Do Knifemakers Know How to Heat Treat? 

Thanks for the tips! Most of the heat treatment knowledge on these videos was gained before your book came out, and there was no real source of what was actually going on. You would read one thing from a supposedly reputable source (places that sold the steel perhaps), and then read something else contradictory somewhere else. I still hear people say to only heat treat during a full moon🙄 So thanks for the book and knowledge gained👍 Id like to hear your thoughts on a video i did following your heat treatment protocol for 1084 and comparing that to purposefully bad heat treatments at the same rc hardness. Anyway, thanks for writing the book its really helped👍

“Metallurgist reacts” is a great concept 👍🏻

Everybody caters to knife makers. Chisels and hammers are pretty cool too guys so could someone make a book for us lowly tool makers? I promise all five of us will buy it. Seriously though, Doc you rock! I have been confused as crap on this heat treating thing since everyone kinda does what they were taught instead of what is right. I look forward to getting your book and hopefully applying what I learn to my future projects. Thanks for making my world a bit better by sharing your knowledge.

Dr. Larin, I bought your book Knifemaking Engineering (Excellent, anybody who is making knifes should read.) I have watched dozens of YT videos from YT knife makers. I am not ignorant it the subject of heat treatment and working with metal. I am a retired Marine Engineer. I have felt that most of the YT knife makers are quite ignorant on the subject of heat treating there blades. This week I forged 3 blades from 52100 material, today I heat treated the blades as per your suggested recipe for 52100. This worked perfect, the blades are about 62 Rc seem to be stout and hopefully tough. There was zero scale (wrapped in St/St foil) and zero warpage. I am sure they will take a very sharp edge and be a tough blade. Thank you for your great videos and research you do in the area metallurgy. I hope to make some blades from Magna Cut one day. Well done keep up the great work.

Thanks for the overview man. When I made that video 3 years ago the intention was to compile the “best practices” I found on bladeforums. With the intention of easily getting a beginner started. The knives I’ve made and tested with those methods performed pretty darn good, so that’s a plus! But I guess they could have been better! I’m curious about annealing. Is it needed on stock removal knives? (When you start with annealed stock?) I think it could be cool for us to do a “re-make” of this old video as a colab! Cheers

Internet Raid siren going off RU-vid knife makers: "Oh lawd he coming!" I'd agree with the colour and heat guessing, mostly because you look at some of these shops with a $3-5000 grinder, $1000 in the anvil and hammers, presses and power hammers worth a 2nd hand car, hundreds into the forge- but at some point most of them missed the simplest and quite cheap option of a about $80 will get you are really good digital thermometer and some spare thermocouples you can just run into the region your heating at. Plus, just as someone who did adult ed in the radio-engineering part of commercial business for a long time, stop staring at really strong emitters of infrared radiation sources- fire is cool, yes it really is but don't stare into the forge too much up close without some eye protection.

18:00 “I’m not crazy”! That made me laugh. My wife just glanced at me, gave me this look. Lol😂.

Thanks for making more stuff for us to rewatch and study, Mr Thomas. You are a backbone of this community in many ways and a reference for the rest of us that have interest, but don’t work in your profession. This is good for the rest of us. Thank you. Great stuff.

You can't go wrong by watching any of Walter Sorrell's videos. I don't agree with him 100 per cent on everything but nobody does- get 5 smiths in a room and you'll get 6 opinions. The man has a solid knowledge base and is good with sharing it.

Great video! This was my biggest concern going into knife making, there was so much theory and marketing but very few really well documented sources, I am an engineer and really wanted datasheets and hard evidence. Your publishing has been such a well needed reality check to the knife community, so Thank you!

I recognized inconsistencies with various methods early in my online quest for knowledge, and then promptly purchased your book. So far so good kind sir. Thank you for your contributions to the world of metallurgy; particularly within the knife community. Side-note: I’m looking forward to getting my hands on some Magnacut. 😁

Crazy, I was reading your book on this topic just last night and then I saw this video today - thank you for taking your time share your knowledge and do all of this.

Thanks for debunking and clarifying, once again, Larrin. Youre a huge asset to our community.

