Surface roughness of bearing seats
The roughness of bearing seat surfaces does not have the same degree of influence on bearing performance as the dimensional, form and running accuracies. However, a desired interference fit is much more accurately obtained the smoother the mating surfaces are. For less critical bearing arrangements relatively large surface roughness is permitted.
For bearing arrangements where demands for accuracy are high, guideline values for the mean surface roughness Ra are provided in table for different dimensional accuracies of the bearing seats. These recommendations apply to ground seats, which are normally assumed for shaft seats.