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Post by blairbob on Jun 30, 2023 8:14:44 GMT
So I practice JSA and have been doing for a fairly long time (since Y2k ish). I have farted around with some HEMA/ARMA guy at Ren faires years ago when they would host mini clinics. Don't currently have any Euro swords but did have a Hanwei Godfred and Irish Bastard sword once upon a time besides handling whatever at knife shops or ren faires (pretty much Windlass and Hanwei stuff)
I've cut some bamboo, dowels, and mats. and apples and citrus fruit though not big melons.
So depending on what time you're in Japan, you were likely dealing with various armor types (we'll pretend that your rich enough to have full decked out yoroi kit and not just a poor Ashigaru).
So like Full Plate Armor, this should make a warrior a walking tank besides the various weak points in the armor. Possibly some chain underneath (which also was sometimes worn just in general without armor)
And there are techniques for that. Raise the skirt to get underneath the legs, slip in at the armpit or neck, etc. Close ranks with grappling and use a stabby knife to pierce armor.
But getting back to it, let's switch to the Tokugawa period. No one is really wearing armor for a long awhile and maybe errant Samurai and Ronin are going around dueling. Maybe some castle guards are wearing armor but dunno if there hasn't been a war or rebellion in a century or two.
Let's say they aren't poor AF, so they have a juban undergarment, maybe a kimono or happi coat or both.
Now how easily is can a fairly sharp katana going to slice through a few layers of silk?
Especially if it's not tight and has some slack.
I suppose over in Europe, your soldier now has some kind of cotton or wool uniform, likely a few layers if it's cold AF. It may be as thick as canvas (let's think about US revolutionary or Civil war uniforms besides what soldiers were wearing during the time of Napoleon where sabers were still being used besides musket balls)
From some of the ppl I train with, I think they feel like a katana being sharp and stabby can just easily slice through multiple layers of garments. Maybe this is too much Hollywood or the fact they haven't ever cut a damn thing.
Stab, sure. But slice even in a draw cut?
I also though silk was tougher than spun cotton?
I do have some cotton kimono but I'm not willing to sacrifice those. I suppose I could find some others ones besides just some army surplus shirts or t-shirts if I were to get some ballistics gel.
I have seen them cut some garments with ballistic gel but I'd have to go sift through Youtube, which I likely will but would love to hear any feedback on.
TLDR, how well can sabers and katana cut through thick cotton canvas, layers of silk or cotton instead of just dead bodies stacked horizontally?
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Post by mrstabby on Jun 30, 2023 9:59:30 GMT
Silk is more tough as in it has more tensile strength, but cutting resistance isn't that different to cotton I'd wager. Cutting resistance is more about the weave density and arrangement of a fabric (unless you throw modern fibres used in cut resistant gloves in the ring, I think structure is more important than material here). Gambeson is tightly woven and very hard to cut. The fabric also needs to have some give to it, stretched fabric is relatively easy to cut, free flowing not so much. I think silk was just too expensive compared to cotton to see many an armor made out of it and the difference too little. I have cut silk with knives and scissors and the light fabrics don't feel more hard to cut than cotton. But as I said, it will depend on the structure of the weave. I have also cut dacron (for bow strings), wich is very tough, but cutting it feels like any other thread of the same thickness.
EDIT: Kevlar is also very strong, and a low level bullet proof vest can stop handguns, but not neccessarily stabs and cuts! There is a seperate rating for cuts and stabs.
EDIT2: You probably could make silk armor more cut resistant to cotton or wool because you can weave it tighter. Theoretically.
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Post by Sir Thorfinn on Jun 30, 2023 19:28:20 GMT
Do your own cutting test and post it. Somewhere in the archives, there's folks who have done cut test with multiple layers of denim etc on meat of some sort. But IMO, MrStabby is spot on. My playing with it has shown cloth to be surprisingly cut resistant....your mileage may vary.  |
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Post by blairbob on Jun 30, 2023 21:39:52 GMT
Yeah, that's what I really think it is the case, especially with multiple layers.
yeah, from when I have seen gambeson and european armor that definitely seemed the case, especially with leather. I had some leather scraps around that I may have thrown out (since I did nothing with them for 15yrs)
I've seen some practitioners assume they can just cut and slide a blade across clothing and cut beyond the cloth (layers) deep into the flesh and I've got a feeling that's too many movies and lightsabers.
