Cutting Knife Blanks from High Carbon steel Jim Colt

[762frmafr]

I have been contacted by a customer to cut some knife blanks from either 1095 or HR1075/1080 steel. I have read on here that the edge should be sized 1/8" larger and then that 1/8" be ground away. Can someone explain to me why this is necessary, or the science behind what happens to the carbon in the steel when plasma cut? Thank you in advance.

[weldor2005]

Well an 1/8" is okay I guess...

What happens is that when the metal is heated to that temperature and then rapidly air cooled, the edge is then hardened because of its higher carbon content. However, is it needed? depends on the knife maker really. I would sincerely hope that they are going to do some grinding/polishing and HEAT TREATING on the blade before trying to sell it, which would mean that it don't matter and you don't need it in my opinion as far as for metallurgical reasons. as for the fact that if the customer wants to grind and put the edge on it and already knows his final dimensions, then you might need to account for that. But really, it should be heat treated after the edge is finished, which nullifies you needing to worry about the ~.080" that is going to harden from the cutting process.