Well if you decide to go through with the hollow grind DIY, I'd love to see pics of the machine you did it with, and the final product. You guys got a really cool idea going. I've often wondered about it myself, but don't think I could make a symmetrical hollow without a jig. Jig making never seems to end well for me. Meaning to say, most of my jigs do their job once, and poorly, before I hurt myself and the jig is broken. There's something about inertia and velocity resulting in torque I just haven't managed to calculate very well. haha.