I too think about it. Our 4th axis is 40:1, which means 80'000 steps per 360 degrees, which means 222.222 steps per degree. How does Mach3, current version e.g. R3.043.62, handle the fractional part? Will it ensure that every 80'000 steps is 360 degrees, such that after many rounds it is still good. Assuming, I enter just 222.22, after 470 rounds I miss 376 steps. When I enter 222.22222, I miss 0.376 steps. When I enter 222.22222222, I miss 0.00376 steps.

I'm not CNC, but IT and Math, needing to set it up properly. What is good CNC respectively CAM practice, and what does matter?

(470 rounds is my sample piece, that's why.)