You have to bring it up to temperature then SLOWLY lower the temperature until the temperature is below a certain point. Usually this is done in a heat-treating oven with a program starting at say 1750F and lowering the temperature say 40F per hour to 1000F then can be taken out to cool to room temp. As always check your references for actual heat-treating info for the exact alloy and supplier you are using.
I use a media to slowly cool the material. I have a 5 gallon bucket of vermiculite for doing this. I also have a chunk of scrap heavy 2" plate that is heated to cherry red. Put the plate in the middle of the vermiculite first to help preheat the vermiculite. Then heat the metal I want to anneal to loss of magnetism and place it in the middle of the vermiculite next to the heavy plate. Then walk away until the next day after it has had time to slowly cool.
You have to cool it slower than just leaving it in air. Depending on the part this can be done by covering it in insulation after heating or maybe you can get away with putting it in the 500 degree toaster oven after heating. The bottom line is that you have to slow the cooling rate enough to allow enough time so the softer microstructures form rather than the super hard ones.
Old gunsmith technique is to clamp a piece of scrap angle iron extending out the side of you vice to form a cradle and place small parts on it and play the flame under the scrap angle, but not directly under the part. The heat will slowly creep under the part and you can observe its color without looking directly at the flame or through the flame. When it gets to the desired color nudge the part off the scrap angle into a waiting cup of water. It slows things down and gives you great control over the process.
So a similar technique to when silver soldering, where you also want to heat the more massive part(s) and let small parts and the solder seam heat indirectly from that. Clever, that.
Brilliant! I see the reply from @autochton, and a similar process can be used to solder PCB (computer) boards, especially when doing the super tiny surface mount stuff, by using a bit of aluminum plate. Comments like yours are why I love this chan, ToT and AvE. Best comments on the interwebs!
Great video, this reminded me of a time in my life many decades ago. When I first got out of high school I got a job at the city works. One of the positions I had was part time equipment operator (jackhammer) and assistant to the blacksmith. The black smith shop was a dimly lit space with a century of dirt, soot and tools every where. The man working as the blacksmith was a welder really and not a blacksmith. He used to sharpen the jackhammer bits which he would heat in the forge and hammer out a new tip on them, then quench them in oil to harden them. He got the bits to a specific colour the quench them. One day he got the city to replace all the old dim lights with new much brighter florescent tube lights. Every bit he sharpened under those lights the tip shattered the very first time they were used. The bits were too hot when he quenched them, his colour perception had changed under the new lights.
Reminds me of the story told by gun nerds about - I had to look this up - the M1903 Springfield rifles. For the first many years of production, the machinists would judge heat treatment temperatures by eye ... and the difference of ambient light levels between a sunny day and a cloudy one could throw off their judgment of temperature by a quite significant amount. Fortunately, the process Quinn is describing is significantly less fussy than that one.
Quinn, great job on making heat treating approachable to your audience. I work in a "big boy" tool and die shop now but 15 years ago this video would have been mind blowing to me. Hopefully this will open doors for your followers. I find great information on Crucible and Carpenter tool steel's websites.
9:12 - in old blacksmithing books that is how they would determine if a steel was tool steel. You would break it like that and take a look at the grain structure. Tool steel like that will have a very fine grain. Contrast that with cast iron, when you smash it, it looks like coarse sand
Or if you have a hardened thing stuck in a hole like a broken tap, you can often anneal it with the torch and drill the centre. The teeth will still be hard due to their engagement in the material, but you should be able to soften the core enough to drill it out
I’ve spent hours the last couple of days searching videos and forums on heat treating tool steel and your video shows up. You just saved me a pile of dough Quinn! Thanks for all you do for the machining hobby community.
I was the QC manager for a 7-acre precision machining shop, and we did our own heat treating. Your primer is as good as it gets on YT. I can't tell you how many times I've muttered under my breath at youtubers "Swish it! Noooo, don't pull it out while it's still red hot!" They don't understand that the object is to keep it hot, dunk it fast, and cool it as quickly as possible. Good job!
6:47 - blacksmithing tip: a good way to know if you are hot enough is to use a magnet. When you get to the critical temperature the steel becomes nonmagnetic.
I was about to make the same suggestion with regards to the magnet. In my old shop I had a magnet I had found with a hole in it (I think it was salvaged from an old hard drive), and just some fence wire. I was able to nail the critical temperature every time without worrying about the ambient light. For annealing, I like to use wood or paper ash that was fluffed up, and my portable charcoal forge's (made from a wash tub and a small hand crank blower) insulation is simply made from whetted and packed ash from the charcoal.
Thank you for another no-nonsense tutorial on how to implement processes and techniques without relying on expensive equipment. The focus on "home gamer" ways of making do elevates your videos' usefulness and appeal significantly.
