Tillering string vs braced string figure.

[Del the cat]

Dunno if anyone has bothered to measure the magical 'dissapearing poundage' when you get a proper baced string on a bow.
So I did a little test (Obviously it will vary with bow design) but it gives an idea.
Using my latest Yew longbow ~72" long 50# @ 28".
Drawn on the tiller using it's correct string to 40#. I then marked on the wall where the tips reached.
The string was removed and replaced with one which would just fit onto the bow without flexing it, I then winched it back until the tips reached the same deflection marks.
And what do you think the weight was?
46#
It was interesting to get a figure as we all know the effect, but I had no idea how big it was.
Maybe if someone tries a different length/style bow we can come up with a rule of thumb without using a load of maths/geometry, then we'll be famous and have our names up in lights (ok I'm getting carried away.... should have been carried away years ago )
Del

[hillbilly61]

Not a bad idea Del. It would be interesting to get some figures like that Just kidding. It really would. I might try to get a couple designs done this afternoon and report on them

[scp]

I think Steve (Badger) explained the phenomenon in another thread. If I understood him correctly, what matters for the drawing weight is not how much the limbs are bent but what is the string angle. Care to test that idea, anyone?

[George Tsoukalas]

The long tiller string I use is 1.5 times longer than most of my staves. Short tiller strings are not needed for this method. This is for a 26 in draw but you can set up a proportion for a longer or shorter draw. I can help. If you want your stave 15# heavier go target weight plus 5#at 10 in.  If you long string tiller out to 10 in and check weight and get your target weight at that distance. Go ahead and string it. This puts your stave 10# over final target weight. Perfect. No strain on the stave or you. So if you want a 50# bow, long string tiller out to 10 in. Get the limbs bending well. String your stave. t will be at 60 # which should be enough to get a good tiller and your target weight. It is all right here. Where are all the years gone? I sure do look young there or younger than I do now. Jawge
http://georgeandjoni.home.comcast.net/~georgeandjoni/directions.html

[Del the cat]

Hey George, I should have guessed you whould have put some figures on it by now .
Del

[George Tsoukalas]

Del, when I first started trying to make bows I was breaking far too many rushing them to the short string. They were just too heavy to be strung. I needed a way to get the stave 10-15# over final draw weight before stringing. That's when I developed the method I outlined above. I still cant get over how young I looked there. LOL. My hair was still brown. Anyway, it can be adapted for use with  longer draw. Lately if bow is twisted or really reflexed I get the short string on quicker. Your method is different. I see that after a couple of readings. You should develop it. I like it. Jawge

[dbb]

Im a newbie and i might be totaly out in the blue,but sometimes you read something and a idea pops up.
Ok here it is:you want a long string to start with so you dont break the wood or yourself,but that makes measuring weight unpredictable..
So what would happen if you fix two rollers (like those nylonrollers from a sailboatblock) side by side on your tillerstock at wanted drawlenght and just pull the longstring between them and right down?
perhaps clumsy and impractical,and maybe friction will make the scale as unpredictable as the long string.But the angles will be right at full draw at least....ah well just a crazy idea in the middle of the night

/Mikael