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Pedro Paulo Gaião




Location: Rio de Janeiro, Brasil
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PostPosted: Thu 02 Apr, 2015 1:03 pm    Post subject: Pros and Cons of blades cross sections         Reply with quote

I wonder what are the benefits and disadvantages of certain types of blades. As far as I know, the fuller serves to reduce the weight but, does that cause any real effect in swordplay? When using a fuller blade, the endurance and the thrust force is weaker? Hybrid styles of hexagonal with fuller are more efficient?

Is there any difference in the performance of cuts / thrust when comparing a lenticular sheet with a hexagonal / diamond shape?


http://upload.wikimedia.org/wikipedia/commons...on.svg.png


Last edited by Pedro Paulo Gaião on Thu 02 Apr, 2015 3:31 pm; edited 1 time in total
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Timo Nieminen




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PostPosted: Thu 02 Apr, 2015 1:54 pm    Post subject:         Reply with quote

Yes, there are real differences.

Lighter makes a real difference in handling. OK, an unfullered blade could be made thinner and/or narrower so that the overall weight, and the weight distribution along the blade, are the same. Then the handling would be the same. The differences then come down to cutting and thrusting.

A rough guide:
1. Wider blades cut better - but width brings more weight
2. Thinner blades cut better - but too thin can be too flexible
3. Thicker blades are stiffer - better thrusting, but more weight
4. Narrower blades thrust better (better penetration, but less damage for the same depth of penetration)
5. A fullered blade resists twisting better than a diamond-section blade
6. More acute blade angles cut better, but are more easily damaged

Thinner blades cutting better (2 in the list) isn't just a matter of more acute angles, but also because less stuff needs to be moved aside to allow the blade to move in. Except 5, you can see these principles in action in kitchen/work knives (and also how this is only a rough guide).

The various cross-sections provide different compromises between the angle of the edge, the thickness/width, and the weight. For example, thickness is very important for stiffness. Hollow-ground diamond sections give a large maximum thickness at relatively low weight, and hexagonal sections put as much steel as reasonable at the full thickness of the blade, which maximises stiffness for a given thickness. If you want stiffness without weight, go hollow-ground diamond. If you want stiff and thin together, go hexagonal. If you want thin and light, but reasonably robust edges, go fullered lenticular or fullered hex. If you want acute edges and thinness, go thin flat diamond (or wedge, if single edged).

But ease of manufacture and fashion also affect it - it isn't all about function.

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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J. Nicolaysen




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PostPosted: Thu 02 Apr, 2015 5:34 pm    Post subject:         Reply with quote

Here is a great article that is always hyperlinked when someone types "cross-section" here.

I revisited it just the other day and so, does any one know of a historical example of the "opposing fullers" cross-section type and what would the pros and cons of it be? I have never seen one, either reproduction or original.
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Timo Nieminen




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PostPosted: Thu 02 Apr, 2015 6:43 pm    Post subject:         Reply with quote

Opposing fullers lets the fullers be much deeper - they won't run into each other. So, for two fullers of the same width, or the same radius of curvature, you can remove more steel if they're offset. Offset fullers also don't reduce the thickness of the blade (or reduce it much less). Take a diamond section blade, and put one fuller on each side, symmetrically. This removes the ridge on each side, and makes the blade thinner (and thus less stiff). Do the fullers offset, and you can leave the ridgeline untouched.

I've mostly seen it on kindjals and African weapons (swords and spearheads). Some African spearheads have an extreme version of it; you could describe them as a flat sheet with a fold in the middle.

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Pedro Paulo Gaião




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PostPosted: Sat 04 Apr, 2015 8:01 am    Post subject:         Reply with quote

Timo Nieminen,

We could say that thinner blades cut better against flesh and clothing while the wider cut a little better against armour or bones?
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Luka Borscak




Location: Croatia
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PostPosted: Sat 04 Apr, 2015 8:44 am    Post subject:         Reply with quote

Pedro Paulo Gaião wrote:
Timo Nieminen,

We could say that thinner blades cut better against flesh and clothing while the wider cut a little better against armour or bones?


