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Post by Robert in California on Aug 10, 2020 12:00:41 GMT
Choice of blades, other than the "cool" factor, is there any reason to prefer a kobuse blade over a mono steel blade? Say, the kobuse is has a non-folded 1045 or 1060 core and a non-folded 1095 or T10 skin? Thanks, RinC
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Post by Stef on Aug 10, 2020 12:13:16 GMT
It entirely depends on what you are trying to achieve, kobuse or any other method to make the best of the steel that was used at the time and create very interesting patterns, effects and activities.
Modern steel will look more plain and less intricate but generally modern steel if used correctly is going to be stronger . I like both.
DH modern steel can be very attractive if used expertly.The cost of kobuse will mean you will most likely not use it for cutting. I am no expert so take my opinion for what it is worth but I fail to see the point of doing kobuse with modern materials using 1045 or 1060.both those materials if used correctly will create very strong blade, making them in to kobuse seems unnecessary
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Post by RufusScorpius on Aug 10, 2020 13:03:30 GMT
I agree with stefano, modern steels don't require kobuse. If you look at it from a broad perspective, Japanese smiths were trying to take very poor iron sand and make a decent steel from it. Because of their poor quality materials, they had to refine and process the ore extensively, which was quite an accomplishment that they managed to do it. Therefore they had to hammer and fold and purify and fold and hammer and heat and hammer until they got something they could work with. However, not taking anything away from their expertise or creativity, all they really managed to do was make spring steel. In modern times we make pure spring steel by the metric ton every hour every day. We have so much of it that we can't hardly give it away.
In the post-apocalyptic zombie infested world, if you need to make a sword, simply find a junkyard and grab a leaf spring from a big truck. Sharpen it and put a handle on it and you have (basically) a samurai sword. The edge hardening is optional at that point, the steel by itself is hard enough to get the job done without any extra work.
Everybody on this forum knows I favor Japanese swords, yet I am also not a "fanboy" of them either. I understand their limitations. So with that in mind, it's important not to buy in to the mythos of the katana and it's folded steel DH glory. It's a great sword, but it's still only spring steel at the end of the day.
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AndiTheBarvarian
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Post by AndiTheBarvarian on Aug 10, 2020 14:08:12 GMT
There is no reason for lamination other than the cool faktor. In former times with less heat treatment knowledge it could help, but nowadays it's just cool.
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Post by Timo Nieminen on Aug 10, 2020 21:43:11 GMT
In former times with less heat treatment knowledge it could help, but nowadays it's just cool. This! Quenching is relatively easy. If you don't have temperature controlled ovens or thermometers, reliable tempering is difficult. If you're tempering by slack-quenching (auto-tempering) or similar, a low carbon unhardenable body guarantees that at least part of your blade will remain tough. Lamination 1095 and 1045, whether kobuse, sanmai, or inserted-edge, is not pointless, since the 1045 will be much tougher than the 1095. But if you differentially harden, you get a tough body anyway, so not so much point. With modern steels, lamination will let you through harden and avoid having a brittle body. Japanese smiths were trying to take very poor iron sand and make a decent steel from it. Iron sand is usually good ore, and Japanese iron sands are good ore. The problem isn't the ore, but using a bloomery furnace, in which the chemisty happens in the solid state, and you don't separate the slag from the iron/steel. Not just a Japanese problem, but a problem everywhere that bloomeries were used, which is why everybody folded bloomery iron and steel.
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addertooth
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Working the tsuka on two bare blades from Ninja-Katana, slow progress
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Post by addertooth on Aug 13, 2020 5:35:38 GMT
I think the historical perspective is interesting, but not entirely applicable. A modern (commercial) Kobuse sword is made with MODERN steel. So the arguments about the poor quality of bloomery foundry Tamahagane, is not entirely germane. So a Modern Kobuse sword has the benefit of modern steel and a different structure.
I have a gyaku Kobuse blade which is differentially hardened. So the edge is Much harder than what is found on a through hardened monosteel blade, and, it has a softer and more shatter resistant spine to boot. These factors are not critical for mat cutting, but in combat, they are important. There were reasons beyond quality of steel, which dictated the creation of some of these different laminations.
Now to argue against myself, most likely none of our blades will ever see combat... so the point is largely moot.
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Post by zabazagobo on Aug 13, 2020 8:03:44 GMT
Ignoring the often stated mantra of "modern steel"...yeah, a kobuse blade should be better than a monosteel blade. Period. Only if it is done correctly, and the performance difference may be insignificant for mat cutter blades and whatnot.
I think rather than fretting about lamination, modern blades by and large need some "meat". Niku it up please. Not for combat, sensei.
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Post by Timo Nieminen on Aug 13, 2020 23:38:07 GMT
yeah, a kobuse blade should be better than a monosteel blade. Period. Why? Today we can do a differentially-hardened monosteel blade with a hard edge and a spring-tempered body. We can do the same with something like a kobuse blade with a 1095 skin and 1045 or 1060 body, and then both have a hard edge and a spring-tempered body. It isn't obvious to me that one is better than the other. If the monosteel blade is 1095, they have the same edge, and the same skin (and cracks are equally likely in the skin in both blades for the same deformation).
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AndiTheBarvarian
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Post by AndiTheBarvarian on Aug 14, 2020 6:11:44 GMT
Afaik theoretically 1045/1060 will always be a little bit tougher than 1095 but lamination can fail too. Modern heat treatment was developed for monosteel blades so it's not unthinkable that laminated blades can have unexpected problems with it.
