Quote Originally Posted by JAZZCNC View Post
Nah much better to replace the bent screw IMO because after you have gone to all that trouble and expense for what amounts to a very costly and mostly un-usable bonus the screw is still bent.:exclaim:
True it is quite costly having already bought the bearings etc for rotating the screw. If the nut is rotating and the screw is tensioned (ideally a lot) then the bend should not matter much. As long as the ballnut is precisely on centre (which admittedly is tricky) then there's no radial force on the screw. If the screw is bent and spinning there is a large cyclical radial force which causes it to vibrate... No doubt there's more to it than that but I bet it would be a lot better.
I'm guessing it's a 25mm screw, what length is it?

Quote Originally Posted by JAZZCNC View Post
RE 60M/min Y axis out of interest how much pulley ratio did you have to use and what sort of accelleration did you achieve.? . . . If you don't mind me asking.!
It was 42:14, but I accidently put 42:12 on the video. See here, post #136:

http://www.mycncuk.com/forums/showth...outer-building...

I can't remember what the acceleration was... think it was 2m/s^2, might have been 3. Either way it only hits 60m/min for about 200mm... except if you smash it into the side :whistling: