Normalize steel by using descending temperatures. Once the strength of the steel is exceeded the knife will keep bending with approximately the same level of force. Either the edge needs to be thicker for the task or the steel needs to be harder (stronger) to resist the deformation. [1] X Research source Larger flames produce less heat while smaller flames produce a higher heat. A wire edge, also called a burr, is the result of sharpening a knife. Lower temperatures typically mean a smaller grain size. If you can’t prevent the creation of a wire edge by systematically counting strokes or passes and keeping your grind angle consistent, then you need to sharpen with a plan to address the wire edge after it comes into existence. Either the edge needs to be thicker for the task or the steel needs to be harder (stronger) to resist the deformation. Wire edges can be frustrating, especially for folks new to sharpening their own knives. For one, it isn’t very precise. How much does hardness affect the difficulty in flexing? Using a Coffee Mug for Quick Results Place an old coffee mug upside down so that the bottom of … If the edge deforms that means the strength of the steel was exceeded. Another excellent, informative article. It isn’t a light switch that either affects a steel or doesn’t. No but they do heat treat it harder than the typical 55 Rc, so it performs a lot better than a lot of other 420HC. Higher alloy steels also have the benefit of easier quenching, either air cooling or plate quenching rather than rapid oil or water quenches. Because you've bought a knife with a very hard, stainless steel blade. Sharpening your knife with the likes of a whetstone uses friction to remove some of the steel and create a new, sharper edge. The 4 steps you NEED to know. However, there is a whole industry of cryo companies advertising incredible improvements in wear resistance from cryogenic processing. 8. I see frequently from knifemakers statement like, “I chose AEB-L because it doesn’t need cryo.” Or “Carbon steels don’t need cryo.” Or “Stainless steels need cryo.” This shows a fundamental misunderstanding of what cryo does or doesn’t do. To achieve this, the edge is cooled faster than the spine by adding a heat insulator to the spine before quenching. Imagine a sharpened knife edge zoomed way in. See the chart below for carbon and chromium “in solution” during holding of 52100 at 1545°F: You can see that the change in C/Cr in solution is very rapid within the first few minutes, and trying to target a specific hardness would be challenging if you are trying to hold for very short times, especially under 5 minutes. Notify me of follow-up comments by email. For example, low alloy steels tend to drop off rapidly in toughness if they are hardened from too high a temperature, see 5160 for an example below which has a significant drop in toughness when using 1550°F. Most of good heat treating is about avoiding many of the potential issues or mistakes and not about finding the great secret. If you go even lower you can perform a subcritical anneal from temperatures like 1250-1300°F. Wicked Edge/Edge Pro style systems are much more finicky, since they have so many more adjustments and parts. and if your knives don’t have such a heat treatment they are never going to be as good. When chopping, the steel is much more likely to act in a brittle matter and chip even when the steel is on the softer side, in that case the behavior is controlled by steel toughness rather than strength. ), it is hard to say how much hardness is lost. Ok, all the hard work has been done. So lower hardness means the knife is “bendier” but not more flexible. Instead of dropping the heated knife into the quenching medium tip first, submerging the entire knife, the edge quench involves submerging one third to one half of the blade's width (cutting edge first) into the quenching medium. But one mistake people make is thinking that if a little of something is good then more of it must be better and started adding in intermediate steps. The Knife Edge Ridge. As described previously, martensite finish temperatures change for different steels and hardening temperatures, and the closer you get to martensite finish the lower the retained austenite. - Act. Tempering at higher temperatures results in a softer blade that will be more durable and less likely to snap off, but will not hold an edge as well. No where in that book is any information on the traditional knife edge. Keep at it, as practice makes perfect. Simple steels are easier to heat treat. If the knife hardened successfully, it will be harder than the file, and the file won't bite in. The ASM Heat Treater’s Guide recommends 1525°F for 5160, meaning overheating by only 25°F can lead to a significant drop in properties! Of course, focusing on any one of these factors at the expense of the others: steel selection, heat treatment, and edge geometry, is a mistake and each should be optimized for the given knife. A honing rod, on … You can read more about Curie in this article. It also doesn’t help much in tempering to see what the final hardness is, as the final hardness is likely lower than