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Post by greatsaiyaman888 on Oct 28, 2015 19:58:46 GMT
Kiyoshi, are you clear on the differences between ha-niku and hira-niku?
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Post by Kiyoshi on Oct 28, 2015 19:59:46 GMT
Again, you are not reading. I never mentioned thickness. I only mentioned mass, angles, etc. I asked which of those you agree and disagree. I will use the definition of resistance as requiring more energy due to ability to not be affected. Example, it requires more energy to push a heavier object than a lighter one due to more resistance to movement. Mass is mass. Total amount of matter, collection of matter, etc. With those definitions, which statements do you agree or disagree with. Disregard all other arguments and assumptions. Do not read between lines. There is no theory. I am only stating premises at the moment.
Ha niku and hira niku are not relevant at the moment. But for the record, yes I do know.
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Post by greatsaiyaman888 on Oct 28, 2015 20:06:48 GMT
Again, you are not reading. I never mentioned thickness. I only mentioned mass, angles, etc. I asked which of those you agree and disagree. I will use the definition of resistance as requiring more energy due to ability to not be affected. Example, it requires more energy to push a heavier object than a lighter one due to more resistance to movement. Mass is mass. Total amount of matter, collection of matter, etc. With those definitions, which statements do you agree or disagree with. Disregard all other arguments and assumptions. Do not read between lines. There is no theory. I am only stating premises at the moment. Ha niku and hira niku are not relevant at the moment. But for the record, yes I do know. I'm not sure I completely understand what you mean? Mass can equal thickness, and thus more weight which means less effort to cut, but I'm not entirely sure what you mean.
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Post by Kiyoshi on Oct 28, 2015 20:13:32 GMT
You can have the same mass with a different shape. You can have the same thickness width wise and have more mass. A 7mm blade with niku has the same width total as a 7mm blade without niku. Mass can increase thickness, but does not necessarily mean thickness will increase overall. Mass does increase thickness where added, but again, I'm not talking about that. I only want to know which statements you agree with, which you don't.
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Post by greatsaiyaman888 on Oct 28, 2015 20:17:02 GMT
You are also wrong about knives being used for chopping. All Japanese knives and chef's use them in a drawing motion and are all convexed, hence there was an issue with European's complaining that there Japanese knives were chipping because they were using them to chop with.
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Post by Kiyoshi on Oct 28, 2015 20:18:36 GMT
It claims that a hollow grind is best for slicing. I agree because the thinner the edge the better the slicer. Razor blades are the best slicers but we can't make a razor-blade katana. The best geometry for a chopping+slicing katana is convex. When you cut with a katana, you don't chop, you slice. I disagree. A katana does either or both, depends on your swing. 1. More mass, especially on the surface area pushing through an object causes more resistance. (eg, pushing a a 2x4 through water compared to pushing a 1/2" piece of wood). I disagree and say your analogy is not fair. I believe that the resistance is a factor of friction and area. More "area" of friction on a flat grind. But a convex blade has a more concentrated friction but at a very small area. The cumulative resistance is less on a convex blade when the media tends to grab or stick to the blade. If the media does not bind to the blade then a flat ground blade wins.2. A convex grind add more mass to the blade while keeping similar geometry adding strength to the blade. I agree.3. Adding mass to an angle makes the angle wider. I agree4. A thinner angle results in a thinner point. & 5. A wider angle results in a wider point. I disagree. The point is the same, but just behind the point is thicker (which is what I think you mean).6. You cannot add positive numbers to each other and get a lower number. 7. Adding material to a thin edge increases mass the near the edge. 8. A wider point of contact results in a wider distribution of force. And I say this creates a larger cumulative resistance (with certain media).9. A finer point of contact results in a finer distribution of force. And I say this creates a smaller cumulative resistance (with certain media).10. Assuming the same mass and initial movement speed, a finer distribution of force displaces material better. 11. Assuming the same mass and initial movement speed, a wider distribution of force displaces material worse. 12. It harder to displace material if you have to displace it faster (ie, it takes more energy to displace the same material in a shorter amount of time, assuming optimal displacement conditions). I would prefer to think of resistance and not displacement. And to use your terms I'd say it doesn't make a noticeable difference if you displace it faster by 2 or 3 mm with a swing that takes a fraction of a second.13. A wider angle must displace the same amount of material fast because its angle increases at a faster rate. 14. A finer angle must displace the same amount of material slower because it increases angle at a slower rate.
