Reading the Micrometer By Stephen Martin

Objectives Identify micrometer parts Determine micrometer reading

This is a English micrometer sleeve thimble anvil spindle frame

For clarity we will use an animated figure. 1 2 3 24 22 0 1 2 3 4 5 6 7 8 9 23

look at the sleeve of the micrometer. Let’s take a close look at the sleeve of the micrometer.

0 1 2 3 4 5 6 7 8 9 0 One inch (1.000) 25/1000 inch (0.025) 0 1 2 3 4 5 6 7 8 9 0 1 2 3 24 22 23 1/1000 inch (0.001) 1/10 inch (0.100)

Now, an example...

Largest sleeve reading Now, an example... Smallest Measurement Largest sleeve reading 15 17 16 14 13 18 0 1 2 3 19 0 1 2 3 4 5 6 7 8 9 18 17 0.000 16 15 14 13 0.300 0.025 0.016 0.341 inches One mark past largest sleeve reading Thimble Reading

A digital micrometer

Another example...

Largest sleeve reading Three marks past largest sleeve reading Another example... Smallest Measurement Largest sleeve reading 0 1 2 3 4 20 19 18 17 16 24 23 22 21 20 15 3.000 0.400 0.075 0.021 Thimble Reading Three marks past largest sleeve reading 3.496 inches

Review... Lightly tighten on object. Determine smallest measurement when micrometer is closed. Find largest visible number on sleeve and multiply times 0.100.

Review... Count number of marks past largest visible number on sleeve and multiply times 0.025. Multiply thimble reading times 0.001. Add all numbers to get answer.