Wide blades usually are thinner or they would be very heavy, so I guess you meant narrower when you said thinner? Anyway, for harder targets like bones it is important that there is enough mass behind the edge. That can be achieved with wide and thin blade or narrower and thicker. Wider and thinner is better for cutting through any target, but for hard targets it is useful if the blade is stiff, so that should be achieved with blade's cross section and distal taper. Soft targets like flesh are not difficult to cut with almost any cross section and blade design except very narrow or very thick blades. Many layers of cloth are quite difficult targets and many aspects are important for that, including stiffness and high sharpness.
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Pedro Paulo Gaião




Location: Rio de Janeiro, Brasil
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PostPosted: Sat 04 Apr, 2015 9:50 am    Post subject:         Reply with quote

Yes, I'm sorry. Would a gamberson (the gamberson used as single armour of levies) offer any considerable armour against an cut?
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Luka Borscak




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PostPosted: Sat 04 Apr, 2015 2:33 pm    Post subject:         Reply with quote

Yes, gambeson made to be used as a standalone armour, not underarmour, would be decent protection against sword cuts.
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Hector A.





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PostPosted: Sat 04 Apr, 2015 8:49 pm    Post subject:         Reply with quote

Luka Borscak wrote:
Yes, gambeson made to be used as a standalone armour, not underarmour, would be decent protection against sword cuts.


Depends what sword, a stiff and sharp blade will go threw a gambeson like butter.

https://www.youtube.com/watch?v=Dn1VmbtEum8
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Alexis Bataille




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PostPosted: Sat 04 Apr, 2015 10:50 pm    Post subject:         Reply with quote

Hector A. wrote:
Luka Borscak wrote:
Yes, gambeson made to be used as a standalone armour, not underarmour, would be decent protection against sword cuts.


Depends what sword, a stiff and sharp blade will go threw a gambeson like butter.

https://www.youtube.com/watch?v=Dn1VmbtEum8

This is padding not really gambeson
30 layers of stiched linen need 200 Joules to be penetrated by a blade cut; perhaps an halberd can do this ; but not a sword .
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Hector A.





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PostPosted: Sun 05 Apr, 2015 4:26 am    Post subject:         Reply with quote

Alexis Bataille wrote:
Hector A. wrote:
Luka Borscak wrote:
Yes, gambeson made to be used as a standalone armour, not underarmour, would be decent protection against sword cuts.


Depends what sword, a stiff and sharp blade will go threw a gambeson like butter.

https://www.youtube.com/watch?v=Dn1VmbtEum8

This is padding not really gambeson
30 layers of stiched linen need 200 Joules to be penetrated by a blade cut; perhaps an halberd can do this ; but not a sword .


I think the kind of protection your referring to was late 15th century and 16th century protection, 13th-14th century a "Gambeson" would pretty much look like this.
Then again i showed you a late 15h century sword in action vs a 13-14th century protection ( so it might as well rock it :P ).
But you are right that the kind of protection you refer to is hard to cut, but not impossible, depends what part of the body your aiming, if there is bone support at a shallow level below you can cut a 30 layer linen jack with a stiff sharp sword.
Later this was fixed by making the 30 layer jack even more resistant, by dipping it in salt water or brine... at which point it was cut proof, but not thrust proof.
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Matthew P. Adams




Location: Cape Cod, MA
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PostPosted: Sun 05 Apr, 2015 11:34 am    Post subject:         Reply with quote

What properties would be most helpful cutting textile armor? I'm guessing wide, thin, stiff, and a highly refined edge? I know for cutting rope in a rigging shop environment, it's common to sharpen a knife with a file or coarse stone, to leave an almost serrated edge. Cuts VERY well, but low edge retention.

Is there any evidence of this or has anyone tried it?

"We do not rise to the level of our expectations. We fall to the level of our training" Archilochus, Greek Soldier, Poet, c. 650 BC
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Timo Nieminen




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PostPosted: Mon 06 Apr, 2015 4:38 am    Post subject:         Reply with quote

Pedro Paulo Gaião wrote:
We could say that thinner blades cut better against flesh and clothing while the wider cut a little better against armour or bones?


Thin and wide is good for cutting flesh. Wide lets you have some thickness to give you stiffness while keeping an acute edge angle. For slicing cuts on soft targets, stiffness is less important (but you still need some), so thin is good.

Too acute an edge angle can be damaged by bones. This, and the previous point, matter for kitchen knives.

What kind of kitchen/work knives do we have to cut bones? Usually, the blade is thicker, and the blade is convex as it approaches the edge, so that the edge is well-supported by lots of metal. But the overall thickness doesn't need to be large; a bone-chopping knife can still be thin compared to most swords. For swords, either the common appleseed edge or a secondary bevel gives this kind of support for the edge. But then it doesn't cut soft targets as well. Given that not all targets are soft, you compromise.

But sharpness matters a lot, and a less acute edge that is very sharp can cut better than a more acute, but less sharp edge.

