Primitive Archer
Main Discussion Area => Bows => Topic started by: LeightonM on March 07, 2017, 10:29:24 pm
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I have this 63" NTN bow that pulls about 40# @ 26". I'm reworking the handle as you can see.( it was too wide) I'd like to bump my draw weight up to 47-50#. I am thinking about cutting the tips off to accomplish this but then I thought about flipping the tips. The bow took about 2-2 1/2" of set. I thought flipping the tips would give it a nice looking profile and give it some more zip. Any advise is most appreciated. Would dry heat be better than steam?
*** I used dry heat to recurve the tips. Any advice on how long I should let it set before I try to retiller? I'm storing it in a room with a humidifier.
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Most of the set is near the handle area. Flipping the tips will add more stress so unless you get the rest of the limb contributing you may only add more set.
You could shorten the limbs by 1" each, flip the tips and add a little heated in reflex then retiller back down to the weight you desire. It may take more set but it might not take too much.
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If you just want to bend the tips a bit, dry heat will work fine. More drastic bends (curves) I use steam. I don't think you will gain as much weight as you are after just by flipping the tips - probably won't gain much at all. Shortening will gain you some weight, of course you will need to re-tiller. Might heat treat the belly too. However, once set has happened, it pretty much has happened. Play around with it and see what you can do.
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if you even out the tiller I dont think you gonna get 10#,, flipping the tips or cutting it ,, you will come out about the same draw weight after fine tuning the tiller,,,, lowering the brace a bit will reduce the strain on the bow,, and give you a bit more cast,,
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I think patb nailed it on all counts, as far as flipping the tips with osage you can bend all you want up to a tight static with a heat gun
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It might make a nice sinew backed recurve short draw if you really feel like a complete rework. It will put you at a higher draw weight than the other options. Cut it, flip it, heat treat, and back it, wait a few months then tiller.
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It might make a nice sinew backed recurve short draw if you really feel like a complete rework. It will put you at a higher draw weight than the other options. Cut it, flip it, heat treat, and back it, wait a few months then tiller.
This would be my route too. There is no way you can fix the tiller and get 10# increase without adding something. I personally would recurve the tips as much as I dared. even if some splinters turned up on the belly side I would grind them off and underlay a new piece of wood or run a saw cut down the center (thinkness) and then bend them. then fill the cut with a thin piece of wood.
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I would probably just build another bow. As mentioned the brace is to high. Also just asking has the bow been left strung for a long period of time. That will ruin one faster than anything. Arvin
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I think you guys are right about the sinew,, you could heat it into some reflex,, and probably come out with a pretty nice bow, the sinew would help hold a new profile,, and give you enough extra weight to refine any tiller issues,, giving you the option to flip or even recurve the tips,,, you could compensate for the reflex in the bow now by gently reflexing the whole limb,,,yes it would be a bit of work, but probably not as much as make a whole new bow,, without the added expense of getting a new stave,, :NN
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Thanks for the advice guys. The bow isnt super special to me and I dont feel like putting a ton more into it so I think I'll maybe try flipping the tips shortening the bow a bit and retillering and see what I come up with. It already shoots much better since I narrowed the handle where the arrow passes. :BB
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OK, heres a radical idea hehehe! Reverse it and sinew it up!
leave it in it's current profile as it is nice and even like that except make the back the belly instead and flip tips into a very slight reflex and then Pike off 1.5" from each end, flatten and narrow the handle just a tiny a bit but leave it a little proud and wide for the heck of it.
Barely scrape off the new back to get to more uncrushed fibers, and sinew the new back. Tie it into a little reflex and wait. I think it could be a sweet sinew redeemed reversed reflexeded reworked rejuvenated repeat reaper.
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Really
Might not even need a lot of tiller work if you are meticulous about keeping initial wood removal equal and consistent and sinew app also even per limb and consistent. Man that sounds like a fun time but I just love this kinda thing!!
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ok I went back and looked in my notes from 2004
I had a bow with some string follow that shot very average,,
I recurved the tips and did gain some speed and weight,, but I did not have to re tiller
the bow was about 62 inches long 45 -47 @ 28 inches
shooting 500 grain arrow with b 50 at ------- 153fps
after recuring the tips,, it was 50# at 28 shooting 160 fps
with fast flight I feel like it would have shot 165 fps,,
the bow had about 2 string follow,,,
based on that,, I feel like you might gain some weight and speed,, if you dont have to tiller much,,
the bow may not be shooting that much more effeciently, but your overall cast of the bow may be improved,,
I was really happy to find that info as it applied to what you are doing,,, :G
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Brad you keep a lot better records than I do . But that info was good. Brad the fast flight was probably half or more of the speed change. Arvin
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Wow DuBois, that is a lot to chew on! I never woulda thought of that.
Brad thanks for that info that is perfect. So if I would do what you did plus pike it I would gain a bit more??