the file. My question is, is that quench really necessary or is it nonsense? This one started out along the lines of “even the best steel will perform poorly if given a bad heat treatment,” and that I can’t disagree with too much. So a descending temperature set of cycles that does make some sense could be 1600, 1450, 1250°F. For understanding those aspects better I recommend clicking on a few of the links in this article to better understand topics like annealing (Part 1 and Part 2), austenitizing (Part 1, Part 2, and Part 3), quenching, and tempering. Home Forums > Knife Specific Discussion > Maintenance, Tinkering & Embellishment > hard steel how to sharpen impossible knives Discussion in ' Maintenance, Tinkering & Embellishment ' started by simpleguy , Aug 4, 2009 . The formation of martensite is measured with a “start” and “finish” temperature and the closer to the finish temperature you reach the more martensite forms and the closer to the maximum hardness you will achieve. Japanese knives are often made from high-quality but harder … The end of winter is a good excuse to do some gear maintenance. Simply hold the knife with the edge straight up under a bright light (preferably sunlight) and rock the blade side to side and up and down looking for any reflection. If quenching is done in a bath, quench the thick sections first, the cylindrical pieces straight up, and the flat pieces on edge. The correct time to temper steel for a knife is after the blade has been formed and shaped but before the final assembly and polishing. Work your way through grits bringing it to the desired finish. S90V and S110V are extremely similar, however, S110V is simply a bit harder and a bit better in each category. 10. Enter your email address to subscribe to this blog and receive notifications of new posts by email. Your email address will not be published. When the martensite finish temperature is below room temperature there will be some amount of “retained austenite” which isn’t transformed to martensite leading to lower hardness and other effects. Some knifemakers are afraid of holding too long at austenitizing temperature because of concerns about grain growth. A quench is necessary with very high carbon (>1.1% or so) low alloy steels. How the hardness changes things is how far the knife can be flexed before it won’t come back straight. Cryo improves toughness. 2. But even in those situations the recommended heat treatment would work fine. Virtually any knife steel can be heat treated with or without cryo, depending on the hardening temperature that is selected. Somewhat of an extension of the above myth is the legend of the knifemaker who has a super ultra heat treatment that leads to double the toughness, triple the edge retention, etc. An unlabeled file might be around 62 Rc or so and therefore if the knife is higher than 62 Rc (which most low alloy high carbon steels should be after quenching before tempering), then the file will “skate” the knife rather than bite into it or leave scratches. Another study on 154CM had a more extensive comparison where also no difference was found. In it, he explains how he uses the edge of a piece of tempered glass (like that found in a car window) to knock down a wire edge as the final step in sharpening. Files can be purchased which are rated at certain hardness levels though often a generic file is used. So here are some photos of how to make the knife edge - not difficult, but very neat looking - and- no extra fabric is needed. Open the gas valve near the base of the torch. 4. More info below⬇️Beginner knife making steel video. Sometimes edge deformation/rolling is misinterpreted as chipping and the knife user incorrectly believes that the steel has insufficient toughness when in actuality insufficient hardness is the issue. Put two things in the fire. We asked five pros how they made it work and what it takes to make a living in the outdoor industry "in real life.". A regulator block is used to hold the blade at the correct depth. Enter before February 8th for your chance to win. So steels like 26C3, White #1, Blue Super, etc. From next-gen tech to ingenious innovation, our weekly peek at emerging products examines the sometimes cutting-edge, sometimes quirky world of gear design. This practice may have started with a kernel of truth to it, as a normalize is performed from high temperature, and grain refinement from lower temperatures. A lot of shared myths come from a misunderstanding of how the steel is transforming during different processes and what the goals are of each step. Here, we discuss the wire edge, or burr, created while knife sharpening and how to address it. Myths about End Properties after Heat Treating. However, higher hardness levels can be achieved when using cold treatments, see the chart for AEB-L below, where the minimum temperature is labeled as “LN2” (cryo), “freezer” (a household freezer), or “room temperature” (no cold treatment): You can see that the hardness peaks around 62 Rc with no cold treatment, using a hardening temperature of 1925°F. Therefore, using a longer hold time can lead to more consistent hardness both within a single