branch compression/tension

[jape]

I haven't done more than break a couple of bits of wood so far in making a bow but I keep telling myself I will persevere, one day, if ever I get my shed back into order and my back allows. I have been eyeing up a branch of crab-apple I need to trim, and the same of cherry that will be big enough next year ...

I assume a branch that is growing laterally about ten degrees from horizontal will have some natural compression to the underneath side. Would you use this for the belly?

Taking that thinking about natural growth characteristics a bit further, would the portion closer to the trunk be best for a slightly shorter top limb as it would be stronger or would you just use tillering to even out? How do you work out that proportion of one limb to the other, I haven't seen it in any buildalong measurements but have read it is a good idea with a longbow.

[longbow steve]

Hi Jape, Check out Dean Torges' site The Bowyers edge, he has a write up on reaction wood ie branch timbers.
I have never tried a shorter upper limb so cannot advise there but shorter lower limb or Assymetric bows are very effective again some good info can be found on Deans site if no self bow makers chime in. Steve

[Glenn]

Jape as Steve said have a look at Dan Torges site on reaction wood. You could make a bow with a shorter top limb, you just have to tiller the bow accordinly. If you make a bow with equal length limbs and you hold the bow in the centre of your hand thean you are shooting the bow around 1.25 inches above centre, so you have effectivly shortened the top limb by 2.5 inches, which will place a lot more strain on the top limb which will need to be strengthend so that the limbs will take even set.
The best bow to make is an assymetrical bow with a shorter stiffer lower limb...Glenn...

[jape]

Thanks to both of you. I got my thinking back to front obviously, it would be shorter lower limb! Oh well, I usually manage to get things back to front when I think them through, my logic capabilities are a bit rusty and bent.
I have heard of Torges from the Masters of the Barebow DVD. Makes a nice looking bow and certainly uses it. I shall look up his site, thanks a lot. I had thought 'reaction wood' was a special kind of 'action wood'...