Primitive Archer
Main Discussion Area => Bows => Topic started by: Badger on August 12, 2017, 07:58:52 pm
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I was asked if I would repost on the no set tiller theory I use. I may have changed some from the last time I posted on it but not sure.
No set tiller is simply a method of monitoring the condition of the wood as you tiller a bow out. It lets you know in the very early stages of set that we need to make some adjustments. Having a basic understanding of tiller logic is helpful in applying this method to your work. Tiller logic in its most basic form is simply knowing that the thickness of wood determines how far it can bend and the width determines how far it will bend.
A pyramid limb is a good example to use, the entire limb is the same thickness yet it bends in a nice even arc because the sides are tapered all the way to the tip. A parallel limb profile has a taper in the thickness meaning it gets thinner as it goes away from the handle. Logic would tell me that if it gets thinner it can handle a little more bend as it thins out. I think most of us these days are using compound tapers, meaning we may go thinner until just past mid limb and then start increasing thickness as the sides start to taper. This gives us stiffer out limbs. Understanding the relationship between limb thickness, width and the bows ability to bend without damage is necessary when applying a no set tillering method.
A lot of us have been doing this by feel for many years and never really give it much thought. Our sense of feel once we gain a little experience can be very sensitive and clue us in early if problems start to arise. The only reason I actually came up with this is because I was trying to explain to a student what I was looking for when I tillered a bow out and had no way of explaining it. Next time he came back I made sure I was able to explain what I was doing hence the name no set tillering.
I am going to explain the way I use it but I am well aware we have plenty of fine bow makers here who do it successfully entirely differently. This past year I have found myself going on to the tillering tree much earlier than I used to and staying on it longer. Once I get a bow flexing I put it on the tree, The first few pulls are only used to even out the tiller, once I have the tiller evened out all my pulls from then on are all the way to target weight. I do basically all my shaving with a scraper on osage and tropical hardwoods other woods I use the rasp a little more and lightly with a spokeshave. I use a tiller string that hangs loose about 5" or 6" not more than 8".
Now for no set tillering. By time my limbs are evened out and I am ready to start pulling full target weight I am usually at about 12" on the tree. I pull the bow about 10" carefully check the weight and then proceed on to full target weight for several pulls, maybe a 1/2 dozen or so. Now I come back to that 10" mark and see if my weight has changed. If it has I need to address it right away. In most cases if I know my dimensions are adequate I would assume moisture and put the stave away for a few more weeks. If I am in doubt about my dimensions I may reconsider the target weight I have decided on and drop it down some. Most of the time this early in the game you won't see any change. Early on I like to try and pick up at least about 1/2" draw between each visit to the tiller tree and wood removal. With each visit to the tree I repeat the process of checking the weight a few inches below where I know I will be drawing, exercising the bow and rechecking the weight at that same point before leaving the tree. As long as there are no changes in that reference point weight I proceed with what I am doing. If you have a nice flat stave you might want to use the gizmo devise as it speeds things up quite a bit. You can develop your elliptical tiller a little later in the process if you like.
Some may disagree here but something I have been doing for years and it seems to work almost 100% of the time is no more guesswork about where the weight of your bow is. It will read the same on the long string as it does as if it were braced. very close anyway. I keep it on the long string until I reach about 24" at full target weight draw and then I brace it. Once you have the bow braced this is where you are more likely to start picking up your first signs of set in that last few inches. Say you just braced the bow, check your weight at say 18", now excercise at 19", check weight at 18, excersice at 20" check weight at 18, excercise at 21" check weight at 18". Do this all the way to target weight at about 24'. If you notice any drop of weight at all anywhere stop immediately and examine your limb for areas you could get bending more. That one area that lost some weight has allready reached it's max and your only hope of not taking more set is to get other areas bending. This is the time you start to use your tiller logic and get the mid and outer limbs bending more if needed or get it bending more near the fades. Bottom line is you have to find somewhere else to bend the limb or lower your target draw weight. If you do this carefully you should be able to get all the way to your target draw length with very little set. Even small amounts of set really hurt performance and shorten the life of a bow so It is to be avoided as much as possible.
Feel free to ask questions. Steve
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Thanks so much for taking the time to explain this. I've been hearing about this method but wasn't sure what all it entailed. I am starting a hackberry static recurve that I'll have to try this on.
