Author Topic: Sinew backed Osage ... shoots better upside down! Any ideas?  (Read 818 times)

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Offline Tommy D

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Sinew backed Osage ... shoots better upside down! Any ideas?
« on: September 20, 2020, 08:14:29 am »
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!

Online Pat B

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #1 on: September 20, 2020, 08:52:08 am »
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.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline bassman

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #2 on: September 20, 2020, 10:22:41 am »
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.

Offline bradsmith2010

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #3 on: September 20, 2020, 11:27:47 am »
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,,

Offline Tommy D

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #4 on: September 20, 2020, 12:22:10 pm »





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.









« Last Edit: September 20, 2020, 12:29:32 pm by Tommy D »

Online Pat B

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #5 on: September 20, 2020, 01:02:30 pm »
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.
Make the most of all that comes and the least of all that goes!    Pat Brennan  Brevard, NC

Offline bradsmith2010

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #6 on: September 20, 2020, 01:09:50 pm »
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

Offline bentstick54

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #7 on: September 20, 2020, 02:56:15 pm »
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?

Offline willie

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #8 on: September 20, 2020, 03:24:40 pm »
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.
« Last Edit: September 20, 2020, 03:32:11 pm by willie »

Offline Tommy D

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #9 on: September 20, 2020, 04:14:51 pm »
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...



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 ...




« Last Edit: September 20, 2020, 04:50:27 pm by Tommy D »

Offline bradsmith2010

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #10 on: September 20, 2020, 04:36:38 pm »
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,,
« Last Edit: September 20, 2020, 04:44:58 pm by bradsmith2010 »

Offline bushboy

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #11 on: September 20, 2020, 04:41:39 pm »
Nocking an arrow to ensure proper hand placement might help in the consistency of the draw
Some like motorboats,I like kayaks,some like guns,I like bows,but not the wheelie type.

Offline Tommy D

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #12 on: September 20, 2020, 04:55:24 pm »
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.

Offline bradsmith2010

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #13 on: September 20, 2020, 05:08:10 pm »
  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,,
 
« Last Edit: September 21, 2020, 06:51:53 am by bradsmith2010 »

Offline bassman

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Re: Sinew backed Osage ... shoots better upside down! Any ideas?
« Reply #14 on: September 20, 2020, 06:12:11 pm »
I thought it was bolt on limbs. My bad.