Hi Jazz,

The screw is of course fixed when tensioned up. I'll play some more tomorrow, maybe adjust the ballnut mount rather than the ballscrew and try different microstepping. I do wish I didn't bother with a rotating ballnut on the X axis and just had them on the main gantry. On the positive side, the main gantry despite being about 50Kg will do over 10,000 mm/min :)