Primitive Archer
Main Discussion Area => Bows => Topic started by: Knoll on September 27, 2014, 03:25:33 pm
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Making a bow with top limb 1" longer than bottom. Bow specs as follows:
Objective: 30-33# @ 26"
Length ttt: 60"
Length ntn: 59"
Riser is 8" long: Handle=4 & Fades=2
Width @ fades: 1 5/8"
Width @ tips: 1/2"
For both limbs, width is 1 5/8" until 12" from tip, then tapering to 1/2"
Glue-on recurve tips
Here's tiller pic. Brace height is 4 3/4", draw is 19", & DW=28#
(http://i884.photobucket.com/albums/ac48/knolltop314/100_2771.jpg)
Though the tips are at the same level, appears to me that left (shorter) limb is bending significantly more than right. If limbs were of equal length I'd definitely be making that right limb bend more. But, due to unequal limb lengths, I'm uncertain what/where I need to remove wood.
Help would be appreciated!
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well the bottom limb is shorter, and the are bent level or the same area of deflection, the short limb is gonna bend more to get to the same spot rrrright
take a yumi for example, although more drastic the top long limb bends less than the bottom, look's pretty good hows it feel shooting it
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Knoll, if I were you I would not hold that bow that long on the tiller board at fulldraw. I personally don't like that tillerboards, I use it mostly only for measureing the drawweight. Switch over to the mirror (a large one), watch yourself while drawing. You will notice this is something different. Watch if the limbs work where you want it to work
Here in this case you have an asym. bow, but the position on the board is like a sym. bow. The bow doesn't rest at the pivot point and the hook isn't there wherw the fingers pull the string.
Draw the bow and close your eyes, concentrate on where the bow wants to go. You will feel the weak limb (tends to go away from you). you also feel easily if a bow wants to twist (needing string alignment).
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I've made a few assymetrical bows lately, I like 'em. I like to go for a positive tiller when the top limb is longer, so the top limb ends up working a bit harder, which would mean a few scrapes off the right limb. But like Simson said, you only get a real sense of the FD when it's in your hand,not the tree.
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i agree the top should work more,, and not to leave it on the tree ,, using a pulley will help with string follow ect,, if you make the bottom work too hard it will take some set and you will loose your positive tiller
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Left limb is close, work an area 2-4" long starting 8" from your tip. Right limb is stiff as a board in the center 10".
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I would check the bow more like where you will be holding it, the string hook I would move more to the top and I would slide the bow over to the left a little more.
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... stiff as a board ...
;D
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Another thing to keep an eye out for is set. If the set of the limbs is roughly equal that is a good sign, a little more set in the top limb is also fine( up to3/8") A big discrepancy in set and it will tell you that the limb with more set is doing more than its fair share of work.
Hamish.
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Thanks all for the inputs.
Here she is ... 34# @ 26". After shooting about 50 arrows through it have 1 1/2" of set.
(http://i884.photobucket.com/albums/ac48/knolltop314/100_2774.jpg)
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Not to shabby sir.
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Came out great! Enjoy. Jawge
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Bow will be a gift for Carol's Uncle Harold. He'll soon be 90 years on this earth and is Carol's last living uncle.
Harold was a tournament shooter back in the day and I've enjoyed his story-telling of those days. While this stick is no match for the Hoyt bows he once shot, I hope he gets a special kick from it.
Thanks, fellas, again, for taking a gander at my efforts and pointing the way.
In a couple days will start next one ... 45 lbs. Working my way up to that Osage and that IPE board laying in the shop!
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looks great congrats