Haven't researched this fully yet as it is a big topic....
Here is a quote by a guy named Roman Landes (I don't know much about him, but apparently he is a dutch metallurgist?)
"Grinding generates energy (heat) and every step of sharpening is grinding even the strop.
This heat can be sucked away by the right coolant such as water.
If the grinding action lacks the coolant, the heat goes mostly into the torn out part and the body (blade/edge) it was torn off.
It becomes obvious to see the induced energy when you see the sparks fly (Burning steel!!).
Depending on how hard you go over the piece the more energy is induced the hotter it gets, thats basic physics.
Than the guys come and say but I can do it so sensitive that the edge will not suffer and I'm dipping the blade each run into cold water....
Well that is a nice effort, but when it comes down to the very edge this tiny fraction is overheated faster, than the eye can see or the wrinkled fingers can feel.
Unfortunately the edge becomes thinner the close you come to the very edge/point means generated heat will get jammed in the tip.
In addition to that tempering colors that would visually proof this are ground away immediately when they appear.
and Stainless steels need a higher temperature to generate tempering colors and longer time to build them up.
Nevertheless one can do metallurgical examination that can proof the issue testing micro hardness
There are some old german study's that examined this issue in the very detail.
I had a book dedicated to general grinding methods, in this book i found a test application.
A normal steel block apx. 2"x2"x4" that had a large number of highly sensitive thermocouples integrated in the surface.
The block was slit dry by hand over a 1000grit grinding paper.
The peak temps measured, walked up to 2000°C for split seconds in the very surface (some microns).
Of course the block did not melt since the volume fraction of induced heat was to tiny to affect such a large solid piece of steel.
But the effect was there and proofen.
In a edge we just talk about some microns of material, here the effect is solid an clear.
Every manufacturer of razorblades knows this and does excessive cooling whilst grinding and polishing edges, that need to hold an super sharp edge for very long.
It seems just some the magic makers out of the custom knife scene think, the physical principles like this, do not apply to them...."
