I am pretty sure for the ones that are flat rectangular metal, you just gouge out where it sits, and then glue it in. but use some epoxy, and the slower the epoxy (setting time) the better.

also, on the tangs with threads, I really recommend not using a nut, but using a pommel that has been tapped, the nut will actually help the pommel right off after enough wear. (I had this happen to a hand and a half broad sword)

good luck!
~Casey

~Casey