strings

[Tee]

I have never made my own strings, but recently I purchased some new fishing line. This kind:

http://users.acsol.net/~wfi/index.html

The braided spectra line.

I purchased 200 lb test - 150 yds. The color is kind of an off Grey.

While browsing the forums here, I wondered if the line could be used to make x-bow strings.

The spectra line if very strong and has very little stretch, maybe 1% or 2% I think. Read someplace, but cannot remember exactly.

Making a line from many, many strands of this braided spectra line seems like a possibility. Also, seems like it would be as good as or better than dacron which some x-bow strings are made from I think.

Dacron has a lot more stretch.

Is stretch desirable?? My uneducated and inexperienced guess would be that you would want as little stretch as possible.

Your opinions???

Would it be possible to make x-bow strings from this braided spectra line??

Has anybody tried??

I also think it would probably make good line for servings. The spectra if very abrasion resistant. I know the Bohning #62 serving line is made from spectra. The diameters are comensurable: 0.028" for the XP and 0.025" for the Bohning.

[ComfyBear]

Here's what BCY, the makers of strings materials, say about Braided string material when used for bowstrings.

Question: Are there any benefits in a braided bowstring as opposed to the standard twisted product?

Answer: We produced braided bowstring material many years ago and have looked at it many times. Generally braided material is expensive. It does not improve the creep characteristics of the bowstring and normally reduces arrow speed.

[Tee]

Thanks comfy bear - Great to have a place with knowledgable people to ask questions and get good answers.

Right after I posted this thread I noticed your thread on your FF strings and notice that you are way ahead of me with your dyneema FF strings.

Thanks again.

[Tee]

Had some more thoughts on this.

The TUF XP spectra line, 0.028" diameter, 200# test, 1200 yds sells for $190.00

The Brownell sells by 1/4 lbs spool for $50.00. Couldn't find out how much 1/4 spool is in length. Couldn't find the strength of the Brownell, but comfy bear said that he started using 24 strands of the Brownell so I ASSUME the strength is probably between 50# and 100#, say 75#.


With that assumption, using the spectra line, the number of strands could be reduced from 24 to 8 or 9. That would seem to more than compensate for the increase in price.

Now there are may be other considerations that dictates using more than 8 or 9 strands.

Noise being one. But I have to ask: Is noise really that big a consideration??

The noise I hear from the strings I use isn't that much. If the noise is more, how much more? It still wouldn't be considered noisy would it? Are you trying to reduce the noise for the comfort of the bowman or the target. If the target, then in my limited experience that wouldn't be a consideration. At 20 yds, increasing the noise isn't going to make the deer jump any faster or sooner (sooner is dictated by the speed of sound, not the level after a certain audible threshold is reached). If I make a clean miss, then a reduced noise level isn't going to make the deer stand still for another shot.

Okay, what other considerations would dictate more than 8 or 9 strands?

You need a minimum diameter to catch the bolt, but what is that?

Other considerations??

I'm asking from ignorance here

[ComfyBear]

Brownell's TS Plus has a breaking tensile strength of 95#/ strand and is approx. .014" in diameter. So using 28 strands on even a 225# crossbow seems like overkill. However, even though one could use fewer strands, enough have to be used in order for the string to align with the centre of the back of the bolt. With vertical bows, the string has to be thick enough so the nock will fit snug. So it's a given that the number of strand used is well beyond the necessary amount. When using Dacron, which has a 50# breaking tensile strength, and is approx, .018" in diameter, 30 strands is the recommend amount for an Excalibur Crossbow.

Here's some interesting reading from BCY Corporation.

Question: If I reduce the number of strands to improve arrow speed, should I be concerned that the strength of the bow string is reduced and therefore dangerous?

Answer: With almost all modern materials used in the manufacture of bowstrings, the strength is well in excess of the maximum tension applied to the string. Consider this – A popular number of strands for Formula 8125 material is 18. The breaking strength of a single strand of Formula 8125 exceeds 100 lbs. Using 100 lbs as the criteria, the total strength of 18 strands is 1800 lbs. Of course when set up on a bow, the strands are split at the loops and a static load test shows that approximately 40% of the strength is lost at this point. This still leaves a breaking strength of over 1000 lbs.

