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					Outside
Micrometer
Measurement

Session 5
Shop Tools and Techniques   2
Outside Micrometer Caliper

 The figure below shows an outside
 micrometer caliper graduated in
 thousandths of an inch. The principal
 parts are labeled




                Shop Tools and Techniques   3
Principle of the Inch
Micrometer
Pitch
  • Distance from point on one screwthread to
    corresponding point on very next screwthread
  • Inch screwthread pitch is expressed as

            1        Where P = Pitch and
         P=
            N        N = Threads per inch

  • Pitch is 1/40 or .025 inch since 40 threads per
    inch
                  Shop Tools and Techniques      4
Principle of the Inch
Micrometer
Lead
  • Distance screw thread advances axially in
    one revolution
  • One full revolution of the thimble moves the
    measuring faces 1/40th of an inch or 0.025
    inch closer or further apart.




                  Shop Tools and Techniques        5
Principle of the Inch
Micrometer
• Zero line on thimble lines up with the
  index line on the sleeve or barrel.
  • Measuring faces just touch when using a
    0-1 inch micrometer




                  Shop Tools and Techniques   6
Principle of the Inch
Micrometer
• Thimble has 25 equal divisions
  • Each division represents .001 in.
  • With one complete revolution of spindle,
    one line appears
  • Every fourth line is numbered and
    represents 0.100 inch.




                   Shop Tools and Techniques   7
Reading a Standard Inch
Micrometer
• Read last number showing on sleeve
  and multiply by .100
• Read number of small lines visible to
  right of number before thimble and
  multiply by .025
• Read number of divisions on thimble
  from zero to line that coincides with
  reading line on barrel and multiply by
  .001
• Add three readings to get total
                 Shop Tools and Techniques   8
 Reading #1
 • Note last number showing on sleeve
   and multiply by .100




2 x .100

 .200


                Shop Tools and Techniques   9
 Reading #1
 • Note number of small lines visible to
   right and multiply by .025




3 x .025

 .075           3


                    Shop Tools and Techniques   10
 Reading #1
 • Note number of divisions on thimble
   from zero to line that coincides with
   index line on sleeve and multiply by
   .001

13 x .001

  .013


                  Shop Tools and Techniques   11
Reading #1
• Add three products to get total reading




 .200
 .075
 .013
 .288 in.


                 Shop Tools and Techniques   12
Reading #2

                                     .300
                                     .050
                                     .008
                                     .358 in.




         Shop Tools and Techniques        13
Reading #3

                                     .200
                                     .075
                                     .008
                                     .283 in.




         Shop Tools and Techniques        14
Reading #4

                                     .500
                                     .075
                                     .018
                                     .593 in.




         Shop Tools and Techniques        15
Reading #5


                                     .075
                                     .005
                                     .080 in.




         Shop Tools and Techniques        16
Reading #6

                                     .400
                                     .050
                                     .021
                                     .471 in.




         Shop Tools and Techniques        17
Reading #7

                                     .700
                                     .075
                                     .007
                                     .782 in.




         Shop Tools and Techniques        18
Principle of the Metric
Micrometer
• Pitch
  • Distance from point on one thread to
    corresponding point on next thread
  • Metric thread pitch expressed in millimeter
    measurement.
  • Pitch is measured as 0.5 millimeter



                  Shop Tools and Techniques       19
Principle of the Metric
Micrometer
Lead
  • Distance screw thread advances axially in
    one revolution
  • One full revolution of the thimble moves the
    measuring faces 0.5 (½) millimeter closer
    or further apart.




