Primitive Archer
Main Discussion Area => Bows => Topic started by: Tommy D on September 20, 2020, 08:14:29 am
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I dug out an old take down sinew backed Osage Self bow that I made about 15 years ago. It had some snakeyness to it but nothing extreme. I never quite fully finished it because it has this strange quirk where I cannot get an arrow to fly consistently off the “shelf” the correct way the bow was built. If however, I turn the bow around and I shoot it upside down the arrows fly beautifully, even though they look like the have much more paradox to deal with. I have tried a variety of spine weights etc and cannot tune any arrows to the bow of used the correct way around...
Any ideas if a bow can have some sort of strange lateral movement on the string as it is released that might cause this?
I could just shoot it upside down but am curious about this phenomenon!
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My first thought is to shoot it up side down. Apparently that's the way it wants to be shot.
Saying that, show us pics of the back profile, braced, unbraced and you holding at full draw.
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If your limb bolts holes match up switch the limbs top to bottom, and bottom to top ,and see how it shoots. Nothing to lose.
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yes,, sometimes the alignment is not as it appears,,,but the arrow is telling you the truth,,can you redo the handle wrap and shoot it the way it likes,, pictures please,,
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(https://i.imgur.com/CU2o09M.jpg)
(https://i.imgur.com/9Jk0rDR.jpg)
(https://i.imgur.com/SijVZru.jpg)
(https://i.imgur.com/SijVZru.jpg)
Ok so unbraced, braced, full draw right way round and upside down. Can see I probably should have more limb moving outer third. I have toyed with the idea of taking the sinew off and heat treating the belly and putting it in a bit of recurve at the tips. I built the bow under the watchful and very generous eye of Ted Fry at Raptor archery who I got to know through a mutual friend, when I was very new to bow building, but I added the sinew a couple of years later and attempted some recurve in the tips. I have some more sinew lying around and I think I could do a better job now. So, I am not against a re-work.
Below I have attempted some pics of the arrow and how much more it sticks out when placed on the non-shelf side.
I guess it’s worth trying a much lighter spined arrow? But the shots of the shelf all seem to come off the bow nock left already. And they fly like darts with the bow upside down.
(https://i.imgur.com/QH2lkgr.jpg)
(https://i.imgur.com/3S5q1Xk.jpg)
(https://i.imgur.com/HrhWiLp.jpg)
(https://i.imgur.com/B7TEryV.jpg)
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The direction the arrow points at brace doesn't matter if the arrows are properly spined. At full drawn the arrow will be pointing at the target.
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ok looks like it should shoot like you made it,,
what spine arrows are your shooting now,,
maybe they are too light, and when you shoot it off the wrong side they are the right spine for the increased paradox,, I would try a heavier spine and see what it does,,
the profile shows me its probably shooting harder than you think and could use heavier spine arrow,, me thinks its the arrow not the bow
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In the next to the last photo it looks like the string is tracking way right on both limbs? Could this be torquing things in any way?
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this might be a long shot, but if you draw it like you do in when actually shooting an arrow, (do you shoot with an open palm and the force against the heel of your palm like I see in the top pics?)
try it with each limb up, and see if you can detect a very slight rotation of the bow handle when you draw it.
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this might be a long shot, but if you draw it like you do in when actually shooting an arrow, (do you shoot with an open palm and the force against the heel of your palm like I see in the top pics?)
try it with each limb up, and see if you can detect a very slight rotation of the bow handle when you draw it.
Willie I made a Gif from a video I made earlier shooting the bow the wrong way round. You can see the arrow seems to clear the shelf nicely. It also kinda looks like the string wants to head to the left. It’s dark now will try and do the same tomorrow with bow the other way round...
(https://media1.giphy.com/media/eF4gIOSPWIdYXBCIip/giphy.gif?cid=4d1e4f298a82906fc4f733cd05cdba72ef7254fb34056f96&rid=giphy.gif)
Am also posting upside down and then right way round full draw pics again as I think I posted two right way round ones earlier ...
