Quote Originally Posted by bluesman7 View Post
I would think that the most gentle quench would be as slow as you could go and still stay left of the nose and the formation of pearlite and bainite in the edge region. Faster than that does not result in higher hardness AFAIK. The depth of the hardness would be affected, but for razors this is not a concern IMO.
By gentle, I mean the whole piece of steel would contain the same concentration of martensite/ferrite/perlite/bainite and any other formation. The damage on quench happens because the size of the martensitic crystals is different from the ones on ferrite/perlite; the one expands, the other stays the same in the end, and, on the weakest part of the blade/place where that formation was the harshest, a crack is formed.
I think, the thermal conductivity is something really important aspect to that. Lead has about 35W/(m.K) and 1095 has 48 or so, where water has 0.591 BUT is faster quenchant. I think.

Mike, once again thank you for your answer. On the Dovo video I remember that they were heating the razors on an alloy, lead as you said, but I thought they were quenching them in oil as the surface tension or viscosity was lower that that of any liquid metal, or so I remember observing, but I won't find it strange if I'm wrong.
So, blacksmiths do think about wear resistance of their blades, and try not to reach the highest point. I would have never think about it, always striving for the highest possible.