Few things are as gratifying as a torch heat treatment that goes successfully. 1 part knowledge. 1 park artistry. 2 parts magic. I always love using home made tools that I machined and heat treated. You did a great cover on what is need to get started and be successful. Anyone wanting to take the plunge has more than enough knowledge with this to get going.
Quinn, thanks for this video! Absolutely clearest concise explanation of basic steel heat-treating I’ve ever seen! I trained and earned a degree to teach high school industrial arts in the 70’s. Have seen various how-to’s and much more technical explanations of heat-treating, but yours is the best! I tried doing classroom demos of a large part of what you did but I’m sure when I turned the lights back on, many of my students were still in the dark. Again, thank you!
14:38 - you can also directionally quench as well. I recall reading in a blacksmithing book how for a hammer you want the center of the face to be glass hard, but you want softer edges of the face so it doesn't chip. To do this you take a can and poke a hole in it. When you go to quench you use this can with the hole in it to direct a stream of water to the center of the face. Since that takes the most cooling it gets the hardest while the edges of the face don't and stay softer
Hi Quinn, what many people don't know is the (matensite) carbon growth is forming for a few minutes after quench, this means you have a short window to do a little straitening. many knife makers take advantage of this window. also after the material is drawn back to say 59RC my happy number you can subzero quench (dry ice or liquid nitrogen) it will typically gain 3 - 5 points of Rockwell C finishing the rest of carbon structure to complete it's growth and with many benefits
Wonderful presentation! For anyone interested in doing this for sheet metal, say for armor for Western martial arts or sport fighting, we had tremendous success with SAE 1050 steel, a water hardening kind that we drew (tempered) to around purple/blue (call it 600-650 F). Be sure to experiment, toughness is far more important than hardness in this application, but any hardening reduces damage from use considerably. SAE 1045 is also quite useful (containing 45 points of carbon instead of 50), but 1015 will not harden and 1065 is probably going to harden too much. Just more in the rather infinite amount of information on heat treatment. No matter what you're doing, have fun, and wear your PPE.
Having spent a little while as a teaching assistant for a college class on heat transfer, that point you make about the inertia of heat is *so* important. Spending time in a lab with temperature probes, I was amazed at how long it would take to get to a steady temperature.
Years ago I took an evening blacksmithing class and "learned" to do this in a coal forge. I say "learned" as I never succeeded. I am not color blind, but I was never able to see the changes that I needed to see. I guess if I want to try this I will have to get my wife to come watch and tell me when it is time to quench! I still have (and use) a cold chisel that I made in the class, but the tempering was don with the instructor shouting now, now as I obliviously pumped the forge.
Great tips for the home shop. Making custom steel tool bits with a grinder, then hardening them and honing them, as Quinn has pointed out, is a good way of increasing your capability without breaking the bank.
I learned how to do this in my junior high metal shop back in 1969. I I'm now 68 and have used it my entire life! thanks Quin, you made the process look as simple as it really is..
Super accessible breakdown of the process, I really like that you showed lower cost/lower stress methods of testing and heating. Awesome content as always.
Oh man. I *love* heat treating. It's so easy and satisfying! I needed to make specialized forming punches to re-create the fancy washers used on old straight razors and I managed to do the heat treat just right on O1 drill rod with no difficulty on the first try. And the second! Even the third! I did use the convection toaster oven for tempering though, and just looked up the temperature to set the oven to for the hardness I wanted. But it was all dead simple and worked great. Watching this video has made me want to go downstairs and make some parts to treat!
If parting off is a nightmare, as it is on my little lathe, try a sprung Armstrong type tool. Winky did a nice video on this type of tool so I made one and it works very well. In essence, the tool moves away from the workpiece rather than digging in, it chatters at the first cut until it finds it's medium and then cuts cleanly. Or use a rear toolpost with the parting blade mounted upside down, if you have space on your cross slide.
The parting tool shenanigans reminds me of an excellent project for the small lathe shop, Winky's Workshop has drawings for a flexible or compliant parting blade holder. it's still very rigid, but has just enough give so that if the parting blade catches, it can deflect enough to get itself out rather than transmit the force all the way into your compound. If you're having problems with parting chatter or parting in general, a flexible parting blade on a solid tool post mount can buy a lot of ease for a small lathe.
Very good instructions as usual. I love watching the colors travel. I have made a few tools and a couple of blades and so far, no exploding knives. That's a good thing. Thanks, and Meow to Sprocket.
An important note when heat treating by eye: The room lighting must be consistent. During early production of the American M1903 rifle the heat treating furnaces didn't have pyrometers. The process was controlled by eye. The area was lit by natural sunlight. On a cloudy day the light would be different. There were multiple receiver failures.
