About this 3D model

This is just the tensioning arm for the thing: http://www.thingiverse.com/thing:74209 Fixed the bearing end. Added a hole where the tensioning screw bears down on the arm to install a nail. Use nail with a large head, like a roofing nail. I use 2 bearings for the belt, instead of fender washers. Less rubbing and easier to adjust. There are 2 very thin spacer washers between the plastic brackets and the bearings. Worksforme