So I built a chuck style rotary. Basics are:

1.8 degree stepper, 5.18 to 1 gear ratio, 128 Micro steps (honestly not 100% sure but the math is close?)

So using lightburns suggested formula we get:

(200 * 128 * 5.18)/360 = 368.35 steps per 1 degree rotation.

This does not turn far enough. In fact using a 6 inch long “arm” and testing the right answer is 415.69 steps per 1 degree (the number input into the Steps/mm section).

Baffled I was messing with the controller settings and changed the y-axis steps/mm from 40 to 80 and the rotary did 2 full rotations (with 415.69)… what? I was under the assumption that this number was ignored or replaced while rotary was enabled.

So I guess im asking if anyone can shed light on this for me as to why lightburn is using this setting, or how it fits into the equation?

And as a note I tried this in a different machine with a ruida controller, calculated the steps for a full rotation as 16576 and it worked flawlessly.