For the most part true. The improved process on heat treat did allow the O3 to be even stronger. The lots you speak of failed when case pressures got to around 70K PSI, the improved process moved that to more like 100K. But the bigger problem was the ammunition of the period, there were a couple of bad lots and from what P. O. Ackley and others found, the failures all involved that ammo.
Great video Quinn. Brings back what I learnt at school 50+ years ago but had all but forgotten. Still have a screwdriver I made which the teacher wanted me to make from mild steel and case harden but I remember insisting on using tool steel.
When teaching students, Use a nail. Heat it red hot, dunk in water, still soft since there is no carbon in it. I made a chisel of tool steel many years ago, and later, while working in industry, I tried making one with a 3/8" alloy steel hex socket wrench. I hardened & tempered it, but It wasn't hard enough. I went back, hardened it again, but did not temper the chisel end at all. I kept it for years. The best chisel I had to my name.
Quinn, I admit i had conscious bias years ago when your videos always popped up. Your videos are so excellent, informative, and on point with what I'm usually doing. THANK YOU!
Thank you for the great video. I need to harden an R8 arbor that I recently turned and this took the mystery our of it. I really appreciate that you make these videos understandable and worthwhile to folks of all levels of interest and experience.
Excellent, thank you. Just found that I have access to an induction heater, and I'm going to try hardening and tempering 1.25" round tubing to make some tractor bucket bushings. I'm sure the same principles will apply. Very helpful.
Excellent video. The statement regarding correcting your mistakes by going in a circle with hardness, tempering is good for an amateur like myself to know. I did not know that hardness mistakes could be corrected. I always figured it was a hit or miss operation without expensive ovens and knowledge about quenching. I also did not know that MAPP gas is no longer produced! That one really surprised me. Thanks.
you are the absolute best at machining for dummies or self taught machinists... always straight forward with the proper visuals the whole way thank you!
Legitimately the best guide I've come across. I've been googling for ages on how to do this, and most guides simply devolve into the author wanting to show off how smart and how much they know about heat treatment (phase diagrams!), and what "toys" they have - all that "complexity people like to add" as you said. Thank you.
Nice tutorial. This is the kind of thing that helps new people take that leap and try new things. I've got some heat treating to do Real Soon, but I'll be using a coal forge, not as controllable as a torch. And thanks to the wonderful circular Annealed-Hardened-Tempered cycle I can always try again if I make a mistake.
This has got to be the best explanation of the process. Blimey, I remember doing this in school and really did not get it at the time, I actually don't think the teacher really got it either.
For those who want to go a little deeper into the subject without getting into textbook-level detail, Book 1 in the Workshop Practice Series is a good source.
Biggest thing to remember to avoid warping as much as possible on a long tool is to make the quenching as even as possible. On a long piece do not enter quench with the part held vertical. Have the length enter horizontal so both ends and the middle enter at the same time. Then once in the quench keep the prat moving. If you hold it static air bubbles can form on the part from the heat. These bubbles will slow the quench and cause incomplete hardening.
This is the best hobby-level / practical heat treating video I've seen. I've got some O1 steel I bought online and the instructions that came with it are industrial-level (incomprehensible and impractical for the hobbyist). Just watching this video has given me the understanding and confidence to do it too.
EXCELLENT tutorial as always. Maybe it’s just all the locomotive builds, but this video makes me feel like heat treating is downright easy! Just in time for holiday crafts. Thanks, as always 😊
Thanks for reminder! I knew all of that in theory, but not having done any hardening or annealing for ages, a repeat course was definitely in place - just in case I after all need to do it.
Great refresher for me! I first learned this in '87 when I was in farrier's school where we learned to do it in a forge. We used it for hardening pritchels (punches) that are used for punching horse shoe nail holes.
I checked my kitchen oven for temp accuracy with a temp probe on my multimeter. Stove was brand new and needed to know accuracy of readout. The temperature variance after reaching setting was 75 degrees, kept fluctuating. Don't know how stable toaster ovens are but, I'd keep an eye on the color. I've never seen a blue biscuit but, the black ones are terrible !!
I learned to temper via the colour route. Over the years I made a metric but ton of hair clip springs. Starting with leaf spring annealing. Shaping hardening then tempering.
Just to add 2 cents from a blacksmith. The heat colors (being a very thin layer of rust) take different time to develop under different temperatures, so are not very reliable for judging temperature. Especially when tempering under direct fire from the torch, heat may not have enough time to travel through the steel and you may end up with soft surface and brittle core. A calibrated toaster oven is by far my preferred way for tempering, as there is no eyeballing needed. As always, thank you for top notch content!
Stainless drill rod has made my minilathe carriage do some very sketchy bounces and snags as such... Oh how I love stainless, so gummy and flexible. Bought some carbide bits just for that purpose of not watching stainless snag and snap hss/cobalt like its a piece of chalk.
