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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. |
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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 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.
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See
the following table for equivalents:
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ABEC
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ISO
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DIN
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ABEC 1 |
Normal
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P0 |
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ABEC 3 |
Class 6 |
P6 |
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ABEC 5 |
Class 5 |
P5 |
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ABEC 7 |
Class 4 |
P4 |
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ABEC 9 |
Class 2 |
P2 |
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