I've seen guys do the heat treat process with fire and I have to say there is definatly an art form to it both with coal and gas. Having that oven can make the process more exact with much better overal results but for guys just getting into it and working with simple steels like 1084 it's a great way to get your feet wet without spending lots of cash. Always fun learning about metallurgy and and how it applies to the knife world. Thanks for the great vid and keep making sharp things fun and enjoyable

There is a lot of miss information on the internet . That is why i follow people like yourself ! I do all my heat treatment in an oven , following time and heat guidelines . When i forge a piece of steel , i might do one normalizing cycle in the forge before going to the oven . Being colorblind makes me very cautious as i can not trust my eyes. The information you have given me , both in your book and in private messages , have been absolutely spot on every time

Based on what I've learned I bit the bullet and now do my HT in an Evenheat and then use Parks 50, following the datasheets on each steel. I've learned the hard way that I can't take cheap shortcuts and expect to get the most out of the steel. Thanks for sharing your expertise, and yes, I'm reading your book for the second time!

great job, thank you. You pulled from several people I have learned from, so it was particularly interesting to see your assessment of their advice.

45 years ago I worked with an old blacksmith in Thailand. Nothing fancy but he beat old truck springs into working knives. Charcoal forge, edge hardened in water. He made good stuff and was very particular in what he did. He was very careful about the quenching and tempering, All was done in a continuous manner after heating. I wish I could go back to that time as I've learned a lot since then.

This was a really fun watch. I would love to see you offer critiques of other makers.

Wax sticks! Haven't heard about them in a long time. They were also used to determine the air fuel mixture on cars or motorcycles by using the exhaust header temperature using wax sticks. Have only be shown once in 2006 by a Volvo technician in his mid 60's. Absolutely fantastic to watch and learn.

Very helpful information. Even though I have no plans to make knives myself it is very worthwhile to have a better understanding of the basics. Thank you.

I'm 62 , been fascinated with knives since I watched my dad sharpened buck knives on arkansas stones . Read a lot of articles over the years . I've watched how the frontier of steel science is being constantly pushed forward. It's amazing how changing the steel ingredients or playing with the heat treat can have such profound effects . For me , it's mind numbing complexity but that's why I find this so fascinating. Love how you make these issues easier for others to understand. Only a teacher who loves learning will understand.

Dr Larin Thomas, I'm a huge knife steel enthusiast, I totally appreciate your in depth metallurgy knowledge 👍 😀 thank you sir 👍 🙋‍♂️ please keep educating us knowledge thirsty knife enthusiasts. 🔪 you the man buddy 🙌 👏 💪 👍 👌

Most RU-vid content creators are not highly educated. I have to take what they claim with much skepticism. Is nice to actually have someone with a PhD dispersing the myth.

I have so much to learn. First, I need to buy a fast quenching oil. Then I need to look at your heat treating with a forge videos. Thanks again.

Finally a nerd I can understand about steel. I don't know a lot about heat treating (stages of crystalization I understand). When I saw your vid on the subject I needed to take a look. You showed all the failures I've seen before in these types of vids and pointed them out. (We aren't in the realm of metal magic anymore. Use a temp gauge or stick.) Now I'm off to watch you do it right. (I'm a knife nerd but have never made them. I can tell you about the things you speak of about the metal stages and why they fail when looking at the metal.) Thanks for sticking to the science of it.

Great video always fascinating to see how even though certain amount of experience is necessary for progress in any given craft without proper knowledge and keeping an open mind to new information you will only regress .

Great video! Thanks for the clarification on many points! Thanks for referring us back to things like the data sheet and specs and tests instead of feelings and less reliable methods!

Thanks for all you do! We (new knifemakers) need you!

Hello Larrin! Thank you for your critiques on the various OPINIONS of heat treatments out in the wild, so-to-speak, on YT. I just ordered your book from Amazon and am looking forward to reading it and using it as a reference in the future. I spent my entire career working around steel (hot rolled JAC270F - 45/45) and heavy die tooling for a major automotive manufacturer, and am just getting into forging and knifemaking. I think the errors, albeit with good intentions, of the various YT creators is quite commonplace when it comes to science and math concepts. Objective facts surrounding forging, annealing, normalizing, austenitization / quenching, etc. of many well-intentioned smiths and knifemakers think that how they FEEL about something, while ignoring objective facts regarding material properties, is somehow germane to the discussion. It is not, and I have learned to immediately hit my browser's 'back' button when something they say is incorrect. People need to understand that the "works-for-me" or "good enough" approach may get close to the actual result, but in no way can be emperically verified. I REALLY have a problem with this, but YT is what it is. Thanks for your content and hard work!

