Sword Blades and the Problem of (Too Much) Flexibility

I know you guys are going to love this one. It's all about thrusting and how stupid it is. Flexibility is quite important for sword blades, particularly for European double-edged swords because they tend to have thinner blades than Asian single-edged swords, for instance, and you want the right amount of flexibility. You don't want the blade to be so hard and rigid that it snaps under use, but you also don't want it to be flopping all over the place because that limits its effectiveness in combat. How much is too much? So in case of a cutting sword, it can get away with quite a lot of flexibility. One way to notice that a blade is way too flexible is if you wave it in the direction of the flat and it just starts flopping all over the place. That is clearly too much. In some cases, when the tempering is right, you can't bend it very far, just like this, just with your hands, but if you strike something or thrust into hard material, in the slow-mo footage, you will see it flex and return to its straight shape. Now, this long sword here, for example, is very rigid. I can't really bend this with just my hands. I mean, this is just as far as it goes. However, when you look at the slow-mo footage in the thrust, it does flex noticeably, so it's still not an extremely hard rigid spike that doesn't flex at all because, again, that would just lead to it breaking. There are several aspects of the blade shape that determine how flexible it is. For one, of course, the thickness. A thicker blade is not going to flex as much. This one here is relatively thick, at least compared to this one here, which is, as you can see, really quite thin. Also, the cross-section makes quite a difference. If it is a thicker lenticular cross-section, for example, it's going to be more rigid than a more drawn-out lenticular cross-section, and also a diamond-shaped cross-section is also going to be more rigid. Many historical rapiers were made with a diamond cross-section. Also, there are bronze swords that have this very prominent central ridge, and that also helps to give the additional stiffness. A bronze, of course, is a lot softer than steel, but with that kind of shape, you can make it more resistant to bending. There are also triangular cross-sections, like on this small sword here. The width of the blade here is extremely narrow, so if this was just flat with a lenticular cross-section, for example, that would be extremely flexible, but this is one way to give additional stiffness, which is very much desired for a small sword, because it's a thrusting sword only. It doesn't have an edge. This is really just for the thrust. Okay, so let's get to the problematic kind of flexibility. This is a rapier made by Hanwei that a friend of mine lent me for demonstration, and this is the kind of problem I was talking about. This blade is extremely flexible. I mean, I can easily bend it very, very far, and also if I slap the pommel here, you can see how much it just wobbles all over the place, and unfortunately, this is a very common problem with many modern rapier reproductions. A lot of them have this extremely flexible blade. Hanwei rapiers have a blades also do, especially the longer ones, and this can lead to some problems, especially in the thrust. You can imagine if you thrust with this blade, a lot of the energy that you put into it just goes into flexing the blade. It's not going to penetrate as far as a stiffer blade, and you could see that quite well in some of the recent tests I've done. So here are a few tests with the Hanwei rapier. You can see just how extremely it flexes upon impact, and this is in fact the exact same block of ballistic gel that I used for the thrusting tests with the Arms & Armor Town Guard, which is quite a stiff blade. So this is as much as I can flex it, you know, putting similar amounts of pressure on it. Take a look at what that does. So it's, of course, a different blade shape, so it's not exactly the same, but in fact, the other one, since it's narrower, should thrust better than this one, because a narrower blade, of course, means that less material is in contact with the target, which in turn means less friction, so that should help. But even so, the Town Guard did a lot better. So in that case, the blade actually came out the back of the block, whereas the rapier didn't get anywhere near as far. Same with the Albion Caithness. You can also see in this case it flexes quite strongly, and it doesn't penetrate as far as the Town Guard does. However, when I use half-sorting, gripping the blade and thereby reducing its flex, the result is a lot better. Now, granted, that also has to do with the fact that I can throw more of my bodyweight behind it, and here is probably the worst case of an overly flexible blade that I've ever come upon, which is rather frustrating, because I sold one of my rifles to be able to fund this. I was very much looking forward to it. It's a rapier made by Vladimir Serenka, which was a well-known reputable sword maker, and the rapier overall is amazing, with that one exception. And the way it handles, the way it's shaped, it's an extremely brilliant piece. But here is the problem. This is an absurd amount of flex. I've actually sent an email to Vladimir Serenka and asked about this. Now, this is a rapier that he made a long time ago, so he wasn't quite sure if he remembers right, but this might have been one that was originally made for fencing practice as a blunt rapier, and then it was later sharpened. That would certainly explain why it has this kind of obscene amount of flex. And even then, this is my Darkwood Armory practice rapier, so this is for HEMA practice, and it's supposed to have a certain amount of flexibility for safety. Even this isn't quite as flexible as the other one. Also, the flex is mainly in the last third. I would have liked to test this one too, but haven't been able to because of the bad weather lately. But just to give you a bit of an idea, this is just a cardboard box. Let's see how the town guard, just even when I hold it in a free hang like this, which makes it a lot harder to thrust into, the town guard, no problem. With this rapier on the other hand, you can tell even against the cardboard, it flexes so much that you can't really get very far. So even though blade flexibility overall is required, more so for some blade types and materials than others, generally it seems like a good idea to limit it. And in fact, there are some sword types for which it was a matter of prestige, like the rapier, the estoc, the tuck, those were all swords that if they were made properly, you know, that was rather difficult with the technology of the time, they would be rigid enough, even in case of a very narrow and not overly thick blade, to withstand the use. So getting the tempering just right was challenging and a source of pride for the blacksmiths in historical times. Nowadays, there isn't so much a focus on that. It seems like a lot of manufacturers focus mainly on how it looks and then things like that can often be off. It is difficult to really quantify flexibility. You can't just say, oh yeah, this blade has foreflex. You can't just really put it in levels and such. You can take a look at things like, for example, if you slap the pommel, how much does the tip move? If it moves more than so and so, such and such distance, then it's too flexible. But of course, it's also very vague. It depends on how hard you slap the pommel and all of that. So it's a little difficult and it's the kind of thing that you can't really expect museums to specify. How flexible is that? It's kind of a subjective thing to say. However, it's pretty obvious when it's way too much. I mean, this sort of flex, I wouldn't even want on a practice rapier, let alone a sharp one. To be fair, it also depends on the material that you use the blade on. On soft tissue, even an overly flexible blade can perform reasonably well, as in this example here. This is foam covered in urethane rubber. But whenever it hits something harder, like wood or bone, it becomes a problem. And either way, the potential effectiveness is higher in a more rigid blade. Anyway, I hope you found this entertaining and informative, and thanks for watching.