Usually when I come across an interesting new idea on the internet, my reaction is along to lines of "cool, I'll check in again in 5 years, see if they've made it worth buying." So many interesting products rush to market and suffer for it (usually due to fears of being undercut and outpaced by cheap imported knock-offs), and it usually takes a long time and a new generation or two to recover from the initial pandemonium, iron out bugs, and bring the original idea to fruition, assuming it even survives that long. This is different. The amount of effort, care, time, attention to detail, and ESPECIALLY transparency that is on display here has me well and truly aboard the hype train. I know you get dozens of comments on every upload saying so, but I'll absolutely be first in line to buy a pair once you're satisfied they're ready.
the problem with magnetism is an interesting one. I've heat treated a few knives that actually came out with magnetic spots, it has to do with how the crystalline structure of the steel breaks down at high temps before quenching, in fact that's the reason why steel is hardenable. It might be possible that when you hardened the blades they became slightly magnetic because somehow the grains of steel aligned in such a way pre heat treat that once the grain structure was locked in they formed a weak permanent magnet. Honestly though i'm not sure, i haven't run into a problem like that. I think blade hardness is a little low but again i make kitchen knives so i tend to shoot for higher hardnesses and considering that you tempered at 600° i think you got max hardness out of the steel. The colors on the steel also look good after they came out of the foil. They only really need to be wrapped to prevent de carb so a little more oxidation at the tip is fine. Also, the tip will have more oxidation because it's thinner and heats up faster in the kiln, so it uses up most of the oxygen contained in the foil package before the rest of the blade gets hit enough to oxidize, or at least that's my theory behind it. you can throw a little bit of paper inside the foil pack and it will burn and use up some of that oxygen to prevent extra oxidation, not sure if it will get rid of all of the oxidation but it might make the blades easier to clean up after the fact. Again hopefully there's some useful info in there, not claiming to be 100% right just trying to provide some potentially useful knowledge. It's exciting to watch these scissors develop!
Austenitic Stainless steel is non-magnetic, while ferritic and martensitic stainless are magnetic. The heat treatment is probably transforming the original austenitic structure into a martensitic one. Going for a harder stainless steel might be a better option than heat treatment, or going for a non stainless steel with some sort of anti oxidation coating. In the worst case scenario you might need to change the magnetic mechanism. Good luck on your project!!!
I’m not sure if the design would allow for this but another possibility is aligning the magnetic fields to save the same purpose as the magnet inserts. It’s most likely due to the heat treatment process due to the changes in the grains which allow for the steel to become harder.
Other option would be to use steel which can be tempered for secondary hardness. It would probably be more expensive but after tempering austenitic structure would be back and part wouldn't be magnetic while retaining hardness.
@@07jvmc Too slow of cooling is what is changing the structure from astenitic (non magnetic) to martensitic. If you heat up the steel it will take austenitic structure and by cooling it down fast is what keeps the crystalline structure austenitic, the structure doesn't have enough time to change into martensitic/feritic fast enough, its the basic idea behind quenching. Also quenching into water should result higher hardness than into oil.
@@justarandomminecrafter9349 I think hes talking about one of those digital hardness testers that you can just press into the metal with a point and it gives you an exact number.
I never thought I would be this interested in scissors. The magic of the channel is that it's all about the failures. The difference between average people and exceptional people really is about how they treat failure.
I've seen some knifemakers throw a piece of paper in their stainless foil wraps to help consume the oxygen inside the pack. Should help reduce oxidation
He is starting off slow, but he is destined for greatness and there is no stopping him. I think once he finishes this project and maybe starts another cool one, he will get a lot more of the recognition he deserves.
S30v stainless steel is martensitic which means in the heat treated and annealed state it becomes magnetic. Equalizing or Normalization means that you heat the steel to this point, then cool it in the air to room temperature. this "resets" the grain of the steel, as heating can do damage to the internal structure. ... by partailly heating the steel, the high stress of the quench is reduced and toughness is added to the blade.
That heat threated parts especially in your Stainless get magnetic is pretty normal, The grain structure if the steel itself changes and therefore it gets aligned especially through Tempering to some crappy sort of permanent magnet. Just buy an little 20$ demagnetiser from eBay which you can plug into your mains, it's handy for all sorts of stuff and should get you going
@@skycorrigan6511 if he makes them titanium all over then yea. But if he makes most of the things out of aluminum then they're gonna cost about 100 or 120
Mech E here. As far as the magnetization, I don’t recognize that steel offhand, but check what your phase transitions are, you may have done the heating in a way that caused it to move to the more magnetic phase. Alternatively you should try them without heat treating. To see if the alloy is more magnetic than you originally thought. In a tool that will likely see soft materials you probably want yield strength over hardness, so pursue that in your material selection. The bends can be done in many way ways, mechanically like forming, machining etc. remember that once you have a structural bias like that the heat treating will affect it. Good luck
If you put a piece of paper into the stainless foil with the blade it will burn off the remaining oxygen inside. This should also reduce the amount of scale that forms when inside the heat treating oven
Which is exactly why the tips discolored. The tips get red hot the fastest (less mass), then scavenge the oxygen in the envelope; turning them blue. Paper will do the same well, but much sooner than the steel.
Hi, mechanical engineer here. I made a knife myself and did some research on steel so here is my explanation on why your hardened steel is magnetic. This has to do with the internal steel structure, this knows a few kinds: Perlite, Ferrite and Cementite are forms regular steels are made of, the rusting kind. Then there is Austenite, a structure that for normal steels only exists at certain temperatures, usually around 800°C. Austenite is non-magnetic. For hardening regular carbon steel this is actually useful because the ideal point of hardening temperature is slightly above the temperature the steel becomes Austenitic, or non-magnetic. This means that for regular steel you can heat your steel until it is non-magnetic and becomes Austenite, heat it a bit longer and the quench it. For stainless steel this isn't the case. Austenite in regular steels only exists on high temperatures, but for stainless steels, it exists on room temperature. This is why stainless steel is non-magnetic, or at the very least a whole lot less magnetic. But when hardening stainless steel this changes, and this is where the last kind of internal steel structure comes in: Martensite. Martensite is a form of steel structure where the steel does not get the time to properly readjust itself when cooling down. It gets cooled too quickly to properly form the structures the steel started with. Martensite has a few useful properties for steels, one of which is that it is extremely hard, but as a side effect, also magnetic. This is why your blades became magnetic after hardening them: the steel took on a different structure. There is a way to get around this, but i don't know if, and how well this is doable in this case: it will take experimentation. The term for it is Differential Hardening, and how it works is that when quenching your blades, you let one part cool down slowly, in this case the part you don't want hardened. A way to do this in an example with oil-cooled steels is only quenching the blade in to the point you want hardened, the rest stays outside and cools on air. With your air-hardening steel this might be harder, but maybe you can do this with something like for example, clay on the unhardened part. The clay keeps heat in and allows that part to cool down slower. That said, If that part will be unhardened it will wear down faster. I can't say anything for the life of your parts when the parts of the blade that hinge are unhardened. The blades would have a longer life when hardened, and pins would be simpler to replace than the whole blade. Maybe replacing the magnets for stronger or different ones would be a better approach, but i can't draw conclusions based on my knowledge about this project. I would recommend to test around with this. Love the series of videos you have going on here, good luck!
