Fixture is made from 1.5" square tubing, note the aluminum spacers used to take up space so the bungee leg is centered properly. Fixture makes both left and right gear. Also note the beads of weld laid up on the fixture. Why? When you weld it the tube draws, so laying a few beads on the convex side of the tube will draw it back. Use a laser or just a good old piece of cold roll steel to verify straightness. Weld, wait, and voila, the tube magically becomes straight again.