Parts:

4 pivot plates (TODO link to guide on making them) (for the ironworker, it's very important that the plates be perfectly flat against each other. If there are any bumps, grind them down.)

0.5 ounces of grease (Dan made this up, Marcin should verify)

Put two pivot plates on each side of the frame tubes over the 4 threaded rods.

Grease the inside of the bushing (round area) on the pivot plates.