It's just incredible the determination you have for one yet simple idea but super complicated to do. I ain't gonna lie, if I was doing this I wouldn't have had the determination to do the second episode and you're already at 18!! That's insane dude congrats for all your efforts it'll pay with your amazing product
Clamping the two aluminium plates together with clamps helps reduse unwanted warping of the blades, also spraying compressed air between the plates speeds up the quenching. Simple little life has great videos on air quenching. Great videos, keep it up.
I’m a bladesmith and I have a couple comments on your heat treatment. 1) your interpretation of the recipe was fine, you do want your piece to heat up with the oven. 2) you want to be really fast with your quench. You were a little slow grabbing the aluminum plate and putting it on your blades. You also probably want to blow some compressed air around the edges of your blades while holding down the top aluminum plate. Also, but all stainless is non magnetic. It needs to be pretty high in nickel and chromium in order to be non magnetic. Overall things seem to be going really well.
I should have said last time I was over there but! When I've done heat treating in the past I make a second small bag (open on one side) and put some paper or some such thing in the bag to consume the trapped oxygen. The bag keeps the ash from contacting the work. Lovin' it!
Following manufacturer they want you to let the steel rise with the oven. From cold to 1600 to 2000. In practice what you did is perfectly fine and won’t hurt anything. For the bend, I would use a vise and put the bend with three points until right amount t is achieved before the heat treat. Probably would mess up tolerances though
I’ve seen blacksmiths on RUclips heat-treating blades by quenching them in oil and then straightening slight bends before the blade cools entirely. Therefore I imagine it would be possible to induce slight bends as well.
I'm thinking milling his heat sinks to curve at a certain point, and aligning the blanks with that curve to knock out two operations at once, then using a heavy duty clamp for pressure. Yay! More fixtures!
Dude, I remembered watching you since "I restored a Balisong" video and you had like 5 or 8k subs? its nice seeing you grow dude it's very entertaining
I've seen makers include a small wood chip to consumer the oxygen left in the bag but I'm not sure if its actually effective without a near-perfect seal. Id bet the point oxidizing the most is due to oxygen leaking in from that direction For those pinholes, pick up some barrel laps off mcmaster and polishing paste. Flitz or
The way I have seen the curve be put into scissor blades on a few videos I have seen is either with a press done automatically, or by hand with 2 spaced blocks of metal and a hammer used to lightly tap the blade as you move it back and forth to get just the right amount of bend through the entire blade.
For the foil, use a tiny amount of baby powder inside the pack. No paper. I also clean the blades prior to going in the packet with acetone. A good heat treat will have the blade come out white, or some form of rainbow, no oxidation though. After messing a ton of the packs up I've found that 2 overlapping folds works good. Make sure the folds are being shaped with a very square corner. I used an old surface grinding magnet for the corners. The corner thing was what was holding me back from sealed packs. You know they aren't sealed if they puff up the second you put them in the hot furnace. I like plate quenching using the cheap arbor press from harbor freight. If you want the cad models for the press plates lmk. Its also got the attachments for holding the plates to the press shaft. Time for a surface grinder! For the pivot, I've found it'll shrink .0002 to .0005" during heat treat. Ive been using a barrel lap in a hand drill with diamond paste to bring it back to size. Also gives the bore a high surface finish. You can get the laps from McMaster, and the paste can be found on Amazon for pretty reasonable. Great progress as always!
Just a couple tips to try and help for next time. 1. If you use a vise you can pinch the blade in between the aluminum for the quench you generally want the quench to be as fast as possible, 2. It’s generally a good idea to delay adding a bevel until after heat treating as it gives less of a chance for cracking 3. Generally you test hardness after the quench. Just a couple things you might want to consider thanks for reading Note: I only have very limited experience with knives so take this with a grain of salt. I also know nothin about scissors in particular I am saying things based off knife experience
Try the method clickspring uses when heat treating of coating the part in boric acid (suspended in alcohol). I'm not sure how well it would work for air hardening steel, but it seems to eliminate virtualy all scale.
For the bend in the blades, you could fixture them to the side of a block and mill an angle (large radius?) tapering down to the hinge. If you thin the blades down, you might have luck bending after heat treating. (not an expert opinion, gloves and safety goggles) Edit: Okay, better idea. If for the blade hole milling op, if your fixture is angled 'in' towards the tip some few degrees, that could cheat the bend. Grimsmo has some OLD videos about them figuring out their in house heat treating using the same method. They use baby powder to suck up oxygen that makes it into the pouch. Google says even the high quality Japanese scissors are only made of 420 or 440.
Definitely keep up the hard work, i may not be able to help give input on any of the issues you are tackling. I am willing to help support you financially when you feel these are ready to be sold. The concept of these has kept me interested since day one, and i keep seeing the progress and cant wait for the day i can get my hands on one. Very cool product, very hand for a desk/workbench pair of scissors.
Cts-xhp is a very good steel, especially for balisongs because it's a very tough steel. I have a bali with cts and the edge and tip hold up very well even though i drop it on concrete often
Very cool if the blades are sharp enough and these end up being sold I might use them as bonsai scissors, excited to see progress and I hope this comment boosts the algorithm or something.
Dial in your heat treat protocols. Research... Consider soda blasting or walnut shells for the scale. You're doing well. Thanks for bringing us all along🤙
It’s a coolant to help keep the material cold so it doesn’t heat up and machine to different tolerances (as the material expands it would cut more). It also keeps the cutting face cold so it doesn’t heat up and dull faster. Hope this helps
You are correct to put the blades into the oven cold and let them come up to temp both on the hardness cycle and the tempur cycle. Depending on the homone line of hardness you are looking for I would run a few drop cycles in the tempur stage to maybe soften the spine a bit.
