[David Evans]

I found on the web, some time back ,the following page http://www.musketeer.org/Garrick/Blade_spec_article.html. If you look at the figures discussed you do see that the rapiers measured all balance at about the 22% area, measuring from the pommel to the tip of the blade. Just checking a few modern rapier figures reviewed here they all seem to fall at the 23% plus end, going up to 27% in one case. Has any one else done any work on checking point of balance figures on period rapiers to add further factual figures and find out where rapiers are meant to balance?

[Peter Johnsson]

[Russ Ellis]

Okay Peter, I'm still trying to think my way through that post. I understand that you are saying that if the mass distribution is not the same between an original and a reproduction that the "feel" of the reproduction is not the same... even if the balance points are the same. The thing I don't understand is why? If the balance is the same is it something to do with aerodynamics... I don't doubt that you are correct, I just don't understand.

[Peter Johnsson]

It is really quite simple, but this simple fact is as a rule overlooked in the industry.

Imagine two rods of equal length and weight.
Both have theur point of balance exactly in the middle.

They should balance and feel the same when you swing them, right?

The thing is though, that one rod has a swelling in the middle and the other swells at the ends.
This makes the first rod having its mass concentrated to the middle and the other has more mass towards the ends.

You will not notice a difference if you just balance the two rods over your finger, but if you try to put them in motion they wll feel very different from each other. If you are to put the two rods in rotation, the one with its mass concentrated to the middle will be much easier to set in motion.
The one with its mass concentrated to the ends will demand more work to set in motion.

The same applies to swords.

If you have two blades that weigh the same, are of same length and has the same point of balance they can still have very different dynamic properties.
These dynamic properties are very important. As important as total weight and point of balance.

Imagine that one blade (let´s call this the original) has a thickness at the base of 9 mm and a thickness at the point of 1,5 mm. (These are realistic dimensions for a rapier blade, but dimensions vary very much between different types.)
The other (let´s call this the replica) has a base thickness of 6 mm and a thickness at the point of 3 mm. (Perhaps a pretty typical situation for many replicas)
Remember, both blades weigh the same and have their point of balance at the same place. Into this also plays the shape of the cross section. The original has a tight diamond section, or perhaps even hollow bevels, while the replica has blunter edges and a "lazy" section that is more oval in character. A "lazy" section swallows more mass and so results in a thinner blade, if the total weight is to be the same.
In between the base and the point the distal taper also varies between the two. The original has an initial distal taper that is drastic, so that the thickness is reduced to 5 mm after 10 cm. It then goes from 5 to 4.2 at a third from the point, after wich it tapers down to 1.5 mm.

The replica has a straight distal taper. It goes from 6 mm more or less straight down to 3 mm at the point. This means that the base is undebuilt, while at the same time the point has too much mass. Also by having a straight distal taper the middle is too thin to carry the extra heavy point. This blade will not only be sluggish in the point, but also wobbly in the middle.

If we compare to the example woth the two rods we will see that the original will have a point that takes less energy to accellerate and control, while the replica demands more work to put in motion and also change direction while in motion. The replica is therefore sluggish even if it is of the same weight and has the same point of balance.
This is a good example of the effects of dynamic balance.

As the replica also has a more "lazy" corss section, that is not as crisp and well defined as the original, the section will swallow more mass.
Imagine an oval and a diamond. Both shapes have same width and thickness. The oval will have greater area. This is normally the case with replicas; they are not as cris and well defined in section as originals.
Therefore, to have the same weigth the "lazy" oval need to be made *thinner* than the original tight diamond shape. This can have pretty dramatic effects both for dynamic balance (as seen above) but also in how the blade reacts in sparring. A less stiff and more wobbly blade will not allow you to use the sword in its proper techniques. It will bounce and wobble, while an original acts with autority in feints and parries.

So, it is not just a matter of how the swords feel in dynamic balance, but also how they actually works in swordplay.
This is basic mechanics for designing sword, but it is still as a rule overlooked in most designs available on the market.
In making safe sparring swords you ned to make a series of compormises to keep the swords safe. It is important to make the right compormizes and keep the effects within a reasonable margin from a sharp authentic peice.

If we are to see good swords on the market it is important that makers do their homework, but perhaps even more imprtant, that customers know what to expect and look for when buying and using swords.
If not the market will keep being flooded by inferior products.