I think the fact that I watch this video and was entertained and it had my complete attention for the entire thing means i might be a little bit crazy myself 🤣🤣🤣 I can't get enough of this knife heat treating stuff I watched a video just the other day done by (Nat from the intent) on and experiment with quenching knives in liquid nitrogen it's fascinating all the ins-and-outs of heat treating steel. Love the video keep it up 👍

I think it’s safe to say you fully geek out when it comes to metallurgy. And it’s delightful to watch. Cheers!

It's nice to see the face behind all that knowledge. This made a great refresher vid for me.

I really enjoyed this! I’ve always enjoyed your very matter of fact approach and reaction to things and this video certainly helps showcase it! That said, your well placed sarcasm always gets me, “Framing hammer for straightening, nice.”

Thanks for expanding upon and explaining some of the common information that is on RU-vid regarding heat treating knife steel…🤘🤠

Never say you aren't crazy. Walter is a good dude. He doesn't get super technical but he is a good teacher and seems like he would be fun to have a beer with.

Please continue sharing your knowlege. We need more videos

A lot of knife makers shouldn't have RU-vid channels. Thanks for making this

Fantastic video Larrin! Totally showing this to my lecturers!

I recently commented on one of your posts that I bought 2 Magnacut blanks, and I did mention I plan to have Peter's Heat Treating to the HT, which is really a general term that seems to be used as it includes annealing and tempering. In the past when I HT in a forge I stick the blade in coal ashes to slow the cooling process. I have never done it more than once though, and I also was taught that after dunking in oil, I put it back in the forge and let it burn the oil off and allow the flame to go out, then finally bury it in coal ashes. I have some old coil springs (5160 ???) and O1 I've used this process using transmission fluid. Probably not the best but what I was taught by my smithy mentor. What I wanted to point out here is that it's worth the cost to have a professional heat treater like Peter's Heat Treating to do it for you. It also requires a computer controlled oven to do it properly, and the cost of a single blade is quite a bit less...with all that said, I have seen most of these videos you annotate and it is the reason I come to the conclusion to let a professional HT for me. I have only done HT on high carbon, and stainless is yet another story.

I used to weld and have some basic metalworking knowledge and wow was I in the stone age. Somehow never really thought about this area of science, which is surprising because I love metal and enjoy spectating science. Before your videos I guess I sort of just had a slightly magical mindset to how it all works to put it simply. However, reading the comments though I'm kind of shocked to find this sort of info is new to the top pros in the field too. It seems I'm not alone in still looking at this with sort of an iron age mysticism lol. Glad the fields are merging. Thanks for your videos, you rock.

Fascinating breakdown from the perspective of someone unfamiliar with the process. Very much appreciate the knowledge given and the corrections being nicely done rather than brutal. Thanks for sharing and thank you for Magnacut!

The most gentle review I've ever seen

I agree the first video went off the deep end for no reason. Flexing.

I'm just glad our dear Walter passed the test. Whew. Thanks for the vid. It was fun.

@knifesteelnerds Larin, I met your dad and uncle at bladeshow west in Salt Lake this year. I love your content. Thanks for what you do.

Finally a heat training video or somebody says something that makes sense thanks for sharing

the totally candid "I'm not crazy" made me crack up

Thanks for this video, giving reactions on heat treat and learning something..

This is analogous to a MD debunking alternative medicine. Great work!

A fellow metallurgist here. I work in a fairly large carburizing heat treat department. I agree with your comments about 13:00 in on the thermo cycling. The grain size change that occurs during the normalize cycle is mostly accomplished with the first normalize and with the subsequent quench. The lower temp reheats are going to affect the carbide vs retained austenite structure. In my business, we want retained austenite instead of carbides, so we quench from a higher temp and try to stay out of the carbide forming temps for extended periods of time. On the quench oil at about 13:45. The temp of the quench oil is important for the quench speed. We want the oil at the correct viscosity so it will carry away the heat at the required speed. Cold oil is not going to quench as well or as evenly. Uneven quenching leads to distortion.

once again - awesome video. Entertaining and informative. I hope there are more comming :)

I think everyone should read your book!

