How To: A-2 Tool Steel Heat Treating

This is my first time heat treating A-2 tool steel. What I find interesting about A-2 tool steel is that it air hardens, meaning you do not need to quench in oil or water to make this harden up. This was a fun one and I learned a lot about heat treating knives, and air hardening steel.
JKeeton Knives: / @redbeardops
Dave Erving - Evader Knives - / daveerving
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Website: www.HouseWork.us

[@bid6413]

Very cool idea. Now all I have to do is talk my wife out of her kiln. In all fairness she hasn’t used it in 19 years, but we all love our tools. Thanks for sharing all you’ve learned. Cheers, Will

[@fixesflyers]

5-7 minutes of heat is more than enough for the knives. 20-30 mins is per 1/2"

[@phoenixwerks4585]

Kickin ass my man ... kickin ass. Have to get together again soon and do a shop day!

[@HouseMadeUS]

Yeah man! Thanks Scott. I’m still working on that lathe. Gotta get that up and running.

[@walterguan5036]

Excellent presentation with details. Hardness testing file set is available in amzon, $80. Will try A2.

[@HouseMadeUS]

Thank you Walter. The latest episode of the KnifeTalk podcast had a great interview with a Dr of metallurgy. Give it a listen. Full of great info.

[@evaderknives]

I've never tried A2, but have done quite a bit of SS. Next time, you might want to get some SS tool wrap to prevent oxidation. I bought a piece of 1"x12x12" aluminium, & cut it in half... Great quench plates, and while the steel is cooling, I use my air compressor(I added a filter for my sandblaster & a "T" for other tools, so I don't have to worry about moisture) to cool it quicker... I've heard a lot of people talk about you have to quench vertical, also have heard, you have to be facing west, but honestly I always quench horizontal, mainly because it's all I have and have rarely had problems. When I 1st starting using a toaster oven, I just used a cheap thermocouple to set temps, might have to check again, it's been a while... I'll test them for ya no problem, just let me know. Hope all is well, take it easy...

[@HouseMadeUS]

Thanks Dave. Can you email me your address? I’ll send you a blank to test. [e-mail] - I am getting setup to build a plate quench, I’d like to try some stainless. I’ll make sure to turn west and throw some holy water on it. 😂

[@aleckohl6585]

Do you have that blueprint for sale?

[@nobuckle40]

Thanks for the insight Brian. My interest in heat treating A2 is the result of needing to make plane irons. I have some precision ground A2 flat stock that I want to use. What I need to know is how to make a "poor man's" heat treating setup so that I can heat treat what I have. What do you reccomend?

[@HouseMadeUS]

The best and cheapest way to get a heat treating setup is to do what I did and use an old ceramic kiln and covert it to a digital control. I made a video on that. Check it out. How To: Convert a Ceramics Kiln into Digital Heat Treating Oven - PID Controller kzbin.info/www/bejne/poPYomuehLmCjbc

[@mcboomsauce7922]

Wow, bad ass channel man, stumbled across you this afternoon cause my Neigbor threw out a treadmill and I knew the motors could be useful....anywhoo, to the best of my knowledge, those knives you just tempered gotta be up there I’ve never heard of a double tempering cycle not an air quench, but dropping 1000 degrees Frankenstein in 3 minutes as opposed to 3 seconds probably isn’t much difference Got something to do with making the steel go austenetic so the martencite crystals can form with layers of cementite around them I bet they’re about as hard as you can get steel to get with an easy bake oven lol Do you plan on doing a blade quench? I hear you can get some clay, a torch and just heat the blade bit up, then quench it so the blade is hardened, but the rest of the steel is tempered so the knife doesn’t explode into a low earth orbit when you’re carving into a turkey and hit a piece of bird shot someone forgot about Pretty dope that freakin knife guy sent you that email, shit seems pretty legit

[@DarthPlagueisTheStupid]

Lol

[@murrellwilhite7760]

I see you moved your PID controller box, off the kiln to the wall......did the controller box get to hot?

