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Main Boards => The Bowyer's Bench => Topic started by: Wolftrail on September 12, 2015, 07:13:00 PM
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I read on here somewhere that some bowyers are ok with a tiller of 3/8" .. Having said that how can the limb timing be spot on and how can the tiller be spot on..? I question this becasue most go by perfect tiller. And is negative tiller OK..?
:rolleyes:
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How one holds the bow (high heel, low heel) and grips the string (split finger, three under) will affect the balance of the limbs as they are drawn. Generally, the bottom limb should be a tad stronger for most shooters, in which case you'll get a positive tiller. This is because the bottom limb, when drawn in hand, is often (not always) made effctively shorter by the position of the bow hand's heel and the bottom limb tip therfore has a longer distance to travel to reach full drawn than the top limb. This is compounded by the fact that the string hand is drawing above the center point of the string.
Thus, positive tiller. Although this inequity is visible at brace and when drawn on the tree, it rectifies itself when the bow is drawn in the hand. Many bowyers, myself included, work the bow out to about 22-24" on the tillering tree and then finish it out by drawing the bow in the hand. That's because the tillering tree and string don't replicate the same forces at play when in hand. A "perfect" tiller on the tree will most often quickly deform in the hand. Hope that helps a bit. :)
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Exactly what I do "work the bow out to about 22-24" Then I shoot it in.. Yabutt, what about negative tiller.?
Thanks.
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I'm no bow doctor, but I can't think of any practical instances when negative tiller is desirable, UNLESS you were to stray from the accepted "norms" of bow design, bow hand grip, string release, arrow shelf placement, etc.
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"drawing the bow in the hand" and doing the mirror shot works ok if you take a photo then draw a straight line from tip to tip on the Computer. True enough you can see innacurate tiller in the mirror but that is just looking.
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4est, I tiller bows for equal limb timing and quite often they end up with a negative tiller. But since doing this limb timing process more and more, I have began slightly over building the top limb and that equates into an almost even tiller.
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You build mostly Wood bows Roy.? Realistically a wood bow will change in tiller over time will it not. It will sure take some set after a few years. I guess what I'm trying to say perfect/even tiller will stay for a while but not forever.
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Yes on wood bows. There is a far better chance of a bow with equal limb timing staying tillered than a bow that is not tillered correctly. But hey, that gives us an excuse to build another.. :)
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"I read on here somewhere that some bowyers are ok with a tiller of 3/8""
I part ways with the majority of bowyers when it comes to 'tiller measurements' and what they mean. I usually don't even measure it. I don't care what it is. I adjust limb strength so that the arrow nock leaves along a line perpendicular to the shelf/handle, relative to the archer's shooting idioms, and then the braced profile simply is what it is... I may not know the measurement, but I know it's RIGHT.
I guaranTEE those predetermined tiller measurements so many use as their bowbuilding and tuning beacons don't always mean what folks think they do.
That said, if I made a bow the way I do, and 3/8" positive tiller was the result, I would be "ok with it". BUT, it hasn't happened yet. The way I design the bows and harmonize the limbs relative to the archer, the tiller is usually even... give or take... sometimes a little negative, sometimes barely positive. Sometimes it depends on the naturally odd shapes or inherent differences within the staves.
I mimic my holds on the tree, tiller/time the limbs all the way to full draw on the tree, exercise it well there, and it's done. Go shoot it. No measurements, no mirrors, no windows, no pictures to study then head back to the shop to readjust. No guessing. Tiller virtually never shifts either because the limbs have been realizing even strain(relative to how it will be shot) since very early in the process.
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look i am really sorry about all the things i have said about you guys in Pa :notworthy:
looks like i need to come down there and learn a thing or two 'bout tillering.
it all makes absolute sense- and those criteria would be exactly the same applied to all bows, irrespective of their construction medium.
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Each bowyer has his own secret sauce, I imagine. For what it's worth (and that ain't much), I'll share mine. I work my bows on the tree with the cradle and string centered on the bow. Using a tillering gizmo, I get the limbs bending evening and symmetrically, exercising the snot out of the limbs with each change and never pulling past a good tiller/final draw weight/final draw length. When I get to about 22"-24" (depending on final drawn length) I begin to slightly weaken the top limb (GASP!) by gently scraping the entire limb evenly. I mark the entire belly of the limb with pencil scribbles to gauge this. I thereby achieve a slightly positive tiller that manifests itself as even tiller/timing as I work the final inches in the hand. I also find that shooting the bow several dozen times with a heavy arrow, beginning 4"-6" shy of the intended draw length, really helps cement things. That's because shooting imparts forces on the bow that a tillering tree alone can't reproduce.
