Markings on bearings

Each super-precision double direction angular contact thrust ball bearing has various markings on the side faces of the washers/rings (fig. 1):
  1. SKF trademark
  2. Complete designation of the bearing
  3. Country of manufacture
  4. Date of manufacture, coded
  5. Identification/serial number of the shaft washer / inner ring
  6. Identification number on the housing washer (for BTW series only)

Identification numbers on BTW series bearings

Identification numbers on the washers indicate bearing components that must be kept together as supplied. To distinguish the two halves of BTW series bearing washers, the identification numbers are followed by the letters “A” or “B” (e.g. 121A in fig. 1).

Identification numbers on BTM series bearings

A “V-shaped” marking on the outside surface of the outer rings indicates how the bearings should be mounted to obtain the proper preload in the set (fig. 2).

The deviation of the mean bore diameter from nominal in microns is marked on the inner ring side face.

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