Primitive Archer
Main Discussion Area => Bows => Topic started by: Del the cat on February 19, 2021, 10:39:12 am
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I got into a silly discussion with some bloke who was trying to school me with physics 101.
He didn't understand that ... well watch the video. Hopefully it might amuse (appologies for wasting your time if it doesn't)
https://www.youtube.com/watch?v=Q1VUSwmWxrs (https://www.youtube.com/watch?v=Q1VUSwmWxrs)
Del
PS. That's pt2... I'd done a first video that looked at what happens when you draw an untapered slat from centre and the off centre:-
https://www.youtube.com/watch?v=HXBHC82NDFs (https://www.youtube.com/watch?v=HXBHC82NDFs)
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Thanks for taking the time to do that Del. Just as a point of note, Yumi limbs are quite a bit different in length, yes, but they're also very, very different in their side profile in relation to each other, and to the handle. When you look at an unstrung Yumi, imagine the handle vertical or straight up and down in your hand, and then take not of the reflex in each limb and their tips location in relation to the handle. I think there's more about that design related to balance and tiller than we realize.
I've been trying to understand all the ins and outs of this limb balance and timing stuff and have also made test bows and equipment and recently altered my tillering tree, again. I'm not going to worry about the Yumi though until I get the easy ones completely figured out ;)
As far as balance while moving the bow left or right on the tillering tree, as long as you pull down on the string from directly below the pivot/fulcrum point of the bow, it doesn't balance too badly. It's when the fulcrums on bow and string diverge, like when we move the string hand up so we can shoot the arrow from above the bow hand.... that's when imbalance occurs and the bow really tilts on the tree... and in the hand... unless we've made provisions in relative limb strengths.
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This guy did something similar with some of the same results you had. What I don't like about this one is that he only assumed what it would take to balance the bow in those instances where imbalance occurred. He never actually did it... never balanced it by changing the tiller, and so, missed his big moment. He assumed conventional wisdom was enough. I've found it often isn't.
http://buildyourownbow.com/the-truth-about-bow-balance/
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Dances, your the reason I changed my point of draw on my tiller tree in the final inches so my bow would balance in my hand. I didn't do that on my first bow and hated how it felt drawing it.
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Good for you Allyn. :OK
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I watched the video , it was information. I hope you feel better now getting it off your chest. ;D
Reminds me of a years long argument I had withy brother. I'm 6ft 5, he is around 6ft. I always beat him arm wrestling and he said it was because my arms were longer. I kept arguing with him that the opposite was true. His shorter arms were grabbing a longer lever and he had the advantage. In addition, i had to stretch my arm out to reach down to his lower arm, losing power myself . He fancies himself smart in these matters and didn't admit I was right until I finally sent literature from the arm wrestling federation...then I felt better!
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Isn't a Yumi bow tillered as 3 separate bows?
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Isn't a Yumi bow tillered as 3 separate bows?
I've no idea!
The problem I was having was with people who also had no idea, but thought they understood it all ::)
I'm sure you've met the type ;D
Del
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...just not on this forum. >:D :o ;D >:D
Your explanation is enlightening, Del. Thanks
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Isn't a Yumi bow tillered as 3 separate bows?
I've no idea!
The problem I was having was with people who also had no idea, but thought they understood it all ::)
I'm sure you've met the type ;D
Del
No. You can't separate it like that. I'm sure some people could try to convince you of it though.
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As far as balance as long as it settles properly in the hand than it should be just fine.
That’s kind of the way I tiller a wobbly stave. If it’s not balancing right ( Bc of a stronger/weaker limb) it gives me some insight on where on either side of the meridian to look for the side that needs some more give.
p.s. added another sub for ya 🤫😉
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I just noticed that on the Fletchers Corner (aka the German bow-making forum)
the winner of this year's Sapling Bow Tournament was with a Yumi design made from Spindle (Euonymus europaeus)
presentation:
https://fletchers-corner.de/viewtopic.php?f=81&t=32090#p574419
and building thread:
https://fletchers-corner.de/viewtopic.php?f=81&t=32071
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Spindle is cool wood :)
Anybody who has a chance to get some shouldn't miss the chance.
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how do you tiller a yumi bow then? im intrigued lol
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Spindle is cool wood :)
Anybody who has a chance to get some shouldn't miss the chance.
I recently found a patch of it growing wild here. What is it like?