If I recall, you cant really cut a rolled mat in a stand by sliding a katana across it. It just sort of indents unless it's scary sharp.
Like I'm sure, if it just skin, it'll cut just fine.
But I also remember the time I went down to Bugei and one of the senior students showed me how you could place a blade against the skin and still move with it touching without getting sliced. I do wonder know if the blade wasn't too keen but it definitely looked sharp with no bevel.
time to get some melons and tshirts whose will get marked for death instead of shop duty in the garage.
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Post by mrstabby on Jul 1, 2023 8:33:21 GMT
Skin and meat are surprisingly easy to cut, but the clothing makes much difference. Some fabrics are easier to cut than others, modern synthetics are easier than wool or cotton to me. Some stiffened fabric almost feels like cutting paper.
An edge can be razer sharp but have no bite (fully mirror polished and/or a relatively high edge angle) you can quite easily run your finger on such an edge without cutting yourself (if you dont push). If the edge has teeth it will not be so easy to do that. Toothy edges are better at draw cuts, polished make better push cuts and are more durable. If a sword edge is very toothy, you can probably draw cut fabric very easily, but the teeth wont last as long as a polished edge will in my experience.
If the fabric is backed by something hard, it will be easier to cut than if there was something soft underneath. Soft backing acts like a parachute, slowing down the blade before it gets enough resistance to cut into the target. For the fabric, the more mass there is in the way, the less you are able to cut, so a tighter woven fabric needs more force because you need to cut more strands for the same length cut. If you add both together, softness and tight weave, you get something that will stop many cuts.
Try cutting a piece of fabric on a cutting board, then put foam or something under the fabric. You can of course go the other way and use something like resin (I dont know what one would have used in ancient times or if this was done) to make hard laminated armor.
I think if there was significant difference in cut resistance between silk and cotton/wool there would be more armor like it around, no matter the price.
My grandpa shot a curtain once to end a discussion. Free hanging silk fabric can stop some big, slow handgun bullets according to him (I have heard this from other sources over the years too). Unfortunate for him the curtain wasnt silk and pretty heavy and he lost the bet. I have been wondering for decades, if real silk could have stopped the bullet from his snub .38 spcl revolver.
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AndiTheBarvarian
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Post by AndiTheBarvarian on Jul 1, 2023 8:38:00 GMT
Your grandpa had a discussion with a curtain?
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Post by mrstabby on Jul 1, 2023 8:44:15 GMT
Your grandpa had a discussion with a curtain? Nobody else woul listen as quietly after all. And it never ratted him out to the police as well! |
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AndiTheBarvarian
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Post by AndiTheBarvarian on Jul 1, 2023 8:55:10 GMT
Anyway, I'm sometimes thinking about "armor" made of the usual clothes in my wardrobe, in case of shtf.
T-shirts, thin shirts, thicker shirts, pullovers, thick woolen sailer-pullovers, felt fabric.
Multiple layers of course, but only many thin layers, or thin inside, thick outside, or the opposite?
Combined with leather jackets, for bikers?
Not to speak of Tupperware/ducktape scale armor (lorica tuppermata) ...
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Post by mrstabby on Jul 1, 2023 9:32:05 GMT
Anyway, I'm sometimes thinking about "armor" made of the usual clothes in my wardrobe, in case of shtf. T-shirts, thin shirts, thicker shirts, pullovers, thick woolen sailer-pullovers, felt fabric. Multiple layers of course, but only many thin layers, or thin inside, thick outside, or the opposite? Combined with leather jackets, for bikers? Not to speak of Tupperware/ducktape scale armor (lorica tuppermata) ... I'd say something heavier on top and something soft underneath, maybe in a few layers. will protect well against cuts. A padded motor bike jacket would fit the bill well as is. A cotton lab coat over a soft pullover is pretty resistant to cuts and stabs, has good resistance to fire as well. Not what I would call armor, but a cutter blade won't get through easily.
