Heavy bow strings

[Kviljo]

I would say fastflight is way too slippery. At least for using timber-hitches on 50#+ bows. They slip like mad, and thus lowering the braceheight.

By the way, I'll have to make myself a two-ply FF string for my flightbow after reading this That should reduce string-drag "a little"

[Yeomanbowman]

I use a bowline knot as I find a timber hitch 'creeps' or slips outright. 
http://en.wikipedia.org/wiki/Bowline
I'll follow this tread with interest, as Mark's maths seems to add up.  I'll let somebody else try it first .  As a historical note, 'stretchy' silk was considered the best for flight shooting in Tudor times.  Whether this was due to a lighter strings being possible or the inherent stretch I could not say.  If a bow was set in a braced position and fitted with a bungee cord and then shot the elasticity would still propel the arrow.  Slightly fatuous, I know, but could the 'give' add something to the cast.  I know this flies in the face of contemporary received wisdom, and I dislike Dacron for heavy draw-weight bows as well.
Jeremy 

[markinengland]

Jeremy,
I've posted this same basic thread on a flight bow forum frequented by many record holding archers. They disagree as much or more than we do on strings, the important or not of stretch etc! Some record breaking shots have been made with dacron strings!
The consensus of opinion is that what works works even if we argue about why, and that a lot of BS is talked and believed and should be tested. What works for one bow type may not work for another, that even on the same bow type it makes a difference what the draw weight is, what the tiller is and what the arrow is. It seems that for a given heavy warbow the string that works best for a heavy military arrow may not work as well as a lighter string with a lighter arrow (but then again it may!). The only way to tell for sure is to try it.
I used to use bowline knots. The only trouble is that they hold like anything and are very hard to undo. When I tie a bowyers knot now I make sure that the string is well waxed. It is of course important that the knot is tied correctly and that when you loop the tail back round you do it the right way. I loop the tail round some 5 or more time so it goes all the way round the loop and then make sure the tail is tucked back under to lay under the knot. Once bedded in this seems to weld itself into one and won't slip. Occassionally a knot will when first tied so I just undo it and tie it again, making sure that all is tighter and done properly and then it seems OK.
I think I owe you a pint by the way. If my slightly bleery memory is correct I knocked one out of your hand while waving my hands around while we chatted about this subject! I hope you had a good time at the Batsford field shoot. I chickened out!
Kviljo,
I have a little bamboo bow with a two strand string. The high note it make when plucked makes you wince but it hasn't broken! The bow is only 20 inches long, must pull something silly like 100lbs at 6 inches and the string kills your fingers but it shot an arrow 100 yards.
Mark

[bobnewboy]

The strings chapter in the TBB was quite an eye opener to me, as it seems to have been many others.  Perhaps the large number of strands recommended by most bowyers I have met reflects the desire to have a lot of safety built into the string.  In the past couple of years (as long as I've been doing this stuff !) I've been fortunate to be able to ask Chris Boyton, Hilary Greenland, and Carol Edwards about this personally, and I have read the same recommendations in Pip Bickerstaffe's book too.  The same answer usually comes back - a 12 strand generic string for my usual draw weight bow - 50 - 60 lb at 28".  I have been trying a 9 strand B50 string, and it seems fine (but see loop reinforcement below), with 3 skeins of 3 strands, on both my primitive Stellmoor style ash bow, and on my other half's wonky ash bow.  I prefer 3 skeins because it seems to make a more rounded section string, compared to 2 skeins.  I am keeping a close eye on my other half's bow, because it has such tiny nocks that i couldn't put in many extra stands for the loops as I would like.  Even so, both strings have been good, with excellent cast, and seem durable enough so far.....

One more question about FF.  Seems that most people in this discussion are only talking about single ended flemish twist strings.  Any particular reason for this, apart from a greater brace height adjustability?  If a double looped flemish twist string is made from FF (and I have done them in B50), does the panel think that the twists themselves will actually provide a bow's nocks with a little shock absoption?  That is, will a double ended string afford the bow nocks a little extra protection from the ultimate shock of an FF string slamming home?

