Dan,
I'm not sure how to reply without getting a bunch of the old mail included
sorry.
But about your lead screws, how do I contact Thompson? As far as the
backlash error, if you preload two ballscrews against each other couldn't you
effectively eliminate the backlash? I know the more expensive mills used
backlash eliminators (see page 97 of "Machine Shop Practice" Vol. 2, if I
ever get a scanner I'll send PICS instead of references) with two nuts and
adj. preload on the nuts with acme lead screws. It not only nearly eliminated
backlash but also prevented damage to the cutters servos, etc., when climb
milling with heavy feeds. This was the approach I was going to take with my
mill, however the ball screw setup seems to be a better way to go to cut down
on the drag and size of the servos required.
Tracey DeChambeau