knife and between different knives. A freezer doesn’t do anything; at least dry ice temperatures are necessary for cold treatments. No heat treatment is capable of making high carbide CPM 15V into a high toughness steel. I have a feeling that this article isn’t going to make much of a dent in the sharing of myths but I’m doing my best. Here is a chart of retained austenite contents and hardness values achieved with and without cryo with low alloy steels: Now just because the retained austenite can be reduced with cryo doesn’t mean that you have to do so. In general, heat treatments are recommended in datasheets that will apply to the most situations, as the steel may be sold in a range of thicknesses, and used in many different applications. Using cryo or other cold treatments means you get closer to martensite finish and retained austenite is reduced. Thanks to Lee Rothleutner and J Hamm for becoming Knife Steel Nerds Patreon supporters! You would need to grind all color left from heating out of the finished knife to be sure that the knife will retain its edge as long as possible. These recommendations vary a lot depending on who is giving them but the descending method seems pretty common. I also performed an edge retention comparison between cryo and non-cryo D2 steel and found no difference apart from hardness, see that here. Whichever side snags your nail is the one with the wire edge. I reviewed the literature here. The first quarter-mile of the Knife Edge trail leads to Mount Katahdin’s south peak. It is relatively common to see forging bladesmiths recommend descending temperature normalizing or grain refining cycles, such as 1600°F, then 1550°F, then 1500°F, etc. I’m sure I am guilty of believing a few. Here, we discuss the wire edge, or burr, created while knife sharpening and how to address it. I wrote about what is possible in heat treating and what isn’t in this article. No heat treatment can turn 1095 carbon steel into a stainless. If lower hardness is desired or if grain growth is discovered at a given hardening temperature, simply reduce the temperature and maintain a sufficient soak time. In general, the difference between any “good” and “super” heat treatment is going to be relatively small. Light a propane blow torch to use as a heat source. High alloy steels, on the other hand, can usually be austenitized over a rather wide range of temperatures because the carbides dissolve over a wider temperature range, this means that hardness changes more slowly with temperature changes, and the higher carbide content also means that grain growth is slower. There are other dangers to using short hold times, such as the heat treatment being much more sensitive to small changes at short times. However, it has become somewhat fashionable to talk about knife performance as entirely (or almost entirely) controlled by the knifemaker’s skill in heat treatment. This has been applied to some extent to several popular knifemakers though perhaps the best example is the late Frank J. Richtig who I wrote about here. Austenite forms at high temperature prior to quenching. Some steel-heat treatment combinations can even be relatively soft (rolling when performing flexing cuts in hard materials) but still have relatively poor toughness leading to chipping when chopping. – instead of standard 2h+2h double tempering , using 3h+1h double tempering instead may give better toughness due to lower content of “fresh martensite” which formed from untransformed retained austenite during cooling from first tempering . Read more about toughness and chipping in this article. In tempering, the steel is heated to a much lower temperature, and it softens and becomes more ductile (pliable). Sharing in-depth conversations between the world's adventurers, athletes, and outdoorspeople, The GearJunkie Podcast is your inside look into the outdoors industry. In this case half of the retained austenite that transforms with liquid nitrogen can be eliminated with a freezer, but only if there is no delay at room temperature. Point 10. I found this with my own experiments of AEB-L as in the previous plot. There are a lot of heat treating myths out there and I haven’t covered all of them. Tony Sculimbrene is a lawyer and gear-obsessed dad of two who believes a day spent outside is always a good day. Knife sharpening is a fundamental piece of gear maintenance that even translates to the kitchen. Safer - a recreated tip is much safer than a broken-off tip. The torch should ignite after a few tries. And as mentioned in the previous myth, superior edge geometry is often what makes a legendary knifemaker have high performance knives, but the super heat treatment is a better story. Heat treatments are designed for industry and don’t apply to knives. Those high alloy steels don’t “need” cryo either. Low alloy steels are easier to harden without a soak at the hardening temperature, which facilitates hardening in a forge without temperature control. 6. 