I don't work with stainless steels, I primarily work with carbon steels. 5160, 1095 & 15n20 specifically. The 5160 is my go to for mono-steel knives, with the other 2 alloys being my go to for Damascus. Depending on the use case of the tool, I try to shoot for 50-55 HRC, any harder, and you might find them to be more prone to cracking. Just looking at my balisong, I know there are areas that impact the steel as I am flipping it, so I would imagine being more around 50-45 in those areas would be better, but I know oven heat treating is harder to achieve a differential heat treat. But you could torch the "impact areas" and arrest the temper around blue or purple color. As far as sharpening goes. I have different techniques that work for me in the pieces I make. I'll talk more about the chisels I make in hopes that helps you a little more. With my chisels, I like to get a perfectly flat grind on one side, and I take that all the way up to 800 grit, hell, I take it past there frequently. with the top bevel getting the same treatment. Once I start to get an even burr on one side of the cutting edge is when I take it to a stropping wheel, stone, or even 15000 grit paper, hell, your pants can do the trick in a pinch. My goal at this point is to roll that burr to the other side of the edge, then back. It's this back and forth motion that causes that burr to work harden at the edge and eventually break off. The burr breaking off the bevel is what creates that razor edge. That is what works for me, and I have had great success in my sharp objects.
Martensitic (hardenable) stainless is magnetic and you may need some sintered nickel (mumetal or similar) shielding linings to the magnets to limit the magnetic permeability otherwise putting magnets in a cavity made of magnetic material actually makes the field stronger. Only austenitic (nonhardenable) stainless is non-magnetic and a lot of production scissors are made with this stuff and they punch the blades out of coils of steel and just rely on the work hardening due to the punching process to strengthen the blades.. Some do a surface hardening and abrasion resistant titanium nitride coating to make up for the inherent softness of austenitic stainless.. In terms of the bend, for most hand made scissors, the bend is put in by hand as well, literally by whacking the blade with a hammer and test cutting until you get a clean cut. For production blade you can machine a mold and press the blade into it, until it takes a set, but it will take some experimentation to determine the correct profile for the mold as the steel will spring back a bit after pressing.
that bend you mentioned at the end is more related to the hinge. the play in the hinge allows the blades to pivot non axially so they still cut after the edge wears.
It looks somewhat like in traditional scissors the the tips are hammered post hardening to give them the slight curve but the real question would be what the angles to aim for are (and how much the handle tolerances need to change to accommodate).
to get the bend you want you could place two bushings on top of the blades at the two ends and one under in the middle of the blade when air quenshing it, it should form the blades to the bend as its cooling down.
In order to get that bend you could clamp it to a preformed object when you go to anneal the blades. Blacksmiths use that technique to remove warps from blades so you may be able to use it to put one in. You could make it out of steel or if you are worried about it ruining the heating of the blade you could make it out of fire brick although it may not be strong enough to have a quenched blade clamped onto it. In any case be careful when bending a blade that has not been annealed because it could snap.
hey, love your work. engineering dropout here with some assistance. s30v is a martensitic stainless steel and when heat treated above 1900ish degrees the grains transform into what's known as austenite as it cools rapidly the austenite is very unstable and so it will transition either to martensite or ferrite or a variety of other types but as far as the ideal situation is mainly martensite with carbides. this transformation causes a bunch of stress which in most ferritic and martensitic steels causes them to exhibit semi permanent magnet behavior. more than likely this is unavoidable but if you have a demagnetizer it may be able to remove this. I would recommend doing so before and after heat treat for the maximum effectiveness but good luck!
If I can recommend there is a documentary on scissor makers in Sheffield UK, the bend in the scissor is probably the hardest and the most important thing to make on scissors :/ and since you said you don't like doing things by hand ( or improvising, sorry English isn't my first language) that's probably going to be one of the hardest parts of this
If you're worried about magnetism, get yourself a plate type demagnetizer. It is a demagnetizer which actually plugs into an outlet and uses alternating fields to demag a part. Very useful when you need make sure your part is absolutely not magnetic. Demag it after grinding and fettling as it's easy to induce magnetism into steel parts via grinding or other abrasion.
the heat makes is magnetic if im not totaly misstaking, and i recommend you to talk with will at his instagram ( @will_stelter ) , he's a knife maker and can surely help you! love these trial en error videos and hope you get there soon! great work!
I think the magnetism comes from the heat treat, I’m not certain but sometimes parts come off our Cnc plasma cutter magnetised, or after you heat a piece of steel up too much by grinding it, it can become magnetic. I would assume just a simple de-magnetiser would do the job but I’m no expert.
i think something interesting to try would be doing a slight ramp to the flat of one of blades, having the pivot area be the thinnest and ever so slightly getting thicker towards the edge to get rid of that gap, that would definitely be interesting and it wouldnt give it that, in my opinion, ugly curve to one of the blades, something different to try, you never know, either way, fantastic video as always my dude
Not a materials engineering, but CPM S30V is martensitic stainless steel and is therefore magnetic to have a completely non-magnetic blade you need to use an austenite steel alloy. A quick read through the paper "Magnetic Properties of Steels after Quenching and Tempering. III. High-Chromium Steels. by G.V. Bida et al" it further suggests that the magnetic properties of a steel such as CPM S30V may increase when tempering above ~450 degC (assuming AISI 440C is comparable to CPM S30V, and AISI 440C is comparable to 95kh18). Note that I've done quite a bit of handwaving in this comparison...
By changing the steels crystal structure via hardening and tempering it makes the magnetic properties change, you can try using electro magnetization on them to change the field again but it would be hard with the blade shape.
Could the blades now be in a hysteresis loop since being heat treated? As soon as the initial magnetism is added its just stayed? If it was something like that it should be easy to test as a sharp hit to the blades (but not enough to shatter the hardening) would remove the magnetic hysteresis.
I have a gut feeling the aluminum blocks you used during quenching might have contributed to the magnetism. I can imagine a small em-flux being generated as you move the top block off and on.
