The components of Micrometers

A micrometer is used to make precise measurement. Most micrometers will measure to 0.001 inch or 0.01 mm. However, to perform some measurements in engine applications, a micrometer capable of measuring within 0.0001 inch or 0.001mm may be required. The micrometer has a range it will work within. Unlike calipers, different micrometers are used to take outside, inside, and depth measurements.
The principle of the micrometer is to record the advancement of a screw for a number of turns or parts of a turn. The major components of a micrometer include:
�?Frame
�?Anvil
�?Spindle
�?Lock
�?Sleeve
�?Sleeve reading line
�?Thimble
English system micrometers have marks on the sleeve in 0.025 inch increments. The marks on the thimble are in 0.001 inch increments. One complete revolution of the thimble equals 0.025 inch movement of the spindle. If the micrometer is capable of measuring to the ten-thousandths inch, a vernier scale is also on the sleeve. Metric micrometers mark the sleeve in 0.5 millimeter increments and the thimble scale in 0.01 millimeter increments.