Thank you for another great video Quinn! You are an amazing teacher, and I continue to learn interesting things from your videos. Thank you for making them.
Awesome video, Quinn! Really good info on hardening and tempering. As you said, this is one of those scary things you run into early on when working in machining, but your discussion of it here really helps demystify the process and make it very clear. Excellent video, thank you!
Cryo tempering is no joke. Have you tried it yet? Dry ice or liquid nitrogen tempering can extend the life of drill bits, I wonder what other materials can be cryo treated.
Usually it is only used on high nickel alloy steels which tend to be prone to retained austenite. The lower temperature forces the martensite transformation to progress to completion. It is almost always specified for 93XX series steels in the aerospace industry.
This reminds me of a student lab experiment to test the notch sensitivity of a steel, so we used a precise version of the vice and hammer, an Izod tester, the identical samples were heated to a range of temperatures, and a couple cooled in ice water and dry ice and acetone. The samples duly broke roughly to order, till we got to the dry ice. Oh, boy. There was a shattering crash and we didn’t find the specimen at all. It went into so many bits I expect the cleaner was finding shards for weeks!
I'm inspired to give it a go (you make it look so easy) I've got torches and fire-brick, what could possibly go wrong? I also have a *huge* piece of tool steel roundstock. It must be five feet long and three inches in diameter: it weighs a lot. I got it from an engineering workshop that was having a clear-out, but I never got around to doing anything with it. If I try water, oil and air quenching on three small pieces, I should be able to work out roughly what flavour of tool steel it is. I also love the colours of tempered steel. Something to do with d-orbitals, IIRC from A level chemistry. Thanks, Quinn, you're the highlight of my Saturday evening.
on a side note. once I was parting some 1" mystery steel with a tapered style hss cutoff blade. Instead of doing what yours did in the intro...mine decided to send itself into orbit...or more specifically, across the shop. somehow didn't snap though. No one and nothing was hurt but I hate parting now so here we are. and side side note i'm green red colorblind so tempering accurately requires oven tempering or a fancy IR meter
When using a Brinell hardness tester you use a similar scope to read the diameter of the ball impression. Easy enough to convert Brinell hardness to Rockwell C scale with a conversion chart.
Firstly, thank you for breaking this down. It is a very good explanation. The only comment I had for you, was if you could have mentioned or touched on (maybe another video? 😁) Is work hardening. Thanks for the vid as always!
01:00 OHHHH, SO THATS WHY! i been trying to improve the edge on shit cheap knives for years, it worked but never worked well like in other tools, the reason its cuz they were all low carb, lmao Thanks Blondie, love your vids
How do you anneal an air-hardening alloy?
Yes, interested parties want to know.
You have to bring it up to temperature then SLOWLY lower the temperature until the temperature is below a certain point. Usually this is done in a heat-treating oven with a program starting at say 1750F and lowering the temperature say 40F per hour to 1000F then can be taken out to cool to room temp. As always check your references for actual heat-treating info for the exact alloy and supplier you are using.
I use a media to slowly cool the material. I have a 5 gallon bucket of vermiculite for doing this. I also have a chunk of scrap heavy 2" plate that is heated to cherry red. Put the plate in the middle of the vermiculite first to help preheat the vermiculite. Then heat the metal I want to anneal to loss of magnetism and place it in the middle of the vermiculite next to the heavy plate. Then walk away until the next day after it has had time to slowly cool.
You have to cool it slower than just leaving it in air. Depending on the part this can be done by covering it in insulation after heating or maybe you can get away with putting it in the 500 degree toaster oven after heating. The bottom line is that you have to slow the cooling rate enough to allow enough time so the softer microstructures form rather than the super hard ones.
I’ll pin this thread since many are asking and you all covered the topic well. 😄
Old gunsmith technique is to clamp a piece of scrap angle iron extending out the side of you vice to form a cradle and place small parts on it and play the flame under the scrap angle, but not directly under the part. The heat will slowly creep under the part and you can observe its color without looking directly at the flame or through the flame. When it gets to the desired color nudge the part off the scrap angle into a waiting cup of water. It slows things down and gives you great control over the process.
So a similar technique to when silver soldering, where you also want to heat the more massive part(s) and let small parts and the solder seam heat indirectly from that. Clever, that.
Brilliant! I see the reply from @autochton, and a similar process can be used to solder PCB (computer) boards, especially when doing the super tiny surface mount stuff, by using a bit of aluminum plate. Comments like yours are why I love this chan, ToT and AvE. Best comments on the interwebs!
Quinn - great job of covering the basics in detail, without overcomplicating the subject.
This is one of her greatest skills, to explain without confusing. Not easy to do.
One of the finest qualities in a teacher.
