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.
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.
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.