That’s what I originally thought too. Maybe it was the belts, however I switched chuck rotaries and this same wavy line result doesn’t occur on the other.
I also ran the same test on a metal card, so I could remove the rotary from the equation, and no wavy lines which means it can’t be a belt issue or speed issue with the x axis bar shaking too much. I just would like to know what about a rotary would cause wavy lines like this. Would it be instability when turning? It’s a chuck rotary. Also, yes I need to fine tune the offset after looking a these squares. Still though, I don’t see how the wavy lines could make the pattern I was getting with the intertwining bars.