Short osage recurve in the works

[sleek]

While cutting the front profile out on the band saw, i found a hidden rotten knot in the heart wood. It is such a location at the fade that chasing a ring under the sap would put the rotten knot into the back of the bow. But If I leave it sapwood backed then the knot may mostly come out if not all together during tillering. So the sapwood will stay on this bow.

I took all the advice on here into consideration and made the profile thus...  1.5 out the fades for the first 8 inches then tapers down to the last 6 inches  where it is at 3/4 inch where it then tapers down to 3/8 at the tips. Ryoon, it looks allot like your first bow in that link you sent. Thanks all for the help, I hope to get a good tiller out of this one and some decent performance.

[PEARL DRUMS]

i think his point is is that if you make it TOO thin you wind up with not enough wood taking compression where as a bow that has more wood in thickness would be able to take the compression better. theres a balance i think and if its say 1/4 inch or even 3/16in then its got too little wood, idk if im right or wrong but thats my thoughts.

Winner-winner chicken dinner. Congrats ionicmuffun. Thanks for reading my post.

[toomanyknots]

i think his point is is that if you make it TOO thin you wind up with not enough wood taking compression where as a bow that has more wood in thickness would be able to take the compression better. theres a balance i think and if its say 1/4 inch or even 3/16in then its got too little wood, idk if im right or wrong but thats my thoughts.

I understand what he is saying, I just don't agreed with it. I have made bows under 1/4" thick before. You know those 1/4" red oak pieces that are 4' long and 4" wide? I play with those all the time. This bow is less than 1/4" thick, with a 7" brace height and a 30" draw:







It may have about 1 1/2" set, but considering that it has less than 30" working limb for a 30" draw, I would not say that is that bad. The bow has one thin layer of sinew with tb3, which did not add any reflex to the bow at all. Previously, when I had tried the same exact design, but a little narrower, and a little thicker, all I ended up with was chrysals, set, and wasted sinew galore. This bow was like 4" wide at the fades, and 1 1/2" where the levers attached. So there is an example right there proving you wrong. I have made better examples without sinew but I don't have pictures nor do I have the bows anymore.

I really didn't intend to get into an in depth discussion, my specific point is that adding 1/2" to the fades of a 1 1/2" wide osage bow would never in a million years cause set. That is just crazy talk to me. Osage is great in compression and all adding 1/2" to the fades would do is distribute the compression a bit more in the limb section right off the fades. Which obviously, osage doesn't even need it, so this argument is just pointless. Either way, I've said my peace, I'm done. I'm sorry for going off topic in your thread sleek, I look forward to seeing that beautiful fulldraw. 

[sleek]

No worries. I don't mind intense descusions on my postings. Its relevant anyway. my thought on it is/was that its an issue of psi. If the pressure stays the same and you increase the inches, then you have decreased the amount of pressure per inch resulting in less stress. And I thought less stress ment less set. But I am watching all this with an opened mind. Not affraid to learn something today

[PEARL DRUMS]

Its the 8:1 (approx) strength ratio that interrupts that thought sleek. Thats what all this stemmed from. There are good reasons you hear guys on here (who know) say they had to leave the thickness alone and start tillering the sides. Its not for a change of pace, its because the bow is getting thin and they need to maintain that thickness, so they head to the sides to finish tillering the bow. Im not telling you how to build your bow. I simply stated my opinion and why I thought so. I should have known better than to not hire a lawyer.

[RyanY]

The thickness of a bow determines how far the bow will bend. Each thickness has a tolerable bend radius that it can take without taking set. A limb that is 1/2" thick will have a larger bend radius than a limb that is 1/4" thick. If they are bent the same way then the 1/4" thick piece will be under less stress and take less set. The reason we don't make our bows super wide so they don't take set is because the extra width uses more mass for the same amount of force. This is where the 8:1 strength ratio comes into play and why the mass principle makes optimal bows. If we are able to tiller the bow so that it's thickness is enough so that it doesn't take set or takes very little, then we can reduce the width and have a bow which is has the optimal mass to do the work asked of it. I see no reason why a bow would "need" thickness.

[steve b.]

I think its a good discussion as I have never considered Pearl Drums premise.  Whether the wide vs. thin vs. set thing applies here doesn't matter to me if I learn something that may be important in the future.

Personally I want my fades to move a little, in the same way I want a D-bow handle to move, SOME.  I'm always worried about set in the handle of a D-bow but I can't just make it wider because it HAS to move, SOME.  So I need to be a better bowyer, not an engineer. 

With a short, stiff handled bow I want my fades moving, SOME, so if I made them wider I have to make them thinner.  And as has been stated, thinning is a sensative procedure--a few extra strokes of the scraper and I've made a weaker bow--set.

[sleek]

Now this is a conversation worth having. Ryoon and PD, this has really got me thinking. I never understood the side tillering thing and thought it was for laminates. Because this is a very good topic I am going to open a new one for it. When belly and side tillering is needed.