That's a good picture of the one brick forge at Anvilfire. Andrew I could have sent mine home with you, I just didn't think of it until now. If you don't get a brick before your next trip over here, I'll do that. But really, that's something everyone using simple steels should have. It's just too easy of a trick to pass up.
Phil, welcome to the forum. Don't hesitate to learn to do your own heat treating. That's one of the biggest benefits to using simple carbon steel, you can do your own HT and not have the expense or turnaround time of having someone else do it. Plus, it's all your own work. It's the heat treating that makes a knife-shaped piece of steel into a knife; if you want to say you made a knife it seems you'd almost have to do your own HT, right?
It's very straightforward. Heat the blade evenly until it comes to critical temp, and allow to cool at least to black, or even to handling temp. You can tell critical temp because that's when a magnet will no longer stick to the blade. As a guide, yhe color will be orange, shifting to red, but that's a very subjective thing. The magnet is more accurate. Reheat to critical, cool. Reheat to critical, cool. This is normalizing and will relieve the stresses built up in the steel from grinding, help prevent warping.
It's important not to overheat the steel, so check often and keep the blade moving in the heat.
Heat to critical a fourth time, hold it there for a slow count of five, and quench in warm (120 degree) oil. You have about one second to get the knife from critical to quenched, so practice your moves a couple of times beforehand.
You can use simple vegetable oil from the grocery store or get very scientific about it. Some people use ATF mixed with kerosene, some use old motor oil. There are also specialized quenchants available but for your first few knives you don't have to worry about that. I still use veggie oil and have good results.
You can quench the entire knife or just the edge. Most makers just quench the edge, leaving the spine and tang softer, tougher. Be sure to move the blade in a lengthwise motion while it's quenching to keep even cooling along its edge. Do not move the blade side to side.
When the blade cools enough that you can hold it in your hand, put it in your preheated oven at 400 degrees (O1) for two hours. (You should wipe the oil off the blade before you do that or you'll be in the dog house for sure.) You can repeat this cycle after it's cooled.
And you're done. Test with a file to make sure the blade really did harden. If a file takes flakes of steel off the edge, start over.
I usually sharpen the knife at this point and do some test cutting with it to be sure I got what I think I did.
Big caveat: This is how I do it. Others have far more experience than I do and may have better suggestions. Listen to everyone and figure out your own way of getting there. You'll have no more satisfaction than learning your steel and getting every bit of performance out of it you can. O1 is very forgiving and even a not-quite-perfect heat treat will yield a workable blade.
On the other hand, you would not go wrong taking Delbert's offer. I'm just showing my bias toward DIY.
Good luck and let us see what you've made!