There is also a quality issue, I have had shirts last for decades, others got holes in them the first time I held my cat. A cats claws test fabrics for damage resistance quite fast.
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Post by larason2 on Jul 3, 2023 1:39:12 GMT
I think that this is a case where the type of cut, and the geometry of the blade matter. For fabrics, there are a lot of different failure modes to consider.
If the fabric is stretched taught, and a slicing action is used with a blade with serrations or micro serrations, then it's the strength of the individual fibres vs. the strength of the individual serration and the only part of the force that matters to this aspect of the cut is the component of the force along the axis of the blade. A denser fabric would present more fibres to each serration, increasing the resistance to cutting this way. If a blade doesn't have serrations of any kind, then the component of the force along the axis of the blade won't cut any fibres.
If the fabric is loose, the complication is that the movement of the fabric may make it so that no fibres get in the way of the serrations. This only happens until the fabric is stretched taught by the action of the blade, however.
For blades that are keen (have a very narrow incident angle), then the only component of the force that matters is that perpendicular to the blade axis. Here, for a fabric stretched taught, the blade has to have a narrow enough incident angle for the force applied to overcome the tensile strength of the material (the keener the blade, the less molecules are being subjected to a cutting strain, and the easier that the blade will overcome their tensile strength).
For a keen blade on a loose fabric, aside from the keenness of the blade and the force being applied, some measure of the force to the blade will be dissipated by the blade stretching the fabric. The property here is young's modulus, and that is separate from the tensile strength. It also may happen that the skin and tissue under the fabric may contribute to the dissipation of force, since it may start pushing back on the blade before the fabric has been fully tensed. In any case, the residual component of the force that is perpendicular to the blade axis has to be enough to overcome the tensile strength of the fabric and the skin, etc. after the deductions produced by the stretch of the fabric and potentially also skin.
Now, for a blade of given weight, the closer the balance point is to the tip, the higher potential local force that can be applied by the blade when it is being swung. This is because the blade is applying a sort of torque to the force, and there is greater relative inertia of the tip. So, a katana of the same length and weight as a european sword, assuming it's point of balance is closer to the tip, should be able to apply greater force than the european sword. Of course, if part of the force is also used in a cutting motion, there will be potentially some of the cutting force lost to achieving the slicing movement. That may also achieve a cut, but it would be in a different way. What kind of steel is used and how it was sharpened affects whether it has serrations or not, and therefore the slicing ability. Since force = mass x acceleration, a heavier sword with the same geometry swung with the same acceleration should strike with more force.
Tensile strength of different materials:
Silk: 500 MPa
Cotton: 85 MPa
Leather: 6-25 MPa
Nylon: 85 MPa
Young's Modulus of different materials:
Silk: (varies, but usually about 10x its tensile strength in one study)
Cotton: ~3-20 GPa
Leather: 50 MPa
Nylon: 2.7 Gpa
Now, the above are just generalizations I found from a google search. They vary quite a bit depending on fibre and material thickness, how they are spun or weaved, etc. Silk in particular varies a lot depending on the spider or moth that produces it, how thick it is spun, etc.
So for a slice, presuming you have different materials of the same thickness, the one with the greatest tensile strength will be the most durable. Of course, silk has the best tensile strength, but silk is usually spun thinner than other fabrics, whereas leather is usually the thickest. This explains why leather can be more protective to a slice than silk, even though its tensile strength is quite a bit lower.
For a cut with a keen edge on stretched fabric, it's tensile strength again, with a particular focus on how many fibres are below the angle of the cut, and how likely top fibres are to be cut before the lower ones are cut. Again, silk, though it has a good tensile strength, is usually thinner, and the weave may be a single layer of fibres thick.
