The Value of Blade Resilience and Good Heat Treatment

[LMarshall32]

Now this was an IMPRESSIVE video!!! Thank you for putting the effort in, WOW!!!

[frozenwalkway]

perhaps the failure most people are worried about is edge chipping? which shouldnt happen when the blade is used for its purpose. nice video.

[knivesandstuff]

@frozenwalkway That may be an issue that most worry about.. but its the same issue to a degree.. the same things that cause a blade to not be resilient are just magnified on the edge. and yes, correctly used most blades shouldn't have too much issue with chipping, although I guess accidents always happen.. especially with machete type blades.

Any blade can and will chip easily if mishandled I think

thanks for watching

[frozenwalkway]

@knivesandstuff i think thats where differential heat treating still comes to play, where as the soft back will allow alot more high degree bends, while still keeping a hard edge. but im not familiar with O1 so exscuse me if im speaking out of my ass.

[edwdixon5]

The title shot looks like you're rescuing a kitten by chopping it out of a tree.

[traderjoes]

Ive found that all of your 01 blades that I have and have used over the years to be the easiest for me (as a novice) to maintain and also perform reliably. The little Micro necker I got from you is one of my all time favorites and has been invaluable to me.

[madhatterjc1]

I feel like 01 is having a rough time because of the new powder steels. But when its done right, its amazing how good it is! I want one so bad now!

[CliffStamp]

One of the things which is critical with your blades is the cutting ability and how it also inherently dampens the shock. Just do a quick cut with one of your blades fully ground and sharpened and then butcher it by putting a 25 degree v-bevel on it with the edge about 0.045" thick. Now cut with that and see the difference. The impact shock in general will be inversely proportional to the depth of cut, which in the second case is much reduced.

[CliffStamp]

Ironically, the working hardness that O1 is often drawn down to to increase toughness, 57-59 HRC or so actually will induce severe embrittlement due to carbide precipitation and the impact toughness is reduced by as much as 50%. The impact toughness actually increases up to about a 400 F draw which (depending on quenchent and soak temp/time) produces about 61 HRC. In short, nice choice.

[knivesandstuff]

@CliffStamp it is weird.. I used to use 57/58 because it was easier to field maintain.. but with the new heat-treat I'm doing the 60+ doesn't seem any harder to sharpen. Crucibles testing shows optimal toughness at 61/62 with good HT.. the difference in toughness is almost neglibible from 57RC.. so as long as done well.. this gives a stronger edge with equal toughness.

[CliffStamp]

@knivesandstuff Yeah, in general I don't like reducing hardness to try to gain ease of sharpening because while the steel grinds a little easier it tends to burr much more readily. I would general prefer a switch to a simpler steel if grindability was a concern and that is really only an issue if the knife is likely to take visible damage in use (like rough machetes) or if it wasn't ground sensibly and you had to sharpen a big wide edge.

[parbitor]

Very informative Dude. Could you please expand on differential heat treat vs. mono?

[knivesandstuff]

@parbitor Expand in what particular way? is there something specific you want to know. I will say that there is no right way or wrong way. each will provide different mechanical attributes.

[parbitor]

@knivesandstuff OK, so as an IT person, I understand differential vs full tape backup but not differential heat treat as opposed to mono heat treat - ? I'm assuming MOno heat treat is one cycle and perhaps differential is multiple, building heat treatments - safe assumption Sir?

[knivesandstuff]

@parbitor ah.. ok.. Mono means that the entire blade is heat-treated to the same level and hardness throughout the entire steel. a Differential heattreat is like the Japanese Swords where the edge portion is hardened to a much higher level than the back portion which is normally left quite soft. the idea of this is a soft back supporting the harder edge so that it doesn't crack or shatter if the entire steel was hardened.

[parbitor]

@knivesandstuff Roger that. Thank you very much. Appreciate your channel.