Cutting armour? The most likely kind you'd be able to significantly cut would be textile armour, which leads us to the next question:

Matthew P. Adams wrote:
What properties would be most helpful cutting textile armor? I'm guessing wide, thin, stiff, and a highly refined edge?


Yes. And slice, don't chop. But better to cut where there is no armour. I expect that sharpness matters more than blade geometry.

Don't know about "toothy" edges. A big difference between cutting with a knife and sword is that the sword blade is usually moving quickly, while the knife moves slowly. There are some swords with full-on serrated edges, like bread knives. Perhaps they work well against textile armour?

"In addition to being efficient, all pole arms were quite nice to look at." - Cherney Berg, A hideous history of weapons, Collier 1963.
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Luka Borscak




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PostPosted: Mon 06 Apr, 2015 5:48 am    Post subject:         Reply with quote

Hector A. wrote:
Alexis Bataille wrote:
Hector A. wrote:
Luka Borscak wrote:
Yes, gambeson made to be used as a standalone armour, not underarmour, would be decent protection against sword cuts.


Depends what sword, a stiff and sharp blade will go threw a gambeson like butter.

https://www.youtube.com/watch?v=Dn1VmbtEum8

This is padding not really gambeson
30 layers of stiched linen need 200 Joules to be penetrated by a blade cut; perhaps an halberd can do this ; but not a sword .


I think the kind of protection your referring to was late 15th century and 16th century protection, 13th-14th century a "Gambeson" would pretty much look like this.
Then again i showed you a late 15h century sword in action vs a 13-14th century protection ( so it might as well rock it :P ).
But you are right that the kind of protection you refer to is hard to cut, but not impossible, depends what part of the body your aiming, if there is bone support at a shallow level below you can cut a 30 layer linen jack with a stiff sharp sword.
Later this was fixed by making the 30 layer jack even more resistant, by dipping it in salt water or brine... at which point it was cut proof, but not thrust proof.


Modern gambeson like the one in the video are meant to be used purely as padding for defence against blunt trauma. That's why I wrote "gambeson made as a standalone armour". They were known from the 13th century, as you can see from the Norwegian King's mirror. This quote is especially useful: "He also should have a good shabrack (14) made like a gambison of soft and thoroughly blackened linen cloth, for this is good protection against all kinds of weapons."
Whole text here: http://deremilitari.org/2014/04/medieval-warf...gian-text/

I agree gambeson is not fully proof against sharp and stiff swords, but it is still a very decent protection against many cuts in battle conditions...
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Pedro Paulo Gaião




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PostPosted: Mon 06 Apr, 2015 8:08 am    Post subject:         Reply with quote

Hector A. wrote:
Alexis Bataille wrote:
Hector A. wrote:
Luka Borscak wrote:
Yes, gambeson made to be used as a standalone armour, not underarmour, would be decent protection against sword cuts.


Depends what sword, a stiff and sharp blade will go threw a gambeson like butter.

https://www.youtube.com/watch?v=Dn1VmbtEum8

This is padding not really gambeson
30 layers of stiched linen need 200 Joules to be penetrated by a blade cut; perhaps an halberd can do this ; but not a sword .


I think the kind of protection your referring to was late 15th century and 16th century protection, 13th-14th century a "Gambeson" would pretty much look like this.
Then again i showed you a late 15h century sword in action vs a 13-14th century protection ( so it might as well rock it :P ).
But you are right that the kind of protection you refer to is hard to cut, but not impossible, depends what part of the body your aiming, if there is bone support at a shallow level below you can cut a 30 layer linen jack with a stiff sharp sword.
Later this was fixed by making the 30 layer jack even more resistant, by dipping it in salt water or brine... at which point it was cut proof, but not thrust proof.



Very interesting, what is the mechanical energy that an arming sword and a long sword (1.12 to 1.16 meters) would normally be on a cutting blow?

They gave a special name for this type of "30 layers of stiched linen gamberson" to differentiate it from other models? It was standardized in foot class soldiers in 15th and 16th centuries?

The Mongols, the Turks and the Byzantines of XIII to XIV centuries would have some protection in this way? I heard that they used very thick gambersons
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Lafayette C Curtis




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PostPosted: Thu 09 Apr, 2015 2:49 am    Post subject:         Reply with quote

Mike Edelson's tests a few years ago show that the acute points of 14th and 15th-century European longswords are really effective for thrusting through padded or quilted armour, even if it has as many as 30 layers:

http://myArmoury.com/talk/viewtopic.php?t=111...light=test

(But, as Mike mentioned in the thread, skill also seems to be a big factor.)
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