The dimensional and geometrical tolerances of bearings are described by their tolerance classes. For general applications, Class Normal tolerances are adequate in nearly all cases for satisfactory performance. Select the tolerance class for a bearing based on the application requirements for precision of rotation and operational speed.
If the application requirements for precision of rotation are moderate and operational speed is moderate, then choose a Normal tolerance class. If the requirements for precision of rotation or operational speed are greater than moderate, then choose an appropriately more accurate tolerance class.
For reference, in table below, examples of applications and appropriate tolerance classes are listed for various bearing requirements and operation conditions.
| Bearing Requirement, Operating Conditions | Examples of Applications | Tolerance Classes |
|---|---|---|
| High running accuracy is required | VTR Drum Spindles | P5 |
| Magnetic Disk Spindles for Computers | P5, P4, P2 | |
| Machine-Tool Main Spindles | P5, P4, P2 | |
| Rotary Printing Presses | P5 | |
| Rotary Tables of Vertical Presses, etc. | P5, P4 | |
| Roll Necks of Cold Rolling Mill Backup Rolls | Higher than P4 | |
| Slewing Bearings for Parabolic Antennas | Higher than P4 | |
| Extra high speed is required | Dental Drills | CLASS 7P, CLASS 5P |
| Gyroscopes | CLASS 7P, P4 | |
| High Frequency Spindles | CLASS 7P, P4 | |
| Superchargers | P5, P4 | |
| Centrifugal Separators | P5, P4 | |
| Main Shafts of Jet Engines | Higher than P4 | |
| Low torque and low torque variation are required | Gyroscope Gimbals | CLASS 7P, P4 |
| Servomechanisms | CLASS 7P, CLASS 5P | |
| Potentiometric Controllers | CLASS 7P |