[Chad Arnow]

[Peter Johnsson]

[Joe Fults]

[Steve Grisetti]

[Chad Arnow]

[Russ Ellis]

Ahh hah! Okay now that made sense, thanks Peter. As you say when the mass is distributed differently it would take more energy to overcome the inertia if the mass was distributed on the ends of your bars. I hadn't really considered that before although I've had some inkling of the rotation points and so forth from other things you've said in the past. Also that the blade would exhibit characteristics if the mass was distributed differently in terms of whippiness etc. totally makes sense. Again thanks for taking the time to explain.

[Gordon Clark]

The physics coming into play here involves torque - a simple example similar to Peter's is the kids see-saw. if you move up, you decrease the rotational force, if you move back you increase it. It is a misconception to say that there is the same amount of mass on one side of the balance point as on the other. Think of the see-saw with an adult on one side close to the pivot, and a child on the other at the end of the board. Clearly the "side" with the adult has more mass, yet the system still "balances" in the middle. To add to this, realize that when you move a sword, you are producing multiple types of motion. Rotation around the balance point is one, but you are also accelerating the entire sword to some extent, so that physically, the motion becomes very complex. A system that is complex enough tends to look like magic - it is not, and one could design a complex mathematical model for behavior of a sword given the mass distribution over the entire length and the force applied to achieve the intended motion. Good smiths though, I believe, have a nice intuition about this question of mass distribution, and its consequences.

Gordon

[Alberto Dainese]

Hi all,
I've found this page on ARMA site
http://www.thearma.org/spotlight/GTA/motions_and_impacts.htm

Maybe it's worth a look.

Ciao
Alberto...

[Glen A Cleeton]

[Craig Johnson]

I do not have a lot to add to Peter's excellent comments above. I will give three small illustrations I use to describe the issue to others.

One is taking a rapier and balancing it on an edge or finger than I will apply a small weight to the pommel and show where this moves the BP. It is usually just a few ounces and the BP will move an 1/8" at most. Then I will apply the same weight to the tip of the blade and show the BP move the other direction by several magnitude of the first move. I use this to explain why a heavier pommel is not a good solution to dynamic adjustment. The heavy pommel issue is the second biggest mistake in rapier construction today.

The blade from the tip to the BP is also the most important area for adjusting the dynamics of a rapier. The way I have looked at it over the years is the way my grandfather described the difference in flying fighter planes with props or jets. (The font and rear wheel drive issue above) The jets pushed you through a turn he would say the props would pull you through. A rapier is very much a jet it is being powered from behind most often in a forward direction thus the dynamic has to balance between ease of adjustment by the user and the mass in motion following through the intention created by the user. If the piece is to whippy or light the opponent can control the last third of your blade with little effort.

The dimensions on many period rapier are more extreme then most reproductions today. It is not uncommon to see a ricasso in the 1/2" range in thickness, yet the rapier will handle very well. The use of taper and dimension on rapier blades is very complex and one of the reasons we moved to 1/4" stock for our stock rapier blades some years ago as a thinner material did not allow us to get the dynamics in the range we wanted. When we do custom blades we are able to do them with some dramatic dimensions and the dynamics are actually a little easier to control.

Keep well all
Craig

[David Evans]

Blimey! Some damm good techincal reponses there! So What we need then is to measure and record the blade shape and distal taper if we are to understand the the relation between the blade and the way it handles.

[Craig Johnson]

Hello David

Yes those need to be known and quite a bit more to get everything to work together to the way they need to. The rapier is something especially that has been misunderstood greatly in modern times. I would even venture to say more than the medieval sword in some aspects. While for Medieval Swords the weight was often ghastly overrated in the Rapier the weight is often depicted as being to light, the balance point to far back in the weapon and the blades flimsy and undersized. The title Rapier covers a fair period of time and there were many variations and changes. Often the rapiers of the very late period of their use are quoted as defining examples and movies and modern fencing have reinforced this conception. They are a far more versatile weapon and one that ranges from holding its own in any street fight to the refined and deadly art of the duel with smallswords.

This is also a note for the examples sited to begin this post. They are being assumed to span just a 20 year period 1590 to 1610 and all but two are of a regional make ( note here as the German one maybe a English made piece as well as German cutlers where very strong in the English market at this time). Also the cutlers are the fellows who put these items together so the blades and hilts where not so much designed to go together as this was what the customers in that area and time where asking for in their items.

Regards
Craig

[Nathan Robinson]

This topic has been promoted into a Spotlight Topic.

