A most excellent video! I really like the idea of making my own specialty tools from older tools that I either have a surplus of or have outlived their original intended purpose. Plus, it gives me an excuse to rev-up my wood lathe.
cutting that slot on a mill is a great idea. I made a smaller version of this not long ago and cut the slot with a hacksaw. first I bent the tip (30ish degrees) and cut the slot parallel to that bend about half way through the material. bent it back the other way and honed the bottom flat until the groove poked through thus avoiding that initial hollow grind. i'll try it your way when i make a bigger edge beveler
