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Main Boards => The Bowyer's Bench => Topic started by: skeaterbait on March 02, 2018, 10:48:00 AM
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I have heard that a bit of negative tiller is what you want for three under shooters. What does a positive tiller gain?
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First of all, two bows, perfectly tillered/balanced at full draw for the same shooter, shooting them both the exact same way could EASILY show different tiller measurements at brace. Right? We could change just one variable of many, like location of bow center, and it would totally blow the theory you heard out of the water.
If someone understands these things, I don't know why they would make such an overly simplified, generalized statement. And if they don't understand, they have no business giving tiller advice, imo.
Secondly, there's so much directly opposing advice offered regarding tiller, it makes you wonder who, if anyone, should be believed. I've found the majority of the advice I've seen offered over the years, some published in books by respected bowyers and archers, to lack objectivity, adequately descriptive reasoning, and/or oppose my own findings.
I don't blindly agree with anyone in regard to this, never did, and prefer detailed, reasoned explanations by anyone offering their 'facts' over generalities like "a bit of negative tiller is what you want for three under shooters". My response to that person would be, "Really? Why?" and then, "Prove it, please". Not because I think they're incorrect necessarily, as much as I want to know if they've actually done the work, seen the proof, or are they just regurgitating what they've heard... perhaps from other unsubstantiated sources.
Heck, I've seen many folks directly contradict their own advice in the same paragraph. It CAN'T be both, so which is it? And others take the bulk of it as gospel. This tiller thing is so largely misunderstood. It's crazy... and kind of sad.
So don't believe everything you hear about tiller. In fact, you'd be better off not to believe any of it, and go forth with an objective mind to uncover the truths on your own.
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Can't argue with that line of thinking. :thumbsup:
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Thats a good reasoning Junkie.
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Agreed, I final tiller based on the bow owner drawing the way they plan to shoot and adjust. Tillering trees do not replicate how we hold the bow which is very variable. I've shot split and 3 under. But with all the variables some are even some are +/-.
If I have a choice, I keep the bottom limb the stronger of the 2 as I seem to stress mine a bit more and it weakens over time.
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"Tillering trees do not replicate how we hold the bow."
That's another generalization.
They certainly can replicate our holds/fulcrums. But most don't even try.
Not all tillering trees are created equal. Some are infinitely more variable than others, and come much closer to replicating various archers' holds than their counterparts.
Unfortunately, the common untruth that they can't, is often used as an excuse for mediocrity or a perceived ease of production. not.
It baffles me how the very folks who go to such great lengths and effort to coax bows from standing trees, choose to try to make things easy for themselves when it comes to, arguably, the most important part.
But I digress, from what I've seen, the stronger you keep a bottom limb, relative to dynamic balance, the more it will weaken with use. Hey, just flip the bow over, right? and oh-oh... gotta repeat.. and oh-oh... gotta repeat.. Things that make you go... hmmmmm.
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I'm certainly no expert, but I just try to get both limbs bending equally. As close as possible. I fully acknowledge that I have a lot to learn on the subject, but it seems to not be as critical as some folks would have me believe.
Honestly, I get it close and my bows seem to shoot just fine. I tiller mine to be balanced on center. Whichever limb is slightly stronger, becomes the lower limb.
I've made myself nuts with this. I've had bows come off the form with identical measurements on both limbs at brace height only to be off by an inch or more at full draw. And vice versa.
Now, if the measurements at brace height are within .250" of each other as measured at four points on each limb and at full draw, I call it good.
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I guess my bow making/tillering could be summed up as the neanderthal method... "arrow hit spot? Kronk happy"
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I believe it is as critical as some would want you to believe. Ye, you can get the tiller out of whack and the bow can be shot fairly well. For a while. It took me a while to figure out that if the limbs are fighting each other(bad tiller) the bow won't hold up. I made several selfbows that started out shooting good, but over time and several shots the limb(usually the bottom) would start to take set. The limbs need to go through the draw cycle together, in relation to how you hold the bow. If they do, assuming decent design, the bow can last a long time.
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I should add that I only build glass bows. I'm sure it's very critical on an all wood bow.
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I try to keep tillering simple. I hang the bow from the scale by a rope loop that I feed through itself and clip on. Early in the tiller on the long string I pull from center of the string so the handle stays level as I work it back . Once I have it braced I clip the pull rope from where the middle finger would be pulling from so that the pull force would be the center of your pull force as if you were using 3 fingers. Hooked up this way the bow will tip towards the top limb, when as you come to full draw the handle section will level out and the limb tips should end up at an even point compared to each other and the handle. When that happens the bow almost always is a smooth and quiet shooter.