I have literally zero interest in buying a pair of these because my hands are far too useless to handle something like this, but watching the process of making them is fascinating and I'm picking up so many tips for machining/making stuff in the process
The reason why the blades are sticking more might be because after the heat treatment, the material is behaving like a soft magnet (like alnico). A soft magnet can change its magnet poles if they are near a strong magnetic field or a strong magnet. It seems in your case this strong field is produced by the neodymium magnets. They sick because the blades are realining their magnetic poles such that the magnetic field follows the least magnetic reluctance path, through the blades due to it's low relative permeability. The magnetic flux of the strong magnet runs through the soft magnet (the blades) causing them to realign the magnetic domains inside the material causing North-South pole pairs matching the neodymium magnet poles. That is why you feel the are sticking more. You can discard or verify if this is the case by sticking the neodimium magnet in any surface of the material. After doing this you pull out the magnet from the metal and flip it and then,you use the neodimium magnet to try to find any repulsion in this area (this forces might be hard to feel). The reason behind this is that we use the neodimium magnet in order to detect if the presence of this magnet has permanently changed the magnetic domains of the material. If you get close enough to the material you will feel attraction instead of a ligh repulsion and you will have to repeat the experiment. I think this might be the case because I've experienced a similar problem when I was developing an electropermanent magnet driver in the past. Sorry if I made typos I am not a native English speaker. Thank you for your attention.
Instead of letting the blades cool after tempering. While they are 600° put them in a vice with three pins two pins on one side one pin on the other centered between the other two and clamp putting a slight bend in the blades. You don't have a lot of time where the steel will accept the bending so work quickly. But that should work.
Oxidizing is losing electrons, Reducing is gaining electrons (Oil Rig) Maybe you could parkerize or blue them? Chemical treatments will wear on the structural integrity though Another alternative is use a vacuum furnace so that that the blades don't oxidize in the heat treatment
- the roller is a MUCH better tool that hands without gloves, but I like to take a piece of stock and hold it perpendicular to the fold of foil I want to flatten, tilt it at an angle and slide the piece of stock over the fold so that the corner of the stock makes a single point with the foil as I slide it along the fold to really crease it. - Stainless steel foil isn't that expensive so I usually just cut it oversized since it saves time. If you cut a piece too small, you'll either have to fight it to get the could to cover the piece and still fold shut, or start over with a larger piece. - definitely throw in a few small pieces of paper scrap into the foil packet. While I mostly do air-hardening tool steels (not as much stainless steel) the little pieces of paper have consistently and categorically reduced the decarburesation of the surface of any part I've treated, I imagine this will hold true for stainless steel. - I looked up some documentation for s30v and 1) from what you were saying, I believe you've got the gist of equalizing correct. While it's more important for thicker parts (just like cooking food, the internals take a while to catch up with the externals) holding the material at a temperature where it starts to radiate allows the internal temperature "catch up" so you don't have a huge differential, i.e., you don't want the center of the part to be lagging behind at 900, 1100, or 1400 degrees F while the outside is at 2000. Firstly, the coeffecient of thermal expansion would cause the outside to expand much more than the inside, and that could introduce unneeded stress into the part. Also, heat treating steels of all kinds are done to temporarily form martensite, it's quite possible that with a thick part, if you don't equalize, the center area could actually never reach the temperature to create the amount of martensite desired. After quenching, you'd lose the guarantee that a whole slew of interesting compounds end up in the steel. - if you ever have trouble with the pin hole sizes, try to bore them 1 thou under so you can use a little expanding arbor lap to bring them up to size post heat-treat. It won't be fast, but it is a way to expand holes in hardened material. - not all stainless steel is non-magnetic - good results so far!! And major props to getting your hands dirty, trying new things, and sharing your results. This attitude and practice will take you incredibly far. - Please wear gloves when dealing with that foil, even when cutting it open, you'll be able to do it faster without worrying about your hands as much lol. Yes, you can get away without it, but you'll save so much time and so many bandaids
Simple little life did a video on air hardening steels. Best bet is to clamp between two pieces of aluminium and then blast with compressed air around the blade to quickly cool
I'm not sure if someone else has already mentioned this, or maybe you already know, but a good way to test if there's a burr is to use your fingernails, after you sharpen the blade, on the other side run your fingernail against it, if your fingernail catches, then you've got a burr.
![You Can Forge a Knife Correctly [Here's How] !](/img/1.gif)
The hype is real every time I get the notification for a new one of these episodes
For real
Facts
Big fax
Faxxxx
Usually when I come across an interesting new idea on the internet, my reaction is along to lines of "cool, I'll check in again in 5 years, see if they've made it worth buying." So many interesting products rush to market and suffer for it (usually due to fears of being undercut and outpaced by cheap imported knock-offs), and it usually takes a long time and a new generation or two to recover from the initial pandemonium, iron out bugs, and bring the original idea to fruition, assuming it even survives that long.
This is different. The amount of effort, care, time, attention to detail, and ESPECIALLY transparency that is on display here has me well and truly aboard the hype train. I know you get dozens of comments on every upload saying so, but I'll absolutely be first in line to buy a pair once you're satisfied they're ready.
the problem with magnetism is an interesting one. I've heat treated a few knives that actually came out with magnetic spots, it has to do with how the crystalline structure of the steel breaks down at high temps before quenching, in fact that's the reason why steel is hardenable. It might be possible that when you hardened the blades they became slightly magnetic because somehow the grains of steel aligned in such a way pre heat treat that once the grain structure was locked in they formed a weak permanent magnet. Honestly though i'm not sure, i haven't run into a problem like that. I think blade hardness is a little low but again i make kitchen knives so i tend to shoot for higher hardnesses and considering that you tempered at 600° i think you got max hardness out of the steel. The colors on the steel also look good after they came out of the foil. They only really need to be wrapped to prevent de carb so a little more oxidation at the tip is fine. Also, the tip will have more oxidation because it's thinner and heats up faster in the kiln, so it uses up most of the oxygen contained in the foil package before the rest of the blade gets hit enough to oxidize, or at least that's my theory behind it. you can throw a little bit of paper inside the foil pack and it will burn and use up some of that oxygen to prevent extra oxidation, not sure if it will get rid of all of the oxidation but it might make the blades easier to clean up after the fact.
Again hopefully there's some useful info in there, not claiming to be 100% right just trying to provide some potentially useful knowledge. It's exciting to watch these scissors develop!
Austenitic Stainless steel is non-magnetic, while ferritic and martensitic stainless are magnetic. The heat treatment is probably transforming the original austenitic structure into a martensitic one. Going for a harder stainless steel might be a better option than heat treatment, or going for a non stainless steel with some sort of anti oxidation coating. In the worst case scenario you might need to change the magnetic mechanism.
Good luck on your project!!!
