Skinny strings, stretch and such?

[LC]

Ok, first off I've been watching all these skinny strings, HP strings threads and such with alot of interest. I'm slow to change and have been making my own TD recurves and B50 strings for years for what it's worth. I've long been shooting lower strands than recommended with  B50 endless loops with as little loop serving as needed and as little center serving as needed and been happy.I'll put my bows up against any bow. My bows have always been built for HP string (built up phenolic tip overlays) but never tried it. Lately I've been dropping bow weight and want to get the most preformance and durablity out of a string that I can.

SO to make a long story short I bought some D97 and made it exactly the same length on my endless loop jig as I had my B50 strings. I've always read how much these skinny strings stretched but that was with flemish twist strings mostly which made no sense to me cause that's why everyone liked HP string material no strech. Anyhow the D97 endless loop string never stretched and my brace height is a good 3/4" stronger. I've shot it lots of times and it's never stretched a smidge! It's definately shooting good, but it's hard to tell since the brace height is so much more. Anyhow that brings up lots of questions for me!

Why do flemish skinny strings stretch so much if the material your making it out of is touted as no stretch and thats the reason your using it?

I'm needing to drop my brace height about 3/4" on a endless loop string so how much longer should I make my string to compensate?

For the record I padded the loops and it's still the same size as my B50 string loops and tapered it in nicely. I do have a chronograph buried somewhere someone loaned to me and when I get my string length right I'm gona try it apples to apples and see what I'm gaining.

[ozy clint]

i'm very interested in what the results will be. let us know.

i would make the string 1/2"-3/4" longer than you make your B50 to allow a few twists to bring it down to the same length as the B 50 strings.

[Jesse Peltan]

How many strands? What is the bow weight? Try making a flemish with the same strands and see if it stretches.

[Jeremy]

It takes time for the twists in the loops of a flemish twist to settle in, and that's mostly dependent on how tightly they were twisted to begin with.

The materials (FF, TS1, D97 etc) are touted as low-stretch.  If I'm remembering the numbers right, once the string has settled in the low-stretch strings will stretch about 2%, to dacron's 4% (linen is 3% and silk is about 6%).

What you're really talking about here is creep though.  Any string will creep and get longer until it settles in.  An overbuilt dacron string will creep almost indefinitely and you'll constantly be adjusting brace height.  Flemish strings will creep more than endless just b/c of the nature of how they're made.

Measure the length of your dacron string while it's on the bow.  Strings should really be measured under tension.  Then spin up an endless D97 string that's maybe 1/4" shorter than that.  That should get you pretty close.

[Rob DiStefano]

the following are some basic questions to resolve before building a bow string, either flemish or endless ...  

how many strands of a given fiber type for a given holding bow weight

how much stretch is inherent in the string fiber

how much creep is inherent in the string fiber

how much pre-tension will be used during the string build

how much fiber twist is required to keep the string intact

the last two questions are very much dependent on how the string will be built - flemish or endless - and will greatly determine any adjustments required to build a string of the required length for a given type and length stick bow.

[LC]

Well made another string 3/4" longer and it came out perfect. It's D97 (local shop couldn't get the type  you use Rob and yes this does have some wax to it!) It's 8 strand with six strands padded in the loops taper down loops. Center serving is Diamondback braided .026 and nocks are just a little to loose for my tastes but the CE nocks snap on. My B50 string was 12 strands and same serving and loops and center serving installed just enough to come off the limbs and just enough my tab fits on it identical to my new D97 string. Cat whiskers installed in the same place and same small size.

Now this bow, my latest and newest, is 47# @ 27" draw shooting CE hertiage arrows with a finished weight of 496 grains which should be around 10.5 gr per inch.

Like I said I had a old chrono a buddy brought up here years and years ago and never came back for it. I had to dig to find it and put a new battery in it. If my memory is correct it was about 5 or 8fps slower than the video shoot we use to go to way back. Anyhow with the B50 string on this chrono it averaged consistently around 160fps. With the new D97 it consistently averaged about 9 to 10 fps faster. Now I'm not speed freak by any means but do like that and the added features that came with it. Like I said I've been making my own bows for about 10years and don't shoot anything else so lets just say I've came to have a real good feel for my bows. With that said I love the way this bow shoots now! It's hard to explain but it's just smoother and I honestly believe alot quieter and I thought it was quiet before. When the wife and kids get home I'm gona do a real scientific loudness test with them if you know what I mean! Anyhow so far I'm liking it alot.

[Bjorn]

Thanks for sharing the info LC; is that an R/D or Recurve you have the string on?

[LC]

The bow is a recurve, home brew. Been out field testing it in the carp waters. Seems to shoot just as good with a solid fiberglass arrow but it might have thrown off my accuracy cause I missed several shots while bowfishing!! lol Wait a minute I  usually miss several shots out bowfishing. Seriously I like it alot. Slow to change but I'm thinking this was a postive change for sure.