Kyle
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Originally posted by Bowjunkie:
First of all, two bows, perfectly tillered/balanced at full draw for the same shooter, shooting them both the exact same way could EASILY show different tiller measurements at brace. Right? We could change just one variable of many, like location of bow center, and it would totally blow the theory you heard out of the water.
If someone understands these things, I don't know why they would make such an overly simplified, generalized statement. And if they don't understand, they have no business giving tiller advice, imo.
Secondly, there's so much directly opposing advice offered regarding tiller, it makes you wonder who, if anyone, should be believed. I've found the majority of the advice I've seen offered over the years, some published in books by respected bowyers and archers, to lack objectivity, adequately descriptive reasoning, and/or oppose my own findings.
I don't blindly agree with anyone in regard to this, never did, and prefer detailed, reasoned explanations by anyone offering their 'facts' over generalities like "a bit of negative tiller is what you want for three under shooters". My response to that person would be, "Really? Why?" and then, "Prove it, please". Not because I think they're incorrect necessarily, as much as I want to know if they've actually done the work, seen the proof, or are they just regurgitating what they've heard... perhaps from other unsubstantiated sources.
Heck, I've seen many folks directly contradict their own advice in the same paragraph. It CAN'T be both, so which is it? And others take the bulk of it as gospel. This tiller thing is so largely misunderstood. It's crazy... and kind of sad.
So don't believe everything you hear about tiller. In fact, you'd be better off not to believe any of it, and go forth with an objective mind to uncover the truths on your own.
EXACTLY. well put, Bowjunkie
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I tiller my bows for equal limb timing, not by inducing a certain predetermined positive or negative tiller.
I let the equal limb timing determine what the tiller will be.
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I tiller mine, glass bows, by where I have to put the nock point to shoot properly and quietly. I like a 7/16 nock point. So when I shoot a bow during build and say it requires a 5/8 nock point to shoot properly. I will sand bottom limb a bit to take some of the positive tiller out until I get nock point to where I want. May take several tries. Of course my preferred nock point may be different than yours. Tiller ends up where it does, +-, for that particular bow.
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So all in all it sounds like the rigid science of tillering comes down to a one rock solid rule.
You definitely have to have positive tiller, unless negative or even is better.
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You definitely have to have positive tiller.
NO
unless negative or even is better.
Maybe
:)
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Tillering for equal limb timing for split finger.
The pull rope follows the black line on the wall, which means both limbs are bending in sync.
https://www.youtube.com/watch?v=v9csLbtfuJI
Tillering for equal limb timing for 3 under.
https://www.youtube.com/watch?v=LBi74lbXkRU
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I try to make it look good in the mirror at full draw. Other than that I do not shoot my wood bows 3 under, it places more stress on the bottom limb. Shooting 3 under on the glass bows works better for me.
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Bowjunkie,
how is your tiller tree set up? i have the typical pulley with a hook attached to the bow string that i put at center or fix with string nocks slightly below for some variation. since people typically draw with 3 fingers and various tension on each finger, i see variations from shooter to shooter even when using both 3 under or split. i personally don't have much variation when i shoot split vs 3 under with my self bows, but i've seen some people with very notable differences. the inherent differences potentially present in various self bows such as knots and holes further effect tiller. i know several proffesional bowyers in wi with glass bows that typically don't worry about slight variations but they also see certain shooters requiring +/- tiller adjustments. Fixed crawl is a whole other tillering challenge as well. ILF bows also have adjustable limbs for various styles in addition to tuning. I wasn't expecting to be attacked for agreeing with you, but if there is a better way to build a bow, i would to know it. Having final tillering done after the bow's owner runs some arrows through it seems to be a simple and effective way to me, i wasn't trying to be lazy.
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In the world of natural bows negative and positive means virtually nothing. Bow hand balance is everything. Glass bows are perfectly symmetrical out of the oven and have a more predetermined tiller. Natural bows can have, for example, reflex off the bottom fade and deflex off the top fade creating a negative measurement. Yet have perfect balance in the bow hand. If you were to take this hypothetical bow and make it appear proper to your eye you would effectively toss it out of balance and make a loud, uncomfortable bow.
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Yupper, Chris. Wood bows are a totally different animal.
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I have read through many of Bowjunkie's post because his method has made the most sense to me, and my bows shoot great right off the tree now.
