The precision of a bearing does affect the guiding properties as well as lifetime, especially with applications at max. speed.
The tolerances for dimensional, form and running accuracy of RHD high precision ball bearings are specified in international (ISO 492) and national standards (DIN 620). RHD high precision bearings are manufactured to precision class 4 and class 2 (P4 and P2) as well as ABEC 7 and ABEC 9. For special applications, e.g. vacuum pumps, gyroscopes as well as measuring engineering and optical systems, RHD bearings to the internal tolerance classes HG (high precision) and UP (ultra precision). Apart from the requirements mentioned, the tolerance classes contain additional selection criteria. All RHD high precision ball bearings are also available in compliance with the American AFBMA standards. The relationship between the various standards are explained below.