I ran across this and thought that it was clever. It looks good, but how effective would it be? From 3:19 to 4:53:
He also mentioned using an aluminum brazing rod to fill the hole, which sounds interesting, but the threads probably failed in the first place because they were aluminum. You need to heat it to 735° and if then you would grind it down?
I am sure that would be a great solution in some circumstances, but I can think of plenty of exceptions.
Curiously, he said that replacement parts are cheaper than Helicoil kits. I wonder how much that is true. If the part were cheap I probably wouldn't be trying to fix it.