Finding the correct ball bearing precision for your application is important in keeping your design rolling. In this post, we review the ABEC scale and the various classes associated with it.
The ABEC scale is a system used to classify the precision or accuracy of ball bearings. ABEC stands for Annular Bearing Engineers’ Committee, which is the same committee that created it, which is from the American Bearing Manufacturers Association (ABMA). The ABEC scale includes grades ranging from numbers 1 to 9, with higher numbers indicating tighter precision. The scale measures various factors such as tolerance, radial play, and other specifications related to the manufacturing precision of ball bearings.
For each ABEC scale rating between 1 to 9, there are tolerance tables that provide the range of values a certain dimension would be between if they are of a certain ABEC rating.
Please see the below tables for the range of values for certain dimensions and their corresponding ABEC ratings:
For the full list of tolerances, refer to NTN’s tables here.
There are other scales of measuring a ball bearing’s precision level developed by other standardization institutions, including the equivalent International Organization for Standardization (ISO) standard ISO 492, the German equivalent DIN 620, and the Japanese equivalent JIS B1514.
The below table highlights the aforementioned other standards and their equivalence to the ABEC standard:
| ABEC | ISO 492 | DIN 620 | JIS B1514 |
| ABEC 1 | Normal Class 6X | P0 | Class 0 |
| ABEC 3 | Class 6 | P6 | Class 6 |
| ABEC 5 | Class 5 | P5 | Class 5 |
| ABEC 7 | Class 4 | P4 | Class 4 |
| ABEC 9 | Class 2 | P2 | Class 2 |
It’s important to note that while the ABEC scale provides a general guideline for precision, a shortcoming is that it does not cover all aspects of bearing performance. Some applications may prioritize factors beyond those considered by the ABEC scale. Some of the aspects that are not considered with the ABEC scale include load handling capabilities, ball precision, materials used, Rockwell hardness of materials, level of ball and raceway (cone) polishing, noise, vibration, and the type of lubricant employed. It’s worth noting that a bearing classified as ABEC 3, when considering these additional factors, may outperform a more stringent ABEC 7 bearing with these aspects overlooked.
To help you select the right bearing for your needs, check out the MISUMI Ball Bearing Finder Tool here.
Technical Data
∆Dmp : Single plane mean bore diameter deviation
VDp : Single radial plane outside diameter variation
