1/2 inch (12mm) tubing straightener

thingiverse

This is used to straighten a roll of aluminum tubing used for compressed air installations. These are expensive to purchase and when you only need it for a single project in makes sense to print one! The wheels are mounted with 10mm hardware. I used 40mm long bolts because that is what I had in stock. No bearings are needed if you print with PLA. PLA is hard enough to make a good bearing for this project. A drop of oil will help too. Clamp the mounting plate in a vise and simply push and pull the tubing through and it is straight.