What is needed:
- A vise
- Some muscle power.
- Intestinal fortitude.
It doesn't always work out as planned though:
I've also had success by grinding the tang with a Dremel. In fact, I got both of my entries to center correctly by doing just that. It's just a matter of grinding them smoothly to the correct angle. This way, I get a nice, even center without the risk of snapping the blade.