Primitive Archer
Main Discussion Area => Bows => Topic started by: Easternarcher on April 14, 2013, 11:56:53 am
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I have made two Hick Backed Osage Bows recently.
First one Blew up directly across the grain...really clean break at full draw.
I saw nothing wrong with the quartersawn slat or the Hickory backing. I think posted that break on here somewhere.
Well I just blew another one on the tree at low brace. I was very picky on my slat and backing strip and all.
Saw absolutely nothing wrong....only thing I noticed was that the Osage slat seemed not very dense, and the limb thickness seemed unusually thick down thru for all the weight I was pulling. So I assume the Osage was not dense enough and was just doomed to fail from the start.
It broke right off the fade....if I recall both slats were from the same supplier(whom I will not mention).
Bummed out for sure....I think I'll stick with Ipe for a while.
Really kills the confidence level.
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Do you have a pic?
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No, I already cut the remains up to salvage what I could for overlays etc.
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Yes I know that feeling all to well! Quess that what make bow builders a unique bunch in the the fact that we all have failures but still reach for another piece of wood.your not alone on this one.
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If the second one broke like the first one I'd say throw the hickory away. The only time I ever saw hickory break across the grain was when it had fingi in it and you can't always see the fungi.
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If the second one broke like the first one I'd say throw the hickory away. The only time I ever saw hickory break across the grain was when it had fingi in it and you can't always see the fungi.
Pat, never thought of that.....I actually found the broken limb after I threw it in the scrap pile...tried to size the pics but can't get them small enough. I can't tell...maybe it was the hickory. but it looks sound.
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Unfortunately you can't always go by looks. Even with hickory that is bought from a reputable wood dealer you can't tell how it was treated after harvest. If it layed on the ground for only a week in the summer I'd say it had fungi in it.
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Unfortunately you can't always go by looks. Even with hickory that is bought from a reputable wood dealer you can't tell how it was treated after harvest. If it layed on the ground for only a week in the summer I'd say it had fungi in it.
Well, I got some nice ash I could try.....can't use bamboo on this bow (by new owners request).
I'll have to source out some new hickory too I guess.
So your opinion is that it is not bad Osage????good vertical grain and all but......maybe I shoulda used flat sawn bellywood??
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I'd almost be certain that its not the Osage. Hickory is much more fickle on how it's treated. Even if the Osage was a lighter density I would expect it to take set and not necessarily break.
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I'd almost be certain that its not the Osage. Hickory is much more fickle on how it's treated. Even if the Osage was a lighter density I would expect it to take set and not necessarily break.
Well, thats twice it went KAPOW!
I'll try different hickory or ask maybe...see if I can blow that one up...
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Dont want to high-jack your thread but I recently finished a little easternwoodlands from a quartersawed piece of osage that MWirwicky gifted to me.....it's a self bow with flipped tips and not backed at all.....43# @ 25" would some pics maybe help?
rich
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I actually found the broken limb after I threw it in the scrap pile...tried to size the pics but can't get them small enough. I can't tell...maybe it was the hickory. but it looks sound.
Upload the pictures at http://www.tinypic.com
Do not resize them, but just upload the entire picture and post the link here. We need a picture to find out how it broke and what the solution would be.
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OK, lets try this.
(http://i49.tinypic.com/5uoilv.jpg)(http://i49.tinypic.com/5cn441.jpg[/IMG[IMG]http://i46.tinypic.com/2v9