Operation CHARM: Car repair manuals for everyone.

Metric Measuring



Metric Measuring

Standard Unit: 1 millimeter (mm) which is equal to about .040".







Metric Micrometer

Micrometer Sleeve (Fixed scale)







Each major line = 1.0 mm
Each minor line = .5 mm

Micrometer thimble (rotating scale)







The thimble rotates .5 mm per revolution and therefore contains 50 lines of .01 mm each.

Some metric micrometers will have 1/2 divisions which represent .005 mm and allow the micrometer to read to the five-thousandths of a mm.

Reading the metric micrometer







1. Note the whole nearest millimeter (if more than 1 mm) on the sleeve and record.
Example: 5.

2. Note the one-half millimeter mark (if appropriate) and record.
Example: 5.5

3. Read the closest hundredth on the thimble and add to the total.
Example: 5.5 + .25 = 5.75

Review of example

Whole mm 5. mm
Half mm .5 mm
Hundredth mm .25 mm

Total 5.75 mm