:) :) :)

I don't think it would matter too much. The higher precision bearing allows you to run the bearings at a higher speed with less heat build up. Unless you plan to run the ballscrews at continuous high speed, you will never get any amount of heat from that source.

In a low precision bearing, it may actually be only two or three balls that carry the actual thrust load. That's what you have to settle for, because the balls are not selected for precision size.

ahh great this will save me some money :) i should never go over 2.6k rpm so i dont think heat will be a big deal