Keep ‘em coming 👍🏻

Great video Larrin, excellent idea👌👍

I do find it comforting that the bulk of the videos that you covered were pretty much in the ballpark with their data. Not too bad…🙆‍♂️

Great job, loved this video. Thank you.

Love this one!

Love this! You are sooooo restrained. I'd be struggling to hold back the sarcastic/sardonic comments. Keep up that no nonsense attitude.

U put in the time doc. And now we can all respectfully learn from u. Thank u & btw if u are a little crazy, its a very good crazy!

Thank you sir. This was great to watch learned a lot.

My favorite scientist bringing the HEAT..what a treat.

This was neat, I learned a lot. Thank you.

Brutal... Good stuff! I'm going to stay on the user side of this hobby... Thanks for the video. : )

It's difficult with a forge but people made knifes this way for a long time

I'll have to listen to this a few more times, but Thank You very much for this information. I know little to nothing, but this interesting. Where I need to saw mo.

"I'm not crazy" ... "Maybe I am a little crazy" haha well I feel you my friend

I have really enjoyed this video because if you read the comment section you will gain even more knowledge thank you for sharing your wisdom with us all godbless and be safe.

Thank you so much for the insight!

Some useful information here that I have not encountered in other videos. First I have heard of Temper sticks.

What a great video. Thanks 👍

Genius!! Thank you kindly for your EMPIRICAL truth!.

I liked the "I'm not crazy" comment at about 17:50

Thanks a lot for this video.

Great video, like I’ve told ppl RU-vid can teach u how to do something but can also teach u many ways to not do something.

Love the video Oh I would like to see more videos like this keep calling out misinformation you did this in a nice way to but got your point across thank you. I kept waiting watching the video thinking one of my misinformation videos would pop up 😂

impressive! thank yoy very much for sharing

You should look at Ed Fowlers heat treating of 5160 and 52100. He is a master smith and has been attempting to prefect heat treating these steels.

Hey Larrin great videos . Not a knifemaker but I love knives and experiencing different steals. But I have a question which I cannot seem to find any straight answer on and I think it would help many guys like myself in deciding if its safe to get DLC coatings aftermarket as its become something a few places offer that I've been quite interested in . Now I no the answer may vary depending on weather we are talking about carbon steel or stainless steel so to keep you from waisting to much time it's going to focus mainly on stainless blades as that's mostly what I own and would be thinking about having coated. I understand it may not be needed but looks are important to some of us and it seems to be the only coating that holds up to any type of abuse while retaining its clean black finish. Also cuz this might be important I believe the temps I found were 500 degrees they said to apply the coating but it did not give am exact time frame. But they do have a warning to no what steel your having done and that the risk is not on them which clearly means that it must be possible that some steels heat treat could be affected. I did here whatever the final temp the blade is run at then it shouldn't exceed that. I believe its the tempering cycle you can correct me if I'm wrong. My fear is every steel could be different depending on each companies specific heat treat protocol. Which if it's that complex I prob will stat away from it. But if its possibly not something that will affect stainless because of its high temps it goes through in comparison to carbon steel then maybe ill give it a try. I just cant see losing any hardness when most companies are still hitting the low end of the hardness spectrum already and I dont want to lose and edge retention or affect there overall performance. I hope that's enough info to give me a basic answer to this question. And thank you for your time if you are able to respond. I greatly appreciate your advice on this topic.

I use the "shadows" in the steel that dissappears when the autenizing occurs. Along with the color. And just leave it for about one minute or so to fully dissolve the carbides before quenching.

Wow, thanks for teaching me...

When you asked why knife makers were afraid of letting their steel soak for me it is because I want to avoid the scaling, it sucks to clean off.

I have some heat treat vids in my playl-ists also in my about tab there is a link to some of the same vids but also some PDFs. Its a work in progress and don't have all the time in the world. I would prefer videos to include developing and testing a protocol with test coupons. But most makers just want to get a protocol from a forum or book or whatever source and assume its good for their application.