For a cut with a keen edge on unstretched fabric, silk will probably reduce the relative force the most (since it has high tensile strength and young's modulus), though again, unless it absorbs all of the force perpendicular to the axis of the blade, it may still be cut (assuming the remaining force is enough to overcome the tensile strength of the now stretched silk). Cotton also does very well, because it still has a decent tensile strength and a pretty high young's modulus. Leather, as would be expected, doesn't stretch much at all, however it may be thick enough it doesn't matter. Nylon, as well, does pretty similar to cotton (though in tactical fabrics that use Nylon and other similar synthetics with very strong fibres, they are usually very thick and have dense weaves).
So in general, silk doesn't do well mainly because it's usually pretty thin, though if it was weaved densely and you had tons of layers of it, it could be the best of all. For the average silk garment, maybe it will stop a cut if it's loose, but I wouldn't depend on it (especially if you've got a slicer like a katana). Leather, though it's not a star in the properties examined above, tends to do well just because its usually so thick. Cotton or nylon can also be ok, just make sure it's densely weaved and you have lots of layers of it.
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Post by blairbob on Jul 4, 2023 2:24:19 GMT
This is great stuff as one of the guys I train with is a mathematics professor.
I was thinking for rank and file, poor commoner or ruffian, they might only be wearing a light happi jacket.
But someone wearing juban and a kimono, wrapped tight enough with an obi
my silk kimono and the juban are thin but my silk happi coat is thicker as are the cotton happi i have (i've got one of those shinsgumi ones and a super light summer one) besides one cotton kimono though i think another is poly blend.
i've also got a "Viking shirt" around and used to have a pair of those generic pirate/Euro pants that are sorta baggy and swashbucklery.
I do have a more modern leather winter jacket (that's sleeveless but lined with wool?) and I was thinking no way it would be sliced by a diagonal or horizontal cut.
I won't be sacrificing any of these for science but could see hitting the surplus or thrift store down the road.
Getting back to it, too much sword movie magic is at hand, especially with people who have never cut.
"I'll just slide the katana across the body and they'll be cut!" The semprini you will!
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pgandy
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Post by pgandy on Jul 4, 2023 16:08:12 GMT
I am not expert here. In fact, I am somewhat baffled and can only give some examples of what I’ve experienced. I’ve heard from several sources that silk is resistant to cuts. My only experience with silk came from a Hanwei’s Oxtail Dao sword. That sword came with a piece of silk attached to the pommel. Just by going through the drill I shredded silk. That is, I cut it in mid-air. I received a gambeson collar from MRL that never was able to cut. Knit cloth is more difficult to cut than broad cloth. Being out of rugs I placed a sweat shirt over two free standing plastic one gallon plastic juice jugs taped together. Using a 15” kukri made for me by KHHI, I sliced the shirt, all but halved the lead jug, and seriously holed the second jug. That was in one cut. I have on the same target using 3 rugs protection and an antique 15” kukri shredded the rugs and made serious cuts from side to side in the lead jug. I have also bounced many a single free-standing bottle with one rug protection using swords.
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Post by durinnmcfurren on Jul 23, 2023 14:25:32 GMT
Just throwing this out there for those who haven't seen it.
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Post by RufusScorpius on Jul 25, 2023 13:54:50 GMT
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Post by mrstabby on Jul 25, 2023 14:12:03 GMT
It also depends on the stand for the target. A firmly attached target is much easier to cut than something that has the ability to move.
