No set tillering question

[DC]

I'm working my way though this. It's going well. When I identify an area that is taking set(call it a hinge) I believe I'm supposed to weaken the rest of the limb to match that spot. Do I always have to weaken both sides of the "hinge" or is there times when one side will do? You can see where the limb is bending away from the line at the red arrow. Can I just scrape from the red arrow toward the handle(on the right)?

[willie]

DC, are you referring to Badgers method of "no set"? I believe he uses the scale to detect set before it becomes visible.

[DC]

I am but I don't see how it can detect set before it's visible. Once the damage is done the bow isn't going to return as far.

[willie]

well, technically you are correct. The method is intended to minimize the cell compaction, that precedes visible set.

[bradsmith2010]

when you wiegh the bow like Bader does, it can detect set before it is visable

[DC]

If it's invisible how are you supposed to know where to correct it?

[willie]

DC,
now that you have made the distinction that set is not invisible, perhaps we should call it excess strain?

As to where the invisible excess strain is located, I would suspect anywhere there is excess bend.
perhaps this is where the badgering technique comes in?

http://www.primitivearcher.com/smf/index.php/topic,61452.0.html

[Badger]

Willie has it, knowing that some excess strain is happening and knowing where to find it is another issue. If you are one of those with a real good eye it helps a lot but just stepping back and carefully examining it for stiff spots and spots bending too much is the best I can come up with. For laminated bows or very straight staves a gizmo can be a big help. It is time consuming and kind of a pain but I really like the results.

[sleek]

I have found that if a limb has a weak spot, and you are not to draw length yet, you can actually scrape the opposite limb to take more of the bend, relasing strain in the weak spot on your other limb. This makes the entire limb with the bad spot the stiffer limb and not just taking care of the one spot. Then tiller like normal, bring the entire limb around to match, just being careful of weak spots.

[upstatenybowyer]

Hold on, a bow can bend before it starts to take set. I've found that if I don't bend it past the intended weight, measuring the weight on each pull, I can simply tiller as I always would... taking wood off a little bit at a time until the bend is even. Hopefully I don't develop a hinge cause I'm going slow enough and if I do, I leave that section alone and either scrape next to it, or on the opposite limb (like sleek was saying).

If I do the above and it still takes set, there was something wrong about my design. Am I getting this right?

[DC]

The thing is, if I can't find the weak spot I'm dead in the water. The bow has taken 1/8" set. I think the weak spot may be here, so I scrape a bit and put it back on the tree. Now I have to redo the benchmark and start again. If I missed the weak spot now I have 1/4" of set. Still not enough to see(at least for me) so it continues. This is where I am now. I have the bow out to 40#@ 24". Almost there but it takes a little set every time on the tree. Still only about 1 1/2" but enough to pee me off. Now I'm starting to doubt myself. I had two primo Yew staves. One in the warm box for six months and the other leaning against the wall in the shop. Did I mix them up? Crap, I don't know. I'm heat treating it now. Thing is, it's going to be a great bow. A piece of Yew like that would morph into a good bow on it's own. Anyway if anyone sees a flaw in my process please point it out.

[upstatenybowyer]

I take it your intended weight is 40#. If it were me and I never pulled past 40, I would be thinking that it should have been wider or longer. And like Badger says, some set often cannot be avoided.

You could always flip the tips a little to compensate for that 1/8. 

[sleek]

Or try what I have been experimenting with. If a bow wants to take an inch of set, heat treat the set out, then deflex the fades to take the tips down 1 inch. This restores the crushed fibers with heat, and unloads the bow of that 1 inch if stress it couldnt handle. Yes, you loose that one inch of draw, but gain effeciency in not having crushed fibers trying to do work.

[DC]

I take it your intended weight is 40#. If it were me and I never pulled past 40, I would be thinking that it should have been wider or longer. And like Badger says, some set often cannot be avoided.

You could always flip the tips a little to compensate for that 1/8. 

Yeah 40#. 68" long and 1 1/2" wide. For Yew that's way overbuilt, I think.

[sleek]

Dude, you shouldnt have any set yet unless you have damp wood, a bad piece thats mostly early wood, or its still damp. Assuming a correct tiller. Can we get a tree pic with it bending?