The precision of precision bearings themselves is within 1 μ m, so they require high dimensional and shape accuracy with their matching components (shaft, bearing seat, end cover, retaining ring, etc.), especially the precision of the mating surface should be controlled within the same level as the bearing, which is crucial and often overlooked. It must also be noted that if the matching parts of precision bearings do not meet the above requirements, the precision bearings often experience errors several times or even more than 10 times larger than the original bearings after installation, and cannot be considered precision bearings at all. The reason is that the errors of matching parts are often not simply added to the errors of the bearings, but amplified by different factors and added