I try and replicate my draw onto my tree. I draw my bow and focus on where the pressure is on my bow hand with my grip. For me, that pressure point is somewhere in the middle of my pointer finger. I make that my pivot point on the tree cradle, and I like that to be close to the geographical center of the bow. Then I draw my bow again and focus just on my string hand. Where am I feeling pressure? Is is just my middle finger or all three fingers? I feel pressure mostly in my middle finger so I pull with a hook and set the hook exactly where it will be on my bow, a little less than 3/8" higher than the bow hand pivot point. If you notice pressure on all 3 fingers a leather strap the width of your fingers would be a good representation. Now that you have it setup the way you draw, draw a perpendicular line from your cradle in the exact line that you will be pulling from. Now just tiller your bow and make sure the hook totes that line and your bow is in balance for the way YOU shoot. If you are building a bow for someone else then have then tell you where they feel pressure on their bow and string hands. The tiller comes out + or - but it doesn't matter.
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And I forgot to mention that this method is easier than other methods I have tried. All you have to do is make sure the hook is toting the line. If it sways one way, then that limb is too strong. Not much thinking involved.
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What about production bows? Those who make large quantities of the same bow (Bear, Martin, Black Widow, etc.). Does anyone know how they do it since there is no way to know what style the archer will be. In fact, it would stand to reason that all styles will be used on that same model.
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I don't make glass bows, but it would seem that those production bows are much more predictable, and they know that let's say a 1/8" tiller works best for balance and the majority of shooters in the style of bow they make.
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Guys who buy production bows have to tune their bows by moving the nocking point on the string up or down till they get good arrow flight.
"Some" of us wood guys have a predetermined nocking point in mind before we even start tillering the bow and that is where we adjust the trees pull rope for and tiller for equal limb sync/balance.
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Originally posted by Roy from Pa:
"Some" of us wood guys....
Don't worry Roy, if you behave someday you can be a real boy.
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Ah tanks.. :)
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Many variables, I wounder about the Yumi bow, how is it tiller'd ?
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Originally posted by skeaterbait:
Originally posted by Roy from Pa:
"Some" of us wood guys....
Don't worry Roy, if you behave someday you can be a real boy. [/b]
LMAO, good one skeater.
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Making one limb shorter than the other doesn't affect the method Roy and I speak of. The string still should ride the line that you are pulling on. I've made bows with 2" shorter bottom limbs and they come out with negative tillers but are balanced.
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This is a bow being tillered for 3 under shooting. The trees pull rope hooks on the bow string where the center of the middle finger will be when shooting the bow. Note the pull rope travels right down the black line on the wall. That bows limbs are bending exactly the same in sync. The bow doesn't move in the cradle as it's pulled. The tiller will be whatever the tiller is. Usually even or a little negative. Makes a very quiet, smooth and accurate shooting bow.
https://www.youtube.com/watch?v=LBi74lbXkRU
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BMorv, you got er down my friend. That's how inherently tuned and sweet shooting bows are made... perfectly behaved from the very first arrow, nocked exactly where planned from the beginning. Now that you know what a well designed and well balanced bow feels like, you're more confident in the flight and feel of that first shot, aye?
By the way fellas, I judge the tiller of all of my bows the same way.... self, backed, glass bows, etc.
I think pro bowyers, and most others, tiller their bows 'generically', with an ambiguous positive tiller, not because it's optimal, or right, but first of all, because it's easier for them. Additionally, they're playing it safe, knowing the archer can raise the nock point to 'tune' the bow.(I prefer to call it attempting to mask the imbalance they created). They play it safe with a positive tiller, because if the bottom limb was too weak, relatively speaking, the nock point couldn't be LOWERED below square to achieve good arrow flight since the arrow would come out low and hit the shelf.
So, if they're not willing or able to achieve dynamic balance relative to the archer's fulcrums, it's best for them to set the tiller slightly positive and let the archer try to make it work.
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Yep Bowjunkie, the bows tillered this way are dead in the hand, almost no vibration, and I really don't need a wrist guard when shooting them. It makes a big difference. Thanks for your explanations over the years on here for me to dig up and learn from :D
I laugh internally when I see someone post something like "you need a 1/4" positive tiller", not because I think they're wrong, but I'm thinking 'boy, if Bowjunkie reads this post you got some explaining to do'....
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Thanks for the Video Roy, Dont think I ever saw it done that way learn something every day.
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Lol. It's not like I'm on a crusade or anything. Well, not anymore. Roy broke me. :dunno: