In subassembly Nema 17 Mtr assembly I am able to rotate the cam about the axis of the motor. When I insert this sub-assembly in the top level assembly and mate it to the cover, I am not able to rotate the cam. Any ideas why? I think I am probably unknowingly constraining the cam but I can't tell where. I would like to rotate the cam in the cover assembly without moving the motor or the cover.