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Peter Johnsson
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PostPosted: Thu 19 Oct, 2006 1:30 am    Post subject:         Reply with quote

Jörg W. wrote:
P.S. I hope that proving these information doesnt touch anyones business secrests.


You could not get more into the core of the matter.
Then it is a matter of how you put it to use in a sword.
This is where the intuition and experience of the maker matters.
Here is why it is so valuable to compare with real, historical swords: they tell us how this was done.

If you have a score of barocque music and an ancient violin, it still takes a trained violonist to bring the the music to life.
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Vincent Le Chevalier




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PostPosted: Thu 19 Oct, 2006 4:28 am    Post subject:         Reply with quote

Peter Johnsson wrote:
Vincent:
The idea is to take the forwad node from the most forward spot you grip, so in a rapier it would naturally be in front of the guard, in most cases.
This still does not bring the blade pivot to the very point. At least not in those I´ve seen.


Ah, ok. Just wanted to be sure of what you were measuring on rapiers... Your earlier explanation makes great sense, anyway.
Any chance you could one day share your measurements? Or maybe you have an agreement with museums not to disclose the things you observed publicly...

Greyson,

Yes, the ' is just to distinguish between two different point that share the same nature. P and P' are both pivot points, yet they are not the same point, hence the '. I could have named them P1 and P2 as in my earlier post in this thread, the equation would become R1 G*G P1=R2 G*G P2. Normally I would put the number in suscript but we are limited by the text format here Wink

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A. Jake Storey II




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PostPosted: Thu 19 Oct, 2006 6:19 am    Post subject:         Reply with quote

Wow. this is some awesome stuff, and it being made a spotlight topic is awesome.Eek! Happy Big Grin Laughing Out Loud One thing I should have said in my original post is that, though I now know of the existence of vibration nodes, I’m not even really sure exactly what they are. WTF?! Question
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Thereby, in your crime, YOU bring Justice on your own head!!!


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John Oliver





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PostPosted: Thu 19 Oct, 2006 6:23 am    Post subject:         Reply with quote

Hi Chaps,

They really shouldn't have threads like this - my head is *still* hurting trying to take it all in...:-)

But seriously guys - this has to be one of the most fascinating and informative threads I've read in a while - it just shows that there is *always* heaps more to learn about our hobby...

Peter - I'm eagerly awaiting my Albion Swords Solingen sword - that and the Saint Maurice are going to be my first two reproduction/recreation Mediaeval swords I think...

This discussion has helped me *enormously* to get a bit more of an understanding of the complexities/interrelationships when it comes to the dynamics of the Mediaeval sword. I had *no* idea there was so much to it - nor any idea that our ancestors of 700 or 800 years ago were so advanced in terms of their maths and physics (although they would have never used these words).

Anyway - enough waffle from me - please continue - I'll be quite honest and say right now I'm going to have to read this thread 3 or 4 times before everything sinks in...

Actually: I will 'throw in' one quick question to you all - given the complexities/intricacies of what you've been discussing do you think that our European swordsmith ancestors of, say, the 13th century, actually worked to specific FORMULAE of some sort? (formulae only available to those initiated into the guild or whatever and subsequently lost to time) OR, do you feel that most of this was simply a matter of some sort of 'evolution' achieved through trial and error... (or both?)

John.
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Angus Trim




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PostPosted: Thu 19 Oct, 2006 8:58 am    Post subject:         Reply with quote

Peter Johnsson wrote:

Gus:
I won´t be in racine next year. It was only that one time, years ago.
It would be really nice to something more about rotation points as they mystify me.
Or is this possibly a secret Wink Razz ?


Hi Peter

No, no secret, actually had this told to me over a few brews, then demonstrated once in face masks with practice rapiers in hand, having the other fellow's blunt bounce of my face mask a few times...... helps get some of these things through.....

There are times and subjects I'm real articulate with, and there are other times I struggle with it {written language}. It would take a lot of time struggling with the language to get it down on screen..... it would be much easier, talking about it over a brew, might even get my point across....*g*

Some of this has come pretty easy, but to really grasp pivot and rotational points, I've had to "play". My practice rapier blades have had some subtle changes made, for just the reasons you mentioned earlier, but only after having fenced with some very fine local fencers, and having had the opponents blade slide around mine, and get the rubber blunt in my face mask, and by doing the same to him.......

