yew sapwood...thicker is better?

[AH]

I was reading in the TBB volume one, and on page 239-240 of the paperback version, it says that thicker sapwood is better on yew bows because it shifts the neutral plane closer to the belly, so more work is being done by the tension-strong sapwood. At the same time, I have heard people say that you want to have thin sapwood too. Since I am not that experienced with yew, what do you guys have to say?

[AH]

Del?

[burn em up chuck]

    the rule of thumb is 1/4" sapwood. so both statements can be true. I have done it both ways. In my opinion always use your own judgement for what you are trying to achieve.
    Example 1 ; if you have 3/4" of sapwood and are building heavy longbow leave it.
    Example 2 ; same piece of wood only you want a 35# longbow, reduce sapwood by 1/2" leave 1/4" of
                       sapwood and cover back w/raw hide.
    hope that made since.

                                                                                                        chuck

[Weylin]

Really, the important thing is that you have heartwood travelling all the way out through the tips on the belly. 1/4" sapwood assures this. 1/2" sapwood is pushing your luck and will likely end up with little to no heartwood near the tips.  ,Just make sure your belly is all heartwood and it will make a fine bow. I think part of it is aesthetic for a lot of people though. They like to see the thin sapwood and lots of heartwood. But I've heard of and seen plenty of really nice yew bows with thick sapwood.

[Roy]

Well on this yew bow it has 1/4 inch of sap wood and 5/8th of heart wood an it came out real sweet, 64" string groove to string groove, 45 pounds at 27 inch draw length. Perfect for an ole man of 64:).

http://s47.beta.photobucket.com/user/ROY-CHRIS/media/MVI_7264.mp4.html?sort=3&o=130

[Del the cat]

Yeah, all right in theory, but.
If you consider the tip of the bow is say 14mm thick and you want it 50/50  heartwood/sapwood the the sapwood is going to be 7mm at the tip and therefore about 7mm all the way along.
But c'mon how's about we get real?
You make the bow from the wood in front of you, if you don't have much heartwood then you can leave the sapwood thick near the grip and may be thin it a bit as you aproach the tips.
Mind I've seen some bows where the tips were all sapwood! (I'd never do that unless I had no other choice).
My personal view is to make the sapwood about 1/4" thick, but then some bows end up with it 1/8" along one edge and 3/8 along t'other edge of the same limb... but that's wood for you.
Often the sap/heart boundary doesn't run parallel with the back of the bow, and sometimes not even parallel with the rings.
I try not to have more sap than heart.
If I picked up a stave with 1/8" thick perfect symmetrical sapwood I certainly wouldn't be looking to glue on some extra .
If you want to get extra performance, heat treat the belly (protect the sapwood whilst doing it) have a look at the bow on my blog (end of Feb start of March 2013) it was a scrawny stave with loads of sapwood and a ton of deflex.

Anyhow, I'm not sure the logic holds good.
If sapwood resist tension well, then more of it resists it even better... so that means the back isn't stretching as much and is thus putting more compression on the belly...!
This is why Bamboo backings need thinning else they can overpower the belly wood.
I think the real point of the story is that too much sapwood used to be considered bad... now we realise it's fine.
I don't think it's necessarilly better.
IMO It is V dangerous to leap to conclusions from an anecdote possibly based on a single bow!
Del