The New Guy
Join Date: Dec 2011
Location: Down south, where the food is good.
^ that guy's right. You could do it at home, but the odds of messing something up are really high. Every metal will harden, regardless of carbon content, but to get the properties you want, you need the right mixture of elements. Too much or too little of one will mess everything up and turn a tool into a paperweight.
Best way to do it is have the heat treating professionally done. But at that point you're better off just buying one already made. You can just sharpen steel. You'll have to resharpen often, but you can do it with just about any steel. Oh, I know, you could try getting a cheap set of wrenches and using them for your base stock. Every wrench is hardened already right?