Circles aren't circles on the CNC....

[GND]

Also worth checking the squareness of your X & Y axes to one another. I had similar problems with my home built machine, and after much checking and testing, it turned out to be down to a v small error in the angle between the axes. Quite tricky to measure, and even harder to fix! But one to consider if the motor settings prove to be OK!

Cheers
Graeme

[Kitwn]

Also worth checking the squareness of your X & Y axes to one another. I had similar problems with my home built machine, and after much checking and testing, it turned out to be down to a v small error in the angle between the axes. Quite tricky to measure, and even harder to fix!

One of the advantages of a twin-motor long axis is the ability to square up the gantry during homing.