Best thing to do is to get a drill tap and dye set. Can get a cheap Craftsman set at Sears. Then go to Ace hardware, find some allen screws a bit bigger than your current ones, run them through the dye set and find the size. Once you do that, set the tap up and re-tap the hole to the new size. When you tap it, screw through once and out once. Then run a small wire brush through your work and you will be good to go. Will cost you less than $20 bucks then you will have your amp fixed, a solid, handy tool set, and no loss time from sending it back to eD. They **** anyway. My eD-15A failed from a design flaw and I got ****ed on the deal by them wanting to hit me up for $150 to glue the shit back together. Lloyd has the shit right with his avatar... Good luck with the tapping man.