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You're the man Badger! I love having this all together to refer to. Thank you! :)
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I think I go to the short string and brace to soon. I'm going to try to stay on the long string a little longer on my current bow. Thanks for posting this Badger.
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thanks I got it saved,,, (SH)
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That was explained very well Steve.Thanks.
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Thanks for posting. You explained it very well. The dozen bows I have made were tillered on long string pretty much like you described, but never thought of checking draw weight at a predetermined spot like you mentioned. I have noticed that my set has come within the last 2 inches of final draw length. This will be a big help to me in the future.
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Steve thanks for your explanations - always an interesting what you have to say!
Let me add my 2 cents:
I try to work as precisely as possible before I do any bend with the bow. On flawless sticks bracing is possible without floortiller (what I don't like) and long string) in most cases. If so, I leave them strung for 30 min and repeat after after another 30 min. I try not to go over target weight and keep on exercising the bow, doing very little scraping here and then. I aim for doing as less as possible tiller scrapings.
My best (fastest) bows did come along like this.
A few weeks ago I had a bow class and one of the students bows didn't need any tiller scrapings at all - never had this before!
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Thanks Steve it is nice having it in one place !
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Thank you for reposting, this is gold dust
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Even small amounts of set really hurt performance and shorten the life of a bow so It is to be avoided as much as possible.
With respect, I disagree. While large amounts of set can be a detriment to performance, small amounts of set are desirable - bows with small amounts of string follow (say, less than 3 inches) don't have the kind of hand shock that is often felt with reflexed limbs, and this leads to more accurate shooting. Bows with heavy reflexes have a pre-strung zero position that is forward of the handle, and upon release, the bow limbs attempt to return to that pre-strung condition, causing the handle to jump forward in the hand, resulting in less accurate shots - bows with slight string follow do not do this. After all, this is the reason that reflex-deflex bows exist - they attempt to maintain the faster performance of reflex bows, but they then have a deflex in order to maintain a zero position that is in line with the handle so as to remove hand shock. Both Howard Hill and John Schulz were advocates of bows that maintained string follow since accuracy was much more important to them than the speed of the arrow.
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The health and longevity of the wood is of more concern here from what I gather with no mention of excessive reflex implied.
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Even small amounts of set really hurt performance and shorten the life of a bow so It is to be avoided as much as possible.
With respect, I disagree. While large amounts of set can be a detriment to performance, small amounts of set are desirable - bows with small amounts of string follow (say, less than 3 inches) don't have the kind of hand shock that is often felt with reflexed limbs, and this leads to more accurate shooting. Bows with heavy reflexes have a pre-strung zero position that is forward of the handle, and upon release, the bow limbs attempt to return to that pre-strung condition, causing the handle to jump forward in the hand, resulting in less accurate shots - bows with slight string follow do not do this. After all, this is the reason that reflex-deflex bows exist - they attempt to maintain the faster performance of reflex bows, but they then have a deflex in order to maintain a zero position that is in line with the handle so as to remove hand shock. Both Howard Hill and John Schulz were advocates of bows that maintained string follow since accuracy was much more important to them than the speed of the arrow.
This is an error, string follow or its lack has nothing to do with hand-shock. By your reasoning a bow with string follow should shoot a 3 GPP arrow and have no hand-shock, we all know this is not the case. I have shot many highly relexed recurve bows using 5 GPP arrows with hardly any hand-shock, I've also shot a few bows with 3" of string follow that kicked horribly even with heavy arrows.
P.S. Good treatise Steve, I usually brace once I get to about 20" on the long string
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You said: "By your reasoning..."
Well, it's not my reasoning, this comes from Howard Hill, and I was merely paraphrasing since I do not have his statements sitting in front of me. I have not looked at the mathematics on string follow yet since it has never been a major concern to me - a small amount of string follow, in and of itself is a poor determiner of the quality of a bow; it simply is not enough data. When I get a chance, I will see if C.N. Hickman, Forrest Nagler, or Paul Klopsteg ever wrote on the topic. I'm pretty sure that they did, but if my memory serves, it was only by means of a passing comment or anecdote rather than by extensive computation as they did other aspects of bow design and construction.
