 large graduations: 4 x = 0.400
2 small graduations: 2 x = 0.050
8 thimble graduations: 8 x = 0.008
Total mike reading ″

17. Reading a Vernier Micrometer
Third scale around sleeve that will furnish 1/10,000″ (0.0001″) reading
Scale has 11 parallel lines that occupy same space as 10 lines on thimble
Difference between spaces on sleeve and thimble is 1/10 of a thousandth of an inch
First obtain thousandths reading, then the line on vernier scale that coincides

18. Reading a Vernier Micrometer Example
Goodheart-Willcox Publisher

19. Reading Other Micrometers
Metric micrometer
Add total reading in millimeters visible on the sleeve to reading of hundredths of a millimeter
Metric vernier micrometer
To the regular reading in hundredths of a millimeter, add reading from vernier scale that coincides with line on thimble

20. Using the Micrometer
Place work in position, rotate thimble until part is clamped lightly
Use very light pressure when turning the thimble
Rachet stop
Friction thimble
Locknut

21. Reading an Inside Micrometer
Hold tool square across the diameter of work
Positioned to measure across diameter on the exact center
Measure by holding one end of tool in place then “feeling” for maximum possible setting by moving the other end from left to right, and in and out

22. Reading a Micrometer Depth Gage
Graduations on measuring tool are in reverse order than an outside micrometer
Graduations under the thimble must be read, not those that are exposed

23. Care of a Micrometer Place and remove tool carefully for measuring
Keep tool clean, wiping with slightly oiled cloth to prevent rust and tarnish
Avoid “springing”
Check for accuracy
Place in safe location
Do not “twirl” the frame
Never use until machine has come to complete stop

24. Vernier Measuring Tools
Vernier caliper can make accurate measurements to 1/1000″ and 1/50 mm
Design permits measurements to be made over a large range of sizes
Standard sizes
Graduated beam with fixed jaw or base and a vernier slide assembly

25. Inside and Outside Measurements
Mahr Federal Inc.

26. Measuring Tools with a Vernier Scale
Height and depth gages
Used for layout work and to inspect location of features
Gear tooth calipers
Used to measure gear teeth and threading tools
Universal vernier bevel protractors
Used for layout and inspection of angles

27. 25-Division Vernier Scale
Can be read to 0.001″
Every inch section on beam is graduated into 40 equal parts
25 divisions on vernier plate occupying the same space as the 24 divisions on the beam

28. Reading a 25-Division Vernier Scale
Goodheart-Willcox Publisher

29. Reading a 25-Division Vernier Scale (Cont.)
The “0” line on the vernier plate is:
Past the 2: 2 x = 2.000
Past the 3: 3 x = 0.300
Plus 2 graduations: 2 x = 0.050
Plus 18 vernier scale graduations: 18 x 0.001= 0.018
Total Reading = 2.368″

30. 50-Division Vernier Scale
Can be read to 0.001″
Every second graduation equals 0.100″ and is numbered
Vernier plate graduated into 50 parts, each representing 0.001″

31. Reading a 50-Division Vernier Scale
Goodheart-Willcox Publisher

32. Reading a 50-Division Vernier Scale (Cont.)
The “0” line on the vernier plate is:
Past the 2: 2 x = 2.000
Past the 2: 2 x = 0.200
Plus one graduations: 1 x = 0.050
Plus 15 vernier scale graduations: 15 x = 0.015
Total Reading = 2.265″

33. Reading a Metric Vernier Scale
Principles are the same as those used for US Conventional measure
Reading obtained in 0.02 mm precision
Goodheart-Willcox Publisher
Goodheart-Willcox Publisher

34. Using the Vernier Caliper
Do not force on the work
Slide vernier assembly until jaws nearly contact section being measured, firm but not tightly
Lock clamping screw
Make adjustment with fine adjusting nut
Lock slide on beam
Make your reading

