The article deals with the study of surface roughness of thin-walled houses bearing rollers for roller mills. Size and shape of the rear end housing was designed in order to measure the surface roughness of the inner cylindrical bearing surface with a wall thickness of 4, 5 and 6 mm. For comparison roughness was measured and a wall thickness of 26 mm. Welded housing and the base plate is clamped in the machine vice jaw of a width of 150 mm. Material components bearing small house has been fine-grain weldable steel bearing S355. Tool for finishing the hole with a diameter of 40 mm was used with a diameter of 32 mm with three cutting blades SDXT09M405R MM. Spindle speed was 1350 rev / min. Tool feed speed was 850 mm / min. The surface roughness was measured with a Mitutoyo SJ 400th.