Some thoughts on string twist

[bawana bowman]

OK, here's my observation.
Purchased 5 longbows in the past 4 months. All came with a flemish string, (fine and dandy). 3 of the strings were twisted up tighter than a barber pole sucking on a lemon,(1 was actually 7 in 1 inch!!), 1 had a full twist every 3 inches, and the last had one in 6 inches.

Now, I've been making flemish strings since about 1980, and before that was making endless loop strings for about 9 years.
My Flemish strings usually have a full twist every 3 - 4 inches, depending on the length of the string.
It has always been my thought that the endless loop strands are parallel to begin with and as such will only stretch or elongate at most about an inch,(on heavy draw weights) and then settle and cease to stretch.
With this in mind it would seem the more twist there is in a flemish string, the more spring there is to elongate to bring the strands towards being parallel. This would seem to add a lot of unwanted stretch to the string creating constant nock point and brace height adjustment.

I've always used Dacron and have actually never fooled with FF of any breed, (never felt the need). So perhaps all the pictures I've seen posted lately with strings twisted up tighter than kite string could be FF material, and the builder thinks they look pretty that way.

But my thoughts are that all those twists are both a waste of time, materials, and efficiency.  

[wtpops]

Most of the strings i have used i have been told there should be no less than 20 twists total in a flemish string to avoid posablility of the string comming apart, and no more than 100. The strings i make for myself i make them so there start off with 20 to 25 and then as they settle in i will need to add 5 to 10 depending on how many strands i used. I have only used FF, no experance with dacron

[30coupe]

I've made both B50 and D97 strings. Since B50 strands are thicker, it takes fewer twists to shorten the string an inch than it does with D97. The skinnier the string, the more twists it will take to shorten it the same amount. Skinny D97 strings need to be shorter to begin with for this very reason.

Once brace height is established, B50 still stretches more than D97, so I have to occasionally add twists to a dacron string. This is less of an issue with D97. If you are only giving your strings one twist in 3-4 inches, that's only 14-19 twists in a 58" string. That may be why you get lots of stretch. I like to start with 25 or so and adjust as the string settles in. With B50 that usually takes another 10-15 twists. That's been the case for me anyway.

[Rob DiStefano]

the excess flemish string twisting is just one of many reasons i prefer endless bowstrings.  

all that required twisting adds 'spring' to the string, puts in an unwanted mechanical stretch factor (regardless of the string fiber - though by nature, dacron will be even more stretchy/creepy).

[Orion]

Bawana:  You've discovered either a difference in string building philosophy or competence. I don't know which.  I agree that too much twisting will contribute to more stretching when strung/shot.  As noted, 25 twists or so seems to be a consensus starting point.  It's understandable that someone who is used to using dacron, making a fast flite string for the first time will end up with more, maybe way too many more, twists with the thinner material, as 30 coupe points out.  Regardless, badly over-twisted strings should be replaced, IMO.  Or, it's not terribly difficult to undo one loop and simply shorten the string.  

[30coupe]

Rob,

I'm not trying to be a wise guy because I haven't used an endless string in years, but how do you adjust brace height with an endless string? Do you just have to be satisfied with the length you get or do you twist it to adjust? What if the string you get puts your brace height higher than you'd like?

I like that I can make my own Flemish twist strings. I wouldn't know how to make an endless loop string. Where are the ends anyway, under the serving? Serving the nock ends looks like it would be a pain as well.

I've not noticed all that much stretch or creep once the string settles in, so I think I'll stick with the twists. I was just curious about the endless strings.

[Rob DiStefano]

hi russ,

endless strings should have a bit of twist in them, to round off the string - don't wanna shoot with a flat ribbon string.

endless strings are created to extremely precise string lengths - there is no guess work or special crafting skills required as the jig does it all for ya.  therefore, once you 'dial in' a string for a brace height range, it can be cloned time after time after time.

the ends of endless strings are served under one of the string loops.  the serving protects the string fiber from abrasion and cushions the limb nocks.  serving the string loops is waaaay easier than you'd imagine.

inherent stretch/creep in any modern fiber string will settle in over time, more so with hmpe string fibers.  flemish strings have lots of twist by necessity of design.  all those twists introduce a 'spring effect'.  if you had a flemish and endless string for a particular bow, and bow rendered the same brace height, the unbraced flemish string would probably be shorter due to the twisting, coil effect.

below is a link to an old online pictorial i did years ago about spinning an endless string ... i'll have a video of my process online in a few weeks.  funny thing, back in the 50's, 60's, most archers/bowhunters used flemish twist strings - at least here in the northeast.

 http://www.tradgang.com/rob/ta/endless/estring.html

and here's how to build a super simple 'n' easy endless string jig ...

 http://tradgang.com/cgi-bin/ultimatebb.cgi?ubb=get_topic;f=1;t=073760#000000

for those that feel that the divided endless loop makes for a weaker string, tim baker reports on p.218 of the trad bowyer's bible #2 ...

