Reading the Micrometer By Mark Zidon University of

Reading the Micrometer By Mark Zidon University of Wisconsin-Platteville Modified by Georgia Agricultural Education Curriculum Office June 2002

Objectives • Identify micrometer parts • Determine micrometer reading

This is a English micrometer thimble anvil spindlesleeve frame

For clarity we will use an animated figure. 3 0 1 212 3 4 5 6 7 8 9 0 24 23 22

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

One inch (1. 000) 25/1000 inch (0. 025) 01234567890 3 2 1 0 24 23 22 1/1000 inch (0. 001) 1/10 inch (0. 100)

Now, an example. . .

Now, an example. . . Smallest Measurement Largest sleeve reading 19 18 0 1 2 3 4 5 17 6789 16 0. 000 0. 300 0. 025 0. 016 15 14 13 0. 341 inches. One mark past 0123 largest sleeve reading Thimble Reading 15 18 17 16 14 13 15

A digital micrometer

Another example. . .

Another example. . . Smallest Measurement Largest sleeve reading 20 15 3. 000 0. 400 0. 075 0. 021 3. 496 inches 0 1 2 3 4 24 23 22 21 19 18 17 16 0 20 Thimble Reading Three marks past largest sleeve reading

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.