Great video, this reminded me of a time in my life many decades ago. When I first got out of high school I got a job at the city works. One of the positions I had was part time equipment operator (jackhammer) and assistant to the blacksmith. The black smith shop was a dimly lit space with a century of dirt, soot and tools every where. The man working as the blacksmith was a welder really and not a blacksmith. He used to sharpen the jackhammer bits which he would heat in the forge and hammer out a new tip on them, then quench them in oil to harden them. He got the bits to a specific colour the quench them. One day he got the city to replace all the old dim lights with new much brighter florescent tube lights. Every bit he sharpened under those lights the tip shattered the very first time they were used. The bits were too hot when he quenched them, his colour perception had changed under the new lights.
Reminds me of the story told by gun nerds about - I had to look this up - the M1903 Springfield rifles. For the first many years of production, the machinists would judge heat treatment temperatures by eye ... and the difference of ambient light levels between a sunny day and a cloudy one could throw off their judgment of temperature by a quite significant amount.
Fortunately, the process Quinn is describing is significantly less fussy than that one.
Metallurgy has come along way.
@@Packbat
Quinn, great job on making heat treating approachable to your audience. I work in a "big boy" tool and die shop now but 15 years ago this video would have been mind blowing to me. Hopefully this will open doors for your followers. I find great information on Crucible and Carpenter tool steel's websites.
I'm currently a tool and die apprentice and and metallurgy is probably about a 1/4 of everything I'm being taught
9:12 - in old blacksmithing books that is how they would determine if a steel was tool steel. You would break it like that and take a look at the grain structure. Tool steel like that will have a very fine grain. Contrast that with cast iron, when you smash it, it looks like coarse sand
Or if you have a hardened thing stuck in a hole like a broken tap, you can often anneal it with the torch and drill the centre. The teeth will still be hard due to their engagement in the material, but you should be able to soften the core enough to drill it out
I’ve spent hours the last couple of days searching videos and forums on heat treating tool steel and your video shows up. You just saved me a pile of dough Quinn!
Thanks for all you do for the machining hobby community.
I was the QC manager for a 7-acre precision machining shop, and we did our own heat treating. Your primer is as good as it gets on YT. I can't tell you how many times I've muttered under my breath at youtubers "Swish it! Noooo, don't pull it out while it's still red hot!" They don't understand that the object is to keep it hot, dunk it fast, and cool it as quickly as possible. Good job!
Sounds like you have some free time. Why not make some videos to show people what to do? Be the change you want to see in the world man
6:47 - blacksmithing tip: a good way to know if you are hot enough is to use a magnet. When you get to the critical temperature the steel becomes nonmagnetic.
Also helpful for those of us who are colourblind.
All those shaded of red/orange look the same to me.
GREAT refresher for me . Thanks, Quinn
That is the best use for canola oil ever!
I was about to make the same suggestion with regards to the magnet. In my old shop I had a magnet I had found with a hole in it (I think it was salvaged from an old hard drive), and just some fence wire. I was able to nail the critical temperature every time without worrying about the ambient light. For annealing, I like to use wood or paper ash that was fluffed up, and my portable charcoal forge's (made from a wash tub and a small hand crank blower) insulation is simply made from whetted and packed ash from the charcoal.
Probably one of the best heat treating vids around. No hype, just pure technique. Nice one Quinn.
Thank you for another no-nonsense tutorial on how to implement processes and techniques without relying on expensive equipment. The focus on "home gamer" ways of making do elevates your videos' usefulness and appeal significantly.
Few things are as gratifying as a torch heat treatment that goes successfully. 1 part knowledge. 1 park artistry. 2 parts magic. I always love using home made tools that I machined and heat treated. You did a great cover on what is need to get started and be successful. Anyone wanting to take the plunge has more than enough knowledge with this to get going.
Things are about to get real heated!
The temperature is really rising here in the comment section!
Well, it is a hot topic
Treat yourself to this hot info
Quinn, thanks for this video! Absolutely clearest concise explanation of basic steel heat-treating I’ve ever seen! I trained and earned a degree to teach high school industrial arts in the 70’s. Have seen various how-to’s and much more technical explanations of heat-treating, but yours is the best! I tried doing classroom demos of a large part of what you did but I’m sure when I turned the lights back on, many of my students were still in the dark.
Again, thank you!
14:38 - you can also directionally quench as well. I recall reading in a blacksmithing book how for a hammer you want the center of the face to be glass hard, but you want softer edges of the face so it doesn't chip. To do this you take a can and poke a hole in it. When you go to quench you use this can with the hole in it to direct a stream of water to the center of the face. Since that takes the most cooling it gets the hardest while the edges of the face don't and stay softer
Ring tempering is a better way to do a hammer.
Not only do I learn a lot from your videos I also love your sense of humor . Thank you for taking the time to share.
Her sense of humor is well tempered.
