Primitive Archer
Main Discussion Area => Bows => Topic started by: pierce_schmeichel on October 06, 2024, 12:47:14 pm
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Billy from Primitive Pathways, came out with a new movie and he had some piaute bow fragments. They had a strange V notch at the tip. Billy said he thinks it was there to wrap the sinew around the tip and I don't think he is wrong at all. In fact I think he is very much correct, but I think it may have also served another purpose. A string groove that you can wrap the string around! I have done some testing and it has a lot of benefits actually. You are able to reduce the weight at the tips significantly, it wears less on the string, and you can leave the string tied onto the bow from both ends.
Here is the bow I tested on, before I changed the tips to the piaute v notch, I had just normal side string socks. It was 46" ntn and 40lbs at 23" draw. It flung a 400 grain arrow 130fps, not awefil but not great either. Then I cut the tips off and did the piaute style v tip notch and it was still 46" ntn and 40lbs at 23" draw, but now it flung a 400 grain arrow 150fps! A major increase in speed. So if somehow that is not what it was for, i found a new way (new to me at least) to string a bow.
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Here is a screen shot of the bow fragments and a picture of how i string it and then a picture of how i unbrace the bow and can still have the string tied on both ends
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That’s pretty cool, never seen that done before, thanks for sharing. May give that a try. Pappy
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Well that’s neat. I may also have to give that a try.
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that's something really interesting! kind of make me think to brush nocks on steroids
It has the potential to use the true FULL length of the bow
Leaving the string always knotted is also another benefit
I wonder if stronger tips are needed
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that's something really interesting! kind of make me think to brush nocks on steroids
It has the potential to use the true FULL length of the bow
Leaving the string always knotted is also another benefit
I wonder if stronger tips are needed
Yes you definitely need to wrap sinew just below the tip so it doesn't split the bow upon the release of an arrow. I had that happen on one of my tests but the sinew holds it together great!
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Really interesting.
By the way beautiful full draw
Bjrogg
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I love it when I check in for the heck of it just to skim the forums and stumble into a gem like this thread. Looking forward to doing this soon. Thanks.
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Hey thanks everyone!! And let me know what you guys find out in your own tests. The more data the better!! Also I found you can make the tips thinner too.. reducing limb weight even more. The tips only have to really be about a couple millimeters wider than the string. Then you can put rather small string groves down to hold the loop. As the string wraps from the back to the front it has some mechanical advantage and does not need as much to hold it down.
One could probably get the limb tips 1/4" to 5/16" thick, depending on your strings thickness.. if you were trying to push the performance even more that is. I don't know how historically accurate that would necessarily be.. but it would work.
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one thing that puzzles me is the pronounced V notch shape of the pajute bow fragments
It seems to me that a U shape would be more appropriate and would reduce the risk of the tip splitting
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one thing that puzzles me is the pronounced V notch shape of the pajute bow fragments
It seems to me that a U shape would be more appropriate and would reduce the risk of the tip splitting
I was thinking that exact same thing, but if you're using stone tools making a U notch is a little more tricky, definitely doable. When you wrap sinew inside the v notch it mellows out that V more into a U shape and then when you wrap the tip laterally with sinew it doesn't have a chance to break.
The sinew wrapped at the tip laterally also has a second purpose. It gives the string loops a little more to grip onto. Kind of like a traditional sinew nock.
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How would one go about using this with a synthetic string? It seems to me the loops can't be served if they need to bend back on themselves to come back over the tips to the belly side.
Mark
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How would one go about using this with a synthetic string? It seems to me the loops can't be served if they need to bend back on themselves to come back over the tips to the belly side.
Mark
If you're doing an endless loop string you could take the loops and flip them in on themselves to turn them into slip knots. I'll post some examples of what I mean(forgive the ugly polyester sting haha, it's all I had on me)
And regarding the serving I'm not exactly sure but it should hold up. I think if you served it normally you would still be fine. Maybe I'm wrong cuz I'm not a huge expert on synthetic stings but the compound bows I've looked at have aggressive curves and bends like that in them and they seem to hold up fine.
