I’ve found a couple that just didn’t seem to be snug enough from the start. Like 6 hex screws on this bike trailer thing. 5 of them fit a 6mm hex wrench perfectly, but on one it just spins and the next size up was too big. Either it wasn’t to spec or it warped at some point or something. I think other fastner heads would be more forgiving in this regard.
I’ve found a couple that just didn’t seem to be snug enough from the start. Like 6 hex screws on this bike trailer thing. 5 of them fit a 6mm hex wrench perfectly, but on one it just spins and the next size up was too big. Either it wasn’t to spec or it warped at some point or something. I think other fastner heads would be more forgiving in this regard.