Back on subject, I discovered my wooden blocks that the belt holders are attached to are just press-fit inside my unistrut rails. I forgot to insert screws in them to keep them from moving… which explains why my belts tend to loosen. I need to reset the blocks and all and secure them. I’m not sure if that explains the wandering or not though. When I cut the wheels for the robot above, I noticed issues with having a stepped cut again (I think it was the top right quadrant of the wheel).