NCB84 3 One of the bearing blocks looks great; however, the other is not as nice. The retaining wires for the bearings appear to be too long causing them to bow out and not properly retain the bearings. This also likely adds extra friction to its movement as well. The block shown on the top in the image has noticeably rougher motion than the other to the point where it feels like some of the ball bearings in it have flat spots.