Hi Quinn, what many people don't know is the (matensite) carbon growth is forming for a few minutes after quench, this means you have a short window to do a little straitening. many knife makers take advantage of this window. also after the material is drawn back to say 59RC my happy number you can subzero quench (dry ice or liquid nitrogen) it will typically gain 3 - 5 points of Rockwell C finishing the rest of carbon structure to complete it's growth and with many benefits
Wonderful presentation! For anyone interested in doing this for sheet metal, say for armor for Western martial arts or sport fighting, we had tremendous success with SAE 1050 steel, a water hardening kind that we drew (tempered) to around purple/blue (call it 600-650 F). Be sure to experiment, toughness is far more important than hardness in this application, but any hardening reduces damage from use considerably. SAE 1045 is also quite useful (containing 45 points of carbon instead of 50), but 1015 will not harden and 1065 is probably going to harden too much. Just more in the rather infinite amount of information on heat treatment. No matter what you're doing, have fun, and wear your PPE.
Having spent a little while as a teaching assistant for a college class on heat transfer, that point you make about the inertia of heat is *so* important. Spending time in a lab with temperature probes, I was amazed at how long it would take to get to a steady temperature.
This kind of fantastic, educational video is one of the main reasons I live your channel. Always so clear and concise, and often with demonstrations!
Years ago I took an evening blacksmithing class and "learned" to do this in a coal forge. I say "learned" as I never succeeded. I am not color blind, but I was never able to see the changes that I needed to see. I guess if I want to try this I will have to get my wife to come watch and tell me when it is time to quench! I still have (and use) a cold chisel that I made in the class, but the tempering was don with the instructor shouting now, now as I obliviously pumped the forge.
Great tips for the home shop. Making custom steel tool bits with a grinder, then hardening them and honing them, as Quinn has pointed out, is a good way of increasing your capability without breaking the bank.
I learned how to do this in my junior high metal shop back in 1969. I I'm now 68 and have used it my entire life!
thanks Quin, you made the process look as simple as it really is..
Super accessible breakdown of the process, I really like that you showed lower cost/lower stress methods of testing and heating. Awesome content as always.
Oh man. I *love* heat treating. It's so easy and satisfying! I needed to make specialized forming punches to re-create the fancy washers used on old straight razors and I managed to do the heat treat just right on O1 drill rod with no difficulty on the first try. And the second! Even the third!
I did use the convection toaster oven for tempering though, and just looked up the temperature to set the oven to for the hardness I wanted. But it was all dead simple and worked great.
Watching this video has made me want to go downstairs and make some parts to treat!
If parting off is a nightmare, as it is on my little lathe, try a sprung Armstrong type tool. Winky did a nice video on this type of tool so I made one and it works very well.
In essence, the tool moves away from the workpiece rather than digging in, it chatters at the first cut until it finds it's medium and then cuts cleanly.
Or use a rear toolpost with the parting blade mounted upside down, if you have space on your cross slide.
The parting tool shenanigans reminds me of an excellent project for the small lathe shop, Winky's Workshop has drawings for a flexible or compliant parting blade holder. it's still very rigid, but has just enough give so that if the parting blade catches, it can deflect enough to get itself out rather than transmit the force all the way into your compound. If you're having problems with parting chatter or parting in general, a flexible parting blade on a solid tool post mount can buy a lot of ease for a small lathe.
As many others have said another very well done breakdown of this process! Awesome content as always Quinn! Thanks again!
Excellent camera work through the scope.
Thank you for appreciating that. It was very difficult but the topic required it 😄
Love the content! please keep showing us the missteps, it helps keep me humble, and thus safe.
Well done. Love how this is broken down from a professional hobbyist perspective
That was one of the BEST education on tempering....sincerely thank you
Very good instructions as usual.
I love watching the colors travel. I have made a few tools and a couple of blades and so far, no exploding knives. That's a good thing.
Thanks, and Meow to Sprocket.
An important note when heat treating by eye: The room lighting must be consistent.
During early production of the American M1903 rifle the heat treating furnaces didn't have pyrometers. The process was controlled by eye. The area was lit by natural sunlight. On a cloudy day the light would be different. There were multiple receiver failures.
For the most part true. The improved process on heat treat did allow the O3 to be even stronger. The lots you speak of failed when case pressures got to around 70K PSI, the improved process moved that to more like 100K.
But the bigger problem was the ammunition of the period, there were a couple of bad lots and from what P. O. Ackley and others found, the failures all involved that ammo.
Great video Quinn. Brings back what I learnt at school 50+ years ago but had all but forgotten. Still have a screwdriver I made which the teacher wanted me to make from mild steel and case harden but I remember insisting on using tool steel.
When teaching students, Use a nail. Heat it red hot, dunk in water, still soft since there is no carbon in it.