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pgandy
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Post by pgandy on Jul 25, 2023 15:54:14 GMT
Here are the photos from the cutting posted 4 July. I tried again today using 2 ply of 15 oz. denim (the heavy duty stuff). The result was cleanly slicing both layers of denim I only creased the led jug knocking all off of the stand. I’ll try later after the denim dries. Showing lead jug almost in half 2nd jug Sweat shirt    The 15" modified GI4 is at bottom. The top two kukris are my antiques, 15" and 13" respectively.  |
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Post by blairbob on Jul 25, 2023 23:07:22 GMT
watched the videos linked besides myarmoury.com/talk/viewtopic.php?t=11131 last night. This really went into how a sharper blade was able to cut into cloth armor but 6 layers of light denim couldn't withstand against one guys katana. 10/20/30 cloth layers seemed to work pretty well in the jacks. i just did an impromptu test on my own with an old thick aikido gi and cheap happi coat. draped it over my computer chair and tried sliding my Musashi (which cuts paper much better than my Raptor) across. yes, it's not a great test but figured wth since I haven't built a stand yet. the chair cushion is a bit cushy. probably should try to find something that would be similar to mus I was able to get a small 1' cut with the Musashi on the happi coat but some strokes got nothing. Sliding the blade across the aikido jacket didn't do semprini all. I'll take some pictures later. found a thick shipping tube one of my Weightlifting bars was shipped in. This is likely a lot more dense than the most ripped and swole dude but the aikido and happi cut were able to be cut with the sliding action hmm |
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Post by takitam on Jul 27, 2023 2:17:14 GMT
You have learned an important lesson about sword cutting. That is - cutting fabric armour is a lot more complicated and difficult than many sword nerds imagine. I still sometimes get a chuckle when I read reviews that state: 'This sword of Oakeshott type X was meant to deal with LIGHTLY ARMOURED opponents wearing GAMBESON and MAILLE'  or: 'It wouldn't cut through plate armour but I'm certain it would easily pierce through an opponent wearing only a gambeson' I'm glad to see more people experimenting with this. I have written about my experiences in some other thread but I failed to document any of it on camera. If you are ok with sharpening your swords, try a coarse diamond stone. Make just a few passes to touch up the very edge and do the same experiment again. Results should be surprising. Like mrstabby wrote, cutting cloth on a hard stand like wood will be significantly easier than on something softer imitating human flesh. Imo, experiments with something like a tough and heavy bolster pillow covered in fabric provide more realistic results. Try some thrusting while you are at it. edit: I have also recently discovered the power of tip cuts against fabric with both European and Japanese style swords. Many reviewers fixate on cutting with the CoP. (You can actually see how inefficient some of the cuts in Skallagrim's video look because of this) I used to as well but then I started thinking: Why sacrifice so much reach and hit with part of the sword that moves slower than the tip? Cutting with CoP has its place but in the context of imaginary unarmored duel or brawl I would expect distance to be the best defence, as both fighters realize that one hit can mean game over. A properly timed tip cut to the hand or knee might be the best you could do if you don't want to risk an exchange of blows, and it would be enough to let one quickly end the fight afterwards. Or you might just stop the duel there, or your opponent might decide to escape, or some brave observers may decide to break up the fight and call the guards. I really have no idea how these sort of fights might have looked a thousand years ago. There was probably a lot less street violence in most parts of medieval Europe (in times of peace) than in e.g. modern day USA anyway. So we just play our RPG games, watch silly movies, and then imagine bs pretending it to be historical But that part of using tip cuts in a fight is just my imagination. Learning to use tip cuts against experimental target is fun. (And super difficult to do consistently. I still miss more than I hit on a stationary target but don't tell anyone  ) |
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pgandy
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Post by pgandy on Jul 27, 2023 9:50:21 GMT
I agree with takitam on many points, especially tip cutting. I discovered this by accident when going from a longer blade to shorter. Sometimes picking up a shorter blade than I’m use to and cutting cold. At first, I was disappointed considering it a bad cut, and from the standpoint of being unintended. But on analyzing the result I considered in an actual case of combat this would have been more than satisfactory.
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Post by mrstabby on Jul 27, 2023 10:22:41 GMT
Tip cutting was/is extensively used with rapiers. The cut has less power than at the CoP, but you concentrate the force of the strike on a smaller point.
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It's primarily about technique. I easily cut a denim wrapped target down to the wood with a simple short strike. This target has frustrated many others.
or: 'It wouldn't cut through plate armour but I'm certain it would easily pierce through an opponent wearing only a gambeson' 
)
