I've finally been able to cut some metal last week!

Programmed up some test cuts, just a simple square with a holes in the center. purely just to check dimensions.

Getting a few strange issues and not sure where to start looking ....

The hole in the center is on size and position, but the flats across the square are 0.8mm undersize in the X and 1.8mm under size in the Y.

I've run various cuts with different size squares and its the same amount out every time.

I thought it was a coding issues as I'm using a MACH 3 post processor in OneCNC and running it on UCCNC, which from researching supposedly normally works.

Or is it more likely a motor/encoder issue?