[knivesandstuff]

@parbitor ... Modern steels have so many options and such good quality forging from the foundries that often, a differential heat-treat is not offering a lot of advantage (IMO) but many people still love them for the aesthetics and historical meanings. a steel like 1095 that might be good at 58/59RC as a mono could possibly be taken to 62RC on the edge with a 40RC softer back to support it. very useful in swords and high impact weapons.

[BrianS3000]

This reminds me of the cold steel DVD they show all their sabers and what not going through similar tests. Apparently they were devised by the British empire after weapons given to the royal army failed metallurgically back in the victorian era

[OriginalOwner777]

man I would love to see in part to silence the haters on custom small makers like yourself you torture testing one of your blades versus a spyderco and cold steel knife of the same size all fixed blades of course. I would bet all I will ever own yours would come out on top

[bassfuryvi]

A W E S O M E ,,(my cleaver blades would rather bend the tree ha ha),,,super heat treat and blade there Kyley!!

[knivesandstuff]

@bassfuryvi Thats the advantage of the even thicker spines. Then it will be snap the tree or snap the knife, but not so much bend.

[Dbear723]

Very impressive flex for a blade of that hardness. A while back you showed a video of a knife blade you had dropped and the tip had bent rather than snapped off even though it had been heat treated to a high Rc. Was that the same O1 steel? If it was I think that video along with this one really demonstrate what a proper heat treat can accomplish.

[knivesandstuff]

@Dbear723 Yes, that was the tip on one of the O1 kiridashi that fell to the concrete when I was sharpening it.

[Dbear723]

@knivesandstuff Yep, that is what I was thinking of. Comforting to know that you can make a knife with steel that performs that well and a geometry that is so effective at cutting without having to rely on an inflated brand name reputation to generate sales. Just saying.

[johnwoodz1220]

You see what I mean about what public perception has done. Now to see something like the Persian in 01 at 62RC do that and flex nicely like that feels surreal, because even though I've seen it in all of the videos it has been drummed into me as a UK Youtuber from constant old reading about the steel being very brittle because of the varied results garden heat treats give.

And it still feels unreal now. So what blades would benefit from differential HT then Kyley,rather than mono except a sword?

[johnwoodz1220]

@johnwoodz1220 I am always amazed at the dental picks I have . They are such fine tips , yet they are so strong and flexible. The heat treat on those must be awesome.

[knivesandstuff]

@johnwoodz1220 There is lots of proof that modern swords with a mono heattreat and mono steel can be far superior in toughness and such than a DT blade. there are some people doing 60RC CPM3V blades. there can be a lot of advantage to a blade DT if you want to hit over 60RC on the edge and have a softer centre or spine because it "handles" differently

[johnwoodz1220]

@knivesandstuff Ok Thanks Kyley. So usually for a sword handling or weapon......longer blades.

[cahoonu]

I think if you want to use your knife as a pry bar, you should just go and buy a pry bar.

One of the big knife manufacturers shows them bending their machete's nearly touching the tip to the handle, yet when you buy one, you find out the edge dents very easily, so you have to put a big bevel on it to support the edge.

Can you cut dry hardwood, like Grey box Eucalyptus with that large Knife.

Nice video. Thanks.

[knivesandstuff]

@cahoonu No idea if I can cut dry hard Eucalyptus. I dont have any.. please bear in mind that this is not an axe, or an over heavy blade. its only 434 grams. its designed for my type of vegetation. Live bush, and woods. it can easily handle 4" trunks without issue, and also deal with light foilage without exertion. The ability to bend the blade as much as you say will also be because its a very thin blade. Bandsaw blades 63RC will also bend like that, but they wont dent.

[cahoonu]

@knivesandstuff I wasn't trying to be smart, I was just trying to see if it would cut that type of timber. I really like the idea of having a knife with a hardness of 60-62. Is the edge retention greatly increased with that sort of hardness or just a little bit.

Thanks.

[knivesandstuff]

@cahoonu I took your question honestly.. I just seriously mean that this blade doesn't have the heft needed to break into a dry hardwood. Its like swinging a sword at a tree.. often they just bounce off, even if they can cut right through a human body.