Also, when I make strings I tend to increase the number of plies at the loops by 50-100% by adding 9 inch strands of the string material waxed and twisted into the main cordage.  I thought that this was a default position, as taught to me by Chris Boyton and Carol Edwards.  Does everyone do this, especially with warbows, as surely the greater bearing area of the thicker loop would go a long way to improving reliability?

//Bob

[markinengland]

Bob,
As far as anyone can tell the habit of using too many strands seems to have developed historically. Linen strings needed to be failry fat to be strong enough. Arrow nocks were cut to suit this and we became used to this. When Dacron came in at 35lbs per strand about the time fibreglass bows did 16 strands or so of dacron was overbuilt for a normal bow (about right for a 140lb bow) but it looked about the right size and fitted the nocks we were used to. Recurve bows need stronger strings to a straight bow anyway. Now that fasflight does 100lb per strand and 450 plus does 150lb per strand a string that looks the right size and fits the arrow knock is stupid overbuilt! A nine strand dacron string should be safe for a 75 lb bow.
You can still put extra strands in a smal loop on a small bow knock. This is a little more difficult on the other end if you have a bowyers knot.
I don't make double ended flemish strings because I can't get the length right! I could could, I would! As far as I know or have heard there is no real difference with a twisted in loop or knot re safety. The twists in the string itself rather than the loops give the little bit of stretch and shock safety. The bow string could have two bowyers knots and work fine.
Yes, I do beef up the ends of the bow string, with the loop and the knot. A really skinny string needs this I think to give increaed wear resistance as well as to avoid any cutting in.
Mark

[Yeomanbowman]

I think I owe you a pint by the way. If my slightly bleery memory is correct I knocked one out of your hand while waving my hands around while we chatted about this subject! I hope you had a good time at the Batsford field shoot. I chickened out!

Hello Mark,
Don't worry, any beer stains were washed out during the field shoot .  I must give the timber hitch another go.
Cheers,
Jeremy
     

[Garry]

Interesting thread,
I was forced into using FF-Plus on my 125# warbow due to the stretch on D50. It is quite difficult to string a 100# plus bow when the string stretches so much.
It seems to me that FF is the material of choice (when quality linen cannot be sourced) because it has about the same stretch as linen.
Weight of the string does not make bugger all difference when you are loosing a 1000 plus gn arrow. (my opinion)
Just for interest I use the 10 times at 15" calculation (tested it on the "Old Oak 110#er" first tho!) FF-Plus weighed in at 53# per strand, 10 strands = 530#, about right. I added a few more totalling 12 strands (yew is very expensive in Aussie). This works just fine.

[Marc St Louis]

I used D-75 for the 2 heavy ELB flight bows I built Marlon last year and I think I used 12 strands on the BBB. It pulled about 170# and the 12 strands worked just fine

[markinengland]

Garry,
From what I have read FF is meant to have about 100lbs per strand. Why 53? Is this tested breaking strength?
I copy this from a flight forum where I asked this same basic question. These guys are good so know whatthey are talking about from formulas through to actually setting records!
"At around 200 fps, the energy lost to the string is about equal to as much as 45% of the string weight getting shot with the arrow.  If your string has a mass of 100 grains, and arrow has a mass of 500 grains, then the bow will feel like it's shooting a total of about 545 grains.  At 200 fps, 45 grains is equal to about 4 ft-lb which is pretty significant.  The 500 grain arrow traveling 200 fps has about 44.5 ft-lb of kinetic energy so right away, nearly 10% just went to propelling the string.  Of course, heavy serving makes it worse since it is moving at the same speed as the arrow."
From my understand an efficient heavy warbow is a fast bow. It needs to be to get the distances being acheived. Though the arrow being shot is heavy at double 500 grains or more, then the string is also probably at least double in mass and things may equal out. This still points to the basic idea that reducing string mass within sensble limits will no doubt increase arrow speed and distance.
I wonder what difference you would notice between a 10 strand string and 20 strands?
Mark

[duffontap]

I've been reading this with great interest.  A couple things I'm wondering:

Not only is FF super strong, durable, and less streachy, it's lighter.  This allows for lighter, faster strings of the same size as Dacron.  Take into consideration that a 16-strand FF string will be much smaller than it's B-50 counterpart and you've gained significant performance advantages by only changing the material.  Beyond this point, how much can you gain I wonder?  If it's only a difference of 20 grains or so, I think I'd rather use a normal-sized string with heavy bow.  There are practical limits to these kinds of things.  Beyond pure fligh shooting, isn't there an obvious impracticality to such skinny strings (not fitting nocks, cutting the fingers, etc.)?