I made a chisel of tool steel many years ago, and later, while working in industry, I tried making one with a 3/8" alloy steel hex socket wrench. I hardened & tempered it, but It wasn't hard enough. I went back, hardened it again, but did not temper the chisel end at all. I kept it for years. The best chisel I had to my name.
Old toolmaker here. Everything was spot on.
Quinn, I admit i had conscious bias years ago when your videos always popped up. Your videos are so excellent, informative, and on point with what I'm usually doing. THANK YOU!
Thank you for the great video. I need to harden an R8 arbor that I recently turned and this took the mystery our of it. I really appreciate that you make these videos understandable and worthwhile to folks of all levels of interest and experience.
Not sure if this helps but I really liked the techniques Clickspring used in his file hardening video. Definitely worth a watch.
Excellent, thank you.
Just found that I have access to an induction heater, and I'm going to try hardening and tempering 1.25" round tubing to make some tractor bucket bushings. I'm sure the same principles will apply. Very helpful.
Excellent video. The statement regarding correcting your mistakes by going in a circle with hardness, tempering is good for an amateur like myself to know. I did not know that hardness mistakes could be corrected. I always figured it was a hit or miss operation without expensive ovens and knowledge about quenching. I also did not know that MAPP gas is no longer produced! That one really surprised me. Thanks.
The factory that made Mapp blew up. I have a couple of really old bottles that are legitimate Mapp that I only use for special occasions. 😂
you are the absolute best at machining for dummies or self taught machinists... always straight forward with the proper visuals the whole way thank you!
Last week I thought I’d be smart and not bother tempering a 5/16 HEX T handle I made. To my surprise when went to use it, it shattered! Great video.
Legitimately the best guide I've come across. I've been googling for ages on how to do this, and most guides simply devolve into the author wanting to show off how smart and how much they know about heat treatment (phase diagrams!), and what "toys" they have - all that "complexity people like to add" as you said. Thank you.
Really excellent video that clears up a lot of the myths and mysteries in this area. Thank you so much for all of the excellent content!
Nice tutorial. This is the kind of thing that helps new people take that leap and try new things.
I've got some heat treating to do Real Soon, but I'll be using a coal forge, not as controllable as a torch. And thanks to the wonderful circular Annealed-Hardened-Tempered cycle I can always try again if I make a mistake.
This has got to be the best explanation of the process. Blimey, I remember doing this in school and really did not get it at the time, I actually don't think the teacher really got it either.
I mostly do my tempering in oil, in an electric wok. I usually allow 1hr per 1" of thickness.
For those who want to go a little deeper into the subject without getting into textbook-level detail, Book 1 in the Workshop Practice Series is a good source.
Thanks!
thanks! For part 2 please discuss warping as a side effect and how to minimize it.
Biggest thing to remember to avoid warping as much as possible on a long tool is to make the quenching as even as possible. On a long piece do not enter quench with the part held vertical. Have the length enter horizontal so both ends and the middle enter at the same time. Then once in the quench keep the prat moving. If you hold it static air bubbles can form on the part from the heat. These bubbles will slow the quench and cause incomplete hardening.
i have been always told not to quench in the tempering, however your explanation for this makes more sense to me
This is the best hobby-level / practical heat treating video I've seen. I've got some O1 steel I bought online and the instructions that came with it are industrial-level (incomprehensible and impractical for the hobbyist). Just watching this video has given me the understanding and confidence to do it too.
Just great content. I was amazed at how you did explained this. thank you so much Quinn,
1:43 jackhammer bits are S7 and in blacksmithing we often use them for tools like a hot cutter or a drift
This is gold! Saved! Will be watching this several times.
EXCELLENT tutorial as always. Maybe it’s just all the locomotive builds, but this video makes me feel like heat treating is downright easy! Just in time for holiday crafts. Thanks, as always 😊
Excellent job explaining! Thanks 🙏
That is probably the best description on how to harden and temper steel.
The best and clearest explanation on TH-cam. Thank you Quinn. 👏👏👍😀
The "change my shorts" comment caught me off guard. I was laughing like a ninny. Thanks Quinn 😂
I've always appreciated your 'temperament' in your presentation.
Thanks for reminder! I knew all of that in theory, but not having done any hardening or annealing for ages, a repeat course was definitely in place - just in case I after all need to do it.
Great refresher for me! I first learned this in '87 when I was in farrier's school where we learned to do it in a forge. We used it for hardening pritchels (punches) that are used for punching horse shoe nail holes.
Aestheticaly the straw and deep blue are amazing colors.
Quinn - you’re a fantastic teacher. Thanks for demystifying this.
Such a great video, awesome work ! 👍🏼👌🏻
I checked my kitchen oven for temp accuracy with a temp probe on my multimeter. Stove was brand new and needed to know accuracy of readout. The temperature variance after reaching setting was 75 degrees, kept fluctuating. Don't know how stable toaster ovens are but, I'd keep an eye on the color. I've never seen a blue biscuit but, the black ones are terrible !!