Intuitive, but for me hard to articulate.........if I can get by all my work and correspondence {which I'm behind on}, I'll try.....

swords are fun
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Vincent Le Chevalier




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PostPosted: Thu 19 Oct, 2006 12:11 pm    Post subject:         Reply with quote

Jörg W. wrote:

any new or recommended old pictures may be good to support the facts for better understanding.


If time allows I might be able to put together an illustration of some of the points discussed in this thread this week-end... But I fear I won't be able to do that earlier, normally I should be working on things other than swords Wink

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Craig Johnson
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PostPosted: Thu 19 Oct, 2006 1:37 pm    Post subject: Sword Movement         Reply with quote

Hello Guys

Good stuff all around here. I may be able to play with Vincent's numbers a bit tomorrow on some of the originals and will report back. Also Vincent thank you for posting the source for the diagram I had meant to add it to the post and forgot by the time I finished writing, For anyone how missed it good site to get some basics is HyperPhysics site

Peter as far as rotational points I can give you my take on where I am at with these. Gus and I have talked about this a while ago and I am unsure of exactly where he was at with them so this should be seen as my own personal take and not referenced to any other use of the term.

In use I started to see some elements that you described in your discussion of the pivot points and the effect this had on a practical use of the sword in play that was at least attempting to be based on the period movements we are interpreting from the manuals. The result was I started to work on the concept of a rotational point; I call this the "Active Rotational Point" of the sword. Sadly this is a fuzzy thing. It will change for each piece and for different actions with the same piece but it is the point where the sword wants to move around in play. The dynamic of this is that there is a point with any given action of the sword that the piece will want to rotate or strike around in action. This in some cases will be the moment of inertia. In other cases it seems to be the "quite" spot in the movement of the body and sword as a complex unit. Does that make sense?

In the case of a falling cut from say vomtag with minimal elbow and wrist action the moment of inertia will be the joint of the shoulder. In the case of the movement of the hand and lower arm in a crossing motion across the body while still keeping the opponent on point you will have a rotational point out mid blade. If you have a rapier and you are keeping the opponent on point but moving the guard into different quadrants to control lines you will be rotating the piece about a point some where near or even beyond the tip. These are all points that will adjust to sword action, grip style, arm action, body motion and our list of sword attributes. This, in a way, is almost a way of thinking about the combat as much as a physical attribute of the sword.

Now the difficulty in measuring and defining this point is significant for the very reasons stated above and my fuzzy brain has probably clouded the issue more than clarified but this is an important working attribute of the weapon in play to me and one that I think is a component of what fencers will call "feel" when they are describing the sword they would like.

Best
Craig
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Vincent Le Chevalier




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PostPosted: Fri 20 Oct, 2006 3:10 am    Post subject:         Reply with quote

John Oliver wrote:

Actually: I will 'throw in' one quick question to you all
- given the complexities/intricacies of what you've been discussing do you think that our European swordsmith ancestors of, say, the 13th century, actually worked to specific FORMULAE of some sort? (formulae only available to those initiated into the guild or whatever and subsequently lost to time) OR, do you feel that most of this was simply a matter of some sort of 'evolution' achieved through trial and error... (or both?)


Maybe I'm not the most qualified around here to answer such a question since I'm not a swordsmith myself, but anyway here is what I think...

In my opinion you don't have to understand everything here in order to make a good sword. Back in the 13th century, they had plenty of people expert in swordmanship, who must have provided a much greater input to the makers of these days. This might have helped the swordsmiths getting a sort of "gut feeling" about what was right for a given type of sword. Moreover, they learned their skills through apprenticeship, with people already specialists in sword making... In these conditions, once a design is agreed on, you don't have to deploy all the mathematical analysis to explain why it's right. You just have to learn how to reproduce it, which is not the same.

Nevertheless, they could have found mnemonic ways to help design. I think there is an article or thread about the use of golden ratio in sword design. And pivot points can be quite geometrical (now I really have to make that illustration Wink ), using essentially geometry known since Euclid. Then maybe there was something akin to the old diagrams used by the architects of cathedrals to remember the right way for building an arch. But not something linked explicitly to physics, I believe, since the equations of motion did not start appearing until the Renaissance, and even then were probably not known by the artisans...