From what I can gather, the philosophy of bow construction has evolved somewhat over the years as regards string follow - where once it was deemed by many to be a desirable trait in accurate and comfortable shooting bows, now it is largely stigmatized. Why? I don't know... I would wager a guess that the construction of our wooden bows has been highly influenced by bows made of modern materials that are not given over to the same kinds of stretching and compressing that we see in wood, so builders attempt to make their bows reflect them because they "look better." There's nothing wrong with that of course, but by the same token, there's nothing wrong with a little bit of string follow either, and according to the mathematics (which I would be happy to share), building a bow according to the MOR of the wood you are using (not merely generic, published numbers) always results in a bow with a little bit of string follow. It is possible to reduce or eliminate this or course, but my suspicion is that in doing so, we are actually building the bow closer to the breaking point. Is a slight gain in the speed of an arrow worth losing a safety margin? I don't know, that's up to the builder.
But if someone is making the assertion that "even small amounts of set... shorten the life of the bow," it's simply not true, and I would direct any naysayer to the works of the gentlemen listed above to prove the point.
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Almost all bows will take some set, the more experience you get the less set you can try for. Another thing not all set is equal. Some set doesn't cause hysteresis and some does. If you heat treat a bow and put some reflex in and then loose some of it while tillering it is not necessarily all set, some of it may be that your bend just didn't hold all the bend. The main thing I look for when I am done is that once a bow is finished and has gotten some arrows through it I like to have some good tension at brace. The other thing I look for is the first pull on a bow after bracing is the same weight as the second pull. Some bows when rested will give you a nice tight braced string when first braced but after a few shots it will loose a little tension. That is set and the kind of set that causes hysteresis. Another thing I have noticed is that if a bow does not recover any reflex once unbraced but stays the same it is usually better than a bow that recovers ever resting.
As for hand shock, most handshock is geometry related. R/d bows with stiff outer limbs and low string angles seldom have much shock. Nice round tillers with full working limbs will often be shocky if not made a little more elliptical. Low string angles give leverage back to the arrow and allow it to suck more energy out of the limbs. Recurves seldom have much shock.
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string follow usually indicates overstressed wood,, not always, if it is avoided ,,,it means the wood is not stressed as much,, and deisigned properly for the draw of the bow,, avoiding string follow does not over stress the bow,, and does not make it "look better"
a great shooting bow can have string follow,,
a great shootin bow can have no string follow,,
and probably better cast,, thats why bow makers strive for as little string follow as possible,,better cast with less strain on the wood,,
if the cast of your bow is not an issue relative to the draw weight,, then string follow will not be an issue,,
that being said string follow is not the same as set,,
etc etc etc etc,,
string follow has not been deemed a desirable trait for decades,, (AT)
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Well said Brad .....
DBar
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When it comes to theories on bow performance I believe I'm going to side with the guy who has world records in flight shooting and has written part of the TBB series.
Thanks again for posting this information Steve.
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Wooden spring let me tell ya something . Shock comes from too much mass in the outer limbs mostly! I have built a few and yes when you build for set to achieve a reflex deflex design my bows of such have shot very good. Not as fast as a no set bow though. As far as Howard Hill style bows . I have never shot one that was not full of shock. He is my hero though. Probably the best shooter ever. Howard's bows did not have a reflex deflex design. There for your comparison does not hold up.now a properly reflexed bow will not have shock if the reflexed parts of the limb work! That's old Arvin's 2 cents. Happy bow building. Arvin
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Even small amounts of set really hurt performance and shorten the life of a bow so It is to be avoided as much as possible.
With respect, I disagree. While large amounts of set can be a detriment to performance, small amounts of set are desirable - bows with small amounts of string follow (say, less than 3 inches) don't have the kind of hand shock that is often felt with reflexed limbs, and this leads to more accurate shooting. Bows with heavy reflexes have a pre-strung zero position that is forward of the handle, and upon release, the bow limbs attempt to return to that pre-strung condition, causing the handle to jump forward in the hand, resulting in less accurate shots - bows with slight string follow do not do this. After all, this is the reason that reflex-deflex bows exist - they attempt to maintain the faster performance of reflex bows, but they then have a deflex in order to maintain a zero position that is in line with the handle so as to remove hand shock. Both Howard Hill and John Schulz were advocates of bows that maintained string follow since accuracy was much more important to them than the speed of the arrow.