As I said, media is important. If you're cutting tatami mats, fresh, or a sheet of paper then the flat grind wins. If you're cutting wood, cardboard, maybe thick wall bamboo then convex wins.
Also depends on your swing. A more slicing type swing then flat grind wins. A more chopping type swing then... depends on the media.
I suppose I should have worded this better. When you cut properly with a katana, you should have a slicing style cut, not a chopping style one. Your analysis of 1 i very correct, I concede and find yours to be a better explanation. 4&5, yes that is what I meant. Would it be better to say the overall average angle of the given area of the blade that makes contact? 8&9 I'm referring to media which is not broken by the force (like chopping ice, where the force often cracks the material instead of displacing it as the blade moves through) but is instead displaced by it (like cutting soft stuff). I think I agree with your assessment overall and admit to probably being bad at wording things well. ^^;
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Post by Timo Nieminen on Oct 28, 2015 20:19:30 GMT
One question I do have concerns the T10 steel. The sellers claims this katana is T10 folded steel. I have to admit I rarely saw T10 offered in folded variety. Is this a load of bull$$$? Cause if I am not mistaken, T10 seems to be the most highly thought of steel as far as durability is concerned - so if that's the case, how come more sellers aren't offering it? Can T10 even be folded at all? As far as durability goes, 1060, 9260, 1055 etc. with somewhat less carbon than 1095 and T10 will be tougher (assuming typical heat treatment for swords). T10 and 1095 will have harder edges (assuming typical heat treatment for swords) and therefore better edge retention. Should be able to fold T10. Usually, when steel is folded, two different steels are used, so you get a higher contrast pattern. Not so common to see a single steel folded, whether T10 or otherwise (it used to be normal, with pre-modern steels).
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Post by Kiyoshi on Oct 28, 2015 20:19:31 GMT
You are also wrong about knives being used for chopping. All Japanese knives and chef's use them in a drawing motion and are all convexed, hence there was an issue with European's complaining that there Japanese knives were chipping because they were using them used to chop with. Some kitchen knives =/= all knives. Please stop assuming what isn't there. Please also use relevant information.
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Post by greatsaiyaman888 on Oct 28, 2015 20:22:06 GMT
You are also wrong about knives being used for chopping. All Japanese knives and chef's use them in a drawing motion and are all convexed, hence there was an issue with European's complaining that there Japanese knives were chipping because they were using them used to chop with. Some kitchen knives =/= all knives. Please stop assuming what isn't there. Please also use relevant information. No. I'd say pretty much all Japanese knives are convexed to some extent.
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Post by DigsFossils-n-Knives on Oct 28, 2015 20:22:07 GMT
It claims that a hollow grind is best for slicing. I agree because the thinner the edge the better the slicer. Razor blades are the best slicers but we can't make a razor-blade katana. The best geometry for a chopping+slicing katana is convex.
When you cut with a katana, you don't chop, you slice. I disagree. A katana does either or both, depends on your swing.
1. More mass, especially on the surface area pushing through an object causes more resistance. (eg, pushing a a 2x4 through water compared to pushing a 1/2" piece of wood). I disagree and say your analogy is not fair. I believe that the resistance is a factor of friction and area. More "area" of friction on a flat grind. But a convex blade has a more concentrated friction but at a very small area. The cumulative resistance is less on a convex blade when the media tends to grab or stick to the blade. If the media does not bind to the blade then a flat ground blade wins. 2. A convex grind add more mass to the blade while keeping similar geometry adding strength to the blade. I agree. 3. Adding mass to an angle makes the angle wider. I agree 4. A thinner angle results in a thinner point. & 5. A wider angle results in a wider point. I disagree. The point is the same, but just behind the point is thicker (which is what I think you mean).