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What is your draw length and the bow is 63" with a stiff handle. How wide are your limbs? Maybe flip the ends 1-1/2" in the last 9-10" . It might pull out . I am not sure about that. Looks like they are bending a bit now. Arvin
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What is that string made from. It looks like about 16 strands of B50. If you make a 8 strand D97 string , pad the loops and serving to 10 strand , use 030 serving you should increase your cast and reduce the shock a lot. You can take off 1/2your silencers which will also at to your cast. Arvin
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arvin, I did not shoot fast flight,, just made projection on what it might have done, I did gain speed with the b 50
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Ok Brad understood about the B50. I argued with Rick Barby for about a year and a half. I finally bought some D97 . He was right!! O:) That's all I use now. Using 1/8-1/4 " wide Osage over lays and not having wood damage from string yet. The results I mentioned happened. You might say this is the second time I have had to eat crow on the Internet about string anyway. B50 works by the way that's all I used for 5-7 years. :BB Arvin
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yes I still shoot the b 50,,, but sometimes I test with fast flight just so I know what it will do for my own records,, all my hunting bows are b 50,, cause I like the feel of the thicker string,, well one bow has a fast flight,, whatever works best for you,, back then I did not shoot much fast flight ,, or just didnt have any,, and was not really aware of how much difference there is in an 8 strand fast flight and a 16 strand b 50,,,
as far as cast of the bow,,
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What is your draw length and the bow is 63" with a stiff handle. How wide are your limbs? Maybe flip the ends 1-1/2" in the last 9-10" . It might pull out . I am not sure about that. Looks like they are bending a bit now. Arvin
My draw is 26. And the limbs are 1 3-8"
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How about mid limb? You might just try the string thing before you change the bow limbs . Looks like it was built by someone that understood bow design. Could have been a bit green . Lots of variables when it comes to wood. Is the limb sectional rectangular D shaped or a mix of both? You asked. ;D
Watch it or you will be chasing rabbits like me. :BB It's a wonderful ride this bowing stuff. Arvin
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How long should I let the moisture return till I start to bend and tiller it?
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hey,, nice job on the recurves,,
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OK, heres a radical idea hehehe! Reverse it and sinew it up!
I like the way you think, Dubois!
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Brad you keep a lot better records than I do . But that info was good. Brad the fast flight was probably half or more of the speed change. Arvin
He didn't actually use ff...
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"Flipping the tips will add more stress so unless you get the rest of the limb contributing you may only add more set."
Maybe. Usually. But, maybe not.
I do what you did here almost as a matter of routine. I let whitewood flatbows take whatever set they are going to, while keeping it as low as possible, of course. That's usually ABOUT 1" to 1-1/2" for a 68" bow. I've never been able to get much less from common woods, but, I can't stand it!!!! So, along with a final heat tempering, I almost always end up flipping the tips just about that much back, so the tips end even or, like 1/2" back. For me, this works really well and I have almost not issues.
First, since the tips were stiff in the last 8" anyway, the net effect on strain seems to be pretty minimal, and I get very little new set, if any. It does raise draw weight often 5-10lbs, but again, that seems to not contribute any more set. And, I know this is counter-intuitive, but it just doesn't seem to bug it much. The one thing it really does is tighten up the string at brace, so even if I re-tiller to the same weight, the bow is a little snappier.
Now, on your bow here, it does look like much of your set was taken in the inner limbs. Recurving it like you did (more than I usually "flip" the tips) actually shifts the limb tip leverage AWAY from the inner limbs out toward the middles and to just below the recurve. If you string it as is, you will see those areas belly out more than they do in the "before " pic. So, you may take more set there, but maybe not where the wood already had. That's what I'd expect.
Either way, despite the experience others are reporting, I usually have to barely tweak tiller, if at all, as long as I don't go nuts on the size and angle of the recurves. The main problem I do have is that the limb tips are usually skinny enough that I can't get away with much curve or they try to lean to the side.
Give it a few days, string it and have a look.
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Thanks for that springbuck! I'm looking forward to working on this and seeing what it becomes!
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Good luck.
See, if I had seen your "after" picture with the recurves, and you had done that profile to begin with on purpose, that would be a really cool and pretty bow.
We pay a lot of attention today to set and the wood degradation it causes. It DOES affect the wood, and that does affect performance negatively, and shouldn't be ignored. BUT, Baker et al addressed this a LOT of times in the TBB's, and geometry, especially side profile still seems to be just as or more important.
For instance, in the Design and Performance chapter of TBB I, Baker says that recurves are faster than straight bows because they have better F/D curves, but in the Design and Performance Revisited chapter in TBB IV, he corrects himself emphatically, and talks about the benefits of reducing outer limb weight on longer bows to raise efficiency.
BUT, (depending on everything else, of course) a deflex/recurve of that length will shoot better than a straight limbed bow that length with 3-plus inches of set, despite the overworked inner limbs.
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You were right SpringBuck, I was working on this bow today and it needed almost no retillering. I got it to full draw and shot it a little with little to no new set. I gained 8 pounds of draw and it shoots sweet and faster. The only thing i need to do yet is align the tips better, they aren't very lined up with the handle.
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Good call, Springbuck!
And glad to hear your bow is up and running again, Leighthon, with the added poundage you wanted.