Primitive Archer
Main Discussion Area => Bows => Topic started by: BowEd on March 13, 2017, 10:48:06 am
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Here's a problem I should be able to figure out myself but will post it.It's something that's never happened before to a handle here.Can't say exactly how many handles like this I've put on bows but dozens and dozens for sure.I've never counted how many bows I've made but over a hundred for sure I guess.The cause of it is what I want to know.It's got to be a construction or location fault.I've had some reasons why told to me already.Looking to avoid it happening again because I'm making another type bow.I have pictures for a visual examination of the problem which can say a lot without words.Then I can answer questions that come up about it.I will say this.I shot literally thousands of arrows out of this bow.Usually 11 to 12 gpp arrows.I just shot a few 9 gpp arrows and noticed it.Highly reflexed bow if that makes a difference.Using FF too if that makes a difference.To me not.Arrow pass is around close to 5/8" wide and close to center shot.
Here's the cracks location.Side view
(http://i920.photobucket.com/albums/ad41/Beadman1/DSCN1528_zps6flh9chh.jpg) (http://s920.photobucket.com/user/Beadman1/media/DSCN1528_zps6flh9chh.jpg.html)
Top view
(http://i920.photobucket.com/albums/ad41/Beadman1/DSCN1529_zpscrirzfdp.jpg) (http://s920.photobucket.com/user/Beadman1/media/DSCN1529_zpscrirzfdp.jpg.html)
Another view
(http://i920.photobucket.com/albums/ad41/Beadman1/DSCN1530_zpsr2yobsds.jpg) (http://s920.photobucket.com/user/Beadman1/media/DSCN1530_zpsr2yobsds.jpg.html)
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Hard to say, Ed. I see no reason its something you did wrong. I've seen dry fired bows do that. The limbs slam ahead and cause delams between rings, just like that.
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Chris beat me to it Ed. If anything it may be a lateral violation that just happened to show after time.
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I've done that a couple times with cut in arrow passes. The trick is to lengthen your fade so it's not trying to bend into the cutout. I now give myself an inch and a half past where the cut out starts to narrow the limb and have had no more issues with it. Josh
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I was thinking same as Pearl Ed. Seems like limbs would have to of move wrong direction to make that crack. It didn't get bumped into something bending limb back?
Bjrogg
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Yes I see you what you mean.It was'nt dry fired at all.This one though is not cracked at the growth ring and it does'nt show a crack on top either.It's sinewed under there though and the wood is hickory.9gpp arrow is far from dry firing yet too.Thanks for the comment though.The bow has around 8" of reflex so when it slams home yes it's hitting hard I guess.
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Josh...Good point man.Glad to hear that worked for you.So this next one has 2" fades instead of 1.5" fades and I suppose I'll have to go with a smaller grip also.The darn bow was a favorite and kinda kicked me in the gut doing that....lol.
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bjrogg....No the tips did'nt hit anything.Did'nt even make a sound.I happened just to see it.
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Josh....You got a pic of your handles done that way?I figure start my arrow pass carve out at the point where it is close to the full depth of my handle then too.
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Been told too to take even amounts off from the center line to get to arrow pass.Then of course no more close to center shot.Which I can definitely live with if need be just need to make special set of arrows for a paticular bow then.
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Both of these are actually longer than they needed to be, but show the general idea. Josh
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Ed maybe that crack started when you warmed it up to reflex it and you didn't get a good eye on it until now? That condition would look much like a dry fire crack would.
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Thanks Josh.How long is that handle then altogether?
Pearl....Not sure what you mean warming it up to reflex it.During construction?Geeze I'm sure that is'nt it.I'm sure I'm misunderstanding your meaning.
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Yah, maybe it was too hot or not quite hot enough when you clamped the reflex in that area on a caul and the pressure popped the grain, then after a bunch of shooting it started showing itself.
