Quote Originally Posted by drumsticksplinter View Post
That is a major concern because even moving the gantry by hand there is some racking and I've tried to create a fair balance for rigidity vs weight!
I'd be wary of compromising rigidity for weight at all. It's much more important to have a strong machine than a fast machine.

Quote Originally Posted by drumsticksplinter View Post
Would I still have problems with my ballscrews being slightly bent if going for then rotating nut?
The rotating nuts would still work well with a bent screw, however it will shorten the life of the ballnuts since you'll be applying a radial force to the nut which is not something they're designed for. How much it shortens the life depends on how much it's bent and the length, since that determines the force the nut has to apply to straighten it as it moves along. It's hard to quantify. How bent are they?