Step 4: Attaching the non-driven wheel
For the non-driven wheel the center hole only serves as a guide to position the “side wheel” in the middle. Mark it out the small “side wheel” on the pulley wheel and drill 4 holes in each in the same pattern. Some small misalignment is no problem.
Now, first attach the “side wheel” on a piece of wood and than attach the pulley wheel on it with 4 small screws (If you would try to do it the other way around, it would be nearly impossible to reach the holes of the side wheel mounting plate). Make sure the screws do not hinder the turning of the wheel assembly.