sinew-backed osage shorty question

[upstatenybowyer]

So I'm working on a bow that's 44"ntn w/ recurved tips. The original plan was for the recurves to work some. I floor tillered until I had a decent little bend, flipped the tips, and then applied sinew. I wrapped the tips to prevent the sinew from lifting off on the recurves (some of you may see where this is going).

When I began tillering, I soon realized that a good deal more wood would have to be removed than I anticipated. I now have a real nice bend, but the tips are static as I cannot remove wood where the tips are wrapped with sinew. Here comes the question:

With such a short bow, should the tips be working to get a longer draw length? If so I could just go through the wrappings then rewrap.

And one more question: How narrow can the tips be with such a short bow? As you can see, they're a little less than 1" currently.

Thanks for looking- any and all feedback is most welcome.

[upstatenybowyer]

forgot to mention it's 1 1/2 inches wide just outside of narrowed handle. Width continues to mid limb then tapers to 3/4" at the tips

[JonW]

Those are long recurves for such a short bow in my opinion. Just a slight flip on the very ends is what I would do. Sinew up to the tips then finish sinewing after tiller. You could keep what you have and leave them static but the sinew to the ends is not necessary. Just my thoughts.

[Pat B]

I like to get a bow tillered out a pretty good bit or even done before adding sinew. I also add reflex while the sinew cures.
 If you used hide glue with the sinew you can re-hydrate the sinew/glue and remove it. Lay it out flat to dry and reuse it later.
 You can narrow the tips to 3/8" at the nock or even narrower. The apex of the recurve is where the stress is.  If the sinew is applied well you shouldn't need the wrap while shaping the bow. I usually add snake skins over the sinew and will add a narrow sinew wrap at the end of the skin  and sinew, usually at the end of the working limb.

[uwe]

I agree with Pat. I tiller my short Osage bows to a minimum of 30 lbs before sinewing them. Sometimes I applied snakeskin to the layer, but most time its the bare sinew layer, which is prevented by grease.
Regards
Uwe

[upstatenybowyer]

Thanks guys. I think I may have misread the sinew chapter in TBB v.1 where Jim Hamm says, "I never pull a bow which is to be sinewed until the backing is on it. Pulling a bow stresses the wood, giving it a greater or lesser degree of set, which tends to counteract the effects of the sinew."

He goes on to say, "Since the sinew is what allows a shorter bow to be made, it stands to reason that pulling it before backing is just asking for trouble. Trouble as in a dead bow. It is acceptable, but not necessary, to mildly floor-tiller the bow before backing in order to bring the limbs into approximate equilibrium."

I would have been fine if I hadn't wrapped the tips, thereby making it impossible to remove wood there once the sinew had cured. I guess I was too afraid that if they weren't wrapped the sinew would separate from the back of the bow during tillering.

[PatM]

Thanks guys. I think I may have misread the sinew chapter in TBB v.1 where Jim Hamm says, "I never pull a bow which is to be sinewed until the backing is on it. Pulling a bow stresses the wood, giving it a greater or lesser degree of set, which tends to counteract the effects of the sinew."

He goes on to say, "Since the sinew is what allows a shorter bow to be made, it stands to reason that pulling it before backing is just asking for trouble. Trouble as in a dead bow. It is acceptable, but not necessary, to mildly floor-tiller the bow before backing in order to bring the limbs into approximate equilibrium."

I would have been fine if I hadn't wrapped the tips, thereby making it impossible to remove wood there once the sinew had cured. I guess I was too afraid that if they weren't wrapped the sinew would separate from the back of the bow during tillering.

 No, you read it right, Hamm just has a different opinion.
 
  I don't think sinew needs wrapping to hold it down in those areas and most people that have it raise up there say it does so over time. So reshape your tips, tiller and then re-wrap as a compromise.

[mullet]

Jim Hamm's book was the first one I read when I started getting serious making bows, but he's also written you can't make a bow from Kiln dried wood.

[Stick Bender]

Love these short bows , my thinking with short bows is just flip the tips enough to keep the string on , this one  im going to get the tips scary narrow in the end & only sinew to 4 in shy of the tips with the tips being heat tempered dont think you would have to worry with osage especialy this sapling hedge is tuff as steel, im not going to wrap the sinew I think if the wood is prepared right before sinew like any wood should be ok but this is my first osage sinew bow so im just guessing.

[upstatenybowyer]

Pat, I like the idea of compromise. I've got the tips reshaped (thinned and narrowed down to 3/8 " wide) and the tiller is now right where I want it- 50# at 24". I've got some serpent skins coming in the mail from a trade (never used them before) and I'll probably proceed as suggested- lay the skins down, then rewrap a little sinew between the skins and the horn overlays.

Mullet, I love your quote about the trigger.

Bender, good luck with your shorty!

P.S. Assuming all goes to plan, I'll post the bow as a new topic when it's finished. Let me know then what you think. 

[DC]

If I was to make a, say, 50#@25" 50"NTN sinew backed bow. Would I tiller it out to 25"? Roughly what draw weight would I want before sinewing?

[upstatenybowyer]

That's a good question DC. I think I read somewhere that a sinew backing can add between 8-15 lbs. of draw weight depending on thickness? Don't quote me on that though.

[bradsmith2010]

I agree that shaping the tips and then re wrapping is a goo plan

[gfugal]

I'm currently in the process of finishing my first bow. Its short (43" ntn) at a 26" draw. I recurved it then sinewed before tillering. When the sinew dried (i left it in my car in 100+ degree weather) it enhanced the recurve and reflexed the bow a little. I didn't even prepare the wood before sinewing but nonetheless it stuck on hard and true. I didn't bother to wrap the tips and they still haven't even shown signs of comming off the back.

When i tillered it i was afraid and hearing the glue crack and stuff i made it too week in my inexperiance. I didn't realize how fast a bow will lose weight. When i finished the tiller it was a measly 25# bow. In attempt to make it stronger i applied another backing of sinew. A thick coat of sinew only increased the weight by 5#. So if you are going to tiller the bow it needs to be pretty darn close to target weight before applying sinew. But hopefully it won't break on you since that would be a lot of stress on a short limb. I agree with ham other than wrapping the tips. Floor tiller it then apply the sinew before getting it to target weight and draw length. I will eventually wrap the tips but only after everything is tillered.

[wizardgoat]

I'm no expert, I've  made a few short sinew recurves so I'll throw in what's worked for me.
I prefer to tiller the bow to full brace, probably 70-80% tillered, coming in overweight.
This allows me to fix any allignment or any other issues, and it gets your limbs thin enough to take on
Sinew reflex more effectively and evenly. I always reverse brace my bow slightly, then after the sinew is on I slightly tourque it tighter. As it cures keep tourqing so there's a bit of tension.
I'll wrap the base of a recurve, but when I'm tillering I just rasp it away to make the bow.
You can wrap the tip when the bow is done, if it's the look you want.
My first layer of sinew I cover the bow tip to tip. Then the next layers I focus more on the working limb areas