oval holes

[svenorr]

When I cut a round hole in my mill it comes out oval. I have checked calibration of x and Y and they are 100% correct.what more can I do. I am cutting 2mm wood so there is not much side load.

[CL_MotoTech]

It's almost certainly backlash or simple lost steps assuming steppers. If you are calibrated as you say, those are the only other options.

[crjohnson]

I recently had a similar issue on my cnc. Measuring round features in X and Y directions was reasonably accurate, but measuring on a 45deg angle to these found large errors.

The problem was that my gantry (x and Y axis) was not square anymore. After squaring it up the round features were within +-0.01mm (50mm diameter).