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Thoughts on tillering

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Kidder:
I knew the old sages of Bowery would get it. But I’m going to articulate it a little better: the quality of the process impacts the quality of the bow, regardless of the quality of the final tiller.

Pat B:
Proper full draw tiller is the destination and the tillering process is the journey. Pretty simple, eh? To get to the end of this journey we have to start with a stave that is shaped evenly before any bending has begun. From this point our journey leads to both limbs bending evenly and together. For me it starts with floor tiller, making sure that both limbs are relatively close but my eye doesn't necessarily see that clearly until I put the stave on the tree with a long string. Initially this is any long string at any length but only pulling the stave enough to see what going on at this stage but in small incremental pulls. If both limbs look to be even I shorten the string so it just fits the stave. All along I mark places that need wood remover and places that already bend too much. Each step of the tillering process, to me, goes through these bending and marking steps and as I'm sure both limbs are bending evenly and together I progress with the bending of the limbs until I can achieve my first low bracing of about 3" to 4". This is a critical point in the tillering process because it not only lets me know how the limbs are bending and in comparison to each other but also how the string is tracking. For me, this is when I work on heat corrections like removing twists and bends and aligning the limbs to the string under tension. Once I'm assured everything is in order and both limbs are still together it can be as simple as just reducing weight evenly without causing other problems but things happen so slow, thoughtful actions from here are necessary.
Also I exercise the limbs by pulling the string, to a measured length multiple times(20-30) but not going over my intended final weight. Once I get to full draw and I'm sure both limbs are bending evenly and together and I'm near the final draw weight I brace the bow at regular brace height and let it "sweat" for an hour or so. I'll also put a few arrows through the bow and gradually make the sweating process longer and longer. BUT, you have to be sure everything is even or you can cause tiller problems even at this stage.
 What I've shown here is my process. Everyone has a different method but the final goal for everyone is the same. Their journey may be different but the destination is the same, both limbs bending evenly and together at the intended full draw draw weight.
 There are other things you can do like reflexing limbs and/or tips, recurving tips, heat treating the belly, etc but these things come later in the learning process. To begin with simply getting both limbs to bend evenly and together is the goal.

lonbow:
The process of tillering a bow is a crucial part of the bow building process for sure. The contributions on this forum have helped me a lot in this aspect. Tank you very much guys :)

Over the last few years, I have picked up several methods that have helped me improving my bows. I feel that it's extremely important not to overload the wood at the early stages of tillering. Here are techniques I've learned:

1. I used to floor tiller my bows excessively. This was the point where my bows developed a lot of set. My bows have improved since I don't do this anymore.

2. Instead I started to tiller more with the long string. At first I switched to to normal brace height at about 1/2 of full draw. Now I see even more improvement when I do long string tillering until I reach almost full draw. This is also the point when I do a slight heat treatment on white wood bows. After that I switch to full brace height. Then I gradually increase draw length until I reach full draw. Often, there are only minor tiller corrections needed

3. I like drawing a pencil line along the entire bow length before I start tillering. This helps me to see the true bend of the bow even when the grain is wavy. After each increase of draw length, I look along each bow limb to monitor the exact spot where set develops. I try to keep it little and even through the entire process of tillering.

4. I usually shoot some arrows at the last few inches of the tillering process, monitoring hand shock and string vibration. I remove some wood at the mid and outer limbs, when I'm not happy. This helps me to reduce hand shock improve arrow speed.

lonbow

Del the cat:

--- Quote from: Selfbowman on November 14, 2023, 10:08:35 am ---Del I noticed you don’t use a long string that hangs below the bow but is tight up against the bow at first of the tiller process. Also why the ring in the string. How do you center the ring as the tillering process goes. I have a good eye for even bending but must be over straining the wood at some point causing set. Most of my bows end up with 1-2” of set when shot in. That’s with 2-3” of reflex in the outer limbs.

--- End quote ---
I do use a 'long string'... but a long string should be as short as possible! E.g. the bow isn't braced, but the string only hangs down a few inches. When it's done like that the poundage and draw length, correlates closely to the figures when braced. (you can prove it by taking a finished bow and putting a long string on it)
The ring is to allow me to use the same long string on any bow. By threading the string round the ring I can adjust it's length from long right up to braced... then I use that length to make the proper string... fool proof way of getting the string length right.
Del

superdav95:

--- Quote from: Del the cat on November 14, 2023, 02:31:55 pm ---
--- Quote from: Selfbowman on November 14, 2023, 10:08:35 am ---Del I noticed you don’t use a long string that hangs below the bow but is tight up against the bow at first of the tiller process. Also why the ring in the string. How do you center the ring as the tillering process goes. I have a good eye for even bending but must be over straining the wood at some point causing set. Most of my bows end up with 1-2” of set when shot in. That’s with 2-3” of reflex in the outer limbs.

--- End quote ---
I do use a 'long string'... but a long string should be as short as possible! E.g. the bow isn't braced, but the string only hangs down a few inches. When it's done like that the poundage and draw length, correlates closely to the figures when braced. (you can prove it by taking a finished bow and putting a long string on it)
The ring is to allow me to use the same long string on any bow. By threading the string round the ring I can adjust it's length from long right up to braced... then I use that length to make the proper string... fool proof way of getting the string length right.
Del

--- End quote ---

I like it Del!  I may have to try that. I’ve seen you use it but didn’t clue in that it was adjustable.  Slick!   

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