A micrometer, sometimes known as a micrometer screw gauge, is a device incorporating a calibrated screw widely used for precise measurement of components in mechanical engineering and machining as well as most mechanical trades, along with other metrological instruments such as dial, vernier, and digital calipers.
Calibration of mechanical and digital external micrometers includes for the calibration of linearity, parallelism and flatness with follow JIS B 7502: 1994 - Micrometer callipers.
Calibrate the external micrometer with using master gauge block set & gauge block micrometer set meanwhile; for linearity & parallelism, use optical parallel and flat set.