"Don Foreman" wrote in message
...
snip------

Tool steel is merely carbon steel harder than the material it must cut
for long enough to do the job at cutting speed that doesn't overheat
it. Any steel can be made thus hard in a charcoal fire,
case-hardened with bone meal in a muffle.

Actually accomplished quite satisfactorily by any source of carbon, it need
not be bone meal. In commercial operations, it's often done with
atmosphere, simply by providing too much fuel. For pack hardening,
carbonized peach pits are often used.

The result can be harder
and sharper than HSS tooling. It's LSS, works just fine.

If you've never tried carbon steel for machining, especially if you're
running reasonably modern machines, you'll never know the frustration that
comes with its use. Once you're used to the performance level of HSS,
it's nearly impossible to revert to lesser cutting tools. It seems so
unnatural to cut so slowly------but then perhaps for many of the home shop
types, that isn't a problem. Having worked in industry, it drives me nuts!
I own a 1-1/8" carbon steel drill, purchased for a buck at a flea market.
Absolutely worthless for anything but non-ferrous use.

Harold