Blade of unknown steel. Should I (try to) harden it?

T

Treme

Joined
May 28, 2020
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Hi wonderful knife makers!

Total noob here. Currently working on my second knife and loving it :)

I'm making a kitchen knife by filing and grinding a piece of 3mm-wide steel into the shape of a blade. All I know about the material is that it is "stainless steel".

I am wondering if it is absolutely necessary to harden the blade by heaing it and then cooling it in oil. Because of my current situation, I don't have a way to access nor make a furnace/forge, so if I were to try this, it would be by chucking the blade into a wood fire for ages until it is red hot and then drop it in car/vegetable oil.

I know what I just wrote must have made you cringe, but I'd rather work with what I have than not make the knife at all.

So, my question is, should I try this very rudimentary approach or should I just skip this step altogether and carry on with making the knife with an "unhardened" blade.

Thanks a lot in advance!

Treme
 
If the blade is stainless, trying to harden it the way you describe won't do anything.
 
If your going to keep the knife for yourself, I say go for it and see what happens. If you don’t already know, you need a hair dryer or something to push air into the fire to get your blade hot enough to harden it. Cryo treating is very important for stainless steels, but if you are going to keep it for yourself, then use what you have on hand.
 
DevinT said:
It’s probably some kind of non-hardening stainless. You’re wasting your time.

Mayday.....Mayday.....

Hoss
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Thanks, DevinT. Do you mean I'm wasting my time trying to harden it or trying to make a knife from it altogether?

Cheers!
 
If it is a common stainless like 304 or 316 they will not harden at least to knife levels. It is designed not to harden and has very low carbon and is none magnetic. It can be good practice for shaping a blade but it won't hold a edge. You can get a piece of stainless knife steel for less than $20 from a place like AKS and send it out to be hardened after you shape it. The stickies at the top of the page will give you all the basics for what you need.
 
Where did this steel come from? The source might be able to tel you what steel it is. Is it magnetic. (magnet sticks to it)? If it is magnetic, it is hardenable, but not an indicator of how hard it might get.What do the sparks look like when it is ground? Are there sparks? Are are they white and fine? That is also an indicator of a usable alloy. Just some easy ways to evaluate the steel. If you could take a small piece of it as a test piece you could try hardening that to see if it gets hard at all. Perhaps using a temperature of 1850 F to 1950 F might might be a place to start hardening it.
 
Go buy some known knife steel. $20 gets ya 4+ blades. not worth all that hand filing work just to find out its a letter opener in the end.
 
I'll try and give you a little information.

Carbon steel needs at least .60% carbon content to be hardenable. Steel like the stuff sold at hardware stores is not knife type steel. There are many suppliers for knife steel.
For people with no real equipment. 1070/1080/1084/5160 are the best to work with because they will harden the simplest.
Carbon steel is hardened by heating to around 1500°F and then cooling rapidly in oil (canola oil works). A wood fire with air blowing into the coals will do this, but may ruin the blade due to overheating ( burning the steel) or decarb (a layer of burnt steel on the outside) if things don't go perfect. A forge or HT oven is required to do it with any real accuracy.

Stainless steel has a lot of alloying and hardens at 1900-2000°F. This has to be done in a controlled oven and the blade has to be shielded from exposure to oxygen. This is normally done by placing the blade in a foil packet made of stainless HT foil. You can not harden stainless steel successfully by sticking it in a fire and quenching it in oil. It will do nothing to harden the blade and ruin it in the process.

Fill out your profile with the info needed so we know more than that you are 38. If we know the city and country you live in someone may offer you some good steel and they might offer to harden it for you when you are done shaping the blade.
 
Buy a known steel, make your blade, and send it out for commercial heat treating. That way you can use any good steel you want.
"Forged in Fire" is mostly fiction, BTW.
 
Some grades of stainless will wreak havoc on your drill bits and other tooling, gum up and wear out your abrasives, etc... and just generally not be worth the effort, even as a practice piece. The whole idea of "saving money" by using found steels is often a very false economy, as makers aren't factoring in the burnt up and broken drill bits, saw blades, grinding wheels, sanding paper, worn out files and other tooling, let alone the amount of time, that may ultimately end up as a piece of steel that won't even harden or take an edge, after hours, days, or even weeks worth of work. Suddenly that free piece of steel cost you $50 worth of tools, hours upon hours of labor and frustration, and may have even turned you off of making another knife before you ever really got started.

