My brother was repairing part of his car's exhaust with a product called Quiksteel. You can check it out here. It is a self-reinforced epoxy putty that "bonds like epoxy, hardens like steel." The website says it is hard enough to use as a permanent repair to metal, and that it can be drilled and threaded.

I am going to use it to fill the large, uneven pivot hole in the tang of a very old blade so I can redrill the hole to 1/16". Is this the stuff that the wiki refers to? I think the wiki just says epoxy, and for some reason it didn't evoke thoughts of epoxy putty. Either way, maybe we could add a reference to Quiksteel Epoxy Putty just to make things easier for people like me who aren't too familiar with workshop products.

And no, I am not affiliated with Quiksteel in any way. :P