Friday, 25 November 2016

Back a Little Further

The Yew primitive character bow is coming back by degrees. I've made a little video showing some of the features and it pulling to about 17":-

Some bows make you nervous and some fill you with confidence, mind you just don't know in reality until it's fully drawn. I've got a nice even bend and I'm working with rasp and scraper now easing off any thick areas and tidying up the back around the knots. I've got it braced a bit higher now and have been working on the upper limb. It's pulling about 45# at 15" which is 3 pounds per inch (45/15) this gives just a rough and ready figure when multiplied to 28" draw of 84 pounds draw weight! This gives some idea of how much wood I've got to remove, taking wood off the thickness has much more effect that taking it off the width. In fact, theoretically I could saw the bow down the centre line and make two bows each of half the width and 42# draw weight.
The main reason for not drastically reducing the width is that I'd have proportionally more knots on the back. E.G:- A 7mm wide hole in the back of a 40mm wide bow is a smaller proportion of the width than a 7mm hole in a 20mm wide bow.
Also a thinner wider bow is less stressed than a thicker narrower, the problem with reducing thickness is that I don't want to remove all the heartwood, or conversely break through the sapwood on the back.
So it's slow and steady, a little off here, a little off there, and I'm taking the working limb further in towards the grip EG:- effectively shortenning the grip and making the fade from grip to limb a little quicker. An extra mm of movement at the root of the limb will give maybe 10mm at the tip, and 10mm at the tip equates to about 30mm extra draw.
In terms of width I can gradually narrow and shape it to an elegant leaf profile which will also be easing off the weigh and increasing the draw.
You can see that despite having a long way to go, small changes and tweaks will ease it inexorably back towards full draw. The lower limbs needs some work, by which time I'll be closer to 20" draw... slow and steady wins the day.

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