Support BladeForums! Paid memberships don't see ads! Here is a real world diagram. I drew it in Autocad to scale: rectangular "stock" 1/4 inch wide by 2" tall: The first one is a random convex surface. I don't know the exact edge angle, I didn't measure it. It doesn't matter because: The second one is a V grind that perfectly matches the edge angle of the first one, whatever it is. The third one shows them interposed. The black area is the area between the two edges. The convex edge is thinner. For some reason that I can't understand you are assuming a full flat grind, as if that is the only grind that exists besides convex.