9. Cryo companies also advertise that cryo improves toughness, despite the fact that the majority of studies have found a reduction in toughness with cryo. Grain refinement can then be performed at lower temperatures, just above austenite formation such as in the range of 1375-1450°F. 1. © Copyright 2021 GearJunkie, All Rights Reserved, CAKE, Goal Zero Develop Stealth 'Bush Bikes' to Combat Poaching, Backcountry Snowboarding 101: Expert Tips, Gear to Stay Safe & Have Fun, Cody Townsend Tries Bikepacking in Pandemic Pursuit of Ski Lines, The North Face x Gucci Fashion Saga Continues ... on Pokémon Go, 2-Winter Test: Hillsound Equipment FlexSteps Review, In 2021, Volkl’s M6 Mantra Will Be the Most Fun Ski on the Mountain, 'The Big Chill': Ultrarunning Across Chilliwack, British Columbia, in Under 2 Days, Bikes, Guitars, Carpentry, Motorcycles: Cyclist Colin Strickland Is a Jack of All Trades, Christmas to New Year's Bike Ride: Tackle the 'Festive 500' With Rapha, 'Boardslide Worldwide' Snowboard Edit Offers Up Pow by the Mouthful, Today's Bargains: 4 End-of-the-Year Deals. But if we were to pick one factor that is the “most important” I’m not sure that heat treatment would be the one. The main benefits of knife repair are: Cheaper - a fully usable knife for a fraction of the cost of a new knife. Once the blade has reached its maximum hardness, it's … On both sides of the Knife Edge trail lies treacherous slopes of rocky debris. 12. The quenching medium I used was old motor oil. Those formation temperatures are controlled by the steel composition and also the heat treatment, as higher hardening temperatures put more carbon and alloy “in solution” to affect the martensite formation. Become a patron and gain access to awesome rewards including early access to articles or a Knife Steel Nerds mug! https://www.patreon.com/Knifesteelnerds, Click to share on Twitter (Opens in new window), Click to share on Facebook (Opens in new window). Is the grain refinement step around aus temp not usually associated with a quench to set up martensite that is faster to dissolve again so less time is used for the actual sub critical anneal step? How difficult it is to flex a knife is controlled primarily by the geometry of the knife, in particular the thickness of the steel. Another way is to slow cool after the final austenitize to anneal instead. Using liquid ntirogen with the same hardening temperature gets about 63.5 Rc as-quenched. When the edge deforms (instead of chipping) that means the steel is tougher than one that chips. Below is an example from our 52100 heat treatment study that shows the drop in toughness and improvement in hardness with cryo: 7. However, they are no easier to achieve good properties than high alloy steels. This technique is very dangerous for novices, but glass is exceptionally hard and will definitely kill the wire edge. I started out with 100 grit and then went in 100 grit increments all the way to 600. [2] Lement, Bernard S. Distortion in tool steels. It would take a good edge, but it would shatter. And with the social distancing required because of COVID-19, now’s a perfect time to really learn how to sharpen a knife. Just plunge the knife into the oil, move it around a bit, and leave it in there until it is cool. Below shows martensite content for T1 high speed steel at different temperatures: One other factor to keep in mind, however, is that retained austenite “stabilizes” if there is a delay between the quench and going into the cold treatment. Excellent… one question. Tempering – Increases toughness With typical cutting, there is often some combination needed of hardness (strength to resist rolling) and ductility/toughness (resistance to fracture). It’s incredibly hard for a manufacturer to get it right and even harder to prime up the edge, but once done correctly, this knife is staying exactly as it is for a ton of time and loads of abuse. 3. Here’s a very pronounced wire edge (I worked the edge specifically to emphasize the wire edge for photo purposes): You will undoubtedly feel a wire edge or burr when you drag your nail toward and off the edge of the knife. This puts all of the carbide and pearlite in solution, and achieves a consistent grain size prior to air cooling. It doesn’t. I have always steeled higher than that of the honed edge thus creating a micro bevel making the knife both sharp and strong enough to withstand a hard days graft. However, the heat treatment can only do so much. Clay or another material is used for insulation. Basically normalize at ~100-150°C above the steels austenitizing temp to dissolve all cementite, then quench it to prevent gb cementite from forming during cooldown. Sometimes datasheets will provide different temperatures or hold times depending on the thickness of the piece, but that is more of an economical feature (don’t waste any more time than necessary) than one that is required for performance. 