I've been researching and trying stuff for around a week and need to figure this out. I will put this out there - I am new to the plasma side of things but been working with CNC mill for over 5 years so I am not a complete newb.

I made my machine and just got it fired up 2 weeks ago - it cuts well and everything works. The issue I am having is that smaller circles turn out more like a square with large radius corners. At first I was thinking it was my plasma settings and then I read a post from Jim Colt about adding a marker to the torch so I did that and low and behold it has nothing to do with the plasma side of things. It still looks the same.

Here is my machine specs:

X, Y and X-Slave is running clearpath servos SDSK 3421S-ELS. I am running gear rack 20 Degree pressure angle with a 20 tooth gear running 1:1 (Direct Drive) . Gantry (X-Axis) weight is 148LBS. I am running UCCNC software and AXBB-E control .

So far I have torn everything back down and checked for any slop or anything loose. Everything is good. I have checked all the step settings and fine tuned them. I have even put them back to what I calculate them to be. In UCCNC I adjusted the Linear Error Max setting like I saw in a post and that didn't do anything. I have been using sheetcam to generate the g-code and thought that maybe it was that so I went into fusion 360 and had that generate the code and it is still is not round.

I am at a loss as to what to try next. Hoping someone had some other ideas to try.

Attachment 471534 Attachment 471538