8. A wider point of contact results in a wider distribution of force. And I say this creates a smaller cumulative resistance (with certain media). 9. A finer point of contact results in a finer distribution of force. And I say this creates a larger cumulative resistance (with certain media).
12. It harder to displace material if you have to displace it faster (ie, it takes more energy to displace the same material in a shorter amount of time, assuming optimal displacement conditions). I would prefer to think of resistance and not displacement, but to use your terms I'd say it doesn't make a noticeable speed difference if you displace it faster by 2 or 3 mm with a swing that takes a fraction of a second.
As I said, media is important. If you're cutting tatami mats, flesh, or a sheet of paper then the flat grind wins. If you're cutting wood, cardboard, maybe thick wall bamboo then convex wins.
Also depends on your swing. A more slicing type swing then flat grind wins. A more chopping type swing then... depends on the media.
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Post by DigsFossils-n-Knives on Oct 28, 2015 20:23:21 GMT
Sorry I changed my wording a little. DOUBLE POST in a way
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Post by Kiyoshi on Oct 28, 2015 20:24:52 GMT
Yeah, the difference is probably not noticeable either way, especially on softer targets. But even if the difference is so stupidly small, there is a difference and the difference is not "convex ground blades are the same as if not better than flat grind blades at cutting." A universal statement like that is simply untrue. An instance where flat grind blades are better disproves it. That said, I prefer niku for durability.
And it's all good. I was confused at first until I saw the wording changes. lol
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Post by DigsFossils-n-Knives on Oct 28, 2015 20:32:24 GMT
Yeah, the difference is probably not noticeable either way, especially on softer targets. But even if the difference is so stupidly small, there is a difference and the difference is not "convex ground blades are the same as if not better than flat grind blades at cutting." A universal statement like that is simply untrue. An instance where flat grind blades are better disproves it. That said, I prefer niku for durability. And it's all good. I was confused at first until I saw the wording changes. lol Which is why I'm interested and value your personal experience. When I chop or slice I don't concern myself with edge alignment. But you katana guys are very finicky about that (and I say this in a good way). Many of you guys/gals analyze the bamboo cuts to determine if your alignment needs adjusting. So I'm very interested in understanding what you Kenjutsu/Iaido/etc. folks prefer and why. Theory is all good and well but I'm more of hands on/practical/real life experience.
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Post by Timo Nieminen on Oct 28, 2015 20:33:20 GMT
The key point Gavko makes is that a flat grind blade has a cumulative friction along the bevel while the friction at the curve of the convex blade is less. So less resistance on a convex blade. Depends on what you cut. Cutting meat at low speeds, I find flat grind is best. Meat isn't sticky, and is fairly soft. Cutting hard vegetables, it depends on how thick they are. For very thick hard vegetables (hard pumpkins, taro), I use a very convex-edged knife (a cleaver with lots of niku for surviving chopping); with a flat grind, the elasticity of the vegetable clamps it against the blade, and there is more resistance. Also, more force is needed, and I'd rather do that with a less delicate knife. Cutting cheese is different again - it's very sticky. Cutting with a sword is different again, since it's a very fast cut. Those who get into competitive tatami cutting often go for thin wide blades with no niku. So not good for comparison, since they're thinner as well as no-niku. Can't say from personal experience since my only plenty-of-niku katana is not very sharp.
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Post by greatsaiyaman888 on Oct 28, 2015 20:37:14 GMT
Like I said to begin with, on soft targets its really not that noticable. That aside, I've never come across a true flat grind katana either. So how do we know your thesis for a direct comparison can be fair unless you have a true flat grind katana and a well shaped full convex one unless you do it yourself or have someone do it for you.
In MY experience, I never bother with a full flatgrind seeing as what i can do with a full convex grind on ALL targets (hair, paper, bottles, beachmats, tatami, bamboo) that a profiled blade from factory would pale in comparison.
