question about yew sapwood

[oneraindog]

sorry to hog up the board with questions about this same yew bow. updated my last post but nobody saw it and/or responded :/

 is 1/2 inch too much sap wood on the back of a yew bow??

i was given some billets spliced and reduced to rough bow shape by someone else.
 the sap wood had already been taken down to one growth ring by the person who had it before me. all the rings below are so  thin i can barely make out the separation between them. i am not too inclined to reduce the thickness of the sapwood but it is close to 1/2 in some places instead of the prescribed 1/4 inch.

[Pat B]

Depending on how thick your limbs will be. 1/4" is more appropriate but as long as you have plenty of heartwood on the belly of the finished bow 1/2" should be fine.
  You can reduce the sapwood to 1/4" and if the rings are too thin it shouldn't be a problem. Yew is one of a few bow woods that a bit of ring violation isn't a problem. If it scares you you could always add a rawhide backing or a cloth backing(silk, linen, etc)

[oneraindog]

thanks pat. dont know if you remember my other posting but my yew has the branch stubs sticking out that i cant cut off enough to cover with a backing. :/

[oneraindog]

by thick you mean from belly to back right?
if i make the limbs a little narrower will that also be better for a thicker sapwood layer?

[Art B]

I once read where sapwood is lighter than the heartwood thus making it more beneficial for the outer portion of the limbs. I suppose if you could add additional reflex to the bow and make the tension strong sapwood do more work then maybe you can leave the sapwood as is. Making it a little narrow may also help as you alluded to.........Art

[Pat B]

Yew can easily handle a narrow, deep rounded belly.
  What dimentions are your bow, length, width and what style bow are you planning on?

[Shaun]

The bow I just posted under "2 western wood bows" is yew that had about 1/2 inch of sap wood. I took it down to about 1/4 inch with no regard for ring violation and then backed it with rawhide thickness snake skin. If you do not thin the sap wood you will end up with all sap wood towards the tips on a round belly ELB and in most of the bow in a flatbow design. The hart wood is better in compression so you want some of it remaining in your bow.

[oneraindog]

hey thanks for all the replies, took me a few days to get back to them

pat the current dimensions of the roughed out shape are 74" long
1 3/4" at the fades to mid limb and 1/2" nocks.
a lot of handle set back at the splice
here is a picture
   

i think the current dimensions are a bit much. i am thinking about a bow with dimensions closer to that described in the bowyers bible vol 1.

shaun the back is disrupted by significant character that make a rawhide backing an unlikely option i think. there are branch stubs protruding and if i can i would like to keep them because they add a lot of appeal to me.

any more advice is much appreciated. thanks  again

[Pat B]

Are you planing to do any heat straightening?  I would give both limbs even backset and do away with the deflexed bend in both limbs. With that much backset glued in at the handle you don't need to add more backset to the limbs. Just straighten them and even the amount of total reflex in the bow.
74" is way long also. For 28" draw you would probably be good with 66" to 68". If you find the limbs getting too thin reduce the width by scraping the sides instead of the belly.
  The knots and stubs on the back are very cool. The wood around limbs is thicker and stronger to support the limb so they should be no problem as long as they are sound. If any(or all) of the stubs and knots have checks(cracks) in them just fill the check with super glue. You probably don't have too but it is cheap insurance.

[fujimo]

you could back with burlap- look nice and traditional on an elb.
but mainly it would allow you to "part" the coarse weave of the burlap, and spread it around  around the knots without destroying the lineal strength of the lengthwise fibers of the burlap.
well good luck

[oneraindog]

im not sure if i understand the advice pat.

you are saying straighten the limbs out from the handle so that the bow is in a "V" shape?  i guess maybe im getting confused between the backset and setback terms.

[Pat B]

Both limbs are in deflex, the left one more than the right. I would straighten each limbs out so they have a flat side profile. You have enough reflex added in from when you glued up the billets.
 I think you have too much reflex added in the handle. With that much there will be a lot of stress on that handle splice. For me I'd prefer to glue up the billets in a flat profile and add reflex on a caul with dry heat. That way I will have limbs that are evenly reflexed making tillering easier.

[oneraindog]

unfortunately  i was not the one to do the gluing. i recieved the bow as you see it.

i think i am understanding what you are saying. flat side profile. so like a "V" as if it where a wide angle.

[oneraindog]

sorry, it is hard for me to understand things sometimes if i cant see a visual representation

[Pat B]

Yes. A wide angle "V".   Communication can be difficult online.
Do you have the tools to make a new splice? I believe you have plenty of length to eliminate the old splice and cut a new one. If so you will save yourself a lot of grief. Just trying to brace that stave the first time will be an ordeal even with a bow stringer.   IMO,too much reflex in one small location! If it were spread throughout the entire bow it would be more managable.

[oneraindog]

i dont have the tools myself but may be able to use friends.
are some bows made with reflex from the handle, going into deflex and then recurving the tips? i seem to recall bows of that sort of shape in bowyers bible or maybe a hamm book but i could be mistaken. have to  look later.
but if so, maybe a shape like that might work?
for some reason redoing the splice seems intimidating. i am not very familiar with the procedure. time to tackle that chapter now i guess