[@HouseMadeUS]

I had an instance where I had one SSR melt on me, now I don’t know for sure if the box was too close to the kiln or what exactly so I added a small DC fan to move the air around and removed it from the side of the kiln just to make sure. You would think both would fail. Just to be sure I took it down, put it a few inches away and all has been working fine since. I use the kiln weekly with zero issues. Thanks for watching and commenting.

[@christopherconkright1317]

Also I looked this up online and saw 10 different answers 12L14 steel some say it melts other say it makes good tools L is lead some say yes some say no. Should I avoid it.

[@HouseMadeUS]

I've never used it so I can't comment. Might check with Larrin Thomas at knife steel nerds. He would know.

[@christopherconkright1317]

@@HouseMadeUS Thanks the lead part worries me.

[@christopherconkright1317]

I have 1045 steel where to I find out how to heat treat it? I want to make punches out of it I think or tongs maybe

[@lindboknifeandtool]

Heat to cherry, dunk, anything below 0.7% carbon is that protocol.

[@iDiveDOTtv]

Hey man. Thanks for the video. Can I ask or request one thing though please. I came here to see how to harden A2 and what I got is a 24 minute video which is far more than I need and makes it difficult to skip to find the places where the essential nugets of info are. I'm only a casual viewer and use YT to find info so am not a knife geek or likely to subscribe to you (just because I like diving and CNC not knives :-) ). So could I request that you use the 'time jump' (not sure what it's really called) function where you can link to times in the video from the description. That way I could get all the great information you have but in 2 minutes instead of 24 . Not dissing your video or being negative here. Hoping this comes across as constructive. Thanks Jools

[@HouseMadeUS]

Hi Jools, I appreciate that input. This video was early on in my YT video career. I get that it lacks the details, or maybe it does have them and they are hard to find. In the future I will make another video on the subject and include only those things that are pertinent to the work at hand. Which, by the way, those videos do far better anyhow. I think the person making these videos years ago was more ego driven, thinking the world cared about his views and comments. I can see now that was the wrong tack. :) I had to let myself go to make better videos. Educate and document. I appreciate your feedback, well said and was very constructive! Cheers!!!

[@iDiveDOTtv]

@@HouseMadeUS No worries. I'm the same. It's very difficult to put your self in the position of the viewer and realise that they only want to know what's in the title and nothing more. Why can't the bastard viewers just love us as people man :-)

[@HouseMadeUS]

One day my friend! 😂 KZbin is the great equalizer. 😁

[@ryanwilson1369]

Any way you could email me the details he provided about the heat treating process of A-2.

[@HouseMadeUS]

Yeah Ryan. Email me [e-mail] and I’ll send them over to you

[@ryanwilson1369]

@@HouseMadeUS the email you provided wasn't a valid email so it failed when sending

[@HouseMadeUS]

Ryan Wilson - that’s my email address. Check it again and give it a shot.

[@HouseMadeUS]

Or add your email address here and I’ll send you one. (I’ll delete it from this comment section once I have it)

[@ryanwilson1369]

@@HouseMadeUS my email is [e-mail]

[@ryanb1874]

Why didn't Mike mention to not let your peice go below 120f before going into fist temper cycle, or Don t start temper cycle until it is cooler than 150 f.

[@HouseMadeUS]

I don’t know, is that a thing? Get back ASAP as I am heat treating some more of this today. 😅

[@ryanb1874]

@@HouseMadeUS I read a book called heat treating for tool steels, The author specifically mentioned that of you want to see a full potential, out of the steel, what is considered tool steels specifically, you want to have your temp cycle ready and not let cool (in this case air cool, or fan cool) past 120 f, because, it basically really limits the effects of tempering. For a hard knife that just cuts succulent fish and paper, this might not be a problem. But if you wanted to do a sword, I believe you would want to start tempering between 150 and 120 f at like 650 or 700 for 2 hours two times. But I'm a little fuzzy on the soak time, if it's a 1/8 inch blade, does it still need the full 20 minutes at 1725 to 1775? I've seen many guys on you tube make wonderfull, sharp big choppers, doing everything but that, and they start chopping when it's only a little cold outside and big chips break out of there blades.

