If you decide to go the plug route, use aluminum. You will have less trouble with it coming loose. If you drill and tapthe head, then throughly clean the oil from the threads.Cut the threads on a piece of aluminum, then under cut it just at the point the die is just starting to cut the stock. Clean all oil off this piece also. Chuck the threaded rod in the drill press and screw it in under power until the under cut snaps off. This will effectively weld the plug in place. You can now face it offon both sides and drill and tap for the plug. You will need to make a good jig to hold the head while you are screwing in the plug and breaking off the undercut. I would take that undercut down to about 3mm. This "welding" will only work aluminum on aluminum.Clean fresh metal on both surfaces is required for it to work.

If you could send it to Clarence Lee, that would be my first choice. I've had him repair a couple and he does very good work and has super fast turnaround time. I would guess it wouldn't take much longer than two weeks total. It took just five days ship to receive for him to do my last one.

Good luck with what ever method you decide to use.

Don