I've not experienced any changes in tiller since adopting this method, so long as the bow has been stored/strung/shot properly and as intended.
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Whether tillered positive, even, or negative... when my bow is done, I know before the first arrow is released that I can set the nock point EXACTLY where I tillered it for, 3/8" to the bottom of the nock point, and fully expect the first arrow to fly perfectly. No porpoising. Inherently tuned(aside from arrow spine). No adjustment needed. These defining benefits are why we strive, or should, for perfect balance at full draw. Why not design/build it in from the get-go? Honestly, in the long run, it's easier.
Statically balanced to carry... Dynamically balanced with minimal shift to shoot... Such bows offer what all bowyers and archers seek. Roy has it and doesn't even fully know how he got it :^) But he's got it, so I'm content. It took me YEARS :deadhorse:
The only reason I would have to alter timing after I've taken a bow to the bales is if I did not place the handle/shelf exactly as I had planned/layed out... and that just doesn't happen :)
4est trekker, I agree with bits and pieces of what you said... the rest, I'm going to respectfully have to disagree with.
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A simple stick and string... who knew?
:knothead:
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Thanks guys, some really good insight and tips. I think that pretty well wraps it up. I know this subject has come up a 1000 times or more. I guess its ok to shed light on the issue the odd time. :rolleyes:
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All I have to add is that like Jeff, Roy, and 4est, I haven't seen the tiller change much if at all on a wooden bow that was tillered well to begin with. Good stuff here; lots to reflect on before I tiller my next one.
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Originally posted by Wolftrail:
You build mostly Wood bows Roy.? Realistically a wood bow will change in tiller over time will it not. It will sure take some set after a few years. I guess what I'm trying to say perfect/even tiller will stay for a while but not forever.
This is only true if the bow wasn't correctly designed for how it is being shot or the environment it's being used in. Or of course if it isn't looked after correctly.
I'd be devastated if all my wooden bows acted like that! In fact I don't think i'd even bother to make anymore!
The real problem is that to own and shoot wooden bows (without killing them) you need to really understand wood and bow design. To get to that point takes quite a bit of learning or a very good teacher and even better ears ;)
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Originally posted by fujimo:
look i am really sorry about all the things i have said about you guys in Pa :notworthy:
looks like i need to come down there and learn a thing or two 'bout tillering.
it all makes absolute sense- and those criteria would be exactly the same applied to all bows, irrespective of their construction medium.
the materials they are made from does make quite a big difference. Treating all bows ,irrespective of materials used, the same will lead to 'issues'!
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Not all wooden bows change tiller over time. Some do though, and there are reasons why.
You know how some bows are trained to bend by pulling the string from the center of the handle, and then shot by pulling the string 2" higher? That'll do it.
Tillering them to a predetermined tiller measurement which isnt exactly what it needs to be balanced with the archer's holds... can cause it to eventually shift as it's used.
Flipping bows end for end? Yep. That too.
Then of course stuff like unseen flaws or weakness inside the wood, poor tillering, abuse... leaving them strung, overdrawing them, letting someone else shoot them who grips or draws the bows differently, etc.
I'm with Mike though, design and build them well, take care of them, and they'll hold tiller and resilience for a long time and a lot of arrows.
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You know how some bows are trained to bend by pulling the string from the center of the handle, and then shot by pulling the string 2" higher? That'll do it.
It sure will do it..
Flipping bows end for end? Yep. That too.
I never could understand the logic to that maneuver. Lay the bow out properly first and go with it as you intended it to be built.
I know guys all have their own secret recipe for building bows, and I'm sure they make a decent bow. But nothing makes a better shooting wooden bow than timing the limbs to bend in harmony. And it all starts with the layout preparations. Most important part is knowing where the arrow rest is going to be and placing the pull rope on the bow string where the center of your middle finger will be, below our predetermined arrow nock point. Jeff and I use a predetermined 3/8th" from arrow shelf to bottom of nock point. Then that 3/8th" measurement above the arrow shelf is where our nocking point is placed on the string when we setup the bow for shooting.
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Maybe you just worded that wrong old timer, but I don't measure 3/8" from the shelf to the bottom of the arrow nock.... I measure 3/8" to the bottom of the nock point.
To the bottom of the arrow nock would be 1/8".
