Just mentioned that to my grandad and he said “piffle - we were making knives in metal shop in HS out of files”
Anza knife company makes knives from files. The files are too hard and brittle for a good knife blade so they need to be annealed some by heating to a moderate temperature for a time and then slowly cooling. The steel becomes less hard, but is also less brittle. Then comes the grinding, polishing and mounting of handle.
I grew up as a metal worker/Welder.
Watching “forged in fire” the other night my buddy asked did you ever make anything like that?
I did not say a word, sipped my beer, shrugged and thought of guns made in shop class