Laser not finishing circles please help!

If you’re using a roller rotary, you shouldn’t need to change anything once you have the roller & "per rotation’ settings right. The only time adjustment might be necessary after that is if you’re trying to compensate for something that’s tapered instead of cylindrical. Anything with a taper is going to be harder to get right.

Awesome thanks! I think I’ve almost got it!

Does the object diameter matter after I find the correct number of steps per rotation?

With a roller rotary it doesn’t. The object diameter value is shown there because LightBurn will compute the circumference for you, so you know how ‘tall’ to make the Y axis of your job if you want to go all the way around the object.

Ok thanks!!