The Edge retention is greatly increased. tests seem to show a step up of about 20% edge retention per 2pt RC increase on carbon steels. each increase 20% more than the last. also, the stronger edge resists rolling better.

[knivesandstuff]

@cahoonu the 13" bladed Forrester-XXL I am building now as an experiment is a 1kg blade, 10mm at the hilt down to 3mm tip.. its 61RC.. that will be a better example of a hardwood cutter. The edge wont be as fine, because it needs to support the mass behind it against deflective blows. but it should show some good information in a week or 2. I just need to find some wood. I may buy a 4"x4" fence post treated wood.

[johnwoodz1220]

@knivesandstuff That's the main event on my calendar that 13" Forrester.

[knivesandstuff]

@johnwoodz1220 I've finished the foundation grinds on one of them. Just need to put a handle on, and then finish the grinds.

[johnwoodz1220]

@knivesandstuff :D

[Killahofosho]

I don't know why but after watching this i want to see a full on destruction test! I fully understand what you meant about not stressing yourself and your blade to the extreme! I just think it would be cool to see you destroy 1 of your own blades! I can't think of any blacksmith that's crazy enough to do it!

[knivesandstuff]

@Killahofosho Haha.. I dont think its worth the risk of having a shard of razor sharp steel fly into my face or leg. :) The goal of a knife is to try and use them in an intelligent way so that you dont break them.. But I fully understand your desire to see "how far it can go".. The answer is.. Further than would normally be required.. if you are doing anything in real life that would damage this, then I think the plan needed serious reconsideration :D

[Killahofosho]

@knivesandstuff wise man! Given the proper protection you gotta admit it would be cool to see and yes I completely agree with you it would be irresponsible!

[Nebulax123]

I will try that with my Persian (When pigs fly over Atlanta singing Yankee Doodle at the same time)

[chavezchavez556]

Great information as always ! Youtuber of the Year type shit !

[sae1095hc]

Is that a cryo heat treatment in action?

Read an interesting article on cryo conversion of residual austenite into martensite, it seems that they don't really know how it works, just that it does.

[gavkoo]

@knivesandstuff I think i will be scared lol. You think my 154cm should be able to do that too?

[knivesandstuff]

@gavkoo a lot of factors. the thickness being a large factor.. the heat-treat also a big factor.. I would expect any blade of that size to flex like that if I was going to trust it in use. The thicker it is, the harder it is to bend, but also it cannot bend as much. make it 1mm thick and it will fold easily like a bandsaw blade. The larger carbides may make it more susceptible to fracturing.. Im not sure though.

[27dcx]

every time you bent that blade i cringed and and winced. It was like a horror movie.

[knivesandstuff]

@27dcx So a slow motion 1000fps video of the average person trying to chop through a 4" log with something like this and you'd cringe watching what happens to the blades :D

[decisiveweb]

Wow... Thanks for the demonstration and information about why this works

[gavkoo]

Awesome stuff. Incredible what that steel can do.

[knivesandstuff]

@gavkoo You can try bending yours when you get it.. lol.. Just dont cut yourself :D

[pennfootball71]

That is a fantastic demonstration Kyley...Thank you for that!

[ndcouey70]

Heat treating is the difference maker on most knives. That's a fine knife you're using, and obviously done right. Thanks for sharing.

[mrvoodoo94]

Makes me wonder what we are going to do with heat treat on our build along LOL. Very nice blade you have there :)

[knivesandstuff]

@mrvoodoo94 hehe.. Tim's got a number of options to show some home HT options that should be adequate. he as also arranged for everyone who wants to send them back to get a heat treat done.

[Kmann071]

Why you gotta be hating on that tree? J k lol

[bigtankatx]

Very bad ass bro one of these day I'm going to stop bsing an order one of your knives

[gitterright]

Damn that's a great demonstration! I learn something every time i watch your videos

[zonzar27]

very informative video Kyley great job love the lines of that blade

[TheBrowningmaxus8833]

thats an awesome knife

[TACsurvivalist]

first lol