I’m not sure if the design would allow for this but another possibility is aligning the magnetic fields to save the same purpose as the magnet inserts. It’s most likely due to the heat treatment process due to the changes in the grains which allow for the steel to become harder.
i have no clue what he said but it sounds right
Other option would be to use steel which can be tempered for secondary hardness. It would probably be more expensive but after tempering austenitic structure would be back and part wouldn't be magnetic while retaining hardness.
@@07jvmc Too slow of cooling is what is changing the structure from astenitic (non magnetic) to martensitic. If you heat up the steel it will take austenitic structure and by cooling it down fast is what keeps the crystalline structure austenitic, the structure doesn't have enough time to change into martensitic/feritic fast enough, its the basic idea behind quenching. Also quenching into water should result higher hardness than into oil.
4:20 "I don't have a hardness tester"
- proceeds to pull out hardness tester
Ye thay doesn't make sense lol
@@justarandomminecrafter9349 I think hes talking about one of those digital hardness testers that you can just press into the metal with a point and it gives you an exact number.
LoL dint know that existed
a file isnt a hardness tester. he is talking about a brinell dimple tester machine.
year lol
I never thought I would be this interested in scissors. The magic of the channel is that it's all about the failures. The difference between average people and exceptional people really is about how they treat failure.
I've seen some knifemakers throw a piece of paper in their stainless foil wraps to help consume the oxygen inside the pack. Should help reduce oxidation
The paper burns reducing the oxygen content not that the paper absorbs the oxygen
I think most people that understand that paper burns and fire consumes oxygen didn't need that clarification
Also borax paste coating is another common way to prevent oxidation
@@brannonhudson6868 I was about top suggest it. +1
@@PollexTheCat it smolders it doesnt burn. flame requires oxygen. stop trying to be a smart ass.
This channel is criminally underrated
More big fax
He is starting off slow, but he is destined for greatness and there is no stopping him. I think once he finishes this project and maybe starts another cool one, he will get a lot more of the recognition he deserves.
i can’t like your comment because you won’t have 69 likes anymore
@@andrewlaeddis5025 respectable
I'm a blade smith my self and every time you said "oh and I cut my self" I get flash backs to every time I cut my self.
S30v stainless steel is martensitic which means in the heat treated and annealed state it becomes magnetic. Equalizing or Normalization means that you heat the steel to this point, then cool it in the air to room temperature. this "resets" the grain of the steel, as heating can do damage to the internal structure. ... by partailly heating the steel, the high stress of the quench is reduced and toughness is added to the blade.
Splendid another baliscissors video
That heat threated parts especially in your Stainless get magnetic is pretty normal, The grain structure if the steel itself changes and therefore it gets aligned especially through Tempering to some crappy sort of permanent magnet. Just buy an little 20$ demagnetiser from eBay which you can plug into your mains, it's handy for all sorts of stuff and should get you going
I can’t wait for the final product! I’ll for sure order one
Same
I’ll definitely pay 100 dollars for one of these
@@changes4339 I'd bet they're gonna cost closer to $500. Maybe more
@@skycorrigan6511 if he makes them titanium all over then yea. But if he makes most of the things out of aluminum then they're gonna cost about 100 or 120
he also might use sv30 steel which is very expensive
Mech E here. As far as the magnetization, I don’t recognize that steel offhand, but check what your phase transitions are, you may have done the heating in a way that caused it to move to the more magnetic phase. Alternatively you should try them without heat treating. To see if the alloy is more magnetic than you originally thought. In a tool that will likely see soft materials you probably want yield strength over hardness, so pursue that in your material selection.
The bends can be done in many way ways, mechanically like forming, machining etc. remember that once you have a structural bias like that the heat treating will affect it. Good luck
If you put a piece of paper into the stainless foil with the blade it will burn off the remaining oxygen inside. This should also reduce the amount of scale that forms when inside the heat treating oven
Which is exactly why the tips discolored. The tips get red hot the fastest (less mass), then scavenge the oxygen in the envelope; turning them blue. Paper will do the same well, but much sooner than the steel.
What dedication. Everyone should remember how people like you stay determinated through incredibly tough projects and try to do the same.
Hi, mechanical engineer here.
I made a knife myself and did some research on steel so here is my explanation on why your hardened steel is magnetic.
This has to do with the internal steel structure, this knows a few kinds:
Perlite, Ferrite and Cementite are forms regular steels are made of, the rusting kind.
Then there is Austenite, a structure that for normal steels only exists at certain temperatures, usually around 800°C.
Austenite is non-magnetic.
For hardening regular carbon steel this is actually useful because the ideal point of hardening temperature is slightly above the temperature the steel becomes Austenitic, or non-magnetic.
This means that for regular steel you can heat your steel until it is non-magnetic and becomes Austenite, heat it a bit longer and the quench it.
For stainless steel this isn't the case.
Austenite in regular steels only exists on high temperatures, but for stainless steels, it exists on room temperature.
This is why stainless steel is non-magnetic, or at the very least a whole lot less magnetic.
But when hardening stainless steel this changes, and this is where the last kind of internal steel structure comes in: Martensite.
Martensite is a form of steel structure where the steel does not get the time to properly readjust itself when cooling down.
It gets cooled too quickly to properly form the structures the steel started with.
Martensite has a few useful properties for steels, one of which is that it is extremely hard, but as a side effect, also magnetic.
This is why your blades became magnetic after hardening them: the steel took on a different structure.
There is a way to get around this, but i don't know if, and how well this is doable in this case: it will take experimentation.
The term for it is Differential Hardening, and how it works is that when quenching your blades, you let one part cool down slowly, in this case the part you don't want hardened.
A way to do this in an example with oil-cooled steels is only quenching the blade in to the point you want hardened, the rest stays outside and cools on air.
With your air-hardening steel this might be harder, but maybe you can do this with something like for example, clay on the unhardened part.
The clay keeps heat in and allows that part to cool down slower.
That said, If that part will be unhardened it will wear down faster.
I can't say anything for the life of your parts when the parts of the blade that hinge are unhardened.
The blades would have a longer life when hardened, and pins would be simpler to replace than the whole blade.
Maybe replacing the magnets for stronger or different ones would be a better approach, but i can't draw conclusions based on my knowledge about this project.
I would recommend to test around with this.
Love the series of videos you have going on here, good luck!
0:32 hey, I see myself haha! Keep up the good work, I can’t wait to see these in full production!
