Long, long ago I welded in the wrong thickness of the outer seat belt attach points. The wall needed to be thicker so the tap for the threads would actually cut into something. I cut the threads and they were shallow…too shallow. The bolt just spun when I tried to tighten it. So I decided to rosette weld in a belt stud. I cut the head off an AN bolt, reamed the bushing a bit to fit, covered the area with heat sick and rosette welded the bolt in place. A lick of paint and it’s fixed.