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Duh, it's early.. I had it right in the sentence before it.. :) :)
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I opened up a can of worms. On the other end of the scale we have arrows and spine, if the arrows are all spined within a given weight why adjust arrows for the bows.
My arrows are 40-45# my bows are 35-44#. In a perfect world everything seems ok, when a bad shot is made I do blame my shooting form. Some guys keep blaming their equipment. :knothead:
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But I don't miss.... :laughing:
You didn't open up a can of worms at all... We all just voice our opinions as to how we do it. If it helps someone, then great. If they care to ignore it, then that's fine too...
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I agree with 4est on most of his experience. After a long of making self and sinew backed bows (hundreds) I would encourage you to use the tiller tree and tillering string to tune the limbs so that there is not a gross over tiller of either limb. Then put a string on it. Nothing can duplicate a bow that is strung. Then work each limb, exercising the bow between wood removal until you get a good (not perfect) tiller. Then shoot the bow, always underdraw it until the tiller is very close to where you want it. No exercise of the bow duplicates shooting it. Then to final tiller your bow remember this if nothing else "tiller it a little and shoot it a lot". These are just some basic tips. Experience will teach you the rest.
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Yeah folks do it that way, and if they try, but can't mimic their shooting particulars on the tree, it may be their best option. But I'm more of a "tiller it fully and accurately... then shoot it." kinda guy. I'm not shooting a bow until the tiller and dynamic balance is as perfect as I can get it all the way to full draw. And then my first shot is at full draw like I mean it.
I must be replicating my shooting idioms pretty well on the tree because after the bows are brought to full draw on the tree and taken to the butts, I don't have to change anything to suit me or the arrow, and the bows don't have to change tiller to conform to my shooting.
Roy, I wish you'd quit dragging me into these things :rolleyes:
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Some folks like our method, Jeff.. :)
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i sure do- and the proof is in the pudding- they say- i have an "ol fart" bow- trilam- it shoots 174fps with a hunting weight arrow- i think it was 11gpp- cant remember exactly- its 50 lbs at my looong draw- its smooth- super smooth- has no stack- no shock, and has some real snap to it.
i will certainly be using this method on my bows in the future.
what i was meaning mike- that irrespective of construction- this tillering system should be able to be used on all bows? right?
on a glass bow- one hopes thats its just a final tweaking- but surely the same theory and dynamics apply to all "bowology"- limb timing and harmony?
certainly not saying that i would treat all bows the same- my self bows are strung for the bare minimum time- as are all my bows in fact.
in fact coming from a self/ wooden bow starting point, i am inclined to treat my glass bows with the same care and attention to detail as i do my wooden bows :dunno: hope thats ok- not screwing things up??
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Me too, Wayne. I build my glass bows similarly... and yep, they go on the same tillering tree as my selfbows, backed bows, and are held to the same standards.
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Somewhere on the forum this Information needs to be posted at the top of the page.
For all styles of holding (grip) of the bow and split/3 under/or thumb ring.
Good Info
I love you guy's :rolleyes:
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What I have done for the last 4 bows is tiller to about 24-25" then I shoot it in. Why..? because it works for me. They are over stressed slightly I also leave them braced for 3-4 hours after shooting them.
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Originally posted by mikkekeswick:
Originally posted by Wolftrail:
You build mostly Wood bows Roy.? Realistically a wood bow will change in tiller over time will it not. It will sure take some set after a few years. I guess what I'm trying to say perfect/even tiller will stay for a while but not forever.
This is only true if the bow wasn't correctly designed for how it is being shot or the environment it's being used in. Or of course if it isn't looked after correctly.
I'd be devastated if all my wooden bows acted like that! In fact I don't think i'd even bother to make anymore!
The real problem is that to own and shoot wooden bows (without killing them) you need to really understand wood and bow design. To get to that point takes quite a bit of learning or a very good teacher and even better ears ;) [/b]
I am making an assumption based on woods Demise.
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I use this way because the only thing touching (grip) the bow is the crotch of my thumb and index finger
:)
http://www.buildyourownbow.com/the-truth-about-bow-balance/
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That is a good article, and covers the basics of what I'm talking about in reference to laying out the bow with respect to string hold, although I did find a few things I disagree with in the article.
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I agree junkie. The way I look at it is not everything is written in stone....
Did you see the televised deal on the bones they found in south Africa.? :rolleyes:
I have found fossils 2-3 hundred feet above sea level. :confused:
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So even that which IS written in stone....
:dunno: