A caliper is a simple device used for measuring the distance between two points on an object. There are a number of steps one should take in order to ensure proper caliper calibration.
Before calibration, it is necessary to ensure that they are not damaged in any way. Common types of damage include chipped measuring faces and points; a loose face, sticking or binding parts; damaged tracks, damaged gears and a failure to repeat back to “0.”
Calipers should be thoroughly cleaned to ensure accurate calibration. Calipers should be wiped with a clean cloth, inspected for dirt and metal chips in the rack and blasted with a light stream of air then demagnetized by rubbing them with a rag that has itself been rubbed on a demagnetizer.
Calipers are calibrated using gauge blocks, which are standard devices used for measuring length. They are calibrated by ensuring that they match the measurements provided by three gauge blocks; for example, a 6 inch caliper should be calibrated using 1-inch, 3-inch and 6-inch gauge blocks. Accuracy should be ensured up to 3 decimal places.