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Oh ok I see what you mean now.Well the reflex I put on this one was put by reverse stringing and sinewing from a flat profile bow core but pre tapered to bend evenly on both limbs gradually increasing in reflex to the tip.No heat involved for reflex.
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Like this.Yes I know I'm crazy!!!!
(http://i920.photobucket.com/albums/ad41/Beadman1/DSCN1531_zpsdlsf8an0.jpg) (http://s920.photobucket.com/user/Beadman1/media/DSCN1531_zpsdlsf8an0.jpg.html)
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The walnut was 11" counting the fades. The hackberry was 10". I was going for long graceful curves on them both. With shorter arrow passes you can safely do them at 9". The center of the bow is 1/4" below the shelf. The arrow pass and fade are the same length from center as the handle and fade. All symmetrical that way, but it does add a little overall length to the bow. Josh
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I'm wondering if the sinew pulled up the splinter while it was curing
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I think you may have put those cracks all by yourself :) That is an already huge amount of pressure pulling the opposite way, then couple that with drying sinew and oh boy!
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I've always wondered how they don't break doing that. I'm sure mine would. I usually don't have that much bend pulling full draw the right direction
Bjrogg
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I see your point,and a good one.One thing too on the tillering tree I pulled this bow to 28" a hundred times or more.While shooting many times not that far.It cracked while I was testing it through a chronograph pulling it close to 28".
One fellow bow maker here said Ed its that prying tension accross the back lengthwise that may have done that on the draw more so then on the release.
I've made longer fades,and plan to leave more meat in the handle for this stress.More gradual taper to arrow pass then too.
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I am calling that the" know ,, unknown,,,," :NN
that piece of wood may just has a flaw or not as strong as the others you made,, but is showing you there is some stress in that part of the bow, that is more than you thought,, I like the ideas above of making it a bit stronger there, just in case :N
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One reason why maybe horn bows have the handle on the back side of bow covered with sinew.Might be a design flaw on my part.Whatever.I'm willing to accept the truth for it happening though.Others in the past have held up in that area I know that.
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I am calling that the" know ,, unknown,,,," :NN
that piece of wood may just has a flaw or not as strong as the others you made,, but is showing you there is some stress in that part of the bow, that is more than you thought,, I like the ideas above of making it a bit stronger there, just in case :N
Still could have happened at that point Ed, reverse string, sinew, then keep it tight, may be just an internal defect made worse by that and u are just seeing the problem manifest before it fails
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when a bow blows up, it might not always be a design flaw, ,just that piece of wood was not quite the same as other successuful attempts,, :)
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I'm no expert but it looks to me like the the area in red has very little support(nothing to hold it down) and the closer to centershot you get the worse the problem gets
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Ed it's hard for me to tell for sure on my phone. Does crack start at limb and progress towards handle? Does it go all the way to back? I might be seeing it wrong but I thought it looked like it started at limb, went into handle and ended before back. That's why I was thinking from a backwards bend. At any rate I'm still really impressed you can bend one backwards that far putting sinew on. I'd be terrified the whole six months or 3 years or however long you had it curing like that. Pretty cool to see you guys push the limits like you do.
Bjrogg
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yes I am terrified, when I see it now,,,,but I know Ed can tame that thing,, (-P
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I bet the reflexing started the weakening and the shrinking sinew kept working on it. I'm sure you can repair it though.
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Yup, a quarter inch hole and a carriage bolt will fix that sucker right up. Don't go cheap and use a square nut though, that's Mickey Mouse ;D ;D ;D
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A shame about the crack.That is a fine looking bow nonetheless.
Never really been a fan of a wooden centreshot bow for this reason as well as visually. They just don't look how a wooden bow should look to me.
Yep centreshot can work, but add a 5/8"wide handle at the arrow pass, heavily reflexed, you are pushing the design to its limits.
I seldom go narrower than 7/8" inch at the arrow pass, I think 3/4" might be the narrowest, and they were all with an orthodox handle alignment not centreshot.
