Linen string question

[Selfbowman]

How many strands of linen for 110# bow . I have 5  count Linen.

[bownarra]

You need to do a set of break tests on your particular thread. Make sure you don't use knots - just friction.
Once you have the strength of your thread divide that number into 440 or perhaps 550 if you want a string with plenty of strength in reserve.

[Selfbowman]

Thanks !

[Selfbowman]

Flemish string ok?

[bownarra]

Yes no problem.

[WillS]

Flemish string ok?

A true Flemish string isn't suitable for linen, but the modern definition is, just to be really confusing!

"Real" Flemish strings are made with full length fibres glued or "gummed" and slightly twisted, with a laid-in top loop and a reverse-twisted bottom section, which is then used for a bowyer's knot.  This is perfectly fine for strings made of full-length hemp fibres, as they can be grown and cut longer than a bow.  Flax however, doesn't grow long enough so needs to be made into a reverse-twisted string.

Your best bet with linen is actually to make a three-ply fully reverse-twisted string instead of pretending it's FastFlight etc and just making up a normal string.  Bundle up three groups of odd-numbers, twist them all one way then twist all three into a string in the other direction.  This way you get the benefit of spreading all the short fibre weakness into a far stronger string, plus that extra thickness in the loop.

This has worked for me for bows over 130lb, whereas other string types consistently fail.

[Selfbowman]

I think this is what I do with two bundles of 4 for a fifty pound bow. I was thinking 14-16 strands total. Two bundles of 7-8 stands. Three bundles might make the string more round. I don’t use a bowyers knot. I twist the loops together. What you think ?

[AndrewS]

Have a look to your linen yarn:
The linen yarn, which is taken as the starting thread, is usually already twisted (usually reverse twisted) Sometimes it is marked with "S" or "Z". If you now twist several threads of it together, pay attention to the twist of the original linen yarn. If the linen yarn is twisted clockwise ( "S" ), then you should twist the threads together counterclockwise and then twist the bundles together clockwise again for your string.

Modern string yarn like FF+ is not twisted. You don't have to pay attention to the initial direction of twist when reverse twisting, it is the same whether you twist the single threads clockwise and then the bundles counterclockwise or first counterclockwise and then clockwise.

I also would use two twisted loops... a knot is always the weakest point.

[meanewood]

I always use a bowyers knot on my linen strings and have not found them to be a weak point.
It is not a 'knot' as such but a 'hitch' which are excellent for spreading the load around the turns and twists.

[AndrewS]

When you do a stress test on yarn, no knot should be used for fastening, the yarn should be held by friction only. The yarn would otherwise break at the knot without the load limit being reached (see also #1).

Where the bowstring passes through the loop and constantly makes a "kinking" motion (back and forth) during use is the weakest point, because the bundle of thread that is there at the loop is "broken off" by the constant kinking in the loop.


In old books it is recommended to reinforce the String with additional threads in the area of the bowyer's knot.

[meanewood]

That is a good point Andrew and it may well be the case.
In practical terms, I have been using linen strings for a number of years and because of using a natural material on 'heavy bows', I have had quite a few breaks.
I always take note of where the break occurred in-order to understand and help improve my technique and knowledge of string making.
I cannot recall any break at the bowyers knot as yet.
I have even experimented with soaking the string in hide glue to increase strength but have left the area that forms the bowyers knot unglued because it is hard to form the knot with a glued string.
Even then, the breaks occurred in the 'strengthened' areas instead!

[AndrewS]

A most often, the string should break exactly where the arrow is nocked or nearby where the string is served....cause of kinking.

if the string breaks somewhere, then this can also be due to the not very homogeneous material or the not homogeneous production of the linen yarn, because linen fibers have only a limited length (see also the post of WillS who recommended long hemp fibers....).