I've been away for a few days visiting family for a belated Christmas dinner... all the fun of Christmas but without the crowded shops (result!) Shortly after we got back home, Tom the guy who gave me the Yew the other week dropped in to ask the question in the title of this post. Excellent, messing with wood a great antidote to a 2 hour drive!
He'd hung onto a very skinny bent yew stick to have a play making a stick bow. It's just the job, not too much wood to remove and no great loss if it breaks, but a great way to learn.
It's only when people come and ask questions that I realise how much thought and experience goes into the process.
As it happens I had a similar curved bit of yew from the same load, but a bit bigger. I'd run it through the bandsaw. I used that to demonstrate the basics. I showed him how the easiest way to make a bow is to leave the back of the bow as the bark and just chop away the belly (or bandsaw it in my case) to leave a flat belly... a 'D' bow, but the opposite way round to the D section of a longbow. I used an axe to improve the thickness taper on my stick, popped a string on it and put it on the tiller so we could see it flex.
First of course is deciding how the bow sits in the bit of wood.
There are 2 main considerations:
1. You want the back to be a clean and free from knots as possible.
2. You want any major bend to be fore or aft, e.g reflex or deflex. That's to say from the archers view point the bow wants to look relatively straight or at least have tips and centre in line like a gentle S, but you don't want a C shape!
Of course 1 & 2 may be mutually exclusive or require some compromise to get the best layout.
His next big question is when do you worry about tapering the width? The answer is, when the bow is drawing about half way, the width and grip etc can be left fairly late as they make less difference than the thickness of the bow.
I needed to width taper the very tips so that I could get an old string on, but I still left 'em plenty wide enough to allow adjustments.
It became obvious that the key message was, remove as little as possible, and generally half as much as you think! This is to allow you to get the bow on the tiller. At that point you can see how it's bending and start to make it do what you want. Also making a bow is a lot of repetition, successive approximation, little and often and similar platitudes. You can't just 'make it' in one go.
This was a revelation to him as he thought you made it look like a bow and then put it on the tiller. Now that might work if you have a nice even laminated stave of machined timber, but it won't work with a natural stave, especially a stick.
Having chopped away at my bit of green Yew I told him how it could be strapped to a former to hold it in shape while it seasoned. My bit of Yew has such a huge deflex (about 6") so I though I'd actually do it.
The pic shows before and after I strapped it to a length of 2x2 with some rubber strapping. I'll let it season for a few months and work it down some more and maybe strap it with a bit more reflex at the tips.
It's highly experimental, but that's the joy of having some 'bad' staves. The shape may pull out, but its good to have before and after pics so we can see what happens.
Much better than worrying that you'll ruin some near perfect expensive bit of Yew. Tom's made a Hazel bow before, but of course a well meaning 'friend' over-drew it and snapped it. That's the risk with short experimental bows, they may be short draw, low draw weight... gotta be careful what arrows you give anyone if they are shooting it, and never let it be drawn without an arrow. Unless of course you want 'em to get a whack on the head as it breaks!