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Post by zabazagobo on Aug 14, 2020 18:38:58 GMT
yeah, a kobuse blade should be better than a monosteel blade. Period. Why? Today we can do a differentially-hardened monosteel blade with a hard edge and a spring-tempered body. We can do the same with something like a kobuse blade with a 1095 skin and 1045 or 1060 body, and then both have a hard edge and a spring-tempered body. It isn't obvious to me that one is better than the other. If the monosteel blade is 1095, they have the same edge, and the same skin (and cracks are equally likely in the skin in both blades for the same deformation). Having a little fun playing devil's advocate.
Theoretically, there should be structural advantages to a kobuse blade...if done correctly. Combining different properties of different steels seems like an interesting trick with the abundance of quality modern materials available for use. The trick is doing one correctly and they're easier to mess up compared to the far more efficient methods more commonly seen today.
I still think having a highly shock absorbent core and a hardened edge using something like a 9260/T10 combo is an interesting thought experiment, and knowing how it helped historical specimens with poorer steel quality it'd just be interesting to see the process revisited with more advanced modern materials.
So just musing and amusing myself, just don't see enough experimentation these days. After all, modern mono-steel does the trick perfectly fine and lamination is error-prone and more complex. Just always been intrigued by the prospect of revisiting those methods with modern advancements.
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Post by Timo Nieminen on Aug 14, 2020 21:03:37 GMT
One problem is that if cracks start in the harder steel, they can spread into the tougher steel. (This is why traditional katanas break more easily if the spine is hit hard against something than the edge - hitting the spine is more likely to start a crack on the hardened edge because it's put into tension, and the crack can spread all the way through the blade.) Laminations like sanmai and inserted edge will be less likely to crack, since there will be tougher steel where it will be under most tension when hitting something or flexing sideways. There's a better case for these laminations being better than than DH monosteel than kobuse.
The other trick to make the blade less likely to break is bad welds. Bad welds can stop cracks. I think this is difficult to do consistently, but in principle it works.
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Post by Stef on Aug 15, 2020 0:00:27 GMT
The other trick to make the blade less likely to break is bad welds. Bad welds can stop cracks. I think this is difficult to do consistently, but in principle it works. elaborate please
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Post by Timo Nieminen on Aug 15, 2020 2:07:00 GMT
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Post by Stef on Aug 15, 2020 2:37:48 GMT
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Post by treeslicer on Aug 16, 2020 0:08:24 GMT
In the poll I only chose the monosteel over the kobuse because there wasn't a choice for "DH Folded Steel", and I don't trust the production swordmakers to know what they are doing with real kobuse......
On the subject of DH folded steel, please don't argue with me without reading the papers that Timo posted.
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Post by zabazagobo on Aug 21, 2020 5:10:56 GMT
In the poll I only chose the monosteel over the kobuse because there wasn't a choice for "DH Folded Steel", and I don't trust the production swordmakers to know what they are doing with real kobuse......
On the subject of DH folded steel, please don't argue with me without reading the papers that Timo posted. Well said. And yes, those articles were very good reads. Thanks, as always Timo Nieminen
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Post by vidar on Aug 24, 2020 8:21:58 GMT
I think modern monosteel is best. Like DH L6 steel from Evolution Blades or MAS. Or TH 5160 steel such as a raptor. These are all very tough blades.
Now, an expert Japanese smith could probably also make a very tough Kobuse blade. But then it takes a lot of experience and requires a smith who knows what he’s doing and who’s testing his blades...
But if we’re talking about discount Chinese smiths making Kobuse blades, then I’m quite sure the result will be far inferior to a monosteel blade...
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Post by stefano2426 on Jan 13, 2024 16:55:11 GMT
Why? Today we can do a differentially-hardened monosteel blade with a hard edge and a spring-tempered body. We can do the same with something like a kobuse blade with a 1095 skin and 1045 or 1060 body, and then both have a hard edge and a spring-tempered body. It isn't obvious to me that one is better than the other. If the monosteel blade is 1095, they have the same edge, and the same skin (and cracks are equally likely in the skin in both blades for the same deformation). Having a little fun playing devil's advocate.
Theoretically, there should be structural advantages to a kobuse blade...if done correctly. Combining different properties of different steels seems like an interesting trick with the abundance of quality modern materials available for use. The trick is doing one correctly and they're easier to mess up compared to the far more efficient methods more commonly seen today.
I still think having a highly shock absorbent core and a hardened edge using something like a 9260/T10 combo is an interesting thought experiment, and knowing how it helped historical specimens with poorer steel quality it'd just be interesting to see the process revisited with more advanced modern materials.
So just musing and amusing myself, just don't see enough experimentation these days. After all, modern mono-steel does the trick perfectly fine and lamination is error-prone and more complex. Just always been intrigued by the prospect of revisiting those methods with modern advancements.
Well, 4 years later and maybe nobody is paying any attention to this thread anymore, but just want to say that I did order a very, VERY custom sword that is on its way to me as I write: a kobuse steel, folded T10 and 9260 spring steel, moroha zukuri blade - clay tempered and oil quenched-, aikuchi wakizashi. If anybody is still interested I might post some thoughts once I receive it. However, please be informed I am completely new to the world of swords, so don't expect an expert opinion. Given zagazagobo ideas in his earlier post, I thought is quite an interesting coincidence that I chose exactly the steel combination he mentioned as a possible experiment with modern materials. Went a bit further, choosing an unusual blade type/shape, which might have been a bad idea, ruinning the experiment, for what I know. I guess, I'll see...
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AndiTheBarvarian
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Post by AndiTheBarvarian on Jan 13, 2024 17:33:09 GMT
Cool! (Welcome to the forum!)
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Post by eastman on Jan 13, 2024 20:29:36 GMT
of course you need to post pictures of your new sword
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