Ball Bearing Identification

by Walt Pickut ; Updated September 26, 2017
Ball bearings are identified by their AFBMA codes.

The Anti Friction Bearing Manufacturers Association, AFBMA, uses a code to identify bearings by size, type and construction. Any bearing user, supplier or manufacturer can identify bearings from this code, which is widely, though not universally, accepted.


The first symbol on the AFBMA code states the diameter of the bearing--also applicable to non-tapered roller bearings--in mm. Plus/minus machining tolerances are not specified with this code.


The next symbol in the AFBMA code specifies bearing types as BC, BL, BD or BF. These refers to ball bearings in single or double rows, radial placement and slot-filling or non-filling.

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Width and Outside Diameter

The next symbols are either 00, 02, 03 or 04, referring to the bearings as belonging to the 6000, 6200, 6300 or 6400 series of bearings, respectively, and the outside diameter of the specific assembly.

Cage Shields or Seals Modification

The next symbol in the AFBMA bearing identification code is X, P, S or G, indicating the manufacturer's standard bearing cage, metal shield and contact seal fastening and snap ring groove on outside diameter.

Not Identified

Machining tolerances, metal alloy and diameter are not identified by the AFBMA code. Such specifications are detailed in manufacturer and end user quality assurance communications and purchaser agreements.

About the Author

Walt Pickut has published peer-reviewed medical research since 1971. Pickut teaches presentational speaking and holds board registries in respiratory care and sleep technology. He is a member of the Society of Professional Journalists and the American Society of Business Publication Editors and is editor for "The Jamestown Gazette." Pickut holds bachelor's degrees in biology and communication, and master's degrees in physiology and mass communication.

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