[David Evans]

Just as an observation. I'm interested in buyinga Darkwood blade to train with, along with the rather nice A&A Italian rapier being lovingly crafted as I speak. So I've been carefully reading the recent two reviews on Darkwood rapiers and caluculating the percenatge of overall sword length that the PoB represents. I was intrigued to see that the Pob on the English rapier lies at 21.97% of the total sword length. Reading the review itself, and I quote

" I have found this rapier to be quite sturdy in keeping the point in-line following a beat or parry. The control allowed by the balance point allows the point to fall in place like the extension of a four-foot steel finger. I have noticed the slightest amount of difference in handling, however, with the addition of a rubber blunt attached to the point. I would not call this difference in handling a problem, however: just a difference. The point falls into place better, I think, with the blunt attached. This rapier, while not a lightweight, has no trouble moving from one guard to another. "

Reading the review throughly I am of the impression that Scott Wilson was very careful in maintaining that balance point whilst crafting the sword. I would like to know how much further forward the weight of the blunt moves the PoB.

Is there any chance both the reviewer, Geoff Freeman, and Scott Wilson could add their comments and thoughts. I also would like to know if Mr.Wilson feels what effect a different blade shape and set of dynamics would have had.

[David Evans]

Apologies for the long post, not quiet long enough for an article! I had al ook and thought that someone might be interested!

From three separate sources on the web I’ve gathered data on the basic measurements, total length, blade length and hilt length on 52 rapiers dated from 1540 to 1650, with 47 rapiers dating from about 1590 to 1630. Some variation has to be expected in points from which the blade had been measured, and therefore some variation in the hilt length. The rapiers are held within the Tower of London and the Wallace Collection and are variously of German, Italian, Spanish, English and one Swiss make. There is no indication of any selection of the blades and are hopefully as random as possible. From the data 25 of the blades could have a point of balance calculated. Given the spread of the rapiers there is some variation in sizes. The smallest rapier has a total length of 41½” long, with a blade length of 36”. The longest rapier is a stupendous 59” long with a blade length of 52”. Weight wise the rapiers range from a feather like 1lb 12 oz to a crowbar like 4 lbs 13oz a German rapier dated 1609.

However, given the spread in measurements, the average rapier that this collection creates is 48” long, with a blade lengthy of 41” and a weight of 2lb 11oz. Not truly remarkable. What is remarkable is the deviation the bulk of these 52 rapiers fall in. The bulk of these hopefully random rapiers are all within roughly 3” either side of 48”. That is to say, out of 52 rapiers, most of them will measure roughly 45” to 51” in total length. With regard to blade length there is the same deviation range of 2”, giving a range of 39” to 43” Weight wise the 52 rapiers give an average deviation of 5oz, allowing weight to range from 2lb 7oz to 3lb.

The 25 rapiers which can have a point of balance (PoB) calculated give quite wild variations. The PoB is being expressed here as a percentage of the total length of the rapier from the pommel to the blade point. The 25 rapiers range from 16.32% to 25.33%. However, the average is 22.06%, with a deviation of 1.35%. That is slightly more remarkable, 25 blades, allowing for the two wild ones, will balance around 20.71% to 23.41% of the total length, a 2.7% variation. If the two odd figures are excluded then the variations tighten up. The average goes up to 22.18%, but the deviation drops to 1.06%. This tightens the range down to just 2.12%. Meaning that 23 rapiers fall within a range of 21.12% to 23.24%.

There is no obvious correlation between rapier length, blade length or weight and PoB. The furthest Pob, at 24.45%, is on a 45½” rapier, with a 38⅞” blade weighing 2lb 14oz. The closest PoB, at 20.05%, is on a 48” rapier, with a 40⅝” blade weighing 2lb 12oz. However, there is a 53¾” rapier, with a 45½” blade weighing 2lb 15oz that has a PoB of 20.47%. The answer there must lie elsewhere. If more blade width figures were available then that might help. However, I’m inclined to believe that the missing factor is the User, the person that bought each rapier for his use.

[Peter Johnsson]

MIssing factor being User is definitly an important aspect, but even more important is the fact that no knowledge of the blade is presented.
The blade itself, regarless of length can add a major factor to the equation.
Different types of blades will invite different point of balance. his is such a major thing that two rapiers of differen weight and length with different point of balance still can have prety similar heft an dynamic balance.
This fact is not visible in this presentation.

Again I want to stress the fact that distribution of mass is a very major aspect in the feel and performance of a sword. You cannot get to this aspect from knowing weight, point of balance and length.
You need to not placing of pivot points and correclate this to the other data.

Still, it was interesting info you presented, David. Thanks!