[img]https://cimg9.ibsrv.net/gimg/www.doityourselft.com-vbulletin/1500x2000/20210110_224640_1_cadfc7c44be7aacd901e5ad1ee385089d923e507.jpg[/img] how can i attach the pulley mount to the truss clamp in a way that will allow it to rotate/spin? doing it this way the nut keeps loosening. i want something that will be flush that wont loosen and will allow it to rotate so i can workout in any direction

I bought some #14 x 2.5" inch Tekk screws to try and support a wall mount bracket for holding speakers. This is in a rehearsal studio that I rent. I was told by management the studs are metal. I used a magnet to locate them and when I put in the screw it seems to penetrate the metal but does not tighten. The bracket is about a 3/4' thick and the drywall is likely half inch so I should be getting enough bite on the screw into the stud. Is this cause I'm not using thick enough screws or might it be the wall thickness of the stud itself that it just can't handle the screw and it strips once tightening? I'm using my impact drill to drive it past the drywall and into the stud.