Broken string discussion

[last arrow]

Breaking a bow string while shooting last night got me to thinking.

I have been shooting recurve bows since about 1970.  Over that time I have had about 10 strings break while shooting.  I have also witnessed about 10 other peoples strings breaking. None of these incidents have resulted in damaged bows (just damaged nerves).  I am talking fiberglass laminated traditional bows.

I learned to make 3 bundle flemish strings in the mid 80's and have used my own strings since.  The old timer that taught me was adamant that the string be sized appropriately for the draw weight of the bow, i.e. number of strands be reduced or increased appropriately.  He believed that the string should act like a shear pin and break in the case of an accidental dry fire to protect the bow.

As I see a lot of worries on this site that if a string breaks while shooting you may damage your bow, I am wondering if I have been lucky with broken strings or whether other peoples experiences have been similar to mine.

As a disclaimer, I started using modern string materials in the mid 90's and settled on 6 to 9 strands on my 50ish pound bows.  This was based on published tensile strengths for dacron and fast flight to give equal strength.  I vary the number of strands as a tuning aid. So I have about 15 years experience with "skinny strings", experiencing none of the negatives people worry about.  I will admit I have no experience with the "standard" 14 to 18 strand fast flight strings you see in the catalogs.  I will also admit that I have had dry fires with my "skinny" fast flight strings and have not experienced any bow damage.  Right now I am thinking the old timer was right and people are using strings too strong for their bows resulting in damaged bows when dry fires occur.

Please discuss your experiences with broken strings and the impacts on your bows. I am very interested.

[Pon]

happened twice last year, no serious bow damage

[Pullonmylimb]

Interesting thought on the "shear pin" idea.  I have no firsthand experience other than 1 or 2 dryfires and 1 string that slipped off the knock due to my error in stringing.  None of these incidents resulted in any visible damage.

The question on my head becomes:  How much more force does the sting/limbs experience as a result of the dry fire?  It seems obvious that there is more force involved due to the limbs returning at a greater velocity.  But how do you determine the appropriate strength for a string so that it handles casting an arrow during typical use but blows when a dryfire occurs?

Very interesting.

[Eugene Slagle]

I still use ole B50 because of 2 reasons.

(1) I still have 4 1/2LB spools of it from around 20 years ago.
(2) I'm chicken & refuse to try the newer stuff on any of my Recurves.

In the past 2.5 years I've only had one string break & I think it was more to the top limb nock having a rough spot, smoothed it out & never had any other issues & the bow shoots really good for me.

For my Grandfather's 50# 69' Grizzly I still use 14 strand B50.
My Zona & my Sky Hawk both are tuned well with 12 strand B50 with 2 extra strands at the center serving for nock fit.

[last arrow]

Pullonmylimb, actual data on the forces in the string a bow limb would be real interesting.  I know of none.  I based my string tensile strength on the sizes of Dacron strings you got in 70's, when strings came rated for bow length and bow draw weight.  As materials have changed some since them I worry that I am over or under estimating the strength of bow string I need.

Eugene, I still use dacron on the older bows too.

[Crash]

I believe that is the reason the "new" skinny strings are becoming popular.  Someone actually looked at the strength of the string, thought, dang I'm overbuilding my strings with the new materials and built them with fewer strands.  Change is hard for most of us and some will not look objectively at the data to discover that 6 strands of the new stuff is as strong as 20 strands of the old stuff.  It sounds like a good concept to me, shear strength or breaking strength rated for the poundage of the bow based on the string material being used.

[snakebit40]

I had 5 B50 store bought string break on my last summer in a 2 month period (shooting a schafer silvertip). They all broke on the same spot, about six inches from the bottom of the limb. I sanded it, sanded and put super glue on it, and finally I just put some mole skin type material and haven't had a problem since. It was ether fiberglass or my brace height was WAY to short. The guy I got it from said to leave it cause of my power stroke and I was shooting decent. Well the brace height was under 5 inches. So I got on here and saw it was suppose to be around 8. Made the change at the same time I did the mole skin and haven't had a problem since. No damage was done to the bow with any breakage.