$20 will get you a very usable piece of quality knife steel that already annealed and ready to drill, cut, file, grind, or do whatever you need to it, with much less headache and effort. Read through the stickies, and then get yourself a piece of basic carbon steel like 1080 or 1084.
 
Thanks everyone for the comments. I learnt a lot just by reading your responses. Maybe I forgot to mention that I was in a very remote location (a far away little village in Patagonia), so I guess the "buy a good steel for 20 bucks" and "send it to HT" pieces of advice didn't apply to me at all. My bad for not letting you know.

Another thing: Forged in fire might be mostly fiction but if it wasn't for that program I wouldn't have made not only one but 2 knives. One of them is, indeed from this non-magnetic crap stainless that nobody recommends. I had a great time making it and it can slice tomatoes as well as any other knife in the house. Plus, all of those hours spent on the knife? I spent them with my dad. He is in his sixties, I am in my thirties. How many people can tell they made 2 knives with their father? No way in hell those hours were wasted, I would have made that knife our of wood if that was all I had. I live 12000 km away from my dad normally, so go figure.

So, my novice's advice to the seasoned knife makers: someone's fist knife does not have to be from the right or proper steel. If it can be, then great. But the most important thing for me was that I managed to make a knife with what I had at hand and I am happy with it. So I will definitely be making another one.

Thanks a lot, guys. I really learnt a lot from you! Looking forward to setting up a proper workshop at some point in my life and undertake more serious projects. Now I'm heading back to my apartment, where I normally live, so no knife making for me for a long while. But the bug has bitten me, so one day...
 
Treme said:
Thanks everyone for the comments. I learnt a lot just by reading your responses. Maybe I forgot to mention that I was in a very remote location (a far away little village in Patagonia), so I guess the "buy a good steel for 20 bucks" and "send it to HT" pieces of advice didn't apply to me at all. My bad for not letting you know.

Another thing: Forged in fire might be mostly fiction but if it wasn't for that program I wouldn't have made not only one but 2 knives. One of them is, indeed from this non-magnetic crap stainless that nobody recommends. I had a great time making it and it can slice tomatoes as well as any other knife in the house. Plus, all of those hours spent on the knife? I spent them with my dad. He is in his sixties, I am in my thirties. How many people can tell they made 2 knives with their father? No way in hell those hours were wasted, I would have made that knife our of wood if that was all I had. I live 12000 km away from my dad normally, so go figure.

So, my novice's advice to the seasoned knife makers: someone's fist knife does not have to be from the right or proper steel. If it can be, then great. But the most important thing for me was that I managed to make a knife with what I had at hand and I am happy with it. So I will definitely be making another one.

Thanks a lot, guys. I really learnt a lot from you! Looking forward to setting up a proper workshop at some point in my life and undertake more serious projects. Now I'm heading back to my apartment, where I normally live, so no knife making for me for a long while. But the bug has bitten me, so one day...
Click to expand...


What you say is true, on the other hand, if you used a hardenable steel, you would have been able to use finer geometry and have the edge hold for orders of magnitude longer. Some unique circumstances such as remote locations do make this much more difficult, but we do have members in South America who do obtain steel for knives.

I’m glad you had fun and spent time with your dad. That is great!
 
Treme said:
I spent them with my dad. He is in his sixties, I am in my thirties. How many people can tell they made 2 knives with their father? No way in hell those hours were wasted,
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Right on! Good to hear.

But don't be too hard on the recommendations, there are a lot of folks out there who, with only encouragement and no discouragement, would go ahead with their plan, then give up, or ask follow up questions such as, "why didn't it harden?" or "what happened?" And the answer most always includes "if you didn't use steel where you know the chemical composition..."

Welcome to the addiction, keep having fun, and everyone always loves to see pics of the progress.
 
Thanks a lot for your responses!

Here are pictures of my first two knives (the second one is the one I made from stainless).

I started with:



Then, some photos of the process...







And finally, the finished tools :)







I think they turned out OK for being our very first and second knives! What do you think?
 
Treme said:
Thanks a lot for your responses!

Here are pictures of my first two knives (the second one is the one I made from stainless).

I started with:



Then, some photos of the process...







And finally, the finished tools :)







I think they turned out OK for being our very first and second knives! What do you think?
Click to expand...

not bad at all! Keep at it.
 
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