I'm looking for one also so I'm following this! I been thinking about making one. I love making my own tools for me it's part of the fun of the hobby iv made about 3/4 of my gunsmithing tools including an action wrench, barrel vice, recoil pad fixture, scope mount jigs. Alot of other jigs also. So I'm considering making one. I do have a stupid question about changing them with the heads on what keeps the valve from just falling inside the cylinder. Doesn't seem like a very safe way of doing it. I guess you would have to do them one at a time and rotate the engine around to let the piston up on the one your working on? I'm thinking of making or buying a clamp type.