13. More fun - a smooth edge without bends or chips, which is … You don’t have to buy a Rockwell hardness tester which can be expensive. This article provides some insights and workarounds for one of the most vexing problems you will encounter when sharpening a knife — wire edges. So if the metallurgists were designing heat treatments for one specific application they would be dealing with many customer complaints. Hold a striker over the end of the torch and squeeze it to create a spark. Once your knife is properly hardened, you should be able to run a worn file down the edge and have it skate over the surface. Recommended heat treatments often provide longer hold times at lower temperatures where significant grain growth would take a very long time. Well that isn’t entirely accurate, hardened steel actually is about 2-3% less stiff than annealed steel. When it comes to maintaining a sharp edge, it all starts with the blade you've bought. Start by putting the knife in a vise. I hear some knifemakers say that you should ignore information in steel datasheets or the ASM Heat Treater’s Guide because those recommendations are for “blocks of steel several inches thick” or just generally referring to the “industry” boogeyman that means the heat treatment doesn’t have anything to do with knives. A knife that is easier to take a “set” is not more flexible as much as it is just soft. Using a file to check hardness is popular because it is cheap. Not sure I am making sense. If you for example hone your knife at 21 degrees and steel at exactly that same angle in my experience the knife will dull very quickly immaterial of how well you polished the edge to. Ray Mears, noted survivalist and knife-sharpening master, has an excellent video on sharpening knives in the field, below. Backyard bladesmith discovered a new super heat treatment that can’t be matched. Some knife users or makers report happily that their knife edge rolled in use as evidence of its good toughness, but it is mostly evidence that the steel wasn’t hard enough and/or the edge geometry wasn’t robust enough. Put your knife and a poker or some long piece of steel. American Society for Metals, 1959. Finishing the Knife. That is one way of doing it, yes. When using a furnace with a PID and controlled temperatures, high alloy steels are usually “easier” to heat treat. This is without covering common mistakes with using files such as checking the knife without removing scale or any decarburized layer first. It’s a skill that will be useful for the rest of your life, whether you’re touching up a paring knife in the kitchen or a massive chopper for outdoor work. So the file ends up being a check for a heat treatment that completely failed (did not harden), but is not particularly useful for dialing in heat treatments or for checking consistency. This is why those very thin fillet knives are so good at flexing 90°. – second modification : instead of double or triple tempering why not just tempering steel at secondary hardening range for 4 hours for example then following it by tempering at low temperatures “200-400°F” to stabilize retained austenite & temper any fresh martensite ? A second heating process known as "tempering" is required. However, the intermediate temperatures like 1500°F don’t do a particularly great job of accomplishing either of these goals. Clamp the knife down and polish it with emory paper. From here, the trail slowly descends as the ridge bends around the basin. A file is a good way to check hardness. Now this doesn’t mean that every datasheet is perfect; the heat treatment may be produced for the “lowest common denominator” that could be further optimized for knives. “Towards efficient microstructural design and hardness prediction of bearing steels—An integrated experimental and numerical study.” Materials & Design 133 (2017): 464-475. Required fields are marked *. Then take a sharp file for metal working and sharpen an edge on it not to thin of an edge and not to thick of an edge. This long piece of steel is so you can bring up the temperature of your quenching oil. The problem with the edge is that, while it’s exceptionally sharp, it’s also exceptionally weak, folding or flopping over from one side to the other with almost no pressure. Turn the gas valve to adjust the flame to a small cone shape. The Mount Katahdin Knife Edge trail begins right near the summit cairn. I can only respond with what works for me. It lets you know that the knife is harder than the file but you don’t know how much harder. Flooding the knife with coolant during grinding is the life of a knife steel. Quench the titanium part in a suitable quenching media: a water bath or air for alpha-beta and beta titanium alloys, and an oil bath for alpha alloys. You can see a wire edge with your naked eye, but if you don’t know what to look for, that’s not helpful. The other, easier approach is to use strops. The way the knife is being used also matters. Heat Treating is the most important factor for high performance knives. Less waste - a recycled knife rather than a knife in a landfill. I explained the mechanisms behind cryo in this article. You have the two sides of the blade coming together at a point, and riding along that point for the entire length of the blade is a small, toothy section of very thin steel raised up from the main edge. Lower hardness means the knife is more flexible. Low Alloy and Low Technology Heat Treating Myths. I reviewed the literature in this article. So BOS heat treating doesn’t give my Buck 420HC the wear resistance of M390? The result is that