Last weekend when I unhitched my trailer, I found that my ball was extremely loose and the nut was only hanging on by a few threads! That could have been a desaster, I thought. I removed the part of the hitch that the ball attaches to and welded the nut (after removing the lock washer and tightening the nut) to the threaded portion of the ball. DO NOT weld the nut to the frame because the ball can still back-out of the nut! Also, if you ever need to remove the ball from the frame, just saw the nut in half and un-screw the other half from the ball.
