bow strings
Not sure if this has been discussed here before. But has anyone tried using modern material low stretch bowstrngs on traditional composites? I'm not really interested in opinions, but those who have direct ecperience ..
HMPE or high moduus polyEthylene, strings such as fastflight , dyneema etc ,have virtually no stretch, and increase bow performance significantly. There are 2 modes of thought however,
1, these strings reduce residual vibration and handshock and are thus better for the bow,,, this is the more recent way of thinking..
2. because of the cushioning effect of stretchy string material like dacron, this string is better for the bow. this mode of thought has been the predominant way of seeing it for many years.
When the limbs slam home to brace position after a shot, the dacron string allows the limbs to travel past brace height,because of the stretch in the material, this cushions the shock, of the limbs returning to brace height. But it is now realised that this also sets up a vibration as the limbs oscilate slightly causing a vibration to travel down the limb.
Hmpe strings stop dead when the limbs return, transfering more energy to the arrow. The question is , does this harm the bow as believed. Only by gathereing data from those who have used it can this arguement be sorted out. This is the reason i have posted this thread.
Does anyone have experience of this hapenning, or is it an archery myth???
I think it is impossible for one man to gather enough data to solve this problem. But If many have the experience of damaged bows then it is solved. So hopefull enough archers will respond.
HMPE or high moduus polyEthylene, strings such as fastflight , dyneema etc ,have virtually no stretch, and increase bow performance significantly. There are 2 modes of thought however,
1, these strings reduce residual vibration and handshock and are thus better for the bow,,, this is the more recent way of thinking..
2. because of the cushioning effect of stretchy string material like dacron, this string is better for the bow. this mode of thought has been the predominant way of seeing it for many years.
When the limbs slam home to brace position after a shot, the dacron string allows the limbs to travel past brace height,because of the stretch in the material, this cushions the shock, of the limbs returning to brace height. But it is now realised that this also sets up a vibration as the limbs oscilate slightly causing a vibration to travel down the limb.
Hmpe strings stop dead when the limbs return, transfering more energy to the arrow. The question is , does this harm the bow as believed. Only by gathereing data from those who have used it can this arguement be sorted out. This is the reason i have posted this thread.
Does anyone have experience of this hapenning, or is it an archery myth???
I think it is impossible for one man to gather enough data to solve this problem. But If many have the experience of damaged bows then it is solved. So hopefull enough archers will respond.
Hi, good questions!
As to the composites Adam Karpowicz would be the man to ask, in his article "Turkish Bow Tests", I believe, he reports that the strings made of high perf. low stretch materials caused the bownocks to fracture.
The old rule of thumb said that for all traditional bows low stretch strings should be avoided as they may endanger the bow.
This is only partly true, from my experience, and in all accounts regarding a low stretch string demaging the bow that I've came across, the problem always concerned the string nocks (bow nocks). If the nocks on a bow are made to resist the extra stress of a low stretch high performance string, the bow's integrity never seem to suffer, regardless of whatever consctruction it is.
I don't have a clue how to explain it scientifically.
Following the issue of the bow nocks, my only experience concerning low stretch modern strings is with wooden laminated and self bows, but I hope it can still be useful in hear.
I've experienced bow nocks fracture only when cut directly into the wood (self nocks), with dacron and linen strings, self nocks are safe.
When using overlays to strenghten the nock some people have reported on importance of using proper glue.
Full horn nocks (English style) take low stretch strings very well, I have never seen a bow, however heavy, old or fatigued it be, with horn nocks broken due to a low stretch string. I recently made a Spectra Flemish type string for a laminated English longbow from the first part of the 20th century, it shoots without problems.
Genuine Flemish hemp, where they were still around had been reported as having "no stretch at all" (Robert Elmer). Of course I take they were still stretching a bit in comparison to the low stretch modern yarns.
Initially I was using only Dacron strings, in this case a switch to low stretch strings on a wooden bow can feel awkward, as there is a big difference.
