A. Design, Purpose, and Construction
- The caliper is a very versatile measuring tool in that this one tool is designed to perform inside, outside, and depth measurements.
- There are three basic designs of calipers. Some have a vernier scale much like a micrometer, some have a scale and dial, and others are digital. Most calipers are graduated in one-thousandths of an inch if they are in U.S. measurements and two-hundredths of a millimeter if they are metric. Some are graduated in both U.S. and metric.
- The inside jaws are designed to measure the distance between inside surfaces. However, the depth that can be measured is restricted by the length of the jaws. For example, you can measure the diameter of a cylinder bore at the top of the cylinder, but you cannot measure the diameter of that bore at the middle or the bottom of the bore.
- The outside jaws are designed to measure distances over and around adjacent surfaces. For example, the diameter of a wrist pin or a crankshaft journal can be measured, using the outside jaws of a caliper.
- The caliper can also be used to measure depth. Such things as the depth of a bolt hole or the distance a seal sets below a surface can readily be measured with the caliper.