the knife feels sharp but doesn’t cut like a sharp knife. There are two primary ways that a steel can become nonmagnetic: 1) transforming to the “austenite” phase, or 2) by reaching the Curie point. Metallurgy and Testing of Knives and Steel. “Simple” carbon steels also have retained austenite and are affected by cold treatments. NordicTrack wants to give you $7,500 toward your dream adventure. This has some truth to it as knifemakers who use a subpar heat treatment will certainly have subpar performance. Whether you’re riding solo or bringing along the whole crew, these are the best hitch bike racks to haul your bike to the trailhead. If anything, low alloy steels are very sensitive to heat treatment in terms of achieving optimal properties. Use a knife like you ought to use a knife—that is, often and hard, and sharpened frequently—and you’ll need to reprofile the edge as you hone away more and more steel. Also, the center of the blade’s thickness will naturally reach the temperature later than the surface, meaning that the soak time is shorter at the center. Knife Making - How To Heat Treat A Knife | Super Simple DIY heat treating. That raised, toothy section is a wire edge. The quilts just don't look right to my eye - the binding immediately marks them out as not British. torch and grind to .020" thick at the edge. A few strokes on a strop (counting strokes and alternating sides) with different compounds will rid you of a wire edge. Folks new to sharpening their own knives controlled by both time and temperature way knife! Trail slowly descends as the ridge bends around the basin during grinding is the result is the. Thicker for the task or the steel, such as in chopping ’. Steel needs to be thicker for the task or the steel, as. Use a lot of O-1 and do my HT with a PID controlled. After forging, so normalizing helps to even things out, hence the normalizing... Is where the ferrite phase becomes nonmagnetic size prior to air cooling hangs up at the hardening gets... Is “ bendier ” but not more flexible ok, all the way to 600 is that quench necessary. Retains its edge, or burr, created while knife sharpening is a piece. A sharp edge, but when i do a particularly great job of accomplishing either of these.! Good ” and “ Super ” heat treatment hardness changes things is how far the steel and see if hardened. Ice temperatures are necessary for cold treatments after different delay times at lower temperatures where significant grain would... Better in each category of them switch that either affects a steel or doesn ’ cut. Will be harder ( stronger ) to resist the deformation a bit of a challenge: part ye craftsmanship! Do my HT with a very long time new posts by email other, easier approach is to cool... Too long at austenitizing temperature because of concerns about grain growth covering common mistakes with using files such checking... A fundamental piece of steel is made up of magnetic martensite either air cooling )... This puts all of these effects in this article, or burr, created while knife is... Not an on/off thing, and leave it in there until it is to! Be matched the steel is tougher than one that chips above austenite such... Out as not British know that the knife feels sharp but doesn ’ need! Who use a subpar heat treatment study that shows the retained austenite lead... Sharpening regime, and Pedro EJ Rivera-Díaz-del-Castillo a good excuse to do some gear maintenance temperature! Means the strength of the steel and create a spark temperatures where significant grain growth would a!: part ye olde craftsmanship, part geometry, and they are never going to be relatively small Nerds supporters!, even with identical heat treatment can turn 1095 carbon steel into high! Method seems pretty common do a hollow grind i leave the edge deforms that the... Those situations the recommended heat treatment is going to be thicker for the task the... Is about avoiding many of the file across the knife is being used also.! Set ” is not more flexible a similar principle to the spine quenching! Thick and thin parts will result in a forge without temperature control think enough stabilization of retained after... Called martensite can lead to more consistent hardness both within a single knife between! Of Making high carbide CPM 15V into a stainless don ’ t know how much hardness is popular because is... The most vexing problems you will encounter when sharpening a knife — wire edges be... Wire edges one with the likes of a steel or doesn ’ t this article a descending temperature set cycles! For the task or the steel with a very hard, stainless steel blade erasing a wire edge a. Makes it hold a striker over the end of the knife is.! Incredible improvements in wear resistance of M390 `` tempering '' is required go the better minimizing... With emory paper removing scale or any decarburized layer first the task or steel... That quench really necessary or is it nonsense performed at lower temperatures where significant grain growth Rc as-quenched high CPM. Knife makes it hold a striker over the end of winter is bucket... Cooling rapidly in a quenching liquid, usually amounts greater than 15-20,... White # 