Nowadays the situation is different. We don't fight with swords anymore. Thus our insight about handling is obviously less intuitive than that of the middle age warriors. We have some antique swords left but no one to explain why they work well... In the 13th century, a beginner swordsmith would have had the advice of his master, but now we don't have that master swordsmith of old. That's why I think we must try to understand the physics of weapons, even though it's not strictly necessary in order to build weapons. It also helps in understanding antique weapons which are maybe the most precise input we can get.

In the end I think at that time it was essentially trial and error with input from users, and continuous transmission of knowledge, maybe with the help of diagrammatic mnemonics. Probably not formulae in the way we would write them now...

Craig,

Good input about rotation points. I don't know if that was what Angus was thinking about but this is important anyway.

The thing is that those rotation points are the result of the interaction of pivot points (which are properties of the weapon) and of the forces you apply on the sword (which are specific to the motion and the individual). Basically when holding the weapon you could make it rotate around any given point with the right amount of force and torque. But given the force and torque applied, you can easily find the point of rotation if you know the pivot points. That's why when searching for a property of the weapon, I limited myself to the properties of pivot points.

In fact my idea now is that what we feel are truly pivot points, and that we adapt our actions to these, generating the needed rotation points. Each individual then has preferences about rotation points (according to the techniques, the morphology, ...) and so the adaptation is more or less easy. That could be what makes some weapons seem more intuitive. Their pivot points are already in the right place to favour the rotation points we need... Once an individual knows what pivot points feel right for him, I don't think he really needs a measure of other rotation points, since they are specific to him anyway.

And now I'm eager to hear about your measurements Big Grin Even if they destroy all that I've been thinking, at least they could provide a basis to build something else instead Wink

Regards

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Angus Trim




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PostPosted: Fri 20 Oct, 2006 9:12 am    Post subject:         Reply with quote

Peter Johnsson wrote:
Jörg W. wrote:
P.S. I hope that proving these information doesnt touch anyones business secrests.


You could not get more into the core of the matter.
Then it is a matter of how you put it to use in a sword.
This is where the intuition and experience of the maker matters.
Here is why it is so valuable to compare with real, historical swords: they tell us how this was done.

If you have a score of barocque music and an ancient violin, it still takes a trained violonist to bring the the music to life.


I'm not so sure I agree anymore..........what we're writing here are our own philosophies on how we do things, and this can be very difficult for someone else to decipher........

Someone, in say, Pakistan, could be copying all this down, figuring he's going to make stuff and blow everyone out of the water..........

But one of us is obsessing on nodes, another on pivot points, and the third on the handle......*g*

Then one could read this thread and figure that one of us obsesses on sitting in front of antiques, taking notes all day. Well, before I walk away from the computer, I'll mention that I think taking what one learns, taking specs etc, and doing something with them is also important. Then taking that sword or sparring implement and applying it, whether form work, cutting, or sparring.........

To understand how a rapier should act, for instance, I've found it quite instructive in pulling on the facemask and getting some snot, spittle, and blood knocked out of me, and working up a good sweat.........After that, a few brewskies, and talking things over with the sparring partners, one learns what folks that actually use these tools expect out of them, and learns it in a different manner than studying antiques, or strictly listening to someone else' feedback and trying to interpret their filter, and there subjective take on things...........All of this is ok, but I've always found it works best for me, to get involved in the blood, mud and dust part of things............

Over the last three years, I've watched WS and Paul Chen really improve........... Paul Chen's stuff generally features reasonable distal taper now, better in his kats, and the western swords are getting better too..........

But, when you talk to martial artists, and collectors with a wide experience level of antiques, its not the Paul Chens or WS' stuff they will tell you handle like antiques.............its the Tinkers, ATs, the A&As, and the Albions.........

My take on this is, that even when we're at our most sincere in one of these threads, we're not really leaving enough "real stuff" down that another swordmaking firm from across the world can immediately take it down and turn out something that matches our best.........they may eventually get there, but its going to have to be by learning the hard way {one of them}.

