Primitive Archer
Main Discussion Area => Arrows => Topic started by: jeffp51 on April 21, 2016, 09:39:13 pm
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I set out with a goal to make a set of arrows matched to my bow--matching spine, weight, and length. I got a set of 4 garden stake bamboo arrows and matched them in spine to my best shooting fletched arrow. they match each other in tip weight, length and spine to within 1/1000 of an inch. --I have OCD sometimes, so sue me-- All of them rolled perfectly on a tabletop.
I have been reading up on bare shaft tuning, and watching lots of youtube videos. I shot these at about 5 yards. The first one hit like you see in the picture --extreme nock left/ point to the right. Classic weak spine, even though it was on the high side of the spine measured in my fletched arrows. I thought I was being conservative. Anyway, the first one hit and snapped on impact. I took the second one, cut it down by half an inch and shot. Still nock right. Cut off another half inch. this time it looked better, so I shot it again, and it snapped. Guess I get some more bamboo and start over with stiffer shafts. the tip was 133 grain--matching my good shooter, so I could cut it down some too, I guess.
Goal was a set of five. Started with 7. 2 were way underspined before I finished them, so they go to kids bows. two broke. Probably not much point continuing with the other two if they are going to have the same problem.
What do you all think? With fletchings all my arrows kinda shoot kinda okay. I would like to eliminate at least one problem so I can see what my bad form is causing. . .
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I am also wondering what effect brace hight will have on this. It doesn't feel either high or low to me, but what do I know?
Low brace height would cause nock left/ nock right?
High brace height would cause nock right/ nock left?
My mind can make brace height work either way, but it seems like low brace would be worse than high for shooting straight (on a non-center shot selfbow)
I should also mention I am right handed.
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Google "tuning longbows and recurves". You should come up with a document by O.L. Adcock. Read that through a few times - I found it to be helpful. I don't think 5 yards is far enough to let the arrow recover (without fletching). Also, I would use a bag of bags or some other softer target.
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I have a very similar problem, also garden stakes but not that straight. sort of "snakey".
I don't think the arrow will recover without fletching... at 20 yards they just went totally sideways 'weak spined', at 5 yards or so it entered at an angle. One hit sideways at 20 yards so hard it broke. And that was without heads :\ also thumb draw, seems harder to shoot an arrow so it doesn't act weak with thumb draw. Only with fletchings, I can actually hit targets at 20 yards..
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is that the bamboo, or how far we are from center shot on a self bow? Without fletchings, my understanding is it will never recover--there is no force to counteract the initial push of the string. Yet I see lots and lots of videos of fletchless arrows shooting pretty darn straight.
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is that the bamboo, or how far we are from center shot on a self bow? Without fletchings, my understanding is it will never recover--there is no force to counteract the initial push of the string. Yet I see lots and lots of videos of fletchless arrows shooting pretty darn straight.
saw a video of someone doing it with a turkish bow, not center shot. guess the spine and release have to be perfect.. and/or need good forward of center - that might allow a fletchless arrow to recover. if the center of mass is behind of center then of course it'd spin wildly. but a heavier point would reduce spine :\ ah
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I'd also like to know how centershot the bow is. my first guess is that you are getting a "false weak" reading, that is, your arrow is too stiff.
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I'd also like to know how centershot the bow is. my first guess is that you are getting a "false weak" reading, that is, your arrow is too stiff. Assuming you are right handed...
Arrow can land tail outside the bow if it's too stiff??
arrgh...
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if the arrow is way too stiff, the nock bounces off the handle and kicks out, producing a false weak reading
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I am right handed. the bow at the pass is 1 and 1/8" thick, but the alignment is shaded toward the shooting side. Hard to get a good measurement but between 1/4" and 3/8" offset from center.
Brace height is just over 7" measured from the back of the bow, and 6" from the belly.
Draw weight is 55# @ 29"
The arrows were spined at .447" of deflection and 32" long tip to tip. which on my chart makes them about 58#.
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hmm.. this extra info is good, but the proof is in the pudding as they say. I'd try the same arrow with double the tip weight and see what happens. May sound counter intuitive, but i'm stickin to it.
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I set out with a goal to make a set of arrows matched to my bow--matching spine, weight, and length. I got a set of 4 garden stake bamboo arrows and matched them in spine to my best shooting fletched arrow. they match each other in tip weight, length and spine to within 1/1000 of an inch. --I have OCD sometimes, so sue me-- All of them rolled perfectly on a tabletop.
I have been reading up on bare shaft tuning, and watching lots of youtube videos. I shot these at about 5 yards. The first one hit like you see in the picture --extreme nock left/ point to the right. Classic weak spine, even though it was on the high side of the spine measured in my fletched arrows. I thought I was being conservative. Anyway, the first one hit and snapped on impact. I took the second one, cut it down by half an inch and shot. Still nock right. Cut off another half inch. this time it looked better, so I shot it again, and it snapped. Guess I get some more bamboo and start over with stiffer shafts. the tip was 133 grain--matching my good shooter, so I could cut it down some too, I guess.
