D97 vs the string stretcher, an eye opener

[sticksnstones]

I like making my own strings, and I make some for friends from time to time. Whenever I make a new string I have always shot a few dozen arrows, adjust brace, and repeat until it settled in. Never really thought much about it. Last weekend I had a winning ticket at the Michigan Longbow Association spring shoot raffle. I walked up to pick something off the table and I saw a set of cargo tie down straps rated to 500 pounds, little light went off in my head.

Today I made a new string for a buddy, he likes 14 strands of D97 with loops at 18. I twisted the loops tight, and counter twisted until it was exactly 61" long. Normal deal, I've made him a few strings exactly like this before. I was curious if a string this beefy would stretch much, or at all. I put it on my stretcher and cranked it up to the max! The initial stretch was 1.5"! I set it back to 61" and burnished the string, after that it grew another 3/8ths! After making a bunch of dacron strings I had considered D97 a great material and thought of it as "no creep" when in fact it's initial creep can be considerable. I'm sure a few guys are laughing at my "revelation",but I'm sure some people will be surprised by how much stretch there is!

Now you can laugh at my K.I.S.S. string stretcher:
   

For the price of a 2x4 8' board and a cargo strap, this is a pretty cool addition to the string making rig! It will also give me good piece of mind before shipping strings that I haven't personally shot to friends for putting on their prized bows.
Thom

[SaltyDawg]

You should see my stretcher. 8^)

And

Yes - D97 creeps out the waazoo.

Rick

[Breeze430]

Like I you...I never realized. Crazy...

[Orion]

Interesting.  Of course, a large part of the initial stretch is just due to the looseness of the braids on either end of the string.  Just not possible to hand braid extremely tight.  

A lot of folks who make strings commercially hang a weight of a known amount on the lower loop, or use a scale to put a certain amount of tension/weight on the string, usually around 100#.  

I stretch mine by hand so no doubt don't get that much tension on the string. But after the initial set on the bow for a while, it doesn't creep much.

Might consider adding a scale to your rig to keep from overstretching and possibly damaging the string.

[Bjorn]

D 97 is a fine string material.........but I found the creep to be too much to make 6-8 strand strings. Generally with a 12-14 strand string after initial stretching the creep is not a factor. IMO

[Reaper TN]

I don't build strings, but after using 12-14 strand D-97 strings the last few years, they do strecth intially quite a bit when first shot. Then they seem to settle in and then no more creep.  My last few strings have been made of 12-14 strands of D-10, they seem to barely stretch at all. I prefer the D-10 material now.

[pitt98]

What Reaper said word for word!

[sticksnstones]

Good thought on the scale Jerry, I was thinking 500# max should be fine, but it would be good to dial it in and know where it's at. I've heard the stress on the string is a multiple of the weight on the bow and a string should be designed for 8x to 10x the weight at draw length. Maybe some super string ninja might want to comment on that. (Or I can rescan the archives.)

I've got a D10 string, and am thinking about ordering a 8190 sometime soon. I've got a lot of D97 to use up, and at *10 strands I think it makes an awesome string once that initial stretch is done!
Thom

[2treks]

I use D97 and D10. Well, I use Josh and thats what he uses. He builds em and stretches em. I get very little creep when they get on a bow.and they are all 10 strand.


Thom, That is a cool stretcher. Good thinking.

Say hi next month,

CTT

[LBR]

How much stretch/creep you get from Dynaflight '97 depends on several variables.  Usually the initial creep is like Orion said--settling in the twist.

You'll get more stretch/creep with any material using fewer strands--more with some that with others.  I don't like using less than 10 strands of Dynaflight '97.  12-14 is better, especially on draw weights of 50+ lbs.

I'm liking the 8190--very little stretch or creep, once settled in--but it's not a big leap over 8125, especially in a moderate size string.


Chad

[LBR]

Almost forgot--you are way ahead of most with the stretcher.  It will save time and aggravation on getting a string shot in.

Chad

[SaltyDawg]

Originally posted by LBR:
Almost forgot--you are way ahead of most with the stretcher.  It will "SAVE" time and aggravation on getting a string shot in.

Chad

Fixed, and ditto on what Chad said here.
It takes a normal draw weight bow quite a while to get all of the creep out of a string, but a good stretcher, and knowing how to use it will get the majority of it in short order.

Rick

[sticksnstones]

Thanks Chuck! I look forward to seeing you there!

Chad, as always I appreciate your thoughts and experience when it comes to strings. Thank you for sharing with the rest of us! I think moving back up to 12 wouldn't hurt on my 63# bow especially if it gets drug through some bushes and briars.

As for the stretcher, I'd been putting off building one for a long time after looking at peoples elaborate systems with weights, rails, pulleys, and such. The 2x4 + cargo strap idea was a big light bulb moment for me. That easy/cheap/quick there is no reason for me not too stretch a string before it goes on a bow!
Thom

I shoot D97 strings on all my bows. I've had guys try to tell me that it really does not stretch but that because it is twisted it settles. I agree with your amounts of "stretch" or "settle" or what ever you want to cal it. I hate getting a new string because I have to keep messing with my BH for the first couple weeks. I like the idea of your "poor boys" string stretcher and may give that a try myself.

Bisch

[LBR]

Dynaflight '97 will stretch, a little at least--I've yet to find a material I couldn't get a little stretch from on my jig. Obviously the fewer the strands, heavier the draw weight, higher the temps, etc. you'll get more.

Just to clarify, "stretch" is elasticity--it will recover when the tension is removed.  "Creep" is permenant elongation--it doesn't recover when the tension is removed.

Every string material I've ever delt with has some of both to some degree.  Draw weight, strand count, type material, etc. all play a part.  

I can stretch an endless string with zero twists in it, but the twist of a flemish does have to settle in.  

Contrary to misinformation I hear now and then, the twist in a flemish string does not act like a spring--settling that in would be considered creep, not stretch, as it doesn't recover (like a spring does).  

SS, if you want to get a little more elaborate with the system (not a lot, but it would require a little welding) you can make a jig that not only pre-stretches your strings, but will also hold them taut for serving, tying in silencers, etc.  

I really appreciate the good word...after 20 or so years and thousands of strings, even I can't help but pick up a thing or two.

Chad

[Night Wing]

Stretching the a new string is the way to go. Both of my recurves shoot 12 strand D97.

[ironmike]

once a string is shot in, what difference does it make, they all get there quick enough, and we are shooting plain old arrows,long as it's stable and they all are,let'r go! but i do like d97,mixed with a little b50 on the older bows.

[sticksnstones]

Someday I'll probably do a rig pretty much like you are thinking of Chad, I just need a basement or a workshop first... In the meantime that 2x4 actually has a bunch of 1' long attachments and a series of clamps that I use for all different string and arrow tuning activities. One of the setup's is for center serving and nock tying where it elevates the string 4". It's getting me by for my *25 strings a year.

Hey Joe, at 12 strands what do you center serve with? I was thinking I'd do one and check .024 helo to see if it was about right.

I don't mind them settling in over a night or two when I'm shooting them on my bow. I'm more worried about the times I'm sending an untested/unstretched string to a buddy with an expensive 68" bow and I just have to trust I got it twisted right. A side benefit is I can stretch it a few times before doing any serving or silencers so those don't creep around on me.

Bisch and Rick, thanks for your thoughts guys!
Thom