Weigh in on this yew profile if you would please

[David Long]

This is the stick of yew I showed in the recent knot compression thread. After working it a little more, I think I might get away with the knots. Now I am wondering about basic design issues, namely how much reflex I should add or take away from the natural curve with heat. The plan is for a sinew backed bow, 48 " NTN, 1.75 " wide most of the limb length. I want to be able to draw it to my normal 26 inches, and I want draw weight to be more than 50 lbs, preferably 60 lbs. So here are the questions: should I add reflex to the flat limb to match the more curved one, which will bring it up to a whopping 6 ", or should a take it out of the curved limb to match the flat one which will bring it down to 3", or do a little of both? A 48 inch bow starting with 6 inches of reflex is a little extreme isn't it? I've never made a short bow like this. Can pin nocks work on such a thing or will the string fly off? Dave



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[adb]

Does this stave have natural deflex, or reflex?

[David Long]

Reflex. Back is to the sky in the picture.

[David Long]

I should have pointed out the stave is thinned out, bending some but I wouldn't say enough to call it floor tillered. I think I'm ready to put the heat to er now, then tiller. Dave

[Pat B]

Depending on how much sinew you add...I would reduce the reflex on both limbs to about 1" or 2" then let the sinew bring it back up to more as it cures. Where is the knot in the limb? Will you post a pic of it?      Pat

[David Long]

Pat here are the pics of the limbs showing the knots. The less reflexed limb (right) has the huge knot near the fade area, although it's not as disruptive on the back because the center of the stave is near the center of the sapling. It appears to me a good dose of sinew will protect the backs of both limbs. The belly of the right one especially looks screwy. The pictures are a Photoshop combo in case it is confusing. Dave



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[Pat B]

I think what I'd do is soak the big knot with super glue and let it cure before stressing. Actually I' put super glue in all of the knots on the belly. That big knot is in the best place it could be in the center of the limb and close to the handle. You could leave that area a bit stiff and after sinewing you should be fine. With my limited experience with yew I have worked around knots and so far haven't had any problems.  Maybe one of the guys familiar with yew will speak up.    Pat

[Keenan]

 Dave,
  I would not add any more reflex. You would be better to take some out of the other limb to even them out. Trying to string a bow with 6" of reflex can be a bear especially on a short bow. The sinew is also going to pull at least an inch more if not two.
  The one thing that you need to be carefull with, is heating around those knots could cause sme cracks to open so stay clear on them as much as possible.
  Also this bow is still puzzling me because what you have marked as the back looks like it should be the belly and the ones showing the sapwood should be the outside back. I know it's a sapling bow but looking at close ups on your pics. I see rings tapering to a point on the back in many places,suggesting that it has been thinned from the handle area towards the tips. And what you have marked as the belly looks to be a fairly consistant ring even having some of the sap still present?
 

[David Long]

Keenan I decided to make the bow like a Homlegaard, backwards in other words with the sapwood towards the belly. So all your observations are correct. The reason I did this is because I wanted to use the bottom, compression half of the sapling. In order to do this and take advantage of the natural curve of the wood the belly had to be the sapwood side. For all I know this was the wrong thing to do. The upper half of the sapling is curved the "correct" way, but it is mainly tension wood (presumably) and less strong in compression. Not a good senario with a bow that will be backed with sinew. Do you agree with this thinking? The reason this type of wood (curved saplings) is so important to me is that this is yew's growth habit in my neck of the woods. If I can develop really good ways of dealing with this situation I am in fat city. We don't have many straight, decent Pacific Yew trees here. Although they can be found I hate to cut them. I have just heat treated the more reflexed limb on a form I made from the profile of the less curved one. I blasted the knots, the whole limb. Did it like Marc says. Thanks very much Keenan for your careful attention to those pics. Dave

[Keenan]

 Right on David, thanks for the explanation, that helps. If you can pull it off that would be great as you said to be able to make use of what you have available. Also helps us all to learn what is possible. Keep us posted on what you observe with this one. Hope it dose work I have a few that would fall into the same category.