Reading the Micrometer

ByMark Zidon

University of Wisconsin-Platteville

Objectives• Identify micrometer parts• Determine micrometer reading

This is a English micrometer

thimblesleeveanvilspindle

frame

0 1 2 3 4 5 6 7 8 90

123

24

2223

For clarity we will use an animated figure.

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

0 1 2 3 4 5 6 7 8 9 00

123

24

2223

0 1 2 3 4 5 6 7 8 9 0

1/10 inch (0.100)

25/1000 inch (0.025)

1/1000 inch (0.001)

One inch (1.000)

Now, an example...

0 1 2 3 4 5 6 7 8 9

15161718

14 13

19

151716

1413

1815

0 1 2 3

Smallest Measurement

0.000

Largest sleeve reading

0.300

Now, an example...

One mark pastlargest sleeve

reading

0.025

Thimble Reading

0.0160.341 inches

A digital micrometer

Another example...

20

15

0 1 2 3 4

2019181716

24232221

0

Smallest MeasurementLargest sleeve reading

Three marks past largest sleeve reading

Thimble Reading

3.0000.4000.0750.021

3.496 inches

Another example...

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.