[Running Buck]

During my "learning curve" of string making, I have broken two strings. One,a two bundle string of 8125 and one other of D97. Both were 6 strand used on a 52lb Morrison Cheyenne. No damage to the bow or the shooters shorts. After breaking the second string I settled on 10 strand, two bundle and all has been well for the past four seasons.

[wtpops]

I have only had one string break while shooting, no harm to the bow or pig i was shooting at, arrow landed 5 yards form me and about 10 yards in front of the hog. I have cut two with broad heads with no ill effects to the bow. I do make my own strings now, 8 strand Ultra Cam, Bows are 55 to 60#. The string that broke was a 14 strand D97. Broke right at the nock, that was when i was still using brass nock points. I assumed then and still do that i had crimped the nock point on to tight.

[Swamp Yankee]

I like low strand count "skinny" strings for three reasons:
1.  They are quieter on most bows.  Don't know why, but they are for me.
2.  Because they are lighter, more energy is available to the arrow; thus more power to the arrow.
3.  I believe skinny strings reduce stress to the bow.  Grossly overbuilt strings (14 strand D97 for example) "give" or stretch very little when the limbs hit home after every shot.  A six strand, being weaker, will stretch and provide a little cushion, or shock absorbtion much like B50 dacron, which also might help protect the limbs from damage.

[Orion]

Some previous threads have suggested that the stated tensile strength is often less than advertised with some of the newer fast flite materials.  Thus, some skinny strings may be on the verge of being too weak for the bows they are made for.

I've been shooting sticks for about 50 years now, making my own strings for about 30 years, and have never broken a string.  I don't make my strings particularly heavy, but I do change the string at least yearly on any bows that I shoot a lot, more frequently if I see signs of fraying or excessive wear in the loops.

[The Whittler]

Last Arrow, very good question and data. Hope some string makers post. I find it very interesting.

[Gordon martiniuk]

So no big deal if a string breakes ,, had one skinny string break , no problem ,put a new one on and went to shooting ..  

[bofish-IL]

I still use the 14 strand strings and I must be lucky because in over 25 years have never had a string break. I do keep them waxed good.

[dan d]

Originally posted by The Whittler:
Last Arrow, very good question and data. Hope some string makers post. I find it very interesting.

I too find this interesting    

[last arrow]

Onion, the strings I broke are generally over a year old and are on my primary bow, averaging 200 to 300 shots a week.  I have only had one new string break when it was less than a week old.  I assume there was a hidden flaw in the material or some other error by the maker (me).  I have never accidentally cut a string.

I have also noted that breaks are generally at the nocking point or where the silencer attaches.  I don't remember one breaking in the loop.  Curious if others have noted the same.

[Marvin M.]

I've got a bow that I made (Bingahm's kit and instructions) that has been eating strings.  I'm working on smoothing and re-shaping the nocks to eliminate the problem.  Breaks occur around the nocks.

I make my own B50 strings (14 strand) and have broken three strings on this bow while shooting -- no visible damage to the bow.

In addition to the three broken during shooting, I've caught two more before the final parting based on the feel of a shot being off and discovering damage to one or more bundles.

Other than this bow, I've never had a string break, so don't have a lot of experience with it, but as I stated, there is no visible damage to the bow.

[Swamp Yankee]

Nope, never had a string break in 50 years.  Replaced a few for broken strands, usually at the nocking point or that were nicked by a broadhead or bull-briars.  I've seen maybe a half dozen break without damage.  Compounds are another story all together; I have seen them come unglued with shrapnel flying all over the place from a broken string or cable.

[Eugene Slagle]

Originally posted by bofish-IL:
I still use the 14 strand strings and I must be lucky because in over 25 years have never had a string break. I do keep them waxed good.

I also wax mine quite often but after a year I tend to make new ones on the bows I shoot normally & have spares ready.

[Cocklebur]

I talked to John McCullough the other day and he recommends the skinny strings. He thinks they absorb the stress at the shot better than the strings with a higher strand count. He also recommends padding the loops to at least a 14 strand.