Quote Originally Posted by Jonathan View Post
I converted a 6" vertex rotary table to use as a 4th axis. It was easy enough to machine a bit of 3" aluminium bar to fit on where the handle/dial used to and hold the stepper. It's very sturdy, however the 90:1 ratio makes it a bit slow to turn. I think the stepper has worn the worm drive prematurely since the backlash has increased a lot from new.
In standard form, vertex rotabs have the worm/handle on an eccentric so you can engage/disenage the worm and also adjust backlash...