The dimensional and geometrical tolerances of rolling bearings have been standardized internationally. In addition to the tolerance class Normal, the ISO standards also cover closer tolerances, such as:
  • tolerance class 6, which corresponds to SKF P6 tolerance class
  • tolerance class 5, which corresponds to SKF P5 tolerance class
For special applications like machine tool spindles, SKF also manufactures bearings with even closer tolerances. These include the tolerance classes P4, P4A, PA9A, SP and UP. For additional information refer to Super-precision bearings.
For tolerance information about each bearing type, refer to Tolerances in the relevant product section. Bearings with closer tolerances than Normal are typically identified by a designation suffix for the tolerance class.

Tolerance symbols

The tolerance symbols and their definitions are provided in table 1.
SKF logo