It was a bearing race two inches wide and about 6 inches across, it was a project at work using nothing but an oxy torch, a big chunk of steel for an anvil and a LOT of hammering, took me two weeks to get the curve out, a lot of peanut grinder work, 24 grit sander and finally belt sanding. Does require a unique three stage hardening process. Its a very hard steel to work with I found out on some knife forums and not suggested for a novice, the best first time knife steel is either good files or an older import axle leaf spring.
Tip for your health:
When you’re grinding these steels, use at least a comfort mask to prevent sucking in grinding dust.
You can become allergic to metal, believe it or not. Belt grinders especially can put off copious amounts of metal dust.
Files are made from something akin to 1095 carbon steel. Nothing terribly special.
O-1 makes for good tool steel to work for knives, chisels and screwdrivers. Quench in oil, not water.
Lots of starting knifesmiths use 440C stainless, which works OK.
There’s so much metal out there as scrap that’s useful, I’m very much considering writing up a treatise for handy people on what metals work for what, where to get them and how to work them. With a half-dozen metals, most home shop people could make acceptable tools, guns, engines, whatever they want...
and making a forge and heat treatment furnace isn’t rocket science either.