Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on October 28, 2014, 03:32:42 pm
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When I'm trying no set tiller I'm supposed to pull to, say 16" and note the draw weight. Then pull an inch past that and then drop back to 16" and again note the draw weight. If it's less than the first time the bow is starting to take set. Then I'm supposed to stop and figure out what is causing the set. What am I looking for? If it's 40# the first time and 38# the second time will there be a noticeable bend/hinge somewhere? What if the bend looks even, what else could it be? I'm a bit puzzled here.
Thanks
Don
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I am sure someone with more experience can help better than I but I will take a shot at it. When tillering for myself I will draw until one of three things happen:
1. I hit my target weight.
2. I hit my target draw length (hopefully at my target weight).
3. The most common durring the tillering process, I see a flaw. Either a flat spot, hinge, or one limb bending more than the other.
If you are drawing and not noticing any problem areas try taking a picture of the tiller. It will allow you to take a closer look without leaving the bow under stress.
There is also a tool you can make out of a block of wood (I haven't made one yet and the name escapes me) but you can use it to run on the belly of the bow to help point out flat spots... Please someone help me out here with this one.
All of my bows so far have taken some set but not enough that I notice it on the tillering tree as I go. For me I notice it after I get to full draw and shoot it a few times. I try to go just over my target weight off the tree, so after shooting in and figuring a bit of set and loss of draw weight.
I hope some of this makes sense and that my method is not way off base.
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Low set tillering, not no set. That's impossible to pull off on a self bow.
Don I wouldn't play the game if I were you. Just build your bow the way you know how.
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maybe wood isnt 100% dry?
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Yep, keeping set to a minimum is a good goal, but you are gonna get some.
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Over thinking again, aren't I? :-[ :-[
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Big time
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maybe wood isnt 100% dry?
I live on the Island, nothing is ever 100% dry ;D
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My suggestion to LOW set tillering. Get your bow bending perfectly on the floor at about 12-18# heavy. Brace it very low and finish tillering the extra weight off. You'll take on very, very little set if the bow is laid out properly for the species used.
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My suggestion to LOW set tillering. Get your bow bending perfectly on the floor at about 12-18# heavy. Brace it very low and finish tillering the extra weight off. You'll take on very, very little set if the bow is laid out properly for the species used.
Excellent advice......I can believe it!
DBar
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DC, if the bow starts to drop a little late in the tiller say around 24" and the drops are small don't worry about it, thats about the best you can do. If the bow starts to drop early at 18" draw you need to find out why. Moisture? Not enough working limb? Bow is too narrow to for the draw weight expected? uneven tiller. No set tillering is the goal but you will seldom ever hit it. When you do it is fantasitc but don't be disappointed if you don't I seldom get past 24" without some loss starting to take place.
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The tool mentioned above is called a tillering gizmo, and there is a how-to on how to make one elsewhere on this site. I think it is a sticky in the how to section. Here is the link: http://www.primitivearcher.com/smf/index.php/topic,23134.0.html (http://www.primitivearcher.com/smf/index.php/topic,23134.0.html) I think it is helpful for us novice bowyers especially.
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If you have paralell limbs the gizmo will give you not enough bend in the outer limbs and too much in the inner limbs. It will likley take more set.
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When I'm trying no set tiller I'm supposed to pull to, say 16" and note the draw weight. Then pull an inch past that and then drop back to 16" and again note the draw weight. If it's less than the first time the bow is starting to take set. Then I'm supposed to stop and figure out what is causing the set. What am I looking for? If it's 40# the first time and 38# the second time will there be a noticeable bend/hinge somewhere? What if the bend looks even, what else could it be? I'm a bit puzzled here.
Thanks
Don
You are describing Badger's no hysteresis tiller that might be impossible. If you are tillering, it is natural for the draw weight to go down at a fixed draw length, as the tillering progress. Otherwise how are you going to arrive at your target draw weight at your target draw length?
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If you have paralell limbs the gizmo will give you not enough bend in the outer limbs and too much in the inner limbs. It will likley take more set.
Interesting. Is that because you are shooting for a more elliptical bend? Because the way I understand it, the gizmo indicates a constant curve, which would give you a perfect circle arc if you were to continue around. I can see how the elliptical shape might cause less set. What is the ideal curve for a bow? Can that question even have an answer?
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Jeff, it won't be perfect but generaly speaking a pyramid bow should be and arc of the circle and paralell limbs should be more elyptical, nothing extreme. Sometimes I use the gizmo early on and as I drop the weight I start getting the middle and out limbs bendig more. I mostly leave about the last 10" pretty stiff if I can get away with it.
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I have used a gizmo and liked it but most of my staves are too lumpy bumpy to use the gizmo.
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Over thinking again, aren't I? :-[ :-[
Don't sweat it. Some of us are born like that. I MUST KNOW!
But seriously, that method is for flight bows and others that are right at the edge odf what is possible. Strain your bow NO FURTHER than the final draw weight you want and you will have very little set.
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Interesting. What is the ideal curve for a bow? Can that question even have an answer?
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The answer to that is "Which bow?"
The basic basis of the basic base of the TBB's is essentially matching the right bow, wood, and front, and side profiles to the correct bend. The correct curve for a pyramid bow would be poor for an ELB.
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IMO if you get no set you probably overbuilt it quite a bit. There should be some.