I’ve been having an issue with my stock knob in the upper bout . I went to tighten it down and a few minutes later it was it was loose again. The stud is rock solid in the guitar. I ordered new Gretsch strap locks. The interesting thing is , I thought the knob was stripped, but it is fine with the new stud. The new knob in the old stud is sloppy even though it is a fine thread. I ended up replacing the whole new assy. Has anyone encountered this problem? Just curious what you found.