myArmoury.com - Type XIX geometry?

Posts: 558 Location: Central PA

Thu 06 May, 2004 12:08 pm

Type XIX geometry?

Greetings,

I have a question about the XIX in Oakeshott's Typology- it is described as having an essentially flat blade with a slight edge bevel , usually sporting a narrow fuller, with a short ricasso.

Seeing as how XIX's are often featured in swords that seem very cut-and-thrust oriented, I'm wondering how they can retain the stiffness (something a nearly flat blade usually doesn't imply) and sharpness (something a really short edge bevel usually doesn't imply) necessary for this style of fighting?

In short, why would a XIX ever be chosen over something like a ricasso'd XVIIIb?

Absolutely nothing personal against XIX's (in case Roger Hooper reads this! :p ), but I've been pretty curious about this for a while...

Thanks!

Last edited by Jeremiah Swanger on Thu 06 May, 2004 12:57 pm; edited 1 time in total

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Roger Hooper

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Posts: 4,393 Location: Northern California

Thu 06 May, 2004 12:40 pm

I've been conjured! :eek:

Type XIX's have a hexagonal cross section. They are much more a cutting blade than a thrusting one. However, the Armart XIX that I have is rather stiff, and certainly can thrust, though not as well a XV could. I remember Bjorn Hellqvist's measurements of the original "Alexandrian XIX", and he mentions that the lower part of the blade had perhaps been reinforced, which would increase its thrusting abilities.

I haven't cut with my XIX, but I have heard that they are unforgiving, and require good technique to cut well. Once you have got it down though, I've heard that they function very nicely.

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Peter Johnsson

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Posts: 1,757 Location: Storvreta, Sweden

Thu 06 May, 2004 3:14 pm

Re: Type XIX geometry?

Jeremiah Swanger wrote:

Greetings,

I have a question about the XIX in Oakeshott's Typology- it is described as having an essentially flat blade with a slight edge bevel , usually sporting a narrow fuller, with a short ricasso.

Seeing as how XIX's are often featured in swords that seem very cut-and-thrust oriented, I'm wondering how they can retain the stiffness (something a nearly flat blade usually doesn't imply) and sharpness (something a really short edge bevel usually doesn't imply) necessary for this style of fighting?

In short, why would a XIX ever be chosen over something like a ricasso'd XVIIIb?

Absolutely nothing personal against XIX's (in case Roger Hooper reads this! :p ), but I've been pretty curious about this for a while...

Thanks!

Type XIX blades can vary between narrow blades with rather substantial thickness to wide flat blades that are more flexible.
As with any type the variation is pretty wide. All cross sections have some inherent combinations of qualities that yields specific benefits, but also comes with certain limitations.

If we compare a flat hexagonal section with a flat diamond section of the same thickness and width it is obvious that the hexagonal section is heavier, but also a lot stiffer. Sometimes heavier is better.
We should also recognize that it is the distance of the midrib to the neutral plane of the cutting edge that yields stiffness: the farther you remove the midrib, the more stiffness you will get. Doubling blade-width gives double stiffness, doubling thickness yields stiffnesss by a much higher multiple. Just how much higher depends on the shape of the midrib. A hexagonal section could be seen as a diamond section with a very wide midrib= more material working in the stiffening action.

If the blade is more cutting or thrusting oriented depends on ratio width and thickness, and the distribution of mass along the blade.
You need a certain stiffness for a blade to be an efficient cutter, but obviously even more so if it is to be efficient in a thrust (through difficut targets).
A short edge bevel is blunt only if the blade is thick. If the blade is thin you will need a wider midrib for it to be stiff enough to be effective in a cut (through difficult targets). This results in a hexagonal section!
A lenticular section will do almost the same as a hexagonal one but will be slightly lighter with same width and thickness.

Blades with little profile taper needs to have a very active distal taper (taper in thickness). If the distal taper and distribution of mass is less than optimal, the blade will be unforgiving in cutting performance. (this is also the case with swords that are primarily intended for thrusting: they *will* cut, but not so effortlessly as a dedicated cutting sword) With a good and dynamic distal taper, a hexagonal blade could well perform in comparison to a lenticular one. Lenticular blades are well known to be efficient cutters.

And here is the compromise one must make: just how much thrusting performance do we want and/or how well suited for cutting must the blade be? If we want a lognish blade with a stiff spine and strong point, that is also light and quick in the handling, we must make a narrow, rather thick blade with a cross section that yields a good stiffness. This might mean we have to sacrifice cutting performance.

If we on the other hand want a sword that is effortless in cutting, quick in delivery *and* recover, we should make a wide thin blade of moderate length, that retains a good deal of width towards the point. We still need to keep it as stiff as possible for the amount of given material, so a hexagonal section might be a good option, especially if we do *not* want the edge bevels to become too acute as they might in a very thin diamond section. Too thin edge bevels can be detrimental when cutting difficult targets. We should also remember that a certain amount of mass is a good thing: the heavier hexagonal section can in some situations add to cutting power.

It is a balancing act in every case.

When examining different cross sections and blade shapes it becomes evident there is a certain amount of overlap in perfomance and character. Outside this overlap however, all blade shapes and cross sections offer certain specific benefits and limitations that can be utilized in various sword designs.

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Angus Trim

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Posts: 870 Location: Seattle area

Thu 06 May, 2004 3:48 pm

Roger Hooper wrote:

I've been conjured! :eek:

Type XIX's have a hexagonal cross section. They are much more a cutting blade than a thrusting one. However, the Armart XIX that I have is rather stiff, and certainly can thrust, though not as well a XV could. I remember Bjorn Hellqvist's measurements of the original "Alexandrian XIX", and he mentions that the lower part of the blade had perhaps been reinforced, which would increase its thrusting abilities.

I haven't cut with my XIX, but I have heard that they are unforgiving, and require good technique to cut well. Once you have got it down though, I've heard that they function very nicely.

Hi Roger

Actually, there's really nothing inherently unforgiving about a XIXish blade in cutting. I think that a couple of the first ones I made got out into hands that weren't prepared to spend the time to learn the "tracking". And I believe that a couple I did in the early days likely had too thick edges......

What I've made since do very well in cutting..........

A very simple observation on blade dynamics. The wider a blade, the easier the "tracking" feel. The narrower a blade, the more subtle the feel.

If a quality blade is brought around onto a target, with the blade online, the target should cut {assuming we're not talking something stupid like a helmet on a pole, or a hardwood branch}. If the blade is a bit offline on its cutting arc, its likely to have a problem cutting....... In other words, its quite often the cutter, not the sword.

So, the rep that XIX's have is likely because of about four swords I made nearly four years ago. A couple with "cutters" that likely had no business with a sword in their hands, and a couple where the edges were too thick to be efficient cutters with that narrow a blade........

En realidad, a XIX with good edge geometry, good hilting, in the right hands, does very well cutting.........

Auld Dawg

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