Good video, it shows the differing advice and misconceptions on heat treating on You Tube. As a new knife maker I originally started using 1084 steel. I then switched to 8670 steel because I was informed it did not need normalizing but rather just heat to 1550F and quench. Is it correct that 8670 steel does not need to be normalized? Also when heating 8670 for the quench cycle should it be heated only to non-magnetic then quenched or heated to 1500- 1550F then quenched? Thank you.

A question from a commercial heat treater: Why the thermal cycling? Especially thermal cycling ending with a spherodize anneal. I agree with normalizing, in my experience a normalized structure is the best structure to have prior to austenitizing in order to contribute to uniform transformation and fine grain size. Spherodizing was only used as an anneal for severe forming and any material that had been spherodized annealed was always normalized prior to hardening. I'm familiar with aerospace and industrial applications with alloy steels, super alloys and tool steels. In fact, military and international standards specifying heat treat procedures specify that most alloys, intended for critical applications, be in the normalized and tempered condition prior to austenitizing.

Great video… I learned a lot with one through and even more second time around. My question is: Is annealing a substitute for normalisation. If I anneal my knife after it has passed critical temp is there any benefit to doing a normalisation after say, grinding in bevels? Can I skip normalisation and go straight to the quench from the anneal.

Thanks so much for sharing your knowledge. I came across some bandsaw blades that has silicon in it . Wanted to use it with 1084 but all I can find is that it is low carbon. Also not sure of nichol content. Any thoughts would be appreciated.

You are a blessing!

Learnt a bunch! Thanks, Dr. Thomas. Another great video. So what is oxidization...?

Fun and educational!

Nice video. I have some 50 quench oil that is over 8 years old. Unused in a plastic5 gallon bucket. Does the oil go bad over time? I’m having trouble getting a 1084/15n20 blade hardened. Normalized then soaked for 10 to 15 minutes in oven at 1480. Testing with file for hardness. Seems like half the blade is hard and the other half the file grabs. Thanks for the videos.

Can you do a video on self-tempering steels like Atlantic-33 "flutagon" and what happens with those when you quench? I've been using flutagon for making tools for a while now and I just call it "magical happy steel" because it has a wide range of temperatures for the quench (as per manufacturer, and I don't particularly care how hard a chisel is as long as it's hard enough), you can quench in water, and it's self-tempering so you can basically just start using it immediately. It's a bit like super-easy-mode for the novice blacksmith. I have no idea if you can make a knife from it though, but it makes great chisels, punches, hammers, drifts, etc. It would be really cool to know exactly what's happening when you quench this steel and exactly how it self tempers and what that even really means.

Hello bro well what's the best knives steel type for daily use (restaurant) something it holds edge for long time possible but also easy to sharpen and get back the edge??

thanks for the info...i have a silly question...watched the oil video and was wondering in it made any difference if you quenched in cold veg oil it would help? since all my work is done outside...thanks so much

I find people understand solubility when it comes to sugar and salt in the kitchen. I have been comparing heat treatment to how some eliminates will begin to change before something melts. It seems like people kinda get it.

When I didn't know what I know now, and I was forging my first knife, would you know why my blade has held up when I have not tempered after edge quenching? I was in a coal forge (which was just a super hot campfire) and heated the edge to just past non-magnetic. Then quenched in like a 2 gallon container of vegetable oil. This was before I knew a lot about tempering but I have put it through a hell of a beating and have not had any chips or rolls or a break. I have still not tempered because why fix it if it ain't broke right?

hello Dr, some years ago i watched lewis razor's video about grain refinement (with O1 steel), there he quench 1 times to 3 times and tested it. what i want to ask is do this method correct? since i watched that video i normalize 2x then quench 2-3x

THANK YOU!

Real interesting video concept - would like to see more of that! I‘m a knifemaker myself and heat treating in an proper heat treating oven these days, but I‘m curious if its necessary to normalize an steel before quenching if the blade never has been forged. Basically I‘m asking if there‘s a chance that knife steels coming with big grainsize and uneven grainstructure from the factory?

Larrin...I got your book yesterday. This video was excellent. My question is how many blades must I "destroy" to ensure success with heat treating?