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What puzzles me is the physics behind it. I can't see how you are getting 20 fps more not that I don't believe you, but the difference in speed could only be marginal in my mind. Guess I will have to try it to prove it to myself.
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I was able to remove a lot of mass from the width of the bow as well. Since the singular V notch only really needs to be about as wide as your strings diameter, you can remove a loooooot of mass. You can get the tips as narrow as a pencil. I didn't get them that thin on this bow, but you definitely can.
The string also may be experiencing less friction due to its singular contact point at the tips. Maybe not on that one idk just a thought.
Another note, I could see this string nock style benefiting heavier woods like osage because reducing mass is more crucial on those heavy woods.
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I just cut string nocks, and a new string for a 50 inch sinew backed hickory bow which shoots about the same velocity as yours before the V string grooves. Left the bow as is. Tomorrow I will shoot both strings on the bow through a chrony, and compare results. If I can gain 20 fps, or even 10 fps I will be elated. IT is worthe a shot. No pun intended. Thanks
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Saturday 8 fifteen AM 38 degrees. Pulling the bow as consistent as I could to 25 inches of draw the original looped string shot 135 fps through the chrony for an average of 10 shots. With the V nocks the bow shot through the chrony at 150 fps average for 10 shots. Even though it is not a scientific test it is clear to me that there was a significant improvement with the end results in terms of velocity. I will be trying it on other bows in the future. The tests were done with a 10 strand B55 string. Thanks for the V nock theory. :OK Bob
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Saturday 8 fifteen AM 38 degrees. Pulling the bow as consistent as I could to 25 inches of draw the original looped string shot 135 fps through the chrony for an average of 10 shots. With the V nocks the bow shot through the chrony at 150 fps average for 10 shots.
That's impressive. Same brace height on both setups? Pics of the bow and nock details?
Mark
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Same type of 10 strand B55 string, and the same brace on both strings. Sorry I don't know how to post pics. My wife did all that, but now in a home with dementia. MM give it a shot at one of your bows that you use to experiment. I have no explanation for the end results, but that was my honest experience with the test. I have some string follow bows that I will be testing in the future ,and post results.
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My opinion about this significant increase is that now the limbs are tecnically longer but should move at the same speed as before (since they have pretty much the same mass as before) so the tips have to move a longer distance then before in the same time, so they must move faster. This means the string and the arrow have to move faster too! correct me if I'm wrong but to me this seems the only logical explaination.
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Zugal... I shot first with the looped string in the original nock grooves. Then tried cutting a v notch in the existing tips which were to small, and split when I strung, and shot the bow, so I cut the tips off and ,V grooved down to sinew I had on the limb tips which would be nearly the same length as the looped string. ???
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Wow, that's amazing Bob!! And yeah I still think it's the mass and the reduced friction of the string on the groves, but the extra leverage hypothesis is a great one and I think you're onto something Zugul!
Also Bob did you reduce width material on the bow at all? If you haven't yet and you did you would see even more improvements!
What we need to find out is how this nock style affects the velocity of different length bows and different material bows. In being consistent, we would want the ntn length to be the same for each test, for the individual bows. For example, if you have a 55" ntn bow with side notches, collect your data and then convert it over to a 55" ntn v notch.
I am curious how this would affect woods like osage. My thoughts are that since it is a wood with a greater mass, one may see more dramatic improvements. I might be wrong though, it could very well be proportional.
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No Pearce... no reduction on limb width. Rather narrow to begin with. What I know for sure is that this bow never shot 150 fps with that arrow, and was built in 2016, so it tells me that something is going on, but I truly have no clue. I know for sure I will be trying it on some string follow bows that I have made over the years that are longer just to see the results. Fun to experiment.
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Pierce and zugul. I think there is a few things going on. String friction and mass reduction are the two that I see. I also wonder something is going on with the length of the string between limb tip to tip. Impressive results guys! I’ll give a try and test some of mine too. I’ve seen a 5 fps increase with tip reduction in mass. Will be interesting to see if this translates to longer bows!
