How many strands in a bowstring?

grimsby archer

New member
Ok, I'm confused!

How many strands do I put in a bowstring?

Can anyone explain or point me to a good resource for this? I am particularly interested in breaking strains and % creep and elasticity or stretch for different materials.

Found one website which offers:
bowweight x 4 / (breaking strain)

So for a 40lb bow on 50lb breaking strain dacron B50, makes 4 strands (doesnt sound right)

Same site has a table showing at 40lb bow to need 12 strands dacron,18 strands fastflight. sounds better but no explanation of how we got there.

BCY website doesnt list B50, but for their newest products, just lists "recommended number of strands=" with no regard for the bow weight at all. The explanation given is this gives the "best nock fit"
Is that what it comes down to? Nock fit!

I could just copy my existing string, but that is too simple! I need to understand the principals involved
 

Shirt

Well-known member
The breaking strain on any modern material is greatly in excess of what a bow will deliver on any one shot. Having shot unlimited flight bows with 6 strands of 8125, even they managed to last for about four shots...

There's doubtless some magical formula for what's the perfect number for maximum efficiency and minimum inconsistency and all that stuff, but really, nock fit is the only important criteria these days.

<40#, 16 strands fastflight/8125
>40#, 18 strands fastflight/8125.
Convert accordingly if using Ultracam, 450 or derivatives, S4, etc...

EDIT: Also, forgot - nock fit has a fair degree of dependency upon centreserving, so you need to figure that out when making a string.
 

Murray

Well-known member
Ironman
American Shoot
AIUK Saviour
As materials have evolved, the strength of individual strands have far exceeded where they need to be in terms of breaking strain so yes, pretty much it comes down to nock fit. If you could enlighten us as to exactly what material you're considering, then perhaps we could suggest a suitable strand count based on experience...
 

GreenSteve

New member
Don`t know if this will help, what worked best for me 42lb on the fingers and 26.5" draw
with FastFlight i found 14 strands
with Angel Majesty 16 strands
and with BCY8125 i started at 18 strands and worked my way down to 10 strands to find out that 12 strands worked best for me
 

Robin the Hood

New member
Just to add that in the past it has always been found that there was the guide line similar to what was just shown by Shirt
But when shooting with the extra strands added, it was found that it could help make the Bow a bit more stable.
The disadvantage was it did reduce the cast slightly. As the case of reducing the strands the bow was faster but less stable and the string was not as longlasting.


:scratchch :thumbsup:
 

grimsby archer

New member
As materials have evolved, the strength of individual strands have far exceeded where they need to be in terms of breaking strain so yes, pretty much it comes down to nock fit. If you could enlighten us as to exactly what material you're considering, then perhaps we could suggest a suitable strand count based on experience...
It was a generalization really. I generally use dacron b50 for the club bows and fastflight+ for my own.
My thought was that if 4 strands was technically sufficient, why does everyone use 14? Seems, on the face of it, like a sledgehammer to crack a nut. Nock fit seems a poor reason as one could make smaller nocks, or build up the centre serving.

Forgive me if I am using thumbscrews. I like to know the "why". Science over religion.
 

tel

Active member
Fonz Awardee
got to build in a little practicality - a four strand string with the serving 'built out' to accept a normal nock (1 or 2) would be ridiculous and would, at a higher poundage, be like trying to pull a cheese wire. t'other consideration is of course speed - I dropped my strand count (and nock size) to give me a better sight mark...
 

Shirt

Well-known member
My thought was that if 4 strands was technically sufficient, why does everyone use 14? Seems, on the face of it, like a sledgehammer to crack a nut.
Because the breaking strain formulas tend to be for either continual force of a given amount, or one-time fast stretches. A bow is repeated fast stretches.

4 strands will be strong enough to string your bow, it'll even be enough to shoot it (once!) but not much more.
 
T

TimCroot

Guest
Because the breaking strain formulas tend to be for either continual force of a given amount, or one-time fast stretches. A bow is repeated fast stretches.

4 strands will be strong enough to string your bow, it'll even be enough to shoot it (once!) but not much more.

Anyone got a Hooter Shooter to do some tests? just how low can you go to keep a string in one pice for a round of 150 shots???
 

geoffretired

Supporter
Supporter
I posted this list of bow materials some time ago. It also showed how many strands of each material should be needed to build a string with breaking strains.
[/IMG]
The number of strands may seem unscientific as we could make do with far less these days, but I think it all comes down to nock fit as others have said.
Nock slots tend to be in two or three different sizes. Imagine the effect of archers requiring twenty different sizes. Also , a four strand string, with a thick serving will not be easily produced. Would you serve it once then go over it and do it again?I suspect that would not be very successful as it would more than likely move. Also a few strands of X material would stretch more than 20 strands, and creep more too, making it a struggle to maintain bracing height.
 

grimsby archer

New member
I posted this list of bow materials some time ago. It also showed how many strands of each material should be needed to build a string with breaking strains.
.
Thanks, this data is very interesting. Would it be cheeky if I asked what the original source of this info was? I mean, is this something you wrote, or borrowed from another person/website/publication?