It's just incredible the determination you have for one yet simple idea but super complicated to do. I ain't gonna lie, if I was doing this I wouldn't have had the determination to do the second episode and you're already at 18!! That's insane dude congrats for all your efforts it'll pay with your amazing product
Clamping the two aluminium plates together with clamps helps reduse unwanted warping of the blades, also spraying compressed air between the plates speeds up the quenching. Simple little life has great videos on air quenching.
Great videos, keep it up.
Been saving up for when the Bali scissors are for sale. Love the quality of these videos and all the work being done. keep up the good work!!
Do you know when? Where And how many he's going to sell?
I’m a bladesmith and I have a couple comments on your heat treatment. 1) your interpretation of the recipe was fine, you do want your piece to heat up with the oven. 2) you want to be really fast with your quench. You were a little slow grabbing the aluminum plate and putting it on your blades. You also probably want to blow some compressed air around the edges of your blades while holding down the top aluminum plate.
Also, but all stainless is non magnetic. It needs to be pretty high in nickel and chromium in order to be non magnetic.
Overall things seem to be going really well.
I love watching your progress even if it doesn’t work out! Keep up the good work, we’re here for you!
I would love a pair of balascissors, can't wait to see them refined!
shut up and take my money! seriously, though, love watching the journey of making something both familiar and original. best of luck.
Keep going man, they're gonna be phenomenal once they reach the market!
I should have said last time I was over there but! When I've done heat treating in the past I make a second small bag (open on one side) and put some paper or some such thing in the bag to consume the trapped oxygen. The bag keeps the ash from contacting the work.
Lovin' it!
we have been blessed with yet another baliscissor video
Following manufacturer they want you to let the steel rise with the oven. From cold to 1600 to 2000. In practice what you did is perfectly fine and won’t hurt anything. For the bend, I would use a vise and put the bend with three points until right amount t is achieved before the heat treat. Probably would mess up tolerances though
I’ve seen blacksmiths on RUclips heat-treating blades by quenching them in oil and then straightening slight bends before the blade cools entirely. Therefore I imagine it would be possible to induce slight bends as well.
I'm thinking milling his heat sinks to curve at a certain point, and aligning the blanks with that curve to knock out two operations at once, then using a heavy duty clamp for pressure. Yay! More fixtures!
@@YoureSoVane That’s a really good idea👏
Dude, I remembered watching you since "I restored a Balisong" video and you had like 5 or 8k subs? its nice seeing you grow dude it's very entertaining
I've seen makers include a small wood chip to consumer the oxygen left in the bag but I'm not sure if its actually effective without a near-perfect seal. Id bet the point oxidizing the most is due to oxygen leaking in from that direction
For those pinholes, pick up some barrel laps off mcmaster and polishing paste. Flitz or
The way I have seen the curve be put into scissor blades on a few videos I have seen is either with a press done automatically, or by hand with 2 spaced blocks of metal and a hammer used to lightly tap the blade as you move it back and forth to get just the right amount of bend through the entire blade.
For the foil, use a tiny amount of baby powder inside the pack. No paper. I also clean the blades prior to going in the packet with acetone. A good heat treat will have the blade come out white, or some form of rainbow, no oxidation though. After messing a ton of the packs up I've found that 2 overlapping folds works good. Make sure the folds are being shaped with a very square corner. I used an old surface grinding magnet for the corners. The corner thing was what was holding me back from sealed packs. You know they aren't sealed if they puff up the second you put them in the hot furnace. I like plate quenching using the cheap arbor press from harbor freight. If you want the cad models for the press plates lmk. Its also got the attachments for holding the plates to the press shaft. Time for a surface grinder!
For the pivot, I've found it'll shrink .0002 to .0005" during heat treat. Ive been using a barrel lap in a hand drill with diamond paste to bring it back to size. Also gives the bore a high surface finish. You can get the laps from McMaster, and the paste can be found on Amazon for pretty reasonable.
Great progress as always!
Please put as much as you can into these videos, I love them
Can’t wait until these are commercially available!
When you suggested different blade types for different materials. My eyes lit up at the idea of these as wire cutters or sheet metal sheers.
This is so cool I can't wait to see a finished product! I want to edc these, not like in my pocket edc, but def. backpack carry.
Can’t wait for these to be available, absolutely something I’d edc
Just a couple tips to try and help for next time. 1. If you use a vise you can pinch the blade in between the aluminum for the quench you generally want the quench to be as fast as possible, 2. It’s generally a good idea to delay adding a bevel until after heat treating as it gives less of a chance for cracking 3. Generally you test hardness after the quench. Just a couple things you might want to consider thanks for reading
Note: I only have very limited experience with knives so take this with a grain of salt. I also know nothin about scissors in particular I am saying things based off knife experience
Try the method clickspring uses when heat treating of coating the part in boric acid (suspended in alcohol). I'm not sure how well it would work for air hardening steel, but it seems to eliminate virtualy all scale.
1:12 7:23 rip
For the bend in the blades, you could fixture them to the side of a block and mill an angle (large radius?) tapering down to the hinge. If you thin the blades down, you might have luck bending after heat treating. (not an expert opinion, gloves and safety goggles)
Edit: Okay, better idea. If for the blade hole milling op, if your fixture is angled 'in' towards the tip some few degrees, that could cheat the bend.
Grimsmo has some OLD videos about them figuring out their in house heat treating using the same method. They use baby powder to suck up oxygen that makes it into the pouch.
Google says even the high quality Japanese scissors are only made of 420 or 440.
That's a good point about angling the pin holes. I would also go ahead and angle the contact face of one blade.
Definitely keep up the hard work, i may not be able to help give input on any of the issues you are tackling. I am willing to help support you financially when you feel these are ready to be sold. The concept of these has kept me interested since day one, and i keep seeing the progress and cant wait for the day i can get my hands on one. Very cool product, very hand for a desk/workbench pair of scissors.
Every single one of these videos gets me more hype to buy the scissors.
Cts-xhp is a very good steel, especially for balisongs because it's a very tough steel. I have a bali with cts and the edge and tip hold up very well even though i drop it on concrete often
Maybe differential hardening, and/or hard milling/grinding the bevels after heat treat?
Very cool if the blades are sharp enough and these end up being sold I might use them as bonsai scissors, excited to see progress and I hope this comment boosts the algorithm or something.
definitely favourite channel on youtube, keep it up
Awesome! Been waiting for the next vid. Can't wait for the production run.
I am always very excited when you drop a video
Dial in your heat treat protocols. Research...
