I bought a rogue ring hanger. It is flat and bulletproof. A buddy then built our garage gym a homemade one with two pieces of 90 degree angle iron and a set of carriage bolts and spacers. We took two pieces of heavy aluminum angle aluminum that were four feet long. Drilled holes spaced with joists and used r inch lag bolts at three spots on the angle brackets to anchor into joists. Then we put in a total of six carriage bolts that were 1/2 inch in diameter and four inches long. We used a piece of conduit cut three inches and filed to make a spacer that fit over the carriage bolts. Then we drilled holes along the angle brackets to fit the carriage bolts making sure they lined up at 30, 33, 36, 40, and 44 inches. You could technically have multiple spacings beyond ours. Then we mounted the thing to the joists three inches apart, fit the carriage bolts and spacers in and tightened with loctite. Its tough and about 25 bucks.