After assembling a round type ball screw support unit, what causes a large coaxiality deviation between the bearing housing’s outer cylindrical surface and the flange’s outer cylindrical surface?

The flange outer diameter of a round type support unit is a non-mating surface and is not strictly controlled for geometric tolerance; it only needs to meet the national standard tolerance values. The root of the flange, which is the outer cylindrical surface of the bearing housing, is the mounting mating surface and is subject to strict geometric tolerance requirements.

The flange outer diameter of a round type support unit is a non-mating surface and is not strictly controlled for geometric tolerance; it only needs to meet the national standard tolerance values. The root of the flange, which is the outer cylindrical surface of the bearing housing, is the mounting mating surface and is subject to strict geometric tolerance requirements.