[@ryanb1874]

Ok one more run at it, so if you let tool steel cool of to room temperature, it forms retain ed austinite structures ARound the grains, and if you try to temper, it will fracticaly start to grow and eroode those grains, into a less fine, more brittle structure.

[@engelwyre]

@@ryanb1874 I know some makers that use cryo after quench/before temper, which would obviously bring it way below 120f.

[@SuperSteelSteve]

​@ryanb1874 this is factually incorrect. All hardenable steels, no matter how fast the quench will have RA. Always. One of the actions happening during tempering is converting RA to martensite. The reason for a second Temper is to Temper the newly converted martensite from the first Temper. Sub zero treatments also convert RA into martensite.

[@miloszivkovic6118]

I will never understand how can quenching be good, when surface solidifies faster than core, just imagine core volume cange in already solid surrounding. How can it be even than?

[@miloszivkovic6118]

@@awashburn6944 i know it is, but there must be a way to quench, stress it from inside out. It is a solid that is stressed on high temps, and as it cools it shrinks unevenly so it leaves lot of microscopic cracks and voids like strings, thats what i ment, yes my bad it is a solid , but very streched solid .

[@miloszivkovic6118]

@@awashburn6944 wait, but not all of the lattice are martensitic, i cant imagine that when lattice is stretched at high temps and it is stressed it can save same formation. In some magnification value it just separates in string like figure and create voids, and I saw it in images. My understanging on martensite is that when cooling rate is high, puling forces between iron atoms are aditionaly elongated (because one C inbetween) and it cracks basicly the same in all C content steels if cooling rate is elevated. So for example, imagine a lattice, and external stessor, and as outside atoms take more stress untill it comes to inner one concave shapes form leaving only half atoms bonded, thats main problem for fatigue I think, like in welds, its not cracks, but exists and its clearly visible under microscope. Those string like voids are actualy small lattice cracks, initiator for visible crack, and its rly hard to track on what magnification value will they be evenly distributed. Its bugging me, cuz well compressed forged steel dont have such problems

[@miloszivkovic6118]

@@awashburn6944 just to make things exaggerated, when liquid glas drop hits water its hollow from Inside , but since its liquid there is no deformation, and if rly hot solid hits room temp fast , bilion microcracks happen in same pattern from inside out! I just hate that so i was thinking there must be a way to stress material from inside out, that would solve so much fatigue problems

[@miloszivkovic6118]

@@awashburn6944 but its still a solid. I take glass as example to compare because less resistance as it adapts to external stress easier. It is irons tendention too if it creates voids after quench. Voids confuses me, and separation in lattice, it cant even be called crack cuz its very small. Thats obvious tendention to behave in direction of like glass drop, but because differences as you said it just "snap" in different way.

[@miloszivkovic6118]

@@awashburn6944 about uneven cooling , actually object tends to even cool trough surface line, so it bares much more stress because its still hot untill signal reaches core , and thats where difference in temperatures strain surface longer untill core catch up. Surface cant cool instantly because thickness dont allow, so difference in temperatures object surface/collant creates strain on atomic attraction force equal -500> celsius object temp( probably much more), without extenal stress. is simple words its squeezing so hard like you freeze it until it crack. But thats not the problem, problem is that stress pulls atoms from inside in surface direction and create voids, those 2 types of cracking are not related, because 1st one happen instantly, and 2nd leaves space for damage under load.I suppose carbon escapes in that voids after temperbecause it has nowhere else to go, I tried by best since english is not me native

[@vettepicking]

hey I sent good info first....lol

[@HouseMadeUS]

Haha! Yeah man. I appreciate it too. Did you hear that I only use .185 - . 1085 - that’s because of your suggestion! 🤩

[@vettepicking]

@@HouseMadeUS yeah, i could understand you . Haha

[@fixesflyers]

Those are supposed to be wrapped in stainless foil. Lmao

[@HouseMadeUS]

Thank you. I have an argon flood system now that works great without foil. These came out great, daily use in my kitchen.

[@machobunny1]

Ijust wanted to learn a protocol to harden A2. This is not the place to find that. This discusses every aspect of building everything you need to heat treat everything. Too much.

[@dariostino]

Less talking more cooking knives