I have to disagree with you Wooden Spring. Not every bow with reflex has hand shock or jumps in your hand. Danznbar made this sinew backed bow with a lot of reflex. I shot it several times and it was as smooth as could be in the hand. If a reflexed bow is designed and built properly it will shoot as smooth as a bow with set.
(http://www.primitivearcher.com/smf/index.php?action=dlattach;topic=58275.0;attach=128272;image)
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Oh and that Badger guy is also my hero. I am going to the salt flats too try and best him. Please wish me the best luck cause I am going to need it. Arvin
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With all due respect, who in their right mind thinks 3" of set is minimal😕
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Oh and that Badger guy is also my hero. I am going to the salt flats too try and best him. Please wish me the best luck cause I am going to need it. Arvin
I almost hope you do beat me. Give me a good reason to come back next year. I still haven't got a bow built for this year. Not 100% sure I am going. I have one I finished up a couple of weeks ago That came out ok but nothing special. maybe I can tweak a little more out of it. I am pretty sure that bow posted by Dansnbar just above would do quite well with the broadheads.
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With all due respect, who in their right mind thinks 3" of set is minimal😕
I would have started dropping draw weight long before the 3" happened.
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Thanks for the write up on the technique of no set tillering, Steve. I have found it helpful to remeasure poundage at old benchmarks, and I appreciate your input when I was asking you about the method when tillering a bow a few winters ago.
Wooden Spring,
Guess I am not one to take sides too much, but I do appreciate hearing opinions formed from experience.
the bow limbs attempt to return to that pre-strung condition, causing the handle to jump forward in the hand
Can't help but think if the string stops the returning limbs at brace height, would there be any further momentum towards where the bow limbs were before bracing?
Of course, just how a limb vibrates, once the string slams home is another issue.
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Wow, and the whole world turns against me because I point out that other authors have said otherwise.
Nothing that I have said in this thread has been of my own invention, I have merely paraphrased the words of others (and I have said as much), so what this boils down to is that you can believe what you want to believe based on who you read, and/or your own experience.
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I tend to lean more to my own experience than what I read. Good thread with a lot of thought provoking comments. :) The great thing about PA is we can have differences and keep it civil. Thanks for that. ;) :)
Pappy
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Willie, I doubt anyone turned against you. These threads are no different that conversations that flow back and forth. We agree, disagree, whatever and then move on. Very few people agree with Howard Hill on his string follow comments but he is still an idol to many of us.
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Wooden spring, Howard Hill may have said that. I don't doubt it. But you have to know several things first. String follow is not the same as set. Some string follow is induced by heat treatment and is not the result of set. This is what's done in reflex deflex designs and is maybe what Howard Hill was talking about. You also need to understand that, yes bow making has evolved, but that doesn't mean for the worse. There have been many traditions that were merely dogma passed on from generation to generation. It doesn't diminish from the skill of the craftsman, they just didn't know better because that's what they were taught. I really appreciate Tim Baker who came into this art and revolutionized how we look at things. He had a very scientific approach and that's what you need in order to filter out fact from fiction from tradition. Our anecdotal experiences and subjective opinions can lie to us. They have no ground against hard data. Tim Baker even said he swore on some things that were just simply not true. I know Steve specifically has tried to continue in a similar fashion to what Tim did and he gathers that hard data. You also have to know that Steve (badger) and Marc are extremely good bowyers and may possibly be remembered in their time to what Howard Hill was in his. Maybe not in shooting, I don't honestly know how good they are compared to Hill, but certainly in bow building. That also doesn't mean their methods aren't going to be improved upon in the future, as happened with Howard Hill, but it would pay to notice what insights they have to say.
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Also, you mentioned something about MOR and how if you build to it you'll get set. This is true but you don't want to necessarily build to the modulus of rupture (MOR). There is also what's called a yield point or a materials elastic limit. For example, I bought some parachute cord that says it has a working load of 150 lbs, but a breaking strength of 500. What's the difference? Well, I assume it is its yield point. I assume that after it exceeds 150 lbs it will start to deform because it's past that yield point or elastic limit. By deform I mean it will stretch and not return to its original length. This is the same thing that happens with set. If it passes that yield point it too will deform and not return to its original shape. Doesn't mean it will break, just that it's past that elastic limit. Now putting two and two together I hope you understand that 1) passing something's elastic limit will make it less elastic which is bad for a bow, and 2) passing that limit also means you are closer to something's break point (MOR) which means it's under more stress not less.