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Made a lot of bows like this many years ago and all were center shot, never had a problem like that because of it. Here's a few pics of the reflex, not quite as much as Ed but close.
In order, Sinew backed Black Locust, Osage, Yellow Birch and Elm
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Ed, I'm not even going to attempt to diagnose the problem let alone offer a prescription. I'm just here for moral support. You can do it buddy! :OK
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Well I just got back from a bow making friend I respect to have a look at this bow.He thought I had the bow working too much into the fades maybe which might be true.Too abrubt a transition from limb to handle was his diagnosis.One of those things that are probably better diagnosed by handling the thing yourself I guess.A pic of full draw here.Tell me what you think.
Next victim is curing here anyway.I think when carving out the arrow pass I'll make sure it is at where the handle is the thickest too.Not sure to try for center shot yet or not.Not the end of the world if it is'nt to me either.Future victim has a full width handle yet.
bjrogg...The crack is what it is in the picture.Does'nt seem to run along the back really.just the corner of the fade there and not to the belly either.
Pat M....I've tossed around ideas to fix this but it seems to involve a complete reshaping of the handle.I just went ahead and started another.
Seems when a bow has a flaw or something I can't trust I just make another.Gary my bow making friend I just visited said I could probably shoot it at 26" yet if I wanted to,but I just said to heck with it.
(http://i920.photobucket.com/albums/ad41/Beadman1/DSCN1335_zps7m58nc7g.jpg) (http://s920.photobucket.com/user/Beadman1/media/DSCN1335_zps7m58nc7g.jpg.html)
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Yup, when you have the materials and you like what you're doing there is nothing to be gained by shooting a sub standard bow ;D ;D
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I know that feeling when one of your favorite bows fail & the kick in the gut feeling and going back over the bow forensically looking and in my inexperienced case I can find the cause sometimes quickly , but other times when I have meticulously done every thing I could and still had a failure it's harder and it just becomes guess work because some times it's just the natural material and unseen factors but in your case with having made the same design so many times and shot so many arrows threw the bow I wood defiantly suspect the wood all though it wouldn't hurt to beff up the weak areas just for confidence, some times it just a mystery ! (W
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I will rarely blame the wood for my failures.Mostly look at myself where I went wrong.Over time and enough bows things work out.It's funny to see yourself change in the way you make bows over time.Especially the first few years.
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Ed I love your bows. You have obviously learned a great deal over the years making bows and pushing the limits. If I didn't see the things guys like you are doing here I wouldn't think they where even possible. Sure keeps me humble and gives me something to shoot for in the future. For now my bows will be pretty conservative but you guys make me challenge myself a little more every bow. Thanks for posting your success and your troubles.
Bjrogg
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Ed I love your bows. You have obviously learned a great deal over the years making bows and pushing the limits. If I didn't see the things guys like you are doing here I wouldn't think they where even possible. Sure keeps me humble and gives me something to shoot for in the future. For now my bows will be pretty conservative but you guys make me challenge myself a little more every bow. Thanks for posting your success and your troubles.
Bjrogg
x2... all of it^
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I agree Ed you make a mighty fine bow.
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The tiller looks good from here.
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The tiller looks good from here.
It is but the perfect curve goes into the area in question.
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I just got a fascination for these composites.I'm sure glad this bows thread is here.Thought about putting it up in the horn bows thread but as slow as action is going on over there I would'nt have gotten the responses I did here.That's no fault of the thread either.Although it seems whenever I get a problem and no solution from questions I usually figure it out on my own or tidbits of info from you guys.Good thing too.Makes a person think!!!What's that song...Oh lord it's good to be humble when your perfect in oh so many ways..... :)Thanks a lot fellas.
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I can't wait to look in the mirror
Cause I get better lookin each day.
That's a good one Ed.lol
Bjrogg
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Now I got that song stuck in my head.lol. Oh well at least it's a good one.
Bjrogg