It has been calculated that on a high poundage bow, say 75 – 80 lbs, it is possible to generate approximately 200 lbs total tension while drawing. Compare this to the breaking strength over 1000 lbs mentioned above and there is at least a 5 – 1 safety factor.

Reducing the number of strands is normally ratioed to the draw weight of the bow, therefore on lower poundage bows, the 5 – 1 safety factor will remain or perhaps increase.

With the newer, smaller diameter materials like 452, the single strand breaking strength is under 100 lbs but many more strands are used so at least a 5 – 1 safety factor is maintained.

Basically, using the manufacturers recommended number of strands x the breaking strength of the string, will assure you have a string with much more than adequate strength and if you decide to drop a couple of strands to increase speed, the strength of the finished string will still way exceed the maximum poundage generated by the bow.

Breaking strengths is rarely, if ever, the cause of a string failure. More likely causes are –
· condition of cam wheels (burrs)
· over twisting
· extremely tight serving/compressive failure
· type of release
· lack of string care and maintenance (lubrication)
· abrasion

Question: What is the difference in strength between Dynaflight and 8125? I previously made my strings and cables out of Dynaflight. My strings were made with 16 strands and cables were 14 strands, now I have started to use 8125 in which I made a string consisting of 18 strands and am wondering if 14 strands for a cable would be strong enough because of the smaller diameter. Could you tell me which is faster and more durable, no.2d.016 end serving or no.2s.018 end serve?

Answer: Both Dynaflight 97 and 8125 are made from the highest quality Dyneema yarn. 97 with its larger diameter is about 23% stronger than 8125, so 18 strands of 8125 would give you similar strength to 16 of 97.

Both materials have excellent durability.

We recommend 18 strands of 8125, perhaps 20 in your cables.

8125 is the faster string material.

If you use too few strands, you are likely to get some "creep"; particularly on the high poundage bows at high temperatures.

Regarding end serving, our 2D and 2S have similar strength and durability. The 2D is popular because of its smaller diameter and 3 ply rounder construction; it seems to serve tighter.

As you can see, even on a compound, having less draw weight than a crossbow, the recommended number of strands is the high teens or higher.

Actually the material you have is kind of thick to use a bowstring material, but seems to be a good candidate to use as serving material. The stuff I use is Brownell Crossbow Serving, which is a resin coated Spectra material and has a diameter of .036". So yours at .028 isn't that far off. Even though it's thinner, it should be great if used with 30 strands of Dacron which at .018 per strand would make up the difference and then some.

[Tee]

Yes, but I notice also that they peg the strength at 100#. Now double that to the 200# of the TUF XP and I'm still wondering if it would be safe to reduce the strands to the 8, 9 or 10 range.

This is all theoretical to me since I seriously doubt that I will be making strings in the foreseeable future. If I ever do get the time and inclination, it would be fun to experiment and see if 9 strands of the TUF XP works reliably and safely and what effect it would have on performance.

But then I am still very curious.

What would be your conjecture on performance by reducing the number of strands to 9 (assuming it could be done safely)?? Does the number of strands effect performance in a practical sense??

I notice on the first question:

"If I reduce the number of strands to improve arrow speed,"

and the answer doesn't refute the assertion of the question. Interesting.

[ComfyBear]

I'm not saying it won't work, it's just that first, .028" per stand is a tad thick to be using as bow string, second if it isn't prewaxed, it would make it difficult to make it into a usable bowstring and finally, using only 9 strands you would end up with a string that will be too thin, to line up with the centre of the bolt, which at best could affect the flight of the bolt, and at worst, cause a misfire/dryfire, if it slipped under the bolt.

Personally, I wouldn't use it to make bowstrings, but it could work very well as serving material. Just my opinion.

[Tee]

I'm not saying it won't work, it's just that first, .028" per stand is a tad thick to be using as bow string, second if it isn't prewaxed, it would make it difficult to make it into a usable bowstring and finally, using only 9 strands you would end up with a string that will be too thin, to line up with the centre of the bolt, which at best could affect the flight of the bolt, and at worst, cause a misfire/dryfire, if it slipped under the bolt.

Personally, I wouldn't use it to make bowstrings, but it could work very well as serving material. Just my opinion.

And one I value highly.

Thanks for taking the time to provide your knowledge and experience.

I find learning from those who have gone before to be the best way for me.