[Tony Brass]

I have read a number of articles on this topic. Mostly, they criticize lower end swords for lacking rigidity. I understand that when a sword is pointy, it probably should be capable in the thrust. But many high end swords lack rigidity, like Albion's Brescia Spadona, or A&A Bohemian Broadsword. What is the advantage of a more flexible blade? Rigid blades seem to cut almost as well, and thrust better. Even Viking styles, meant for the cut, seem rigid, and more capable of splitting a shield than a whippy blade.

I would love to have a way to quantlfy flexibility, from "whippy" to rigid, and understand the real plus of the thin flexible blade in a combat situation, or even a dueling situation.

[Nathan Robinson]

Sword blade flexibility ranged a great deal depending on the type of weapon and its intended purpose. They could be found as being extremely flexible, to the point of being able to flex a full 90 degrees or even more, to being extremely stiff and virtually inflexible. History has brought us an incredible diversity of sword types with a tremendous variety of intended purposes. Such a question is far too broad to be able to answer. Even if the question were limited to one particular sword type from one particular period of time and one particular region, the answer would still include a fair degree of range. The real answer to such question is simply that the science of sword design required tools be made to cover an almost infinite number of needs encompassing a large number of limitations and other variables.

This doesn't address most of your question, directly, of course. I'll leave it to others to describe the benefits and needs that dictated sword flexibility in various designs. This could be an interesting discussion.

[Lancelot Chan]

Hmmm perhaps I can relay some experience since I have both low end whippy swords and the brescia spadona. They are very different. With the spadona in hands you can change motion very fast and the tip follows tightly so that virtually you don't feel it's whippy at all. Not the same for the low end swords. The blade will ripple all along the length and the tip will get delayed to arrive the position if you perform the same change. It's like comparing a honda to a lamborghini in handling characteristic.

I think it's one of the keys of high quality swords.

[Charlee Garvin]

Hi Tony,

Great subject. The question of blade stiffness contains hundreds of variables—probably as many as there are different types of swordsmen. Personally, I prefer a stiffer blade for uncompromising thrusts through cloth, chainmail, bullet proof vests, car hoods , and medieval armor . Usually a sword of this caliber needs to have around 3.0 to 3.7 pounds of mass to be a dragon slayer so to speak.

I’ve noticed that my four pound Grossemesser training sword of 1050 carbon steel flexes a bit with quick thrusts, which surprised me considering its thick, stiff back. Thinking from a practical standpoint, a swordsman would choose a sword that best destroys an anticipated adversary, also taking into account the sword the enemy carried, armor, fighting style, and their character. I know that if I used a kriegsmesser in a 17th century court duel against a rapier artist, I would probably be pin-cushioned before I could move the thing. And rapiers are much more flexible than three pound kriegsmessers to be sure.

Charlee

[Chad Arnow]

As people will keep telling you, it really will vary widely. More thrust-oriented blades should be stiffer, and the lower ones that are criticized for being whippy or floppy are simply not rigid enough, usually due to non-optimal cross-sections.

In my experience the Brescia blade is somewhat stiff. The complex cross-section (hexagonal during the fullered section, and octagonal once the fuller is replaced by the mid-rib) gives it that. There are stiffer cross-sections, but we have to keep in mind that not every period sword or repro is designed to be super-rigid.

Albion's swords, as well as A&A's and Atrim's, vary a great deal in rigidity and have changed many people's perceptions about what swords should be like.

Just as one screwdriver won't fit every circumstance, so swords varied according to technology, materials, and intended use.

As for rigid swords splitting shields better, we'll need some tests to prove that. Rigid swords are typically rigid because they have thicker, more robust cross-sections. Those thicker blades may not pass through all targets with the same ease as a thinner, more flexible blade when cutting.

[Tony Brass]

Thanks for your helpful comments. The image of a sword following its point through its target, as opposed to flexing under the stress helped me to understand the importance of rigidity, as does the idea of a sword changing directions quickly, without dragging its point behind.

But what are the advantages of the really flexible blade? Lightness? Durablity? (i.e. instead of chipping on the iron rim of a shield, it flexes). Why not get that stiff sword, and just cast off the flexy sword completely?

I understand the different swords for different purposes principal, but I am wondering in what scenario does the flexible blade really exceed the rigid one?

[Chad Arnow]

Here's a previous discussion on the issue: http://www.myArmoury.com/talk/viewtopic.php?t=10522

[Joe Fults]

IMO, its really a question of preference and how stiff you want it to be. Perhaps that's part of the reason why there is so much variety in design.

[Jean Thibodeau]

With a thrust one want's a blade rigid enough to penetrate the target before starting to bend too much.

A properly heat treated blade will bend easily or not mostly depending on the cross section and the thickness of the blade all things being equal.

An extremely flexible blade is that way mostly because it's maximum thickness is small compared to a blade of the same hardness of the same material with a thicker blade.

A blade optimized for cutting will meet less resistance being thin but I doubt that it being flexible is more than a side effect of being thin: Bending easily doesn't add to it's effectiveness but it does make it much more resistant to breaking than if it was stiff because of being harder rather than being thicker i.e. heat treated so as to be harder but more brittle.

A little bending when passing through the target may be of some value to avoid damage to the blade ?

( Just my opinion: Could be wrong ).

[Craig Johnson]

Good questions.

I will do what I can to help illustrate some of the issues. You can also check out this article which touches on some of this as well. Blade Hardness

The stiffness of a blade incorporates many factors that contribute to its rigidity or lack there of. To start with it helps to understand that the smiths of the day here aware and capable of producing the best the material for the blades were capable of whether this was hard or soft.

This was also adjusted to what the combatants wanted and where prepared to pay for. In a particular batch of metal one needs to look at the difference between elastic deformation and plastic deformation. (Side note: I had recently queried an expert on this very issue so that is why I have it to hand, I do not claim to have this off the top of my head)

Elastic is temporary, plastic is permanent. Stiffness is resistance to elastic deformation; hardness is resistance to plastic deformation. The strength of the blade is a combination of both. Some of you may well have heard or seen me post that a blade is a balance of attributes there are few absolutes and those that are tried are often on the exterior edges of the design envelope.

Thus if one has a hard edge on a sword it will resist plastic deformation better that a soft edge, obvious. But if the edge is too hard it will fracture when stressed, thus it needs to be less hard and this introduces more elasticity to give it durability. To stand with a broken hard sword is not as helpful as to stand with a slightly bent whole sword. So one would be looking for the balance that best matches what the material can achieve and the designer wants.

Material attributes are not the only aspect of a sword one can adjust for such issues. One can manipulate the blade design as far as size and cross section, which can enhance or deter stiffness or flexibility. Some blades are obviously made to promote one or the other. This would have been a distinct choice made by the consumer as he or she saw fit for their sword needs.

If one looks at the many period swords that have an exceptionally thin cross section near the tip it becomes obvious that the need for a stiff thrusting blade was not seen as an absolute need in period. This ranges from the earliest blades of iron right through to the sabers of the 18th century. Many blades have thicknesses near the tip that are little more than paper.

In fact there are some references in some of the manuals that seem to indicate this was a distinct choice one made on stiffness in a blade based on the type of weapon they used and the combat one was expecting. The literature that comments on this is under some high-end translation at the moment so I fear trying to be more specific until we have better info.

Best
Craig

[Tony Brass]

Thank you Craig. Those were terms that I was unfamiliar with. Also Thanks Chad, that thread you recommended was very infomative on exactly the issues I was wondering about.