Primitive Archer
Main Discussion Area => Bows => Topic started by: 4giveme on April 05, 2013, 08:00:53 am
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Hi everyone,
I have some info and would like to have all you help me interpret it.
So maybe a can improve the design of my short bow.
The limbs on the 48" osage are 1 1/2" the last 8" taper to 3/8".
The sinew on the this bow dried for thee weeks and was applied with titebond 3.
It was cut true center shot and Pulls 55#@28"
Took 1" to 1 1/2" set.
So I took it to the range and shot about 40 arrows. I felt no hand shock or twisting.
All shots were taken at my draw of 26" which is 41# on this bow. also all arrows shot were
496gr. (thats all i have right now)
I then took it to the chronograph, shot 15 more arrows and here's the results:
Average fps- 108
high- 117
low- 104
If further info is needed let me know. i don't know if its good or bad please let me know what you think.
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Lots of bend for that short,looks like all the bend is right out of the fads,to late I would think to do anything about it unless yo want a kids or light ladies bow. Don't understand why you tillered out to 28 if you only draw 26,that will only add to the stress and set on the bow.No need for that IMO. Good looking design,just needed to get more bend through out the limb,that would have helped the set issue. :) Sorry ,not much help with this one,just some observations for the next. :)
Pappy
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Thank you pappy,
so if i get it to bend more on the upper 2 thirds of the limb do think the fps would go up with this design? as far as the tiller to 28" goes you are right i should have stopped at 26" and trained it from there.
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I would think so,set robs speed. Little over 400 grain arrow would give you
better results and around the 10 grain per pound most go for. I know you see some speed demons posted on here but about 3 x bow weight is pretty good speed as a rule of thumb. :) Lots more 50 lb bows shoot in the 150/160 than
in the 200+ range and I am talking about well built and good performing bows. :)
Pappy
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Thanks for your help Pappy, any further help you can give is taken and will reflect in the next bow.
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SWEETTTTTTTTTTTTTTTTTTTTTTTTTTTTTTT
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Very cool. Its not too often you see a short bow like that with such a large stiff handles section.
For future reference, you might want to try a shorter handle/fade section or a slightly bending handle section. It'll give you more working limb and, if its tillered well, it will probably take less set and have better cast.
That's what I'd do but I'm no expert. Still looks pretty good though. :)
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Good thoughts C S. I am not big on bendy handle bows myself but that would help a lot on short bows with that kind of draw. :)
Pappy
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That wood be much better 10-12" longer ,or if it was a bend in the handle plus a few inches for your draw and skill level..less set,less stress,and longer leverage for better fps...your chrono speeds testify that its belly has been crushed too much.....I like these designs,yours just needs some tweaking...there not easy to make and make them well without crushing the belly too much and losing lots of cast....try just 64-68" flat bow types and learn how to tiller more carefully...its not just the end result of tiller,its about how you get there and never over stressing it by never pulling past a flaw in your tiller and never pulling past your intended weight....it can take several bows to get the basics down,and once you do then start going shorter and into the more high stressed designs,and you'll get much better results with this type of design and bow....just my two cents n I don't know jack
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I agree with Pappy in that your bow looks to be doing all of its work, in a short section just outside of the handle. If you were to divide your limbs into thirds, the second 2/3 is doing very little bending. With that in mind, that section is just added weight (mass) that the first 1/3 of the bow is carrying along, thereby robbing your performance. Observations and things you might try on your next one:
Hide glue: TBIII although it works, doesn't allow the full potential of the sinew. Sinew all the way to the tips.
Handle: Your handle section appears rather long, maybe because of your center-shot desires. Try a shorter, narrower, thinner handle section that just starts to bend in the last inch or two of your draw. I think I see a shelf, eliminate it and try shooting off your hand.
Overall width: Try 1-1/4-inches parallel to mid-limb then taper to the tips. One of my 1-1/8" shorties (48" long) pulls 60# at 24 and gains aprox 6 lbs per inch, if my memory serves me right.
Working section: Tiller so that the entire limbs are bending except for maybe the last 3 inches at the tips.
Recurve tips: Keep static but flip the tips at the last 3-4 inches. Your bow appears to be static at around 8 inches from the tips. This will give you more working limb length.
Your bow looks really cool and is quite an accomplishment. It is doing some amazing work in a short section that is a tribute to your workmanship, the osage and the sinew combination.