And swords done right are not cheap............ none of the three of us are making money on this, and true "business' for profit" will have to raise their prices, just a tad, even working in countries with rather inexpensive labor by western standards........

Studying antiques, feedback, blood and mud, and reverse engineering are better for learning this stuff, than just reading these posts..........

swords are fun


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Angus Trim




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PostPosted: Fri 20 Oct, 2006 10:05 am    Post subject:         Reply with quote

Vincent Le Chevalier wrote:



Craig,

Good input about rotation points. I don't know if that was what Angus was thinking about but this is important anyway.



Actually, I think that Craig hit it pretty good. Particularly the part about how you "hook up" to the sword changing the rotation points in practice. This part of it is very important, the "points of rotation" have as much to do with the interaction of operator and tool, than just the sword alone.

Take a rapier...... if it has a four inch handle, say, you can handle it with a 'hammer grip", or you can finger it, or you can slide another finger up on the ricasso, assuming the guard and ricasso are such that it will let you.......

The handling will be different, each way you grab the sword. The points of rotation change, just a little bit each way you grip the sword........

You'll find the same thing with a longsword........grip with one hand, the points of rotation are in one spot....add a hand, it changes....... move one hand back, changes again..........

I do tend to believe these are related to the pivot points, just as the pivot points are related to the nodes........ and I generally get a headache when I think about this stuff too much, and try and separate too much......

I'm not real comfortable yet, with the points of rotation, nor am I as liable to really want to discuss these like I do the nodes....... and that's because I don't have the same level of experience and comfort with them.......

Swordsmanship and swordmaking are a lot closer related than many would believe, they're both remaking something that's been lost, and both are quite often more intuitive than scientific in practice.......

swords are fun
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Vincent Le Chevalier




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PostPosted: Sat 21 Oct, 2006 7:06 am    Post subject: A drawing         Reply with quote

Hello all,

I've tried to make an illustration for pivot points and their geometrical meaning, and here is what I ended up with...

I've based the drawing on the Talhoffer, but it should be taken with a grain of salt since I don't have a really good idea of where its pivot points are... So it's mainly an illustration of the geometrical construction.

So here you have what Peter Johnsson calls forward pivot point (P2), aft pivot point (P1), and the center of gravity G. I've added a third couple of reference/pivot point H3, P3 to illustrate the geometrical construction.

Here goes the explanation:

Let's say that we know that the pivot point associated with the cross (in H2) is P2. I've drawn it close to the tip, based on an earlier post from Peter Johnsson ("Pointy longswords will by nature therefore have a forward pivot point close to the point (at the point or a short distance behind it)..."). These two points define a segment upon which you can build a circle with diameter H2P2.

Now if you raise from G the perpendicular to the axis of the sword, it intersects the said circle at point O (like, origin since it plays a central role in the following). Note that by construction, the triangle H2 O P2 is a right triangle.

And here is the interesting bit: for any reference and pivot point H and P, this holds true, the triangle H O P is always a right triangle. I can give the mathematical demonstration of this if anyone is interested, it proceeds from the relation I wrote in my answer to Greyson.

Anyway, finding other pivot points is now easy, because it only involves building a right triangle. So for example to find the aft pivot point P1, I draw the line H1 O, and then an orthogonal line from O that intersects the axis of the weapon in P1. Same goes for any reference point... For example I've drawn the pivot point associated to the riser, here P3. I've given a different color to each of these triangles to make them stand out better.

Each distance in this diagram has a physical meaning. For example, the square of the distance OG, multiplied by the mass of the weapon, is the moment of inertia of the weapon, i.e. it measures how difficult it is to get it to rotate around G. Similarly, the square of the distance 0H1 gives the moment of inertia around H1, so that would be how difficult it is to rotate around H1... If you just use torque, that is.

And finally, you could put several weapons on the same diagram, placing them such that they share the same origin O (it's simply a matter of moving their center of gravity vertically). And then you are able to visualize simultaneously the lengths, the center of gravity, the inertia, and the pivot points, by rotating a right triangle around O. Every dynamic and geometrical properties just in one drawing...

Sadly, as far as I can figure out, the harmonic nodes cannot be represented by such simple means. So I have left them out of this...

