[native34]

Could anyone please give me some insight as to why my x axis bearing nut keeps backing of creating backlash in my mill? Both the x and y are configured the same way, but only the. A is is giving me this trouble. When I tighten the bearing nut. The machine has about .0005 backlash. But after running tests in the axis. The x axis is the only one to have backlash of about .004-.006 thousandths of an in.

[native34]

I have tried using a double nut configuration with the same results. When I turned the threads in the screw, there was just about no play between the shaft and the nut.

[Azalin]

Check the screw. It is probably bent.

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[Mel White]

There are several things to check,Your bearings must be angular contact if you are using a cheap pair of bearings you need to carefully check the preload if the bearings are mounted with too much pressure your nut will back off. If your bearings are installed properly you can either use a Nylon locking nut or double nut to eliminate this problem.Properly installed bearings on a quality ball screw should give you zero backlash.
Mel White

[native34]

Thank you, I do have the bearings set pretty tight. Tight enough to cause a pretty good amount of drag when turning them by hand. how can I figure out the proper preload? I'm using nsk7202bep angular contact bearings. Should I be using a different bearing?