Bearing is a high-precision mechanical parts, its main feature is the bearing parts of the dimensional accuracy and geometric precision is very high. In order to ensure that the parts of the high precision of the realization of the need to use high-precision measurement methods, so the bearing size measurement method is through the high-precision ring gauge (inside and outside the diameter of the standard parts) to directly compare the measurement to achieve, so these inside and outside the diameter of the standard parts of the calibration of the value of the accuracy of the higher and the calibration value of the measurement calibration of the value of the bearing that has become a key factor in the manufacturing enterprises, the standard parts of the inaccuracy of the calibration value will result in the whole enterprise's Inaccuracy of the standard calibration value will cause the whole enterprise's benchmark value to shift, which will cause the product to be scrapped in batches.

Measurement calibration of ring gauge is usually carried out in the measuring room with certain environmental conditions (constant temperature and humidity), the measuring equipment should be a high-precision length gauge, and to ensure the accuracy of its traceability.

Bearing ring gauges (internal and external diameter standards) usually need to carry out periodic metrological calibration, and data monitoring to ensure the accuracy and stability of these benchmark data.