ABEC: What Dose It Mean ?

What Does ABEC Mean?
The ABEC scale is a system for rating the manufacturing tolerances of precision bearings. The system was developed by the Annular Bearing Engineering Committee or Council (ABEC) of the American Bearing Manufacturers Association (ABMA). The American Bearing Manufacturers Association was formerly known as the Anti-Friction Bearing Manufacturers Association.

Bearings rated under the ABEC system are typically called "precision bearings", and they are rated with a number from 1 to 9, with the higher number assigned to bearings manufactured against a higher standard of precision (high number = tighter tolerances = more expensive bearing).

What Does Tolerance Mean?
Tolerance is the amount of variation from an absolute exact measurement that is permitted during the manufacturing process.

Other Bearing Rating Systems
ABEC is only one system for rating bearing tolerances. The International Standards Organization (ISO) and the German National Standards Organization (DIN) use similar scales to rate the precision of bearings. In the ISO and DIN systems, a smaller number means a tighter tolerance and a larger number means a looser tolerance. This is just the opposite of the ABEC system. See the following table for equivalents.

ABEC SYSTEM || ISO SYSTEM || DIN SYSTEM
.....ABEC 1...........Normal............P0
.....ABEC 3...........Class 6............P6
.....ABEC 5...........Class 5............P5
.....ABEC 7...........Class 4............P4
.....ABEC 9...........Class 2............P2

Example: (Skate Bearing)
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