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Starting dimensions for yew warbow

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WillS:
A really nice way of working out an actual taper for each limb (if you want to get all mathematic instead of using instinct / feel etc) is to take the overall length from tip to centre in mm, divide it by the difference between centre thickness and tip thickness and that gives you the measurement in mm for each mm you drop.

For example :-

76" bow = 38" tip to middle

38" in mm = 965.2mm

33mm thick in the middle, and 16mm thick at the tip is a difference of 20mm

965.2mm divided by 20mm = 48.25mm

That means you mark a point every 48.25mm from the centre, and each time you get to a new mark you take off 1mm from the thickness.  That is to say, you start at the middle with 33mm in thickness, mark a point 48.25mm away and make it 32mm in thickness.  Then mark a point 48.25mm from that and make it 31mm and so on. 

This works beautifully with reasonably clean staves and if you're brave enough to cut the bow out to exactly those marks you normally get an almost perfect tiller without doing anything at all to it.  That's as long as the wood itself doesn't throw up any surprise areas of dense/less dense material which changes the properties and so on.

Ruddy Darter:
Ah, that's great Wills, thanks a lot  8)

That gives me a real good picture of what to look for and hopefully cut out a fair bit of dust making, I'll mark it out a couple of mm oversized with the method you have shared .COOL  ;D I'm going for 74" in length, maybe 75" and I'm not chasing a weight but hopefully around the 130lbs@31". Your help is very much appreciated.   :). Ta very much guys.

  Ruddy Darter.

Del the cat:
Oh dear... I'm may appear argumentative here :-[
Be wary... working out an even taper is fine for ROUGHING OUT... but beware, the outer 1/3 of each limb tapers at a faster rate to give that Spitfire's wing look that the MR bows have.
Where the knocks fit, you don't want to more than 1/2" (12.5mm) diameter.

If you plot actual limb thickness I think you will see it's not an even taper.
Del

WillS:
Works for me ;)

It's how I've been doing it for ages now.  I've had a couple of bows since doing it that have gone on the tiller for the first bend on the long string and I've not touched the belly for adjustments until around 28" or so at full brace.

Everybody does it differently though!

Ruddy Darter:
Good point Del and thanks for bringing that up, I was just thinking that myself, although I will use this method from 6" from centre to 6" from the nock, I'll have a separate sharper taper there and play it by ear, I'll scan through all the dimensions given for a nice starting shape giving myself some play room for error.
You just beat my post WillS ;D, I don't doubt it will work well WillS for you, but I'd better give myself a margin of error for my novice disposition.   :D
  Ruddy Darter.

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