Introduction

A micrometer generally provides greater precision than a caliper, but can measure a smaller range of lengths. A micrometer is depicted in the drawing below.

Parts of a Micrometer

Missing pieces:
Compression Nut
Screw Nut
Lock Nut
Clamp Ring
Rachet Sleeve
Cap Only
Rachet Spring

Reading a Micrometer

To use a micrometer, place the part in the opening. Next, turn the thimble until the spindle contacts the work. To apply a consistent pressure to the part, use the ratchet stop. Use the clamp ring to hold the thimble in place while you read the micrometer. To read the micrometer:

Read the exposed number on the barrel.
Read the number of divisions past the number. Each division represents 0.025 inches.
Read the division on the spindle. These usually read to less than thousandths of an inch.