But then the point would get dragged along when the diameter rotates right? I mean that still sounds cool (I’d buy that), but not the desired behavior.

If one could “compute” the tangent of the angle knob using a gear system which then sets the ratio between x and y motion, we could keep the main drawing mechanism the same. Basically an analog polar-cartesian calculator for the motion of the etcher.

This would allow for angles to be set/changed at arbitrary positions without changing the position of the etcher. Idk how hard it’d be to design though, and if the dust/sand gets into the gear system we have a problem.