Quote
KtB
Only other thing i can think of it play in the belts.
I have some belt tensioners on mine made from peg springs as i found it very hard to get the belts all tensioned the same.
It should be fairly easy to get consistent belt tension. Just loosen the stepper mounting screws and push the motors down before you re tighten them. You could also move the top vertex up a bit but you would then have to re level the bed. I've built a lot of Cherry Pi machines now and it's never been an issue. The trick is to get them as tight as you can before you alter the stepper height.
Andy