Consider soda blasting or walnut shells for the scale. You're doing well. Thanks for bringing us all along🤙
What is the white liquid at 0:50 ? I don’t know much about machines but this series is super fun to watch
It’s a coolant to help keep the material cold so it doesn’t heat up and machine to different tolerances (as the material expands it would cut more). It also keeps the cutting face cold so it doesn’t heat up and dull faster. Hope this helps
@@ukjt89 This does help. Thank you so much!
You are correct to put the blades into the oven cold and let them come up to temp both on the hardness cycle and the tempur cycle. Depending on the homone line of hardness you are looking for I would run a few drop cycles in the tempur stage to maybe soften the spine a bit.
I don't work with stainless steels, I primarily work with carbon steels. 5160, 1095 & 15n20 specifically. The 5160 is my go to for mono-steel knives, with the other 2 alloys being my go to for Damascus. Depending on the use case of the tool, I try to shoot for 50-55 HRC, any harder, and you might find them to be more prone to cracking. Just looking at my balisong, I know there are areas that impact the steel as I am flipping it, so I would imagine being more around 50-45 in those areas would be better, but I know oven heat treating is harder to achieve a differential heat treat. But you could torch the "impact areas" and arrest the temper around blue or purple color.
As far as sharpening goes. I have different techniques that work for me in the pieces I make. I'll talk more about the chisels I make in hopes that helps you a little more. With my chisels, I like to get a perfectly flat grind on one side, and I take that all the way up to 800 grit, hell, I take it past there frequently. with the top bevel getting the same treatment. Once I start to get an even burr on one side of the cutting edge is when I take it to a stropping wheel, stone, or even 15000 grit paper, hell, your pants can do the trick in a pinch. My goal at this point is to roll that burr to the other side of the edge, then back. It's this back and forth motion that causes that burr to work harden at the edge and eventually break off. The burr breaking off the bevel is what creates that razor edge. That is what works for me, and I have had great success in my sharp objects.
babe wake up, there's a new baliscissors video
Martensitic (hardenable) stainless is magnetic and you may need some sintered nickel (mumetal or similar) shielding linings to the magnets to limit the magnetic permeability otherwise putting magnets in a cavity made of magnetic material actually makes the field stronger. Only austenitic (nonhardenable) stainless is non-magnetic and a lot of production scissors are made with this stuff and they punch the blades out of coils of steel and just rely on the work hardening due to the punching process to strengthen the blades.. Some do a surface hardening and abrasion resistant titanium nitride coating to make up for the inherent softness of austenitic stainless..
In terms of the bend, for most hand made scissors, the bend is put in by hand as well, literally by whacking the blade with a hammer and test cutting until you get a clean cut. For production blade you can machine a mold and press the blade into it, until it takes a set, but it will take some experimentation to determine the correct profile for the mold as the steel will spring back a bit after pressing.
Here is my sacrificial comment. May the Algorithm look favorably upon your videos.
Really excited for these, as they will most likely be legal in Canada!
i would die if my girlfriend bought me this when it comes out soon! Keep up the good work!
that bend you mentioned at the end is more related to the hinge. the play in the hinge allows the blades to pivot non axially so they still cut after the edge wears.
to add, its also to allow the scissors to cut at the tip where the lateral forces holding the blades together are the smallest.
This is very interesting if he is selling these when he is done I will definitely look into buying one
I know that when you harden Stella it can become magnetic but you can get demagnetisers to remove the magnetic thing from the blade
It looks somewhat like in traditional scissors the the tips are hammered post hardening to give them the slight curve but the real question would be what the angles to aim for are (and how much the handle tolerances need to change to accommodate).
to get the bend you want you could place two bushings on top of the blades at the two ends and one under in the middle of the blade when air quenshing it, it should form the blades to the bend as its cooling down.
In order to get that bend you could clamp it to a preformed object when you go to anneal the blades. Blacksmiths use that technique to remove warps from blades so you may be able to use it to put one in. You could make it out of steel or if you are worried about it ruining the heating of the blade you could make it out of fire brick although it may not be strong enough to have a quenched blade clamped onto it. In any case be careful when bending a blade that has not been annealed because it could snap.
hey, love your work. engineering dropout here with some assistance. s30v is a martensitic stainless steel and when heat treated above 1900ish degrees the grains transform into what's known as austenite as it cools rapidly the austenite is very unstable and so it will transition either to martensite or ferrite or a variety of other types but as far as the ideal situation is mainly martensite with carbides. this transformation causes a bunch of stress which in most ferritic and martensitic steels causes them to exhibit semi permanent magnet behavior. more than likely this is unavoidable but if you have a demagnetizer it may be able to remove this. I would recommend doing so before and after heat treat for the maximum effectiveness but good luck!
If I can recommend there is a documentary on scissor makers in Sheffield UK, the bend in the scissor is probably the hardest and the most important thing to make on scissors :/ and since you said you don't like doing things by hand ( or improvising, sorry English isn't my first language) that's probably going to be one of the hardest parts of this
If you're worried about magnetism, get yourself a plate type demagnetizer. It is a demagnetizer which actually plugs into an outlet and uses alternating fields to demag a part. Very useful when you need make sure your part is absolutely not magnetic. Demag it after grinding and fettling as it's easy to induce magnetism into steel parts via grinding or other abrasion.
the heat makes is magnetic if im not totaly misstaking, and i recommend you to talk with will at his instagram ( @will_stelter ) , he's a knife maker and can surely help you!
love these trial en error videos and hope you get there soon! great work!
or maybe Alex steel (yt under same name)
@@de8173 Will should have better information as he's a knife Smith and Alec is a blacksmith
Oh man! I would love he if he got some help from Will!
I think the magnetism comes from the heat treat, I’m not certain but sometimes parts come off our Cnc plasma cutter magnetised, or after you heat a piece of steel up too much by grinding it, it can become magnetic. I would assume just a simple de-magnetiser would do the job but I’m no expert.
Have you considered hard milling the blades? Then if the material is already hard you wouldn’t have to worry about tolerances changing
I am so in deep with this project
Really love your videos man. Keep up the amazing job. It looks very good. Don't be to harsh on yourself please
Could you degauss the blades to remove the magnetic field?
i think something interesting to try would be doing a slight ramp to the flat of one of blades, having the pivot area be the thinnest and ever so slightly getting thicker towards the edge to get rid of that gap, that would definitely be interesting and it wouldnt give it that, in my opinion, ugly curve to one of the blades, something different to try, you never know, either way, fantastic video as always my dude
looking into how its made, seems like the scissor curve is made after the ends are bolted together
Could you induce a bend in heat treating/quenching?
