How do you read micrometers?

Answer 1

Difficult to explain without diagrams, but the micrometer relies on an accurate screw which advances the caliper a precise amount with each revolution. So you turn the screw until the object is lightly held, then read the axial scale and add on for the number of screw turns above the nearest scale reading. The most accurate type also have a vernier scale for very small distances. I suggest you look at Wikipedia 'Micrometer' which has a thorough explanation with diagrams.

Answer 2

To read a micrometer, first look at the main scale reading plus the number of revolutions on the thimble scale. Add the main scale reading to the thimble scale reading and the additional value from the vernier scale if your micrometer has one. The final value is your measurement in millimeters or inches, depending on the micrometer.