I learned to temper via the colour route. Over the years I made a metric but ton of hair clip springs. Starting with leaf spring annealing. Shaping hardening then tempering.
Thanks for the information. Funny enough I just bought some O1 tool steel and was wondering how to harden and anneal. Well done.
This has to be the quickest and best video on this subject i have ever seen. Great work ❤
A really good teaching video.
Thank you.
This is the exact same thing I was taught in the 70’s in school metalwork class.
Just to add 2 cents from a blacksmith. The heat colors (being a very thin layer of rust) take different time to develop under different temperatures, so are not very reliable for judging temperature. Especially when tempering under direct fire from the torch, heat may not have enough time to travel through the steel and you may end up with soft surface and brittle core. A calibrated toaster oven is by far my preferred way for tempering, as there is no eyeballing needed.
As always, thank you for top notch content!
Went to school for jewelry, this is a great video. Easy and correct information. Thank you. Also really like you harness tester.
Stainless drill rod has made my minilathe carriage do some very sketchy bounces and snags as such... Oh how I love stainless, so gummy and flexible. Bought some carbide bits just for that purpose of not watching stainless snag and snap hss/cobalt like its a piece of chalk.
In the states if you need a metal sampled Fastenal can do so relatively cheaply.
Thank you for another great video Quinn! You are an amazing teacher, and I continue to learn interesting things from your videos. Thank you for making them.
Awesome video, Quinn! Really good info on hardening and tempering. As you said, this is one of those scary things you run into early on when working in machining, but your discussion of it here really helps demystify the process and make it very clear. Excellent video, thank you!
Thank you sooooo much for clarifying this technique and making it clear: I've always thought that it would be beyond me.
Hey Quinn , thank you for taking some of the mystery out of the heat treating prosses.
Excellent! Excellent! Excellent!
Thanks so much for a simplified and very informative demonstration of this process Quinn. Love this.
Cryo tempering is no joke. Have you tried it yet? Dry ice or liquid nitrogen tempering can extend the life of drill bits, I wonder what other materials can be cryo treated.
Usually it is only used on high nickel alloy steels which tend to be prone to retained austenite. The lower temperature forces the martensite transformation to progress to completion. It is almost always specified for 93XX series steels in the aerospace industry.
Wow! What an incredibly useful video! Thank you so much, Quinn! Cheers from Outback Australia, Rolf
This reminds me of a student lab experiment to test the notch sensitivity of a steel, so we used a precise version of the vice and hammer, an Izod tester, the identical samples were heated to a range of temperatures, and a couple cooled in ice water and dry ice and acetone. The samples duly broke roughly to order, till we got to the dry ice. Oh, boy. There was a shattering crash and we didn’t find the specimen at all. It went into so many bits I expect the cleaner was finding shards for weeks!
I'm inspired to give it a go (you make it look so easy) I've got torches and fire-brick, what could possibly go wrong? I also have a *huge* piece of tool steel roundstock. It must be five feet long and three inches in diameter: it weighs a lot. I got it from an engineering workshop that was having a clear-out, but I never got around to doing anything with it. If I try water, oil and air quenching on three small pieces, I should be able to work out roughly what flavour of tool steel it is.
I also love the colours of tempered steel. Something to do with d-orbitals, IIRC from A level chemistry. Thanks, Quinn, you're the highlight of my Saturday evening.
Excellent introduction to metallurgy.
Great discussion / demonstration
on a side note. once I was parting some 1" mystery steel with a tapered style hss cutoff blade. Instead of doing what yours did in the intro...mine decided to send itself into orbit...or more specifically, across the shop. somehow didn't snap though. No one and nothing was hurt but I hate parting now so here we are.
and side side note i'm green red colorblind so tempering accurately requires oven tempering or a fancy IR meter
Thanks for this great video. It contained everything I always wanted to know about hardening, enhanced with your nice sense of humor.
When using a Brinell hardness tester you use a similar scope to read the diameter of the ball impression.
Easy enough to convert Brinell hardness to Rockwell C scale with a conversion chart.
foreshadowing more learning... again
thank you
Firstly, thank you for breaking this down. It is a very good explanation. The only comment I had for you, was if you could have mentioned or touched on (maybe another video? 😁) Is work hardening. Thanks for the vid as always!
Ha, I usually have to change my shorts every other time I’m in the shop.
Thanks for the demonstration on heat treatment
Hi. I use the body of an 100W soldering iron to temper small tools.
best video about this i have seen, thankyou so much for putting it clearly
01:00 OHHHH, SO THATS WHY! i been trying to improve the edge on shit cheap knives for years, it worked but never worked well like in other tools, the reason its cuz they were all low carb, lmao
Thanks Blondie, love your vids