Fits for drawn cup needle roller bearings with or without closed end

The main dimensions of drawn cup needle roller bearings with or without closed end have tight tolerances. In order to achieve a good bearing seat while at the same time being easy to assemble, the outside diameter of the shafts or the inside diameter of the bores are tolerated according to the fit system. The recommended shaft and bore fits are given below.

Recommendations for the shaft

Diameter tolerance Roundness tolerance max. Parallelism Tolerance max. Recommended
maximum mean roughness value (μm)		 Hardness
h6 IT3 IT3 Ra 0,2 (Rz 1) [grinded] min. 58 HRC
If the shaft cannot be produced with the above properties, the bearings can be combined with our inner rings.

Recommendations for the housing bore

Housing material 1) Tolerance class Roundness tolerance max. Parallelism Tolerance max. Recommended
maximum mean roughness value (μm)
Housing bore seat
Steel, cast iron N6 IT5/2 IT5/2 Ra 0,8 (Rz 4)
Aluminium (Al) R6 IT5/2 IT5/2 Ra 0,8 (Rz 4)
Magnesium (Mg) S6 IT5/2 IT5/2 Ra 0,8 (Rz 4)
1) For non-rigid housings, the appropriate shaft tolerance for the desired operating clearance can be determined through trial and error.
Dimensional tolerance limits

This information is to be seen as a recommendation. The data has been carefully compiled from various sources, but no guarantee is given for any information.