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Awesome bow. Although it is bending right off the fades, which ain't the best thing. It can fail in compression in those spots, take set, and maybe even fail outright. Best thing to do is keep the bend through out the entire working limb distributed as evenly as you can, I mean getting the entire limb to do the bending without having one area bending too much. Awesome bow though, I love the profile, looks like a screamer!
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Super feedbak guys thank you,
Christian Soldier,
For future reference, you might want to try a shorter handle/fade section or a slightly bending handle section.
The handle is 4" and the fades are 1 1/2" Are you saying to elimiate the fades and work them into the 4 inch handle?
MWirwicki,
pionts well taken and you may see them in the next build!
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The entire handle section including the shelf area appears to be 2 fistmele's in length. My suggestions do however, eliminate the center-shot design. If you're desire is to keep the center-shot then you don't have much choice but to leave them as is. Then, just try to get more of the limbs working.
Glad my points were well taken. They were meant well. ;)
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4giveme is this the Youtube bow build follow along I hear about by chance?
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Another point is that your brace height is very high for a self bow. The lower the brace height - the longer the power stroke - the faster the arrow! Always shoot a selfbow with the lowest brace height that gives clean arrow flight.
My advice is to completely forget about centershot. Well spined arrows and a well shaped arrowpass are just as accurate. In terms of pure accuracy the person holding the bow will always be the problem not how centershot or not the bow is.
Make your next bow a longer straight limbed unbacked design.
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If you have a tripod or someone else taking the pics, you can use the multiframe /action setting on the camera to give you a really good indication of where the bow is bending as you draw. I've found this quite usefull . As the others have said, you'll likely find that your limbs are only working at the fades.
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You have read all the advice I could ever give. I will say one thing. Your bow is a testament as to osages' undeniable strength. No other wood would allow that, sinewed or not.
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Hi drums,
How did you hear about the you tube video? And you are correct , that is why I used osage, next one will be black locust, or maybe maple. And it will be a similar design.
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Ive seen plenty of others make that same bow in the past and they referenced Youtube.
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Ohh I see, thanks for your help
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I shall not disagree with what Pappy says... ;).. but hopefully things work out. That is one RANK looking little fella......... 8)
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Super feedbak guys thank you,
Christian Soldier,
For future reference, you might want to try a shorter handle/fade section or a slightly bending handle section.
The handle is 4" and the fades are 1 1/2" Are you saying to elimiate the fades and work them into the 4 inch handle?
Yeah you could do that, in a 'slightly bending handle' (different than a 'bending handle' mind you) the transition is pretty smooth and slight. As Pappy and BH said, you need all the working limb you can get on shorter bows. The solution there is to make the handle/fade slightly working or just use longer staves ;) . Also as others said, the outer portions of your bow are a little stiff so making those work more would contribute to better cast.
Again I am still fairly new to this archery game so take that into consideration. I have several bows with those exact handle dimensions you gave (minus the cut in shelf), but those are on 5-6 foot bows. You've got to adapt some things when you are working with shorter staves, and one of the easiest ways to do that (IME) is to make a smaller, slightly working handle and shoot off the knuckle (take a look at the plains style bow handles). Just things to keep in mind. Keep on building. :)
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Hi 101'
That is one RANK looking little fella......... 8)
Maybe I am out of the loop but what does rank mean? I am not sure to be insulted or not. Lol
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Hi Christian Soldier,
Thanks for the help.
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this is a 4 " grip with 1 1/2" fades, it appears that you measured the handle/fade area and then made your "fades", or maybe you just have tiny hands :laugh:http://i623.photobucket.com/albums/tt320/bubncheryl/Picture006-10.jpg
http://www.primitivearcher.com/smf/index.php/topic,32928.0.html
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That's very slow for Osage backed with sinew it has to be do to the fact that you have a lot of bend near the fades and also that it's such a light poundage normally a 40-45 pound bow should shoot upwards of 140 fps
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Lol good one buddy ;D
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Hi 101'
That is one RANK looking little fella......... 8)
Maybe I am out of the loop but what does rank mean? I am not sure to be insulted or not. Lol
In my time Rank went "Cool"........ 8)
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Lol very cool Ty
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Thanks all for the help, starting the next bow in a few days and will post pics on this bow when I finish it out.