Goal was a set of five. Started with 7. 2 were way underspined before I finished them, so they go to kids bows. two broke. Probably not much point continuing with the other two if they are going to have the same problem.
What do you all think? With fletchings all my arrows kinda shoot kinda okay. I would like to eliminate at least one problem so I can see what my bad form is causing. . .
About 7 lines up you say "still nock right". Did you mean to say left? Puzzled.
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Arrow spine calculators are based on the assumption that your arrows are 28" over all length. You have to subtract 5# of spine for every inch over 28". With your 32" long arrows you must subtract 20# from your readings. So your arrows are not actually 58#, but rather 38#. This is why the are continually hitting nock left.
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DC they definitely hit all nock left. Sorry for the mix up.
Aaron, I figured (after the fact) that the length was probably the culprit. I was trying to match an arrow that already shoots well. I guess I way underestimated the effect of the fletchings.
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Yeah, I bet if you removed the fletching from your good arrow it would fly nock left too. Also bamboo is a little different than wood in it's behavior, the math and formulas can still be applied to help tune but I wouldn't expect a bamboo arrow and a wood arrow of the same specs to behave the same.
Loon, you're shooting thumb ring so when you read these tuning guides and such remember to reverse the right/left stuff...
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Also those spine calculators are based on the assumption that your points are 125 grain. A heavier point will also reduce spine, another contribution to your arrows being spined too weak.
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Sounds to me like false weak, as others stated. Your shaft is likely bouncing off the shelf kicking it way left.
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I do my bareshafting starting at 5 yards and moving out if I have a good arrow that's shooting well. Wood arrows tend to break if they hit too angled. Also what helps is a layered target with the layers going horizontally. It can allow the arrow to slide in on an angle a bit easier.
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The box I am shooting at is filled with horizontal layers of cardboard, Having been shot at so much, it is pretty soft at the moment.
I have two remaining bare shafts. I will try adding more weight to one tip first. That should answer the false weak theory.
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You can start your bare shaft test at half draw or less. See how it flies. Then start increasing your draw a bit at a time. If at any time the arrow goes nock left it's too limp. This method doesn't give any better results but you won't break arrows. Especially with a 55# bow.
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You can start your bare shaft test at half draw or less. See how it flies. Then start increasing your draw a bit at a time...
^^ this is very good information.
also, a good bamboo shaft should hold up to a fair amount of stress. the way those arrows fractured almost implies that the material is too brittle or that the integrity has been compromised in some way (excessive heat treating?) some of those garden stakes are too dry to begin without heat treating. some of the better quality ones can almost be bent into a "U" shape before they snap.
the arrow in the target failed at the node, it appears like a clean break with no long-running splinters. did you sand the nodes?
i'd be inclined to believe those particular shafts almost failed as they left the bow, so be careful with the remaining shafts from that package.
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I think this was a combination of things. A heavy(ish) bow, long arrows and heavy tips. All of these effectively reduce the spine and you end up with kindling. I'm not sure how many boo arrows Jeff has made but when I made my first ones any that broke, broke at a node. I think it takes a little experience to straighten the kink at the node without overstressing it. I think with a 55# bow and 32" arrows I would try a deflection of around .3-.35". I made a set of test arrows just for this purpose. Six unfletched arrows between 30 and 50# spine(.5-.8" def) 125 grain point. When I make a new bow I start with the heaviest first. If it hits nock right, I work my way down until it goes straight. I don't use them much now because most of my bows are in the low 40's and I know what spine works for them. It still changes a bit bow to bow.
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The nodes are sanded--never had one break at a sanded node before--but they were also from a batch of bamboo bought some time ago, and were noticeably dryier than other shafts I have worked, although I managed to straighten them all without scorching them. Just bought a whole bunch more last night for the "do-overs" These look greener and I hope they will be sturdier.
DC I have made close to 50 bamboo arrows at this point, and I do feel like I am getting better at the straightening part of the process. I think it is more the other things you mentioned that are causing the problem.
As for the false-weak theory--would not the arrow make a loud whacking sound as it hits the bow if it were actually strong and just being kicked wide? I don't recall hearing that last night, but I wasn't really listening for it either.
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I know people with much more smarts than me say to not sand nodes but when I started I found I had a bunch of nice shafts in the 50-70# range that I had no use for. I put them in my drill and spun it up while holding it against my belt sander. I just kept going until they were in the 40# range. They are beautiful and straight and (touch wood) none have broken. Between this and watching the Japanese Master video many, many times and seeing him cutting off the nodes and sanding a lot I just feel it's not that big a deal. Mind you, you have to get the shaft dead straight before you start to sand or you will get a thin spot.
I have also made about 50 or so arrows so we're in about the same spot on the learning curve.
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Just bought a whole bunch more last night for the "do-overs" These look greener and I hope they will be sturdier.
sounds better already ;)
you can always make one of these green ones with the same specs as your last batch, repeat the test.
good luck!
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Wait... did someone say thumbring.? How exactly are you shooting and off what side of the bow. .?
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Wait... did someone say thumbring.? How exactly are you shooting and off what side of the bow. .?
That would be Loon and me, Jeff is shooting normally.