Primitive Archer
Main Discussion Area => Bows => Topic started by: Don Case on December 09, 2013, 08:40:42 pm
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If I'm tillering and everything seems to be going OK, I've got the bow on the tree and I'm pulling. I've got to this point and I'm afraid it's going to break if I bend it just a little more. How do I get past this? Will the stave tell me something?
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If everything looks right and there's no reason besides fear to not pull, then keep going. It will or it won't.
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If it feels tight and you at your weight scrape it some more
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It will tell you a lot of things. If you have a scale attached to it it will tell you how much force it takes to bend it. It will tell you if it is starting to take set. It will tell you if it is bending evenly. What else do you need to know?
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I have a really thick skull so I dont get this issue :D
Pull it until it works or blows up. i have a few upper limbs lodged somewhere up there on the ol' cranium, doesnt hurt much!
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It will tell you a lot of things. If you have a scale attached to it it will tell you how much force it takes to bend it. It will tell you if it is starting to take set. It will tell you if it is bending evenly. What else do you need to know?
If it will bend any more? :D
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OK joking aside, I guess I need a better scale. I'm using a 50# fish scale that only has about 3" of travel. I calibrated it so it's pretty accurate but 1# is about 1/32" so it's hard to see. I bought a new pulley for the tree but I think the sheave is egg-shaped. Tomorrow I'll go to a marine store and get a ballbearing block. I'm not sure what to do about the scale, I'll check oround.
Thanks
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You just have to get past this. I've had bows come apart on the tree for no apparent reason. That's why I use a tree until I completely trust the bow so no one gets hurt. When they break (and if you build enough bows you will break some) you dust yourself off and get right back in the saddle.
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If it breaks start another. I don't have any cojones. I am of Greek ancestry. I have adhethia. :) Jawge
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Seriously, if you knew how much mass you needed for the design you are building you would aslo have a much better idea of what to safely expect from a bow in any particular design. It will also tell you if it is too wet or too dry. The more you know about your design, your wood and your ability the more confidence you will have while building a bow. If I have my doubts bout a bow I know exactly why I have my doubts cause I did my homework and I know what I can expect. I did it over a period of years though so don't be too hard on yourself.
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Don, are you using a tillering stick. If yes, then you do have adhethia. Read Gordon's post again. Jawge
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Don, you have the same questions that every newcomer has. If I were starting over today I would have kept records on my bows. Just going thrugh the motions of writing it down drills it into your head to some extent even if you never go back and look at your records.
Type of wood
Length, draw weight, style, width, mass weight,
Outcome- finished, amount of set, starting position of limb tips. Broken, what stage it broke, Your opinion of tiller when it broke. Anything else you might think of. You can cme here and talk about them and get solid answers and help.
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Don,
Can you post some pics of your progress? Would love to see where your at with the tiller...
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It can be nerve wracking... muttering 'Break... break...break' under your breath can help minimise the shock if it does go ;D.
It's an odd thing some bows I feel I could just draw back for ever, some make me nervous as hell.
Just check there is no one creeping up behind you with a paper bag to burst ::)
Del
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I broke one on the tree while teaching a class two years ago and I'm still nervous sometimes. You have to know it will happen. I ease into it now more than before.
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Just pull it until it explodes! You'll never learn anything if you don't break wood. Besides, big splinters make a really cool whirring noise as they zip by your head.
When in doubt, wear a helmet!
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I once pulled a hazel deliberately further than sensible.
I squeezed my eyes, ears and nostrils, awaiting the blow...
The damn thing just got soft and folded :P
The mass formula really is a big help in cases like this (ie when you're not sure if a bow can take some more) and I'd like to thank badger for working so hard to spread it in the community. ;D It would have taken me many years to work this out by sheer experience.
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You might be experiencing stack. Beginners typically get mid and outer limbs bending, but dont seem to get the inner limb/fade area working. Basically, whip-tillered bows have higher string angles, which equates to stack. If it feels like it is hitting a wall, check your inner limbs and see if you might need to get them working more. Pulling it further after it is really stacking, is just going to cause lots of set.
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I guess if you are on a "long string" the bow is going to stack sooner, right? So maybe shortening the string may help?
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Yup. How long is your long string? It should be only long enough.
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I just wanted to take a quick look to see how stiff it was so I just grabbed the nearest string. It's a couple inches too long. I'll shorten it. I also got a new block for the bottom of my tillering pole. The old one had a 1" sheave and the new one is 2". Makes a big difference. It's also a much better block which helps. While I was at Canadian Tire I got a luggage scale. It goes to 70# which is more than I will use. It has a 3" dial so I can see it. It cost $7. I'll test the calibration tomorrow.
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Long string: 8)
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That's kinda infinite string isn't it? Is that your 2 piece?
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Get a bigger pulley Don. If your hands feel less weight your mind wont try to scare you. Sounds crazy, but its real.
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Yea, its the TD. I was actually thinking about you Don when I was working this because I could see I was going to have to do some bending, reflexing, decrowning, and backing of this OS bow and thought it might help answer some of your earlier questions.
These are two different billets of OS. One is flat, bumpy, and snakey and the other is smooth and crowned. The crowned limb has a lever that is leaning to the side and causing the string to be just off center. So that will need correcting.
The flat limb has some drying checks and a deflex near the lever fade. So that will need correcting. I wasn't sure but it looked like one drying check was moving toward the edge as I was tillering. This pushed me to make the decision to back that working part of the limb and cover that check.
And so I'd have to decrown the other limb and do the same. (which I had desperately been wanting to do from the beginning).
Pics are lousy as usual but you can see the check moving to the edge, the bent lever (corrected it last night, came out good), the decrowned limb (decrowned only the working part). Today I'll begin backing and/or reflexing that one outer limb.......
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.
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I guess I'm missing the point here. I realize your previous scale was a bit sketchy, but, assuming you have a good scale, you would never exceed the target draw weight. If you haven't reached the target draw length at that weight, you have more reducing to do.
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The new scale and pulley have made quite a difference. Now I just have to man up and pull.
Thanks for al the input.
Don