Quote Originally Posted by Zeeflyboy View Post
Sure that’s not due to backlash?

Other than improving the backlash situation, the only answer to that is backlash compensation in the control software.

To square the gantry the best I found was to drill 2 holes for precision dowels in the y axis and butt a precision square up against it. I then run a dial indicator along the edge in X axis, and then loosen the gantry bolts and smack it with a mallet until it’s as square as I can get it. You won’t get it perfect as the gantry isn’t completely flat.
Could well be backlash.
I just measured it again and my 22mm diameter is 0.04 under in the Y and 0.14 under in the X.
It is pretty close but next week I need to do a 190mm diameter hole and close fit a bearing in it.
Yes I am using a caliper... Need a bore gauge.

It is not as off as I thought but if I can get it close as possible, would be less nervous about the big part.