(https://i.imgur.com/P4kvvBP.jpg)
(https://i.imgur.com/SijVZru.jpg)
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in the video,, you are not pulling the arrow very far,, that is going to effect spine,
it does look like to me,,if the arrow was the correct spine the bow would shoot,,
if you are drawing the arrow shorter,, just experiment cutting it shorter and shorter until it shoots,,
if you are not drawing the bow very far,, then the arrow might need to be spined lighter to match the reduced draw weight,,,its hard to tell from the video, but it should come off alot smoother than that, I think,,but I still think it is the arrow not the bow,,as
please tell me the spine arrow in the video,, and how far you are drawing the bow now... and what the poundage would be at that draw
I can probably tell you an arrow that should shoot well,, most of my experience is with osage an osage sinew bows,,they are usually forgiving in what spine they will shoot,,
you noted its coming of the rest well,, that may be so,, but the way the arrow is wobbling down range indicates some adjustments needed,,but nothing serious really,, just some tuning of arrow and brace ,, should make it shoot great,,
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Nocking an arrow to ensure proper hand placement might help in the consistency of the draw
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in the video,, you are not pulling the arrow very far,, that is going to effect spine,
it does look like to me,,if the arrow was the correct spine the bow would shoot,,
if you are drawing the arrow shorter,, just experiment cutting it shorter and shorter until it shoots,,
if you are not drawing the bow very far,, then the arrow might need to be spined lighter to match the reduced draw weight,,,its hard to tell from the video, but it should come off alot smoother than that, I think,,but I still think it is the arrow not the bow,,as
please tell me the spine arrow in the video,, and how far you are drawing the bow now... and what the poundage would be at that draw
I can probably tell you an arrow that should shoot well,, most of my experience is with osage an osage sinew bows,,they are usually forgiving in what spine they will shoot,,
you noted its coming of the rest well,, that may be so,, but the way the arrow is wobbling down range indicates some adjustments needed,,but nothing serious really,, just some tuning of arrow and brace ,, should make it shoot great,,
My draw is about 27 inches. Arrow is a full length Trad lite Tapered Carbon arrow so it looks like a short draw. Bow is 65# at that draw. I can obviously cut the shaft to increase spine but I have some bamboo shafts that I may play with first. Thanks for advise.
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ok I cant advise with carbon arrow,,it still does not look like you drew to 27 inches,(hard to tell on video) please mark with tape and draw to that,
what is the spine of the arrow,, can you translate to what a wood spine would be,,
if it was a wood arrow,, it would shoot a 70# spine full length arrow..
I think you really not going to be able to tell what the bow is doing till you get some properly spined wood arrows, ,or the bamboo like you said, its easy for me to say,, I have so many arrows from years past, I can just try things till I see what will work,,thats a huge advantage,, I do shoot some arrows that are nearly full length in some bows,, but not all,,
there might be a carbon that will shoot well,, I just have no experience with them,,
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I thought it was bolt on limbs. My bad.
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My advise is to stop shooting your bow upside down! The true upper but lower when upside down limb is bending too hard. You will induce more unecessary set by doing this.
If it were me I would rework it to bend more in the outer limbs.
Your issues are almost certainly arrow spine.
you can 'cheat' spine if you have some loooong boo shafts :) Make them 40+" and you just have to have them stiff enough. This is why a lot of true primitive arrows are longer than the drawlength. As you use arrows closer and closer to your drawlength spine, tuning etc becomes much more important.
Arrows can bend the brain some times :)
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good advice (SH)
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Tommy, check your alignment...This may help?
http://www.primitivearcher.com/smf/index.php/topic,63133.0.html
Make sure, absolutely sure you have the right spine on your arrows...You look under spined in the video from my computer...
Way to much oscillation there...Deflection looks beyond maxed out right at release...Broadheads would magnify this flight into a possible curve ball...
Don
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Thanks everyone. I have started with a 78# bamboo Bare shaft 32 inches and a 160 grain point. It’s coming off very nock left. Going to slowly shorten it till she comes off straight. Beginning to think even those full length carbons are also weak spined and I’ve been going the wrong way to fix the problem. I think they are about 65 spine equivalent. Will keep you posted.
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thanks Tommy,, looking forward to seeing it shoot great for you,, I dont do alot of bare shafting,, so if you getting it shooting with some feathers, you can always fine tune with bare shafting too,,dont worry it gonna shoot,,
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I have had to flip the bow around to get good arrow flight on occasion. These days I make the limbs the same size and do not cut in a shelf expressly because of that. Jawge
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I have had to flip the bow around to get good arrow flight on occasion. These days I make the limbs the same size and do not cut in a shelf expressly because of that. Jawge
I believe you! I started with a bare shaft bamboo arrow at 65# spine and it was coming off the bow nock left. I have shortened it and shortened it. I thought I was getting somewhere. It even went nock right sometimes when I shortened it enough. But no matter what I do it comes off the bow nock high. I have moved the nocking point ridiculously high and low and it still comes off the bow mostly nock left and high. I have tried three fingers under and Mediterranean. It doesn’t seem to matter. And none of the shots are consistent.
I flip the bow around and every arrow, carbon, long bamboo, short bamboo, high foc, low foc seems to fly like a dart. I just don’t get it! But it is just so... I thought I was going mad ... but I’ve truly tried it all...
One of the quirks of self bows I guess!
I think I am going to stop over thinking this!
I am going to take Bownarra’s advice and get my outer limbs bending a bit more - but beyond that if she wants to shoot upside down I am just going to accept it!
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You are in the Southern Hemisphere aren't you? ;D
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... you think it could be the Coriolis effect...
;D ;D ;D
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ok just a long shot,, please try putting more pressure on your top finger,,
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As in draw the string back with more pressure on the top finger... or push the top finger more against the arrow?
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draw the sting back with more pressure on top finger and less on third finger,,