The precision of a spindle ball bearing does affect the guiding properties as well as lifetime, especially with applications at max. speed.
The tolerances for dimensional, form and running accuracy of GMN high precision ball bearings are specified in international (ISO 492) and national standards (DIN 620).
GMN high precision bearings are manufactured to precision class 4 and class 2 (P4 and P2) as well as ABEC7 and ABEC9 (according to ABMA).
For special applications, e.g. vacuum pumps, gyroscopes as well as measuring engineering and optical systems, GMN manufactures bearings to the internal tolerance classes HG (high precision) and UP (ultra precision).
Apart from the requirements mentioned, the tolerance classes contain additional selection criteria.
The relationship between the various standards are explained below.
| ISO | DIN | ABMA |
| class 4 | P4 | ABEC7 |
| class 2 | P2 | ABEC9 |
Moreover GMN offers its own factory precision classes HG (high precision) and UP (ultra precision).
These have partly stricter tolerances than precision class P2.
Please see Precision classes and tolerance tables of GMN High precision ball bearings
or contact our
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