Hi,
interpolated circles will, and can only be, round if:
1) No backlash
2) No backlash
3) Correct steps per unit, both axes
4) No backlash
5) Related to 3), no missed steps in either axis, its equivalent to having incorrect steps per unit programmed. It as bad as backlash.....
have I mentioned that backlash prevents interpolated circles from being round?
Craig