Not a materials engineering, but CPM S30V is martensitic stainless steel and is therefore magnetic to have a completely non-magnetic blade you need to use an austenite steel alloy. A quick read through the paper "Magnetic Properties of Steels
after Quenching and Tempering. III. High-Chromium Steels. by G.V. Bida et al" it further suggests that the magnetic properties of a steel such as CPM S30V may increase when tempering above ~450 degC (assuming AISI 440C is comparable to CPM S30V, and AISI 440C is comparable to 95kh18). Note that I've done quite a bit of handwaving in this comparison...
Two questions
Will this come out for people to buy them?
Will these be legal in states where balisongs are illegal?
1. Probably, he said it would be
2. Good question, but seems unknown as of now
1) that's his stated goal, so hopefully he succeeds and I can get one, too
2) currently they are legal everywhere, but that can change at any time
Ok thanks so much for the answers!
By changing the steels crystal structure via hardening and tempering it makes the magnetic properties change, you can try using electro magnetization on them to change the field again but it would be hard with the blade shape.
Could the blades now be in a hysteresis loop since being heat treated? As soon as the initial magnetism is added its just stayed? If it was something like that it should be easy to test as a sharp hit to the blades (but not enough to shatter the hardening) would remove the magnetic hysteresis.
cant wait till you finnish! im totaly gonna buy one!
To de magnetize you could try using high amperage AC current. Not sure how it would work on stainless
I have a gut feeling the aluminum blocks you used during quenching might have contributed to the magnetism. I can imagine a small em-flux being generated as you move the top block off and on.
I have literally zero interest in buying a pair of these because my hands are far too useless to handle something like this, but watching the process of making them is fascinating and I'm picking up so many tips for machining/making stuff in the process
not every steel can be tempered, some stainless steel became more ductile after quenching!
The reason why the blades are sticking more might be because after the heat treatment, the material is behaving like a soft magnet (like alnico). A soft magnet can change its magnet poles if they are near a strong magnetic field or a strong magnet. It seems in your case this strong field is produced by the neodymium magnets.
They sick because the blades are realining their magnetic poles such that the magnetic field follows the least magnetic reluctance path, through the blades due to it's low relative permeability. The magnetic flux of the strong magnet runs through the soft magnet (the blades) causing them to realign the magnetic domains inside the material causing North-South pole pairs matching the neodymium magnet poles. That is why you feel the are sticking more.
You can discard or verify if this is the case by sticking the neodimium magnet in any surface of the material. After doing this you pull out the magnet from the metal and flip it and then,you use the neodimium magnet to try to find any repulsion in this area (this forces might be hard to feel). The reason behind this is that we use the neodimium magnet in order to detect if the presence of this magnet has permanently changed the magnetic domains of the material. If you get close enough to the material you will feel attraction instead of a ligh repulsion and you will have to repeat the experiment.
I think this might be the case because I've experienced a similar problem when I was developing an electropermanent magnet driver in the past.
Sorry if I made typos I am not a native English speaker.
Thank you for your attention.
Instead of letting the blades cool after tempering. While they are 600° put them in a vice with three pins two pins on one side one pin on the other centered between the other two and clamp putting a slight bend in the blades. You don't have a lot of time where the steel will accept the bending so work quickly. But that should work.
Oxidizing is losing electrons, Reducing is gaining electrons (Oil Rig)
Maybe you could parkerize or blue them? Chemical treatments will wear on the structural integrity though
Another alternative is use a vacuum furnace so that that the blades don't oxidize in the heat treatment
- the roller is a MUCH better tool that hands without gloves, but I like to take a piece of stock and hold it perpendicular to the fold of foil I want to flatten, tilt it at an angle and slide the piece of stock over the fold so that the corner of the stock makes a single point with the foil as I slide it along the fold to really crease it.
- Stainless steel foil isn't that expensive so I usually just cut it oversized since it saves time. If you cut a piece too small, you'll either have to fight it to get the could to cover the piece and still fold shut, or start over with a larger piece.
- definitely throw in a few small pieces of paper scrap into the foil packet. While I mostly do air-hardening tool steels (not as much stainless steel) the little pieces of paper have consistently and categorically reduced the decarburesation of the surface of any part I've treated, I imagine this will hold true for stainless steel.
- I looked up some documentation for s30v and 1) from what you were saying, I believe you've got the gist of equalizing correct. While it's more important for thicker parts (just like cooking food, the internals take a while to catch up with the externals) holding the material at a temperature where it starts to radiate allows the internal temperature "catch up" so you don't have a huge differential, i.e., you don't want the center of the part to be lagging behind at 900, 1100, or 1400 degrees F while the outside is at 2000. Firstly, the coeffecient of thermal expansion would cause the outside to expand much more than the inside, and that could introduce unneeded stress into the part. Also, heat treating steels of all kinds are done to temporarily form martensite, it's quite possible that with a thick part, if you don't equalize, the center area could actually never reach the temperature to create the amount of martensite desired. After quenching, you'd lose the guarantee that a whole slew of interesting compounds end up in the steel.
- if you ever have trouble with the pin hole sizes, try to bore them 1 thou under so you can use a little expanding arbor lap to bring them up to size post heat-treat. It won't be fast, but it is a way to expand holes in hardened material.
- not all stainless steel is non-magnetic
- good results so far!! And major props to getting your hands dirty, trying new things, and sharing your results. This attitude and practice will take you incredibly far.
- Please wear gloves when dealing with that foil, even when cutting it open, you'll be able to do it faster without worrying about your hands as much lol. Yes, you can get away without it, but you'll save so much time and so many bandaids
just subscribed. Love your videos man. Keep it up!
I would look at trying D2 Tool steel. It's easy to work with and you can heat treat it with an oxyacetylene torch
Loving these videos
how about adding a pop out finger hole one you push to click and it pops out or clicks in flush?
Love these videos!
I hope this one day becomes a product cause I definitely would buy it
Simple little life did a video on air hardening steels. Best bet is to clamp between two pieces of aluminium and then blast with compressed air around the blade to quickly cool
Also Gough Customs has great videos on knife making.
I'm not sure if someone else has already mentioned this, or maybe you already know, but a good way to test if there's a burr is to use your fingernails, after you sharpen the blade, on the other side run your fingernail against it, if your fingernail catches, then you've got a burr.
I don't sure exactly, but I heard that then more hardened steel then it is more magnetic and less stainless
I’ve been watching the TV show available on Netflix called “forged in fire” and I’ve learned a lot.