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Overweight tiller best approach?
BowEd:
Good sound advice by others here.Hav'nt made many yew bows but I'd be patient and sneak up on it myself.
I generally start out from brace a little closer to my final draw weight though.
I really don't see why you pulled it to 80#'s if you wanted 60#'s.You should be ok yet hopefully because it was only to 16".
Removing even amounts or counting strokes from each limb.Stay away from the hee haw syndrome of overly positive and negative tiller showing if you can.That means a little at a time.Exercize it properly between wood removal.Check amount of draw weight loss from removal at same draw length previously checked.Good place to be though with it already bending evenly.
stuckinthemud:
I'm used to wrestling really "characterful" staves to brace height, to do that usually means finding the place where a hinge (or hinges) is going to be and smoothing the rest of the stave down to the same level before the weak points become a problem. I am so used to pulling it an inch, finding the weak points, correcting then pulling 2 inches and repeating until the stave is bending nice and even. Often weak points don't appear until the bow is bending a good few inches and the stresses have all evened out. For me, this is a really good stave (two or three knots and a bit of twist and a bit of sideways correcting is a good stave !), and this stave ended up overweight by a long way. Its only the second or third time this has happened and it kinda freaks me out. Why bend it? So I can find and correct any weak points before they become a problem. They were there, they got corrected, but no-where near as bad as I am used to and now I am a long way overweight. The stave came with a bit of reflex where I could fit my little finger under the handle rubbing the bow and the bench, the reflex is still exactly the same, so no set yet, and the 16" draw on my stretchy long string is more or less brace height.
Del the cat:
Its one of the fundamental questions... how much wood to remove to drop a certain poundage.
It's down to experience... but to drop 20-30# requires a fairly enthusiastic rasping along the belly of each limb.
I tend to follow the mantra of "remove half as much as you think you need... then check the tiller".
Of course you have to take it off proportionally... less off as you move towards the tips (e.g 1mm off a 23mm thickness near the grip, has less effect that 1mm off a 10mm tip)
Del
stuckinthemud:
The alternative is to thin the sapwood but I have been caught out by doing this as if it goes wrong you have to start all over on another ring and it is very easy to end up going too far and lose too much weight. In this case the sapwood is relatively thin at one point and I am not at all certain reducing the sapwood is a good idea in case I go through to the heartwood at that place. What is the minimum ratio of sapwood to heartwood before performance is affected? Is 30:70 sapwood to heartwood too much sapwood for example?
superdav95:
I wouldn’t recommend taking down any of the sapwood. I know others do it but the rings on yew is often very thin and can be a challenge to get to a single ring. It may not be a deal breaker to violate a ring with yew I don’t like to do it if it can be helped. 1/4” sapwood is sort of the standard but wood is wood. If you e got thick sapwood maybe consider a narrower limb design to get more heartwood to sapwood ratio. I don’t think I would even make a wider limbed recurve type bow with yew that had real thick sapwood. I think you’d be fine with a ratio of 30/70 like you say generally. I’ve got a yew bow I’m doing now that has some character and the sapwood is thicker on one side of the limb then the other. Wood is wood and we just have to roll with it and make the best bow we can with it. I certainly wouldn’t violate a ring to even sapwood out imho. Best of luck.
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