Now I only use fast-flight/spectra or natural plant fiber strings. I can emphasize that after I got used to low stretch strings, shooting a bow with a Dacron string is a horrible experience; in my experience the same bow shot with a Dacron string will have a considerable more hand shock, overall vibrations, jar etc., than when shot with a low stretch string, so according to your point 1., I agree, high performance strings reduce handshock.
Also a Dacron string is much more troubelsome in adjusting to the correct bracehight, and stresses the bow much more when bracing.
Now if I were to make a Dacron string it would be of the endless type only, a Dacron "Flemish" string of course stretches much more.
As to the composites Adam Karpowicz would be the man to ask, in his article "Turkish Bow Tests", I believe, he reports that the strings made of high perf. low stretch materials caused the bownocks to fracture.
The old rule of thumb said that for all traditional bows low stretch strings should be avoided as they may endanger the bow.
This is only partly true, from my experience, and in all accounts regarding a low stretch string demaging the bow that I've came across, the problem always concerned the string nocks (bow nocks). If the nocks on a bow are made to resist the extra stress of a low stretch high performance string, the bow's integrity never seem to suffer, regardless of whatever consctruction it is.
I don't have a clue how to explain it scientifically.
Following the issue of the bow nocks, my only experience concerning low stretch modern strings is with wooden laminated and self bows, but I hope it can still be useful in hear.
I've experienced bow nocks fracture only when cut directly into the wood (self nocks), with dacron and linen strings, self nocks are safe.
When using overlays to strenghten the nock some people have reported on importance of using proper glue.
Full horn nocks (English style) take low stretch strings very well, I have never seen a bow, however heavy, old or fatigued it be, with horn nocks broken due to a low stretch string. I recently made a Spectra Flemish type string for a laminated English longbow from the first part of the 20th century, it shoots without problems.
Genuine Flemish hemp, where they were still around had been reported as having "no stretch at all" (Robert Elmer). Of course I take they were still stretching a bit in comparison to the low stretch modern yarns.
Initially I was using only Dacron strings, in this case a switch to low stretch strings on a wooden bow can feel awkward, as there is a big difference.
Now I only use fast-flight/spectra or natural plant fiber strings. I can emphasize that after I got used to low stretch strings, shooting a bow with a Dacron string is a horrible experience; in my experience the same bow shot with a Dacron string will have a considerable more hand shock, overall vibrations, jar etc., than when shot with a low stretch string, so according to your point 1., I agree, high performance strings reduce handshock.
Also a Dacron string is much more troubelsome in adjusting to the correct bracehight, and stresses the bow much more when bracing.
Now if I were to make a Dacron string it would be of the endless type only, a Dacron "Flemish" string of course stretches much more.
Dragonman - I think we corresponded about this subject via PM. Let's see the responses of others who experienced the damage caused by FF strings.
I my experience, the stiff strings are beneficial to all bows. Unfortunately, the heavier composites are damaged at the nocks as Ashbow explained. It is because the string tension at brace, and therefore at the moment the bow returns to the braced position on release is extremely high in these bows. The stress is so high that the nocks break (the bottom lip is sheared off). These is for nocks made of wood and reinforced with natural materials, such as horn and sinew. I have not tested modern materials.
In longbows or other self bows, and in bows where the whole limb is working, the tension at brace is lower and the nocks are less stressed. It is also possible that the geometry of the nocks and the size of the loops have something to do with this.
In lower weight composites, under 60-70lb, the stresses are lower as well and the damage is less likely to occur.
Adam
I my experience, the stiff strings are beneficial to all bows. Unfortunately, the heavier composites are damaged at the nocks as Ashbow explained. It is because the string tension at brace, and therefore at the moment the bow returns to the braced position on release is extremely high in these bows. The stress is so high that the nocks break (the bottom lip is sheared off). These is for nocks made of wood and reinforced with natural materials, such as horn and sinew. I have not tested modern materials.