Thanks again
 

geoffretired

Supporter
Supporter
The sheet was given to me by a friend who works for a well known archery supplier. The original source of the data I can't help with I'm afraid, I simply don't know.
 

Kae

The American
American Shoot
Nock fit is important and is the deciding factor when choosing a string.

But don't forget, us humble recurvers pull the string on either two or three pinkies, and using a 4 strand string would be somewhat painfull!

I use an 18 strand 8125 string on my bow and its just thick enough to be comfortable at my draw weight.

Kae.
 

Rhys

Active member
AIUK Saviour
I found that a 16 strand string (8125), with 43lbs on my fingers and 31" draw length was a tad noisy. Going to 18 strands just felt and sounded a lot better.
 

grimsby archer

New member
Nock fit is important and is the deciding factor when choosing a string.

But don't forget, us humble recurvers pull the string on either two or three pinkies, and using a 4 strand string would be somewhat painfull!

I use an 18 strand 8125 string on my bow and its just thick enough to be comfortable at my draw weight.

Kae.
Couldnt both these issues be overcome by building up the serving, or laying extra strands only under the serving?
 

geoffretired

Supporter
Supporter
Imagine a very thin bow string. Then serve it twice, one over the other or add some strands then serve over once. The serving would have very poor grip on the bowstring.The tendency to unwind would be increased. Also, it would not shoot so many shots before needing to be replaced.This constant maintenance would be enough to put off most people. Another aspect is that on an endless loop string of say 4 strands, one end loop would have only two strands round the nock at the limb tip.
 

tel

Active member
Fonz Awardee
I think its 'The Art of Repetition' - I said 'The Art of Repetition' - that advises placing an extra strand at the non-crossover end to make both loops the same thickness.
 

ThePinkOne

New member
There's speed/criticality issues too seem to recall, i.e. a thinner string is a faster string- but also more critical to shoot....... I seem to recall the Bowyers Bible (I think) has a good description of the processes involved including the whole thing about limb design in the equation...

Incidentally, the thing about putting reinforcing strands in the nock loops is old, it's described in "The Archer's Craft" as a standard method when making strings.

P.
 

Meddler

New member
I think its 'The Art of Repetition' - I said 'The Art of Repetition' .
How very droll... :cheerful:

- that advises placing an extra strand at the non-crossover end to make both loops the same thickness.
If someone could tell me why this should be necessary, I would like to hear it...

:stirthepo

[Tongue very firmly embedded in cheek]

What is the point of putting the extra strand at the opposite end to the crossover?

Surely there are enough strands there so that the string won't break at the loop? Or damage the limb tips?

How much extra material do you have to have there to balance up the material at the crossover end?

The easiest way to have the same amount of string material at either end is to have an odd number of strands in the string.

Ah, but doesn't that cause more problems? Because you will have one "rope" of say 9 strands on one side of the string,and one "rope" of say 10 strands on the other side, causing a lateral imbalance in the string. So then you have a problem.. what is the effect of having an even number of twists in the string as against an odd number?

The usual reason for putting the extra material on the non-crossover loop is to "balance" the weight of the string. Except that the string cannot be equally weighted from top to bottom, because the nocking point is not at the mid point of the string, it is slightly higher. So then, logically, there should be more weight on the bottom of the string, to counteract the weight of the nocking point on the top part of the string.

This coincidentally would also help with some tuning aspects of the bow. Because of the way the bow is drawn, slightly above the mid point, the bottom limb is pulled back slightly further (in relation to the top limb, and will therefore move off more smartly than the top limb, which pulls the nocking point down (hence why the nocking point is slightly above square on the string). With a heavier weight on the bottom limb, this would mean that this tendency for the bottom limb to move more quickly than the top limb could be limited by the extra weight, and this is why I would put the loop with the crossover point on the bottom limb.

The serious point in all this is as follows...

The string will be slightly heavier at one end than the other because of the position of the nockingpoint.

But it will not change from one arrow to the next. It is fixed, and should therefore have no great effect on tuning.

With the same input into the bow from the archer there will be no difference from one shot to the next.

To go back to the original question of this thread, how many strands do you need on a bowstring?

Enough.

Enough strands so that the string will not break on release or after a small number of releases

Enough strands so that the energy is transferred to the arrow and not stored in the bow (as in a dry loose)

Enough strands to give an acceptable level of speed, so that decent sight marks can be had.

Enough strands to ensure the archer is not pulling back a "cheesewire", and therefore has control.

There is enough information out there about the number of strands to put in a string, but the ultimate decision rests with the archer and a whole lot of experimentation regarding the number of strands.

:innocent::duck::flamed:
 
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