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Zugal... I shot first with the looped string in the original nock grooves. Then tried cutting a v notch in the existing tips which were to small, and split when I strung, and shot the bow, so I cut the tips off and ,V grooved down to sinew I had on the limb tips which would be nearly the same length as the looped string. ???
You eliminated the wood that was above the old nocks and made the V nocks so the string lenght and the brace height stayed the same, correct? If this is the case then you took off "dead weight" that was just slowing down the return of the limbs from full draw to brace height, plus reducing the surface area between the string and the nock thus reducing friction (I think this leads to a marginal improvement in speed). As stated inTBB1 "On bows of average lenght and strenght, 65 grains of weight at each tip affects arrow speed by about 1 fps". I think the reduction of limb tips mass is the key here, but we neeed someone else to try and replicate your results because this still isn't enough to explain such a big difference in speed IMHO.
EDIT: it's nice to see my thoughts are in line with someone that has so much more experience then me, superdav95! :BB
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I will be trying it soon again, and post results on longer string follow bows to see the difference in speed.
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So I did another test but with a small sinew backed osage bow. It was 39.5"ntn, 37lb draw weight, 23" draw, and with side nocks. It shot a 400gr arrow 120fps on average.
I then converted it to a vnotch and removed 130 grains of total mass. The bow was still 39.5" ntn with a draw weight of 37lbs at a 23" draw. This time it shot the same 400gr arrow 135fps on average.
My conclusion is that the bow wood must not matter much at all, it seems to be a fairly proportional change. Also, it tells me that, if what tim baker says is true 65gr tip mass reduction 1-2fps gain, there must be something else going on here giving us this extra speed. The mass reduction only accounts for about 2-4fps of speed gain.
The photo is an example of how tiny you can get these tips!
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The V notch nock has to be cutting string friction at the draw, and release.
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Today I tested a 60 inch nock to nock moose sinew backed Osage bow that has one, and quarter inches of string follow. The bow is 31lbs, at my draw, and has a 14 strand FF 652 string. With the regular limb nocks the bow shot through the chrony at 140 fps. Ten shot average. With the cut in V nock the bow shot through the chrony 140 fps. Ten shot average. Really confused, but that was my honest results of the test. ??? ??? ???
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I just piked that bow 2 inches. The bow is now 59 inches long, and 35lbs at my draw. I can still handle a 35 lb bow. It shot through the chrony at 145 fps average 10 ten shots with regular nocks. I will leave it go at that. Good building , and hunting.
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Today I tested a 60 inch nock to nock moose sinew backed Osage bow that has one, and quarter inches of string follow. The bow is 31lbs, at my draw, and has a 14 strand FF 652 string. With the regular limb nocks the bow shot through the chrony at 140 fps. Ten shot average. With the cut in V nock the bow shot through the chrony 140 fps. Ten shot average. Really confused, but that was my honest results of the test. ??? ??? ???
That is really odd! I don't understand what would cause that one to have no change. It should have at least gone 2-3fps faster because of the mass reduction alone. I guess best thing to do is more testing haha!
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Just finished testing on a 40in 40lb @19.5" draw sinewbacked buck thorn bow. It shot my 400gr arrow 131fps with the traditional side nocks and then I did the conversion. Same weight same ntn length same draw length but it now shot the arrow 139fps on average. So only an 8fps increase this time.
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That is still a good increase in speed. Maybe it works best with shorter bows. I will be testing another short bow soon, and post results.
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Maybe it works best with shorter bows.
That's a thought. If you have the set up for it, comparing before/after full draw pictures or the full draw limb bend traced onto a board or paper on a tillering tree might give some more hints as to what is going on. Normally I would say that if you are gaining speed you must be adding extra strain into the bow somewhere. I don't know where that is happening here, but comparing full draw shapes might make it more apparent.
Mark
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I dont know if it's relevant but if you have the exact same brace height the tip grooved bow is less tensioned and there is also a smaller angle with the string at brace
I's a small difference but in shorter bows is more pronounced
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It's not that. When I do these tests I cut off the tips so that it's a comparison of a ntn bow of the same length.