Tolerances and tolerance classes for bearings

These tolerances are prescribed in JIS B 1514-1, JIS B 1514-2, and JIS B 1514-3 (roller bearings - bearing tolerances part 1: radial bearings, part 2: thrust bearings, and part 3: permissible values for chamfer dimensions). (These JIS standards are based on ISO standards.)

Bearing tolerances are standardized by classifying bearings into the following six classes (accuracy in tolerances becomes higher in the order described): 0, 6X, 6, 5, 4 and 2.

Class 0 bearings offer adequate performance for general applications; and, bearings of class 5 or higher are required for demanding applications and operating conditions including those described in Table 7-1 High precision bearing applications.

These tolerances follow ISO standards, but some countries use different names for them. Tolerances for each bearing class, and organizations concerning bearings are listed in Table 7-2 Bearing type and tolerance class.

Boundary dimension accuracy (items on shaft and housing mounting dimensions)

•      Tolerances for bore diameter, outside diameter, ring width, assembled bearing width
•      Tolerances for set bore diameter and set outside diameter of rollers
•      Tolerance limits for chamfer dimensions
•      Permissible values for width variation
•      Tolerance and permissible values for tapered bore

Running accuracy (items on runout of rotating elements)

•       Permissible values for radial and axial runout of inner and outer rings
•       Permissible values for perpendicularity of inner ring face
•       Permissible values for perpendicularity of outer ring outside surface
•       Permissible values for thrust bearing raceway thickness