I'll have to go weigh the FF string on my warbow.  Great thread.

Another thing, the published strength of currently-availible linen thread is adequate to build a 1/8" safe string for about a 150# warbow--using the draweight at ten inches (or fifteen, I can't remember either) formula.  I haven't tested this yet, but I don't see what the big deal is with everyone (perhaps Pip started this theory?) saying it's impossible.  I think you could go do it right now with linen bought off the internet.  Before long I'll put my money where my mouth is. 

            J. D. Duff

[ChrisD]

Well, the very best of luck to you on that one! I'll be really really interested to hear how you get on.

C

[duffontap]

Chris,
I believe Howard Hill used a linen string on his 170# osage flight bow.  I don't know how thick it was but it set a world flight record so it seems it would have to have been reasonably light.  It's ALL speculation and unscientific until you put the 1/8" linen string on a bow of 'X' weight to prove that it can be done. 

Question:  If I built a 150# bow and shot it a hundred times in a row with a linen string that fits into a 1/8" nock--would Pip pull his string theory out of his second edition?  Would you reconsider your opinion?  Would it change anything?  Would anyone say, 'I was wrong, you were right'?  (  this is a good-natured ribbing). 

            J. D. Duff

[ChrisD]

JD

Good natured ribbing aside , I certainly would say 'I was wrong' and and I would consider a big proportion of what I had previously thought keel hauled and requiring reconsideration. I would have said 'I'll eat my underpants' - but this is an online post and someone one day might hold me to it.

I can't speak for Pip - but if you're right, then the replica warbow using public (and I realise they'd probably all fit in a winnebago if stacked properly) would start using them  - its a population which likes tradition after all.

C

[Garry]

Mark,
From what I am gathering is that there must be more than one type of FF availiable. I can only get "Fast Flight Plus" here in Canberra Australia. I measured single strands, 10 times, and every time it came out at between 50 and 55# averaging 53#. The FF+ that I used is supposed to be 50# per strand, but it is very thin!
I used 4 strands on one of my 50# and it is like using spider web for a string. Took a bit to trust the stuff.
I agree with your statements, however I am not into flight just getting a heavy arrow to go 240 yards and yes a 125# yew bow is fast! (and fun)
I tell you what I will do is make a 10 strand string and a 20 strand string and tell you the difference (on my Old Oak 110#er, not my good yew tho) but I am thinking that due to FF being so light anyway that it will make very little difference.

Cheers

[sagitarius boemoru]

Sheesh, we use linen, my friend Iktomi has osage bow of 116# and uses linen...its no big deal. Anyway, I found out there are some people growing hemp and doing research on it in czech,  I have contacted them, hopefully I ll be able to get some raw material or to have a hemp custom grown tended to specified requirements.
Rob, my shooting buddy (Rhunter on PP) just made himself a rather sharp Ipe/hickory bow 105#/31´´ and hes got linen string on it as well, I m having linen on that 90# yew bow now, no problems so far. He did some research on the material in lab where he is working, he found basically its about the asme in strenght as Dacron per thread, but it does not have the stretch. He did hovever tested dry fibre, not the one reinforced with hide glue as old bowstrings were made.
This is czech unbleached linnen, which is (and historically was) too often exported to britain and sold as Irish harbour.
I suspect the glue is the important additive to make the strings slightly stronger than now.
We use 18 strands for 90#, 21 strands for 105#, but again this is just a normal string without hide glue. They look rather fluffy, but they are not exceptionally thick once you string the bow. 21 strands would be probably alright even for 120# and there is no problem with a reasnoable nock size on 3/8´´ arrows.

I will try hide glue reinforced strings in close future, I expect to have at least 25 percent of gain in strenght.

When these fail, its usually when they get dry. Its basically wood and in this fibrous form it dries too quickly and too much, so its reasonable to moisterise these strings prior shooting.

Jaro