Specifications for shafts and housing support surfaces
Shaft bearing seatRecommended fits for bearings on solid steel shafts in cast iron housings are provided under Bearings, units and housings and in the SKF catalogue Rolling bearings.
If adapter or withdrawal sleeves are used, the sleeve seat on the shaft should be machined to tolerance class h9 or better. The total radial runout should be IT5/2 for tolerance class h9.
If bearings are to be mounted directly onto the shaft, the cylindricity tolerance and total runout tolerance of the bearing seat should, depending on the requirements, be one to two IT tolerance grades better than the prescribed dimensional tolerance. Abutments for bearing rings should have a perpendicularity tolerance and total axial runout tolerance that is at least one IT tolerance grade better than the diameter tolerance of the associated cylindrical seat.