I finally got to tear down my mill to find the source of 0.01-0.015" play I have in my Z axis. When I use a bigger drill or plunge an endmill I can see a good bit of play in the Z axis movement. On smaller tools, the weight of the spindle is sufficient to keep this from affecting my work.
I tore down the head and found that the two bearings holding the ballnut have a significant amount of play between the inner races and outer races. The bearings is in now are Fafnir 9114PP. These appear to be deep groove ball bearings, I would have expected AC bearings in this application.
Are these the bearings used from the factory?
Is it standard to shim the bearings to remove backlash and carry on?
If I replaced the bearings with the same would that remove the backlash or will I still need to shim them?
Thanks in advance