Main Discussion Area > English Warbow

working details for higher poundages

<< < (2/6) > >>

willie:
Colin

to help answer your questions, I will point you to a few threads in the bow section, I hope you forgive that some of my experiments in materials and methods are not too traditional, they are just some ideas I have been meaning to try.  I am hoping to tiller to a traditional bend profile, and maybe keep a similarity in appearance.

http://www.primitivearcher.com/smf/index.php/topic,54581.0.html
http://www.primitivearcher.com/smf/index.php/topic,54495.0.html

hopefully my soon to be made double nocks will allow the use of a proper stringer. I was leery of doing the step thru, as I have barely got the bow bending, and I could see problems if I over stressed a limb before I even got a chance to start tillering it.

thanks
willie


Del- thanks for the clarification

meanewood:
Hi Willie

What Del said plus
To avoid some of the effort when stringing the bow, I have found by continuing to use the long string quite a bit past brace height it makes it easier and you can give it a good long bend when stringing and know that the tiller is good while doing so!

willie:
meanewood-

yes that would make things easier for sure, and I suppose that I could learn to judge tiller both with a long string and a short string  (by putting a finished bow back on the long string) so that I would not be tempted to thin the limbs too much. I presume you are advising a "short-as-possible" long string.?

Btw  can you over stress the center of a bendy handle bow by pulling out too far with the long string? I suppose that you might have to pull much harder with the longstring than you would with a normal string to get the same bend?

thanks

willie

Del the cat:
Have a read of this post:-
http://bowyersdiary.blogspot.co.uk/2013/12/yew-stick-bow-and-draw-weight-to-brace.html
Del

colin1991:
Willie,

Firstly, don't be discouraged by mistakes, that's how you learn.

Second, Try not to drive yourself mad by overthinking it all and trying to crunch numbers, just make it and see how it goes. Even if it breaks there was a lesson to be learned.

Your long string should be nearly straight along the bows belly when its on the bow... excessively long long strings will give a very different bend profile to a short string because of the force vectors at the tips.

If you over stress a bows handle on the long string your tips were far too stiff so you should be able to pick that up fairly fast.  Just remember that going from long to short string will make the outer mid-limb and tips bend a bit more (again, force vectors at the tips do this)

I personally don't ever go over desired weight when tillering, even before brace, doesn't matter if its 40lbs or 140lbs.

Can you post photos of the bow so we can see what its looking like?


Del, I read through the thread on bowyers diary you posted and found an error in it.  You say towards the end that "80# on a long string is less strain on the bow than 80# on a short string, due to string angles etc. In the same way that at brace there is 40# of tension on the sting but no draw weight."

I agree with the first part, 80lbs on a long string is less strain at the same stress than a short string, but I disagree with the second part about there being 40lbs of string tension... because of string to tip angle and line of force (and the vectors the force splits into) the string tension is higher than half the weight it took to brace the bow.

Colin
Colin

Navigation

[0] Message Index

[#] Next page

[*] Previous page