Now I've had thin, flat blades with a small secondary bevel that are will roll, chip, and dull rapidly on waterbottles and beachmats. I can convert these too with ha-niku and still be razor sharp with no edge damage after tackling the same targets after 100's of more cuts... So I'll ask again if you can make a realistic comparison of a full flat grind katana vs either a ha-niku katana or one with hira.
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Post by greatsaiyaman888 on Oct 28, 2015 20:39:22 GMT
The key point Gavko makes is that a flat grind blade has a cumulative friction along the bevel while the friction at the curve of the convex blade is less. So less resistance on a convex blade. Depends on what you cut. Cutting meat at low speeds, I find flat grind is best. Meat isn't sticky, and is fairly soft. Cutting hard vegetables, it depends on how thick they are. For very thick hard vegetables (hard pumpkins, taro), I use a very convex-edged knife (a cleaver with lots of niku for surviving chopping); with a flat grind, the elasticity of the vegetable clamps it against the blade, and there is more resistance. Also, more force is needed, and I'd rather do that with a less delicate knife. Cutting cheese is different again - it's very sticky. Cutting with a sword is different again, since it's a very fast cut. Those who get into competitive tatami cutting often go for thin wide blades with no niku. So not good for comparison, since they're thinner as well as no-niku. Can't say from personal experience since my only plenty-of-niku katana is not very sharp. Do you chop or draw when you cut meat? Me and my generation always draw meat with a convex blade and it's like cutting butter.
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Post by Kiyoshi on Oct 28, 2015 20:40:08 GMT
As far as practical, you had it pretty much on the nose. Niku is all about durability. Hira blades are for slicing soft targets cleanly. A lot of the modern tameshigiri people prefer hira blades because of how clean and easy their cuts are. Assuming good edge alignment, a hira blade will slice through tatami like butter. I've used a thin blade a couple of times and it felt like cheating. It cut better than any expensive blade I've seen. However, it would bend on a bad cut and chip on a hard target. The flat blades are all about soft targets. You can cut bamboo with it, but experience says it'll chip sooner rather than later. I have the kissaki of a katana that chipped a little and I had to redo it because I got bold and tried to cut something harder than I should have. It looks fine now, but yeah... lol
I prefer niku because of tradition and durability. You have to sharpen a blade with niku less. It also doesn't bend very much. On bad cuts it just send the target flying or the target gets stuck on the blade part way through. Also, to get the cut to do the initial "bite," you have to have good alignment. The tradition comes from battles where you'd accidentally hit edge to edge or hit armor or something. The niku blades lasted through that better. Sadly, I've only used one blade with real niku and I don't have access to it anymore (was a fellow school mates).
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Post by greatsaiyaman888 on Oct 28, 2015 20:47:19 GMT
As far as practical, you had it pretty much on the nose. Niku is all about durability. Hira blades are for slicing soft targets cleanly. A lot of the modern tameshigiri people prefer hira blades because of how clean and easy their cuts are. Assuming good edge alignment, a hira blade will slice through tatami like butter. I've used a thin blade a couple of times and it felt like cheating. It cut better than any expensive blade I've seen. However, it would bend on a bad cut and chip on a hard target. The flat blades are all about soft targets. You can cut bamboo with it, but experience says it'll chip sooner rather than later. I have the kissaki of a katana that chipped a little and I had to redo it because I got bold and tried to cut something harder than I should have. It looks fine now, but yeah... lol I prefer niku because of tradition and durability. You have to sharpen a blade with niku less. It also doesn't bend very much. On bad cuts it just send the target flying or the target gets stuck on the blade part way through. Also, to get the cut to do the initial "bite," you have to have good alignment. The tradition comes from battles where you'd accidentally hit edge to edge or hit armor or something. The niku blades lasted through that better. Sadly, I've only used one blade with real niku and I don't have access to it anymore (was a fellow school mates). No, the reason they use hira blades is because they are lighter.
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Post by Kiyoshi on Oct 28, 2015 20:49:50 GMT
The two aren't mutually exclusive. They are both lighter and easy to cut with.
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Post by greatsaiyaman888 on Oct 28, 2015 20:50:23 GMT
Which is why you see them pulling off 5 successive cuts in a second.
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