35. Using a Dial Caliper Direct-reading instrument
Make outside, inside, and depth measurements
Lock permits tool to be used for repetitive measurements
Beam graduated in 0.10″ increments
Caliper dial is graduated in 100 divisions

36. Universal Vernier Bevel Protractor
Dial
Is graduated into degrees
Blade
Can be extended in either direction and set at any angle to the stock
Can be locked against the dial
Base or stock

37. Care of Vernier Tools Wipe with soft cloth before using
Wipe with oiled cloth after use and before storage
Store the tool in its case
Never force the tool
Use magnifying glass to make readings
Handle as little as possible
Periodically check for accuracy

38. Gages Several specialized tools Gaging Statistical quality control
Checking parts with various gages
Shows whether piece is made within specified tolerances
Statistical quality control
Handle carefully, very important tools

39. Types of Gages Plug gage Ring gage
Used to check whether hole diameters are within specified tolerances
Double-ended cylindrical – go and no-go plugs
Ring gage
Used to check external diameters
Go and no-go gages are separate units

40. Types of Gages (Cont.) Snap gage Thread gage
Designed to check internal and/or external diameters
Adjustable, nonadjustable, dial indicator
Thread gage
Used to check screw thread fits and tolerances
Thread plug gage, thread ring gage, thread snap gage

41. Gage Blocks Known as Jo-blocks or Johansson blocks
Precise steel measuring standards
Various sets available
Used to verify accuracy of master gage
Used as working gages and for setting up machining work requiring great accuracy
Federal accuracy grades

42. Working with Gage Blocks
Improper handling can cause temperature changes in the block, resulting in measurement errors
Handle as little as possible, use tips of fingers
When wringing together, wipe blocks and carefully slide together
Separate when finished
Wipe with soft cloth with oil

43. Dial Indicators Two types Faces available in wide range of graduations
Balanced
Continuous
Faces available in wide range of graduations
Use for centering and aligning work, checking for eccentricity and inspecting work
Digital electronic are available as self-contained and remote readout units

44. Dial Indicators (Cont.)
Goodheart-Willcox Publisher

45. How to Use a Dial Indicator
Hand on dial is actuated by a sliding plunger
Place plunger lightly against the work until the hand moves
Dial face turned until the “0” line coincides with the hand
As work is slowly moved, the indicator hand will measure movement

46. Other Gaging Tools Air gage
Uses air pressure to measure hold sizes and hard-to-reach shaft diameters
Especially helpful when measuring deep internal bores

47. Operation of Air Gage
Goodheart-Willcox Publisher

48. Other Gaging Tools (Cont.)
Electronic gage
Used to make extremely precise measurements
Comparison gages
Laser gaging
Used in communication, medical, and industrial applications

49. Other Gaging Tools (Cont.)
Optical comparator
Uses magnification for inspecting parts
Optical flats
Precise measuring instruments that use light waves as a measuring standard
Made of quartz
Shape of bands indicate the accuracy of part

50. Optical Flat Patterns
Goodheart-Willcox Publisher

51. Other Gaging Tools (Cont.)
Thickness (feeler) gage
Pieces or leaves of metal manufactured to precise thickness
Ideal for measuring narrow slots, setting small gaps, determining fit between mating surfaces, and checking flatness of parts in straightening operations
Screw pitch gage
Used to determine pitch or number of threads per inch on a screw

52. Other Gaging Tools (Cont.)
Fillet and radius gage
Used to check concave and convex radii on corners or against shoulders
Use for layout work, inspection, and template when grinding form cutting tools
Drill rod
Used to inspect hole alignment, location, and diameter

53. Helper Measuring Tools
Tools which are not direct reading
Calipers
Makes internal and external measurements of 1/64″ (0.4 mm)
Distance must be measured with steel rule
Require considerable skill

54. Helper Measuring Tools (Cont.)
Telescoping gage
Intended for use with micrometer to determine internal dimensions
Small hole gage
Used to measure openings too small for telescoping gage