Types and Purpose of Micrometer

Micrometers are made in various shapes and sizes, depending upon the purpose for which they are to be used. Some micrometers are graduated to measure in thousandths of an inch and others will measure as close as ten thousandths of an inch. Others are metric and measure in hundredths of a millimeter. There are two basic types of micrometers, with two distinct jobs. One is the outside micrometer, used to measure outside dimensions and the other is the inside micrometer, used to measure inside dimensions.

Outside micrometers. Outside micrometers are widely used in the automotive field to measure such components as crankshaft journals, piston pins, and valve stems to determine if they are within serviceability specifications. Most outside micrometers have a chrome plated or enameled steel frame to resist corrosion or tarnish.