I can't believe how this thread has taken off. I'm always up for a knife discussion, but 8 pages in one day, such thoughtful contributions... Such little banter... Where am I...?
Having run the gamut of production knives, I turned to the study of metallurgy, dabbling in knife and tool making along the way. This gave me a greater appreciation for what a master bladesmith can really do.
It's kind of like the difference between a factory rifle and a custom rifle.
Through careful attention to detail, some custom knife makers endeavor to squeeze all the performance they can out of the best available materials.
As
@osok-1k and
@Methow Packer emphasized,
heat treat is critical. This is one area custom makers can really leverage performance over production facilities who typically work on larger batches at a given time.
Geometry is also critical. Custom knife makers can grind to finer tolerances. Steel is more difficult to work on after it's been hardened, and a master bladesmith will be proud to put in a little extra time and consumables at the end to offer the best performance possible.
The thinner a blade is, the less of a wedge it makes, and the better it cuts.
Another way to think of it is, it's the geometry that cuts, the steel is just there to hold the geometry.
Knife nuts often talk about thickness "BTE" or behind the edge.
Production knives typically measure .020-.030" behind the edge. This way they can grind a knife soft (or annealed), send it for hardening, then finish it a put an edge on. Limiting the amount of work after thermal processing is critical to economy.
High performance knife makers will grind to .010" - some even less. If a blade was ground this thin and the sent for heat treating, it would warp ... So this means grinding
after hardening, which is much more laborious.
If the heat treat is good, thin edges will cut (seemingly) forever and are a lot easier to touch up when the time comes.
Support your local knifemaker!