"Many archers and writers of the past and present have assumed the loop of an endless string is weaker than the string itself. The following argument is presented (to supposedly corroborate such a statement) -

The loop is only half as thick as the main string, therefore only half as strong. For the loop to have sufficient strength, string thickness has to be doubled, doubling the entire string's mass in the process.

This seems to make perfect sense, and if my engineer friend Dick Baugh hadn't set me straight on the matter the above argument might have stood.

It's easy to prove that an endless string's half thickness loop is a s strong as its full thickness body: Determine the strength of a single strand. Loop it over a smooth hook of a pull-scale, two strands hanging down. Pull on both strands, noting the scale weight at the breaking point.

Double that of a single strand.

[LBR]

In my experience, if a flemish string is "springy", it's got WAY too much twist in it.  I can't recall ever seeing a flemish string that I'd call springy.  I can put an endless string or a flemish string on my jig and stretch it--how much depends on the material.  If both are shot in, the stretch will be pretty much equal.

Flemish strings have more initial creep, due to the twist--all that slack has to be settled in.  After that, it's six of one and a half-dozen of the other.  That's why I have a jig that I use to put around 300# of pull on almost every string I make.  I say "almost", because on some kid's strings I don't put as much pull on them (they break).  I do this with both endless and flemish, and both have initial stretch and creep.

Endless jigs are more precise, but they don't accomodate for variances in string material, different ways the string is made, etc. I might personally know one, maybe two people that can shoot the difference in a string with a lot of twist vs. a string with just a little bit of twist.  They both use flemish strings.

There's a few bows out there that are touted for their speed--off the top of my head I can think of A&H, Centaur, Morrison--and they all sport "factory" flemish strings.  Some of the better tournament archers and hunters in the sport use flemish strings.  Makes no sense to handicap yourself in the performance department with the string when one of your selling points is performance.......right?  

A properly made flemish string isn't a handicap.  It might seem that way just thinking it over, but I've talked to and read about way too many tests to believe otherwise, besides my own experience.

Chad

[Rob DiStefano]

flemish or endless, take yer pick, both will get the job done.  it really just comes down to personal preference.

[Bjorn]

I am a fan of Flemish twist. I use endless on my '50s Bear bows-but the new ones all have skinny flemished D97 strings; both types work well.
Either way Chad makes a great string!

[30coupe]

Cool pictorials Rob. Now this will bug me until I make one and try it I suppose.

I have another question (go figure). Since some of us have been experimenting with skinny strings, could you pad the loops on a continuous string and make a skinny string or would it be too much of a pain? Have you tried it?

Thanks,

Russ

[Bjorn]

TRAP sent me a 12 strand CL string -B50- the other day for a 1959 Kodiak. It is the quietest bow/string combo you could ask for. What was different is he tapered the ends of the loops; OL emphasised the importance of tapering to reduce noise-see the long "skinny string thread" I started a while back. Whatever; it works. There is no need for any kind of silencing devices or material on this string/bow combo.

[30coupe]

Bjorn,

Did he add strands to the loops to make the tapered ends then? That's the only way I can see making it work. So then the loops are the same diameter as the string rather than half diameter?

[30coupe]

BTW: I have read the ENTIRE skinny string thread...and contributed to some of it's length. I am hooked on the skinny strings    

[Rob DiStefano]

Originally posted by 30coupe:
Cool pictorials Rob. Now this will bug me until I make one and try it I suppose.

I have another question (go figure). Since some of us have been experimenting with skinny strings, could you pad the loops on a continuous string and make a skinny string or would it be too much of a pain? Have you tried it?

Thanks,

Russ

skinny strings are the way to go for me.  

i'm now using an 8 strand endless on a 55# longbow.  the loops are easily padded with 4 to 6 strands of the same string fiber.  the padded strands are added under tension, too.  

i could easily go down to 6 strands and will test that out soon.  

i use #4 nylon to serve all loops, and either bcy halo or #62 for the center serving, sized to give a loose fit to the arrow nocks.

my upcoming amateur endless string making video will show the spinning of an 8 strand bcy d'02 2 color endless string, with padded loops.  i'll post it on powwow.

[Bjorn]

30 coupe: Yes, TRAP padded the loops and what Rob said, add strands to the loops and wrap them.
I am going to try a 6 strand continuous D97 string with padded and tapered loops and tapered serving area, like Rob is describing.

[30coupe]

Okay, this brings up one more question. How do you put tension on the added strands?

[30coupe]

Maybe I should wait for the video...any idea when it will be ready, Rob?

[Rob DiStefano]

the padded strands are simply wrapped around the jig arm under tension.  the vid should be ready next week ... you'll clearly see how i've been spinning strings since the early 60's, using a one arm endless jig.

[30coupe]

Thanks Rob. I'll look forward to the video. I like the Flemish twist strings just fine, but I have just enough arthritis creeping into my hands (too many dislocated knuckles as a kid) to mean making them is becoming a pain (literally). The endless loop ones look pretty painless once you figure out the string length part.