There are other observations you can make with that. For example, note how the distance between H1 and P1 is almost the same as the distance between H3 and P3, but greatly less than the distance between H2 and P2. This means that pendulum-like motions around H1 and H3 (for example, during cutting) share some properties in speed of realignment with the motion of your arm. It would be a totally different story from H2... You could also note how the tip control properties vary greatly with just a small modification of H2... And I could go on and on Happy

I hope this can help clarifying some of the complexities...



 Attachment: 18.46 KB
pivots-all.png
An illustration of the geometrical properties of pivot points

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Travis Canaday




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PostPosted: Sat 21 Oct, 2006 2:19 pm    Post subject:         Reply with quote

Angus Trim wrote:


Then one could read this thread and figure that one of us obsesses on sitting in front of antiques, taking notes all day. Well, before I walk away from the computer, I'll mention that I think taking what one learns, taking specs etc, and doing something with them is also important. Then taking that sword or sparring implement and applying it, whether form work, cutting, or sparring.........

To understand how a rapier should act, for instance, I've found it quite instructive in pulling on the facemask and getting some snot, spittle, and blood knocked out of me, and working up a good sweat.........After that, a few brewskies, and talking things over with the sparring partners, one learns what folks that actually use these tools expect out of them, and learns it in a different manner than studying antiques, or strictly listening to someone else' feedback and trying to interpret their filter, and there subjective take on things...........All of this is ok, but I've always found it works best for me, to get involved in the blood, mud and dust part of things............



Studying the antiques (measuring dimensions, getting a feel for their dynamics) seems to be of the utmost importance. If we modern folk want to understand how swords were designed and made back when people’s lives depended on these tools, this seems to be the only way. How else are we to know correct blade geometry, balance, heft, etc.

I don’t think we should down play the contributions Peter Johnsson has given the western sword community. If we want to make swords that are correct for the arts we practice, it has to start with studying the originals. If the sword one is using is not accurately built to represent how historical examples felt and handled, one won’t fully understand what is possible and not possible in the sword art one practices. In other words, having a correctly made sword that would match historical standards is a must if we want to practice swordsmanship as accurately as possible.

Travis
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Angus Trim




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PostPosted: Sat 21 Oct, 2006 3:09 pm    Post subject:         Reply with quote

Travis Canaday wrote:
Angus Trim wrote:


Then one could read this thread and figure that one of us obsesses on sitting in front of antiques, taking notes all day. Well, before I walk away from the computer, I'll mention that I think taking what one learns, taking specs etc, and doing something with them is also important. Then taking that sword or sparring implement and applying it, whether form work, cutting, or sparring.........

To understand how a rapier should act, for instance, I've found it quite instructive in pulling on the facemask and getting some snot, spittle, and blood knocked out of me, and working up a good sweat.........After that, a few brewskies, and talking things over with the sparring partners, one learns what folks that actually use these tools expect out of them, and learns it in a different manner than studying antiques, or strictly listening to someone else' feedback and trying to interpret their filter, and there subjective take on things...........All of this is ok, but I've always found it works best for me, to get involved in the blood, mud and dust part of things............



Studying the antiques (measuring dimensions, getting a feel for their dynamics) seems to be of the utmost importance. If we modern folk want to understand how swords were designed and made back when people’s lives depended on these tools, this seems to be the only way. How else are we to know correct blade geometry, balance, heft, etc.

I don’t think we should down play the contributions Peter Johnsson has given the western sword community. If we want to make swords that are correct for the arts we practice, it has to start with studying the originals. If the sword one is using is not accurately built to represent how historical examples felt and handled, one won’t fully understand what is possible and not possible in the sword art one practices. In other words, having a correctly made sword that would match historical standards is a must if we want to practice swordsmanship as accurately as possible.


Thank you Travis

That's a big part of my point. I don't believe its possible to make a good sword just reading threads like this. There's too much research and work that needs to be done to be able to do this well........

Since you brought up PJ, then lets take Albion as an example. Its not any secret, be it heat treat, a formula about nodes, pivot points, or anything else that makes the historical lineups special. Its Peter........

Its not just dry knowledge, something you can put in a book, its what Peter as a human being, a very special artist and swordsmith brings to the table, that makes the Albion historical lineups special.

Is that clearer?