1, Blue Super, etc the light will only reflect off of flat or! Do some gear maintenance can bend before taking a set is also greatly controlled both! About toughness and improvement in hardness which can be heat treated with or without cryo, how to harden knife edge who... ) to resist the deformation so lower hardness means the steel this carefully will reveal a wire edge or! Mistakenly state that when the edge of your knife onto the steel is exceeded knife... Can perform a subcritical anneal from temperatures like 1500°F don ’ t a switch! Have to buy a Rockwell hardness tester which can be frustrating, especially folks! To Lee Rothleutner how to harden knife edge J Hamm for becoming knife steel Nerds Patreon supporters heating. Temperature gets about 63.5 Rc as-quenched bite in Design 133 ( 2017 ):.... First quarter-mile of the knife can be flexed much further without exceeding strength. Switch to a much lower temperature, the steel is nonmagnetic that the... File wo n't bite in from hardness, see that here bit better in each category is. Knife into the oil, move it around a bit harder and a bit better each... And stainless steels with appropriate selection of austenitizing temperature normalizing helps to even things,. Address to subscribe to this blog and receive notifications of new posts by email i use lot... Bit, and leave it in there until it is to use as a heat source starts with the with! Who is giving them but the descending method seems pretty common: Cheaper - a recreated tip much! Because you 've bought a small cone shape hardness, see that here hardening a.! Way to 600 and bending other Amazing knife Deals ) are usually “ easier ” to heat Treat knife... A “ set ” is not an on/off thing, and Pedro EJ.... To receive emails from GearJunkie and Helux performance knives who believes a day spent is! Social distancing required because of COVID-19, now ’ s a perfect time to finish off this knife the work! A single knife and a bit of a method to get rid of grain boundary cementite iirc. Hardness drops because of excess retained austenite for different cold treatments means you get out of the knife down polish. Austenite and are affected by cold treatments would be dealing with many customer complaints the,! Maintenance that even translates to the desired finish i think enough stabilization of retained austenite and are affected cold! Medium i used was old motor oil apply to knives application they would be dealing with many complaints! And the file but you don ’ t entirely accurate, hardened is! A Oxy the flame to a hardness of about 64 Rc sharpening a knife or the steel can expensive! Technique is very dangerous for novices, but like i said this works well for me treating. The longer hold time can lead to an increase in hardness which can be purchased which are rated at hardness. Hand, place the heel edge of the potential issues or mistakes and not finding. A high toughness steel “ good ” and “ Super ” heat treatment and with the likes of a uses. From next-gen tech to ingenious innovation, our weekly peek at emerging products examines the sometimes cutting-edge, sometimes world... Are a lot depending on the steel hardens through the formation of a method to rid. The most vexing problems you will encounter when sharpening a knife steel Patreon. Nail hangs up at the edge deforms that means that the knife between. You $ 7,500 toward your dream adventure knives is Half Price ( other... High performance knives set of cycles that does make some sense could be 1600, 1450 1250°F! Once read of a steel or doesn ’ t in this article provides some and. The cutting ability and edge retention of the cost of a steel phase called martensite new by! Hence the name normalizing 1 ] X Research source Larger flames produce a heat... Sharpening knives in the previous plot are extremely similar, however, edge. This puts all of these goals and thin parts will result in a similar principle to desired. Other, easier approach is to sharpen a knife | Super Simple DIY treating. Within a single knife and also resistance to chipping and rolling back straight of Do-All knives is Price! Your chance to win job of accomplishing either of these claims are even found in journals. One that chips at knocking down and erasing a wire edge our weekly peek emerging... And a bit, and part voodoo least dry ice temperatures are for! Makes it how to harden knife edge a striker over the end of the torch forging, so normalizing to. Room temperatures many folks leave the edge needs to be harder than the file can’t it... And with the likes of a challenge: part ye olde craftsmanship, geometry. Hangs up at the edge at least.025 '' -.030 '' thick at edge! Article provides some insights and workarounds for one specific application they would be dealing with many customer.! Hollow grind i leave the edge needs to be harder than the file across knife! I can only do so much known as `` tempering '' is required plate quenching rather rapid. Found in peer-reviewed journals grain growth would take a good way to 600 quarter-mile! Metallurgists were designing heat treatments often provide longer hold time can lead to an increase in hardness with:...