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Some string follow is induced by heat treatment and is not the result of set. This is what's done in reflex deflex designs and is maybe what Howard Hill was talking about.
In most cases string follow is actually due to set. Deflex/reflex bows are typically deflexed in the riser or non-working portions of the inner limb.
Howard's string follow comments probably originated when he was still shooting selfbows that were showing slight set.
Hard to say if his later laminated bows were glued up to show string follow or just shot until they did.
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I am not one to idolize many people, howard hill was a great shot. But some of his reasoning is suspect. In hunting the hard way he stated, and i paraphrase, that short bows and shorter recurves were no good for hunting as u cant be accurate with one, he concluded that since he was terriblle with shorter bows they weren't any good. Does anyone still think this is true?
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Gfugal well put. Arvin
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Todays best bowyers would embarrass most of these "legends".
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Steve,
over in another thread, about tillering an ELB, you posted......
Are you going for as much weight as you can get out of it? There is a technique you can use for that.
perhaps you can give us some pointers about your methods when one does not have a fixed weight goal.
thanks
willie
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Thanks Steve. It is these types of discussions that first brought me to this sight some years back and it is these types of discussions that interest me still. Especially coming from someone with your experience. I am inclined to listen. Then I will see if my experiences match up with what I have read. I'm not on here much any more. No biggy, just a lot going on, but I do appreciate the good posts like this one. We know so much more about these bows today than we did 30 years ago. Some things written by our predecessors as concrete facts 30-40 years ago or even longer, aren't even worthy of discussion today. Those writers brought us the best information they had at the time. Osage was considered inferior to yew at one time. White woods were not worthy bow woods. Boards were not a good choice for self bows, and on and on. These things were published and were in fact proven wrong by people that, through experience, showed the rest of us a new way. I am grateful to them all, as I was then and I am still looking for data. Information. So again, keep up the good work!
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Hi Badger thanks for explaining your tillering process so clearly its really interesting and helpful. I was really surprised to hear you tiller on the long string up to 24". I thought that the general opinion was that its best to get off the long string and to low brace as soon as possible? Doesn't the long string give us a mistaken view of the tiller? I personally would be happy to stay on the long string till a later stage cos I hate trying to brace a strong stick. It's a stress inducing exertion I could do without! :o
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sidey.
I think everyone finds their own way in this pastime of ours.
We do what works for us.
I long string tiller to 10"...looking for target weight or 5# over and good limb bending. Then I string it.That puts me 10# over target weight.
It's all good. Personal preference.
Jawge
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I was really surprised to hear you tiller on the long string up to 24"
That kind of surprised me also, but perhaps Steve is measuring the 24" with the initial droop. It would be nice to know how close to full draw this approximates.
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Willie, the initial droop doesn't matter, it measures the same with the droop as if it were braced. If I am pulling 50#@24 on a long droopy string it will still be 50#@24" when I brace it. As long as the string hangs down about 6" or so not too long.
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As long as you know how long string effects the tiller I think you could stay on it longer, which might be more beneficial at reducing set. However, I don't necessarily know so I brace it as soon as possible.
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As long as you know how long string effects the tiller I think you could stay on it longer, which might be more beneficial at reducing set. However, I don't necessarily know so I brace it as soon as possible.
It makes the mid and outer limbs look slightly stiffer than they might look braced not a big difference.
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Something I left out that I think is an important part in making this work. You want all parts of the limb to finish at about the same time, as close as you can anyway. By this I mean you don't want to find yourself in a situation where you say, this is bending enough, now I will concentrate on other areas. If you are pulling to full target weight each time this method could possibly overdraw sections of the limb. The best method I can find is to simply keep " perfecting" the bend in small increments as it eases toward full draw and target weight. This might be the most important aspect of no set tillering that I hadn't really put my finger on and identified.
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Wow. Steve, you have a gift for putting things into words. What you've written above is something that I've only recently started to understand. I used to say, "this is bending enough, now I will concentrate on other areas" all the time. Then I noticed as I continued that sections seemed overdrawn and overstressed.
About 6 months ago I read something that either you or Marc said about getting a nice even bend throughout as soon as possible then gradually reducing the weight without loosing that balance. Ever since then that's what I've been trying to do. For me, it takes tremendous patience.