Originally Posted by
dinnermint
If heat treating was minimally invasive in regards to depth of the metal, then every old well honed or reground razor would be soft. It has been a few years since my materials science courses; but if one considers the cooling rate of the metal as dependent to the hardness of the metal, then hardening would be proportional to the rate of cooling with the depth of the razor. So, it would theoretically change with depth, but final grinding after heat treat would remove that top layer anyways. Since razors are relatively thin metal, it would lead me to believe that a large portion of the metal itself from spine to edge is uniform. Of course, this also considers the cooling to be applied instantaneously in the described area. Dipping toe first or edge first and that rate of immersion would have to be taken into account if we're going to the extreme nitty gritty.