                  Shop Tools and Techniques    20
Principle of the Metric
Micrometer
• Zero line on thimble lines up with the
  index line on the sleeve or barrel.
  • Measuring faces just touch when using a
    0-25 millimeter micrometer




                  Shop Tools and Techniques   21
Principle of the Metric
Micrometer
• Thimble has 50 equal divisions
  • Each division represents .01 millimeter
  • One complete revolution of spindle, one
    line appears
  • Every line represents 0.5 millimeter
  • Every 5th line long is numbered and
    represents whole millimeters


                  Shop Tools and Techniques   22
Principle of the Metric
Micrometer




            Shop Tools and Techniques   23
Principle of the Metric
Micrometer




            Shop Tools and Techniques   24
Reading #1


                                     21.00
                                       .21
                                     21.21




         Shop Tools and Techniques           25
Reading #2


                                     13.00
                                       .27
                                     13.27




         Shop Tools and Techniques           26
Reading #3

                                     9.00
                                      .50
                                      .44
                                     9.94




         Shop Tools and Techniques      27
Reading #4


                                     4.00
                                      .08
                                     4.08




         Shop Tools and Techniques          28
Reading #5

                                     5.00
                                      .50
                                      .09
                                     5.59




         Shop Tools and Techniques          29
Testing Accuracy of 0-1” or 0-
25mm Micrometers

• Test periodically to ensure accuracy
• Clean measuring faces before testing
• Turn thimble using friction thimble or
  ratchet stop until measuring faces
  contact each other
  • If zero line on thimble lines up with reading
    line on sleeve , accuracy is good


                    Shop Tools and Techniques       30
Testing Accuracy of Larger
Micrometers
• Clean measuring faces before testing
• Place standard between faces
• Turn thimble using friction thimble or
  ratchet stop until measuring faces
  contact standard
  • If zero line on thimble lines up with reading
    line on sleeve , accuracy is good
• Known size gage block can be used

                   Shop Tools and Techniques        31
Other Micrometers
•Digital Micrometer




                 Shop Tools and Techniques   32
Other Micrometers
• Electronic Digital micrometer




                 Shop Tools and Techniques   33
Shop Tools and Techniques   34
Other Micrometers
• Big Micrometer




                   Shop Tools and Techniques   35
Other Micrometers
• Big Micrometer




               Shop Tools and Techniques   36
Special-Purpose
Micrometers
• Deep-Throat micrometer




               Shop Tools and Techniques   37
Special-Purpose
Micrometers
• Deep-Throat
  micrometer with
  electronics




                Shop Tools and Techniques   38
Special-Purpose
Micrometers
• Steel-Mill micrometer




                Shop Tools and Techniques   39
Other Micrometers
•MultiAnvil Micrometer




                Shop Tools and Techniques   40
Other Micrometers
•MultiAnvil Micrometer with Electronics




                 Shop Tools and Techniques   41
Other Micrometers
•Can Curl Micrometer




               Shop Tools and Techniques   42
Other Micrometers
•Can Seam Micrometer




              Shop Tools and Techniques   43
Other Micrometers
•Ball Anvil Micrometer




                 Shop Tools and Techniques   44
Other Micrometers
•Blade Micrometer




               Shop Tools and Techniques   45
Other Micrometers
•Crankshaft Micrometer




               Shop Tools and Techniques   46
Other Micrometers
•Disc Brake Micrometer




               Shop Tools and Techniques   47
Other Micrometers
•Hub Micrometer




                  Shop Tools and Techniques   48
Other Micrometers
•Insulated Frame Micrometer




               Shop Tools and Techniques   49
Other Micrometers
•Paper Gage Micrometer




               Shop Tools and Techniques   50
Other Micrometers
•Indicating Micrometer




                Shop Tools and Techniques   51
Other Micrometers
•Disk Micrometers




               Shop Tools and Techniques   52
Other Micrometers
•V-Anvil Micrometers




                Shop Tools and Techniques   53
Other Micrometers
•Wire Micrometer




               Shop Tools and Techniques   54
Other Micrometers
•Tube Micrometers




               Shop Tools and Techniques   55
Other Micrometers
•Screw Pitch Micrometers




               Shop Tools and Techniques   56
Other Micrometers
•Long Range Micrometers




              Shop Tools and Techniques   57
Other Micrometers
•Hi-Precision Micrometer




                Shop Tools and Techniques   58