I use heat all the time - I put Johnson's Paste wax on all the parts, glue together with G/FLEX, shape everything on the knife tang, put the knife in my toaster oven at 250 F for awhile. Then I wrap the blade, put the blade in a leather covered vise, tap on the guard with a piece of wood, and the whole shebang comes apart. Then I'll do the file work on the spacers and reassemble. Two things to watch out for: when you tap off the handle, it may come off like a bullet and bounce off your lathe, so be prepared to capture the handle; during final assembly you may need to open up the mortise a bit when putting a bit more of G/Flex on the tang.