In longbows or other self bows, and in bows where the whole limb is working, the tension at brace is lower and the nocks are less stressed. It is also possible that the geometry of the nocks and the size of the loops have something to do with this.
In lower weight composites, under 60-70lb, the stresses are lower as well and the damage is less likely to occur.
Adam
This is likely something that can be compared to shooting light and heavy arrows. While a light arrow puts more of a shock into the bow, the heavy arrow let the bow return gently to brace.
A static string will put a shorter but more energetic shock into the bow, while a stretchy string will make the shock last longer and be more gentle. That's probably the reason it can feel like there is more handshock in a bow with a stretchy string - the vibrations are going on for longer and the frequency of them are probably slower which makes them easier to feel. It is probably better for the materials to be subjected to low impact shock over a longer time than it is to subject it to a high impact over a short time.
A static string will put a shorter but more energetic shock into the bow, while a stretchy string will make the shock last longer and be more gentle. That's probably the reason it can feel like there is more handshock in a bow with a stretchy string - the vibrations are going on for longer and the frequency of them are probably slower which makes them easier to feel. It is probably better for the materials to be subjected to low impact shock over a longer time than it is to subject it to a high impact over a short time.
Interesting topic!
I wonder how the thickness of the strings takes influence on the case of nock splitting.
Most strings I see here on Atarn and elsewhere seem a lot thinner than any original hornbow bowstrings... However, in my bows I like the strings thicker than necessary with modern materials. And in wooden bows I use a lot of linen strings, which have to be thicker than Dacron strings, too...
Adam, how thick were the loops of your FF strings? Did you try a FF string with a thickness comparable to old original hornbow strings?
Bede always says linen strings break on his hornbows when flight shooting. I wonder again if the used strings were simply too thin. Of course thicker strings mean less speed and distance, but life often has compromises...
For evaluating what bows and arrows were capable of hundreds of years ago, we have to use natural materials anyway.
JJ
I wonder how the thickness of the strings takes influence on the case of nock splitting.
Most strings I see here on Atarn and elsewhere seem a lot thinner than any original hornbow bowstrings... However, in my bows I like the strings thicker than necessary with modern materials. And in wooden bows I use a lot of linen strings, which have to be thicker than Dacron strings, too...
Adam, how thick were the loops of your FF strings? Did you try a FF string with a thickness comparable to old original hornbow strings?
Bede always says linen strings break on his hornbows when flight shooting. I wonder again if the used strings were simply too thin. Of course thicker strings mean less speed and distance, but life often has compromises...
For evaluating what bows and arrows were capable of hundreds of years ago, we have to use natural materials anyway.
JJ
The FF strings I used were thinner than the originals, but the loops were served to be about the same thickness as the loops in original strings. I normally used the 4x draw weight for the strings and did not want to overbuild, since the stiffness woud be even greater. I hoped for some stretch to avoid breakage (did not help).
I would like to try ramie strings, if I find a source (Turkish bows from the Dresden collection had these strings). Anyone? our South Asian members? Ramie fiber can be bought on the net, but I have not been able to find the thread.
Adam
I would like to try ramie strings, if I find a source (Turkish bows from the Dresden collection had these strings). Anyone? our South Asian members? Ramie fiber can be bought on the net, but I have not been able to find the thread.
Adam
Adam, I imagine that a thicker, heavier string reduces the speed of the limb movement and could prevent damage at the nocks.
Why do you think that a thinner string has more stretch? I imagine that a virtually no-stretch material doesn?t even allow stretch in very thin strings.
My wife recently purchased some ramie sewing thread (Sternzwirn, which is normally of a very good quality). I did not yet try to make a string from it. It?s a little disappointing in breaking strength: the thread (app. 0,3 mm diam.) breaks at around 2lb, while a 0,6 mm linen thread breaks at around 8 lb.
If you are interested I could purchase some of that stuff for you.
JJ
Why do you think that a thinner string has more stretch? I imagine that a virtually no-stretch material doesn?t even allow stretch in very thin strings.