A company elsewhere, can't duplicate Peter {not yet anyways}....... and they're still going to have to have someone do the research....... and even then, someone is going to have to have the "touch" in order to put it all together..........

As far as a top notch future swordsmith that's already far along the "path" picking up something that might help him, is that so bad? If you look at the "swordsmiths", the guys that do the one offs, the custom work, well, they "ain't getting any younger". We've already lost some real promising folks because of injury {remember Erik Stevenson?}, illness, etc.......And a few of the other "names" are not taking orders anymore............

swords are fun
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Taylor Ellis




PostPosted: Sat 21 Oct, 2006 4:13 pm    Post subject:         Reply with quote

Angus Trim wrote:
To understand how a rapier should act, for instance, I've found it quite instructive in pulling on the facemask and getting some snot, spittle, and blood knocked out of me, and working up a good sweat.........After that, a few brewskies, and talking things over with the sparring partners, one learns what folks that actually use these tools expect out of them, and learns it in a different manner than studying antiques, or strictly listening to someone else' feedback and trying to interpret their filter, and there subjective take on things...........All of this is ok, but I've always found it works best for me, to get involved in the blood, mud and dust part of things............

Over the last three years, I've watched WS and Paul Chen really improve........... Paul Chen's stuff generally features reasonable distal taper now, better in his kats, and the western swords are getting better too..........

But, when you talk to martial artists, and collectors with a wide experience level of antiques, its not the Paul Chens or WS' stuff they will tell you handle like antiques.............its the Tinkers, ATs, the A&As, and the Albions.........

Hey Gus,
I'm not sure that I agree that there are any fencers (WMA'ists at least), alive today that are skilled and experienced enough to be able to positively influence sword design. Pulling on a mask is fine, but sword designs should be made to handle as close to similar antiques as possible if the market is WMAists, and not the other way around. Otherwise the western sword market would be full of short, light longswords that handle like kats, and swords that exhibit historically correct yet unusual designs like the Albion SoSM would never see the light of day. Thankfully this is less prevelent today than it was a few years ago. YMMV of course.
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Travis Canaday




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PostPosted: Sat 21 Oct, 2006 6:31 pm    Post subject:         Reply with quote

Taylor,

I agree with what you are saying. In almost all (maybe all?) WMA’s, we’re recreating a dead art; so how are we to properly recreate the art without properly recreated tools? The emphasis should be placed on making the sword as historically accurate as possible. Then our art should adjust itself to the use of the well made weapon.

However, it really is a misconception that katana are light weight. They usually weigh about same as a longsword and have quite thick spines with significant blade presence. Deep cutters indeed. Some katana are built with thinner blades and less weight for the practice of iaido, but these are not accurate of what would have been taken into battle.

Travis
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Taylor Ellis




PostPosted: Sat 21 Oct, 2006 7:09 pm    Post subject:         Reply with quote

Hey Travis,
You are right about the kat weights, but I was talking more of the handling properties. Shoulda worded it better. Happy
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Travis Canaday




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PostPosted: Sun 22 Oct, 2006 12:29 am    Post subject:         Reply with quote

Just thinking more about this topic… Studying the antique weaponry is really just as important as studying the fight books. These really are the only direct links to the history we study.
Travis
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Vincent Le Chevalier




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PostPosted: Sun 22 Oct, 2006 2:29 pm    Post subject:         Reply with quote

Which leaves an important question open: how do we study antiques ? I'd be especially interested in this with respect to martial art weapons, indeed...

You could have a purely geometrical approach, measuring every single length on the antique, and try to reproduce that exactly. I'd imagine that it's almost impossible technically. Plus, if you don't use the exact same materials, you can still end up with an unbalanced weapon. I think everyone here agrees that there is more to it than just geometry... Reproducing materials with enough precision would be extremely difficult, not to mention measuring the properties of the materials on the antiques in the first place (remember that for proper balance you'd be interested in the inside of the weapon as well, which would probably mean destroy it while trying to reproduce it. Not a good deal at all Eek! ). As far as I know, all the makers try to copy not just the geometry and materials, but the balance as well.

In order to adjust balance there are two attitudes I can think of. You can just trust your feeling, or you could try to measure the balance.

The first case can be very successful indeed. But it's not something anyone else can re-use, since there is nothing measured. It's purely personal and subjective. You have no mean to describe what you were adjusting. That, and different individuals could be sensitive to different effects of dynamic properties. Though it feels the same to you, it does not necessarily means it feels the same to me. And it could require having access to the antique weapon during the whole process, in order to be able to compare...

As far as I'm aware, the full intuitive approach is not really used today for the making of reproduction. Mass and center of gravity are two things that are often measured, along with the center of percussion and possibly other nodes of vibration. Those properties of antiques are interesting because they allow objective comparison with the reproduction. Apparently, Peter Johnsson adds pivot points to those significant measurements of balance, an idea I strongly agree with since they are the most precise way to measure the inertia, a quantity that is important for any rotating object.



That's not to say that there should be nothing subjective left. There will always be, since perfect reproduction in every aspect is probably not possible.

One immense value I see in these threads is that they can enhance our comprehension about what is possible or important to measure on antiques. Remember that those measurements can then be transmitted to someone who hasn't been in contact with the original, or that you can keep them if you don't have an access to the original anymore. I really believe it's important to measure objectively what we can, and what is proven to be significant. Hand-on contact with antiques still is a rare thing...

Then the part about the interpretation of measurements in terms of handling properties is more debatable. I do that more from a user perspective, because often I'd like to have a more precise idea of the dynamics of a weapon for sale, than just a center of gravity and a mass. Of course there are reviews... but they are often subjective on the matter of handling anyway Wink Should the comprehension of the dynamics of weapons be limited to sword makers ? In my point of view, as users we can use this knowledge as well. At least I hope so, since I'm not becoming a swordsmith in any foreseeable future Sad

Anyway I hope that through threads like this people can get a better grasp of the physics involved in swords... This could help anyone that considers a sword as a dynamic, living object. Understanding and measuring does not mar the beauty of the object, to me it had quite the opposite effect...

Regards

--
Vincent
Ensis Sub Caelo
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Jörg W.




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PostPosted: Sun 22 Oct, 2006 4:20 pm    Post subject:         Reply with quote

Quote:
Vincent:
Understanding and measuring does not mar the beauty of the object, to me it had quite the opposite effect...


.. my opinion too.


about Vincents illustration of the geometrical properties of pivot points:

If pivot points (as defined in here) are just a matter of the law of the lever, don't you have to take into account that mass distribution isn't homogeneous in swords? I assume that the model gets far more complex if you include that every (infinite small) cross section segment has its own weight (due to taper e.g.).

The steels of history and today don't differ much in density. And considering that we talk about mono steel weapons wouldn't it only change the overall mass (scale of the sword) anyway?
What differs a lot is the alloy of the used metal and structure (due to heat treatment). But we even can measure that to a good degree without destroying the sword. I guess modern sword smiths have a good idea of what works here (to get swords having hard edges, yet being flexible) and may even exceed our ancestors. Though they might not be able to exactly copy what we have in ancient weapons (which are very different among themselves too).
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Angus Trim




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PostPosted: Sun 22 Oct, 2006 8:47 pm    Post subject:         Reply with quote

Jörg W. wrote:
Quote:
Vincent:
Understanding and measuring does not mar the beauty of the object, to me it had quite the opposite effect...


.. my opinion too.


about Vincents illustration of the geometrical properties of pivot points:

If pivot points (as defined in here) are just a matter of the law of the lever, don't you have to take into account that mass distribution isn't homogeneous in swords? I assume that the model gets far more complex if you include that every (infinite small) cross section segment has its own weight (due to taper e.g.).

The steels of history and today don't differ much in density. And considering that we talk about mono steel weapons wouldn't it only change the overall mass (scale of the sword) anyway?
What differs a lot is the alloy of the used metal and structure (due to heat treatment). But we even can measure that to a good degree without destroying the sword. I guess modern sword smiths have a good idea of what works here (to get swords having hard edges, yet being flexible) and may even exceed our ancestors. Though they might not be able to exactly copy what we have in ancient weapons (which are very different among themselves too).


Yep, mass distribution is key.......

And you're right, steel density isn't that much different....... Its the mass distribution, blade, tang, hilt pieces........

swords are fun
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