Quote Originally Posted by blackburn mark View Post
im assuming you slackened everything off at one end (nut housing and bearing housing) and ran the gantry to that end and nipped it up, then did the same at the outher end... back and forth a couple of times to make sure
Yes I did exactly that. I think I'll try it again.

I saw on you-tube a video about making ballscrews and they straightened it by putting the screw between two blocks, and pushing down in the middle with a lever to bend it.