My wife recently purchased some ramie sewing thread (Sternzwirn, which is normally of a very good quality). I did not yet try to make a string from it. It?s a little disappointing in breaking strength: the thread (app. 0,3 mm diam.) breaks at around 2lb, while a 0,6 mm linen thread breaks at around 8 lb.
If you are interested I could purchase some of that stuff for you.
JJ
A thinner string has less strands. Then there is more stress per strand and therefore each strand extends more. But as you say the differences may not be enough.
Thanks for the offer, but I think I have bought something similar. A ramie thread breaking under forces less than flax. Not good enough - these threads must be made of short fibers. We need a thread with long fibers for more strength (it is the same with other string materials).
Adam
Thanks for the offer, but I think I have bought something similar. A ramie thread breaking under forces less than flax. Not good enough - these threads must be made of short fibers. We need a thread with long fibers for more strength (it is the same with other string materials).
Adam
The linen strings broke becauseofthe low humidity on Bonneville Flats . The humidity is the key in my problem. The strings were tested in Georgia at 70-90% humidity and they had no problems. In 10% humidity in Utah, they failed catastrophically.
I wonder if the linen could be treated with something hycroscopic to enhance moisture uptake. Perhaps glycerol?
Jaap Koppedrayer and I tried various approaches. Remember that we were using the strings in flight archery, so that added weight to the string would impair the efficiency of the bow. Ultimately, it was Alan Case who came up with a solution. He wetted the strings down before shooting and waited until they were almost dry before shooting. Of course delays in shooting could be fatal to the string.
Some of the things tried were a lacquered linen string made by Jaap with urushi lacquer; heavily waxed strings and thicker strings. I have spectacular photos of the lacquered string disintegrating in mid shot. Heavy waxing made a heavier string and so did thicker strings.
Last year I made a silk string with separate end loops (silk also) for Jaap and it lasted the whole shoot. He even let me shoot with it on his bow. That year I even managed to break a three year old three strand gut string shooting a light arrow from an arrow guide.
Some of the things tried were a lacquered linen string made by Jaap with urushi lacquer; heavily waxed strings and thicker strings. I have spectacular photos of the lacquered string disintegrating in mid shot. Heavy waxing made a heavier string and so did thicker strings.
Last year I made a silk string with separate end loops (silk also) for Jaap and it lasted the whole shoot. He even let me shoot with it on his bow. That year I even managed to break a three year old three strand gut string shooting a light arrow from an arrow guide.
I have been trying to reaearch what type of material was used on asian composite bows, but find very little info, I read that silk and animal skin/gut strings where used, but with all natural materials it is a question of quality, same with linen, not all linen has anywhere near the same strength....so it all depends on the quality of raw materail, growing conditions,manufacture process etc. It isnt for certain that if one linen string breaks another made elsewhere will!!! In this part of the world Irish linen is considered much better quality than English, for example..
Does anyone have more info on traditional string materials ?...I heard recently that Newzealand Flax is a very good fibre, but havent had chance to try it yet.....
Does anyone have more info on traditional string materials ?...I heard recently that Newzealand Flax is a very good fibre, but havent had chance to try it yet.....
Dragoman,
I think we can rule out NZ flax since it was not available to ancient string makers. In Asia, the major materials according to the written sources are in order of utility, silk, ramie, sinew, gut and cotton. Horse hair is mentioned, but that may not be as common as Hein thought.
Silk was used in different ways, but it was always unreeled filament silk, never spun silk. Ramie may have been more widespread than thought. There are ramie strings in the Dresden and Karlsruhe collections associated with Turkish and Tatar bows. Sinew and gut are always available to nomads and mage functional extremely strong strings.
As you pointed out, the quality of the materials influences the quality of the finished product. It is important to realise that there were two different requirements of strings. One was a light strong string to shoot long distances, whether in flight or warfare. The other was a solid heavy string for accuracy, mainly used in target shooting and medium to close range shooting. While a lighter string could be used for both purposes, the heavy string was limited to medium and close range.
I think we can rule out NZ flax since it was not available to ancient string makers. In Asia, the major materials according to the written sources are in order of utility, silk, ramie, sinew, gut and cotton. Horse hair is mentioned, but that may not be as common as Hein thought.
Silk was used in different ways, but it was always unreeled filament silk, never spun silk. Ramie may have been more widespread than thought. There are ramie strings in the Dresden and Karlsruhe collections associated with Turkish and Tatar bows. Sinew and gut are always available to nomads and mage functional extremely strong strings.
As you pointed out, the quality of the materials influences the quality of the finished product. It is important to realise that there were two different requirements of strings. One was a light strong string to shoot long distances, whether in flight or warfare. The other was a solid heavy string for accuracy, mainly used in target shooting and medium to close range shooting. While a lighter string could be used for both purposes, the heavy string was limited to medium and close range.
Adam, in my opinion the tension in the string at brace position has little to do with breakage of the nocks.
The siyahs, the ears of the bow are moving and when they reach the biggest speed they instantly stops. So, to do that is needed a force, applied from the string in the nocks of the ears. The fastest the bow, the biggest is the force. Also the mass of the ears is in direct relation with the force in the nocks.
I think the breakage of the nock has to do with the direction of this force. In a turkish bow the force in the direction of the string can split the wood. In a korean bow, the nocks work different way, the string will never split the ear, in my theory korean bows should never break the nocks (this can be verified, has somebody seen a korean bow with broken nocks?).
Longbows nock works more like korean nocks but there is a component of the force in the direction of the limb who can split the nocks, however, this force is only a small part by comparison with a turkish bow.
Now I wonder if the korean nock is a solution for the splitting issue or just a random design evolution.
The siyahs, the ears of the bow are moving and when they reach the biggest speed they instantly stops. So, to do that is needed a force, applied from the string in the nocks of the ears. The fastest the bow, the biggest is the force. Also the mass of the ears is in direct relation with the force in the nocks.
I think the breakage of the nock has to do with the direction of this force. In a turkish bow the force in the direction of the string can split the wood. In a korean bow, the nocks work different way, the string will never split the ear, in my theory korean bows should never break the nocks (this can be verified, has somebody seen a korean bow with broken nocks?).
Longbows nock works more like korean nocks but there is a component of the force in the direction of the limb who can split the nocks, however, this force is only a small part by comparison with a turkish bow.
Now I wonder if the korean nock is a solution for the splitting issue or just a random design evolution.
It is important to remember that the modern Korean bows are all light target bows (less than 80 pounds). The nocks on war bows and heavy crossbows from Korea are much more like Turkish bows than modern Korean target bows.
If I understood Adam correctly, he was talking about the lower lip of the nock on the back shearing off. Is that correct, Adam?
If I understood Adam correctly, he was talking about the lower lip of the nock on the back shearing off. Is that correct, Adam?
Fast and heavy bows normally all have high tension at brace, but your observation about the Korean bows is interesting. Perhaps the tips would not break, even if the bows were as heavy.
Yes, the lower lip is shearing off.
Adam
Yes, the lower lip is shearing off.
Adam
Like to add some datas for this topic.
Here is some natural gut string datas http://www.physics.usyd.edu.au/~cross/P ... gTests.PDF
http://www.epinions.com/review/Babolat_ ... 78788?sb=1
Here is one from modern materials http://www.hbvachilles.nl/downloads/Mak ... trings.pdf
Here is some natural gut string datas http://www.physics.usyd.edu.au/~cross/P ... gTests.PDF
http://www.epinions.com/review/Babolat_ ... 78788?sb=1
Here is one from modern materials http://www.hbvachilles.nl/downloads/Mak ... trings.pdf
I have made a test set up for measuring tension at brace height and during the draw. I shall test some modern Korean bows and see how they compare. The brace height tension is a direct measurement, but because the scale remembers peak weights the during the draw measurements require calculation.