Yew longbow dimensions
Help! Just about to make my first (bamboo backed) yew longbow and I find that I've lost my book with bow dimensions in it. I can remember that it said that a yew bow has different dims (for the same draw weight) as a non-yew bow but cant remember whether they should be bigger or smaller. Can anyone provide a list or diagram please?
Why are you bamboo backing Yew? Doesn't it have any sapwood, or is the sapwood damaged in some way?
Assuming you mean an English Longbow as oppsed to what the Americans call a Longbow, I can give you a start point for an unbacked Yew longbow depending on poundage.
A good start point is 74" long 30mm wide & thick at the grip and 20mm wide and thick at the tip. With an even taper, you then start tillering from there. Once it's fairly well tillered you can taper the last 1/3 much more steeply and fit the nocks. That should see you right for anything from about 70# downwards.
The extra initial tip width allows for some adjustment of string line etc.
Google bowyers diary to see I've done it with a variety of draw weight bows over the last couple of years.
You can't make a bow 'by numbers' so it's just a start point.
Thanks for the reply. The bamboo backing is a done deal- its an integral part of the pre-glued stave I bought. Got all the dims I need for non-Yew ELBs, and have made a few quite successfuly. Just needed to know what are the differences (if any) between Yew and non-Yew ELB dims for the same draw weight ie generally thicker or the reverse.
Don't s'pose you want guesses! But I'd expect a BBY to be thinner than a self Yew, I'd keep the width about the same.
Just my guess tho', mind I'm hoping to make one later in the year as I have some Oregon Yew with sapwood that got wood boreres in it. So let us know how it turns out!
Found my lost book down the back of the book case! It says that a self-yew bow should be about 10% thicker all round than a Lemonwood and Hickory bow, for the same draw weight. I have worked on this basis (lots of head scratching working out 10% of dims given in fractions of an inch!) and have so far got to 55lb at 18" on the tiller. Doing some sums this should work out somewhere around 80 to 90 lbs at 28". Far too much for me. So it looks as though you are right regarding the dims for yew and bamboo Del. As I want to end up with a 55lb @ 28" bow I now have to decide whether to slim the width down before carrying on tillering and scraping, or just carry on with the stave at the width that it is at the moment (1.35" at the handle) and scrape away until I acheive my target weight. No pun intended. Any thoughts anybody?
I'd say keep going as you are until you get to 55# at about 22" then clean up the width to give a nice comfortable finished width and at this point you can slim the tips down to give the final string line and get the dimensions about right for the horn tips (say 16mm x 16mm ish).
Cleaning up the width won't loose too much draw weight and by the time you've done that you'll will probably be at about 55# at say 25" the last few inches can be done scraping the belly.
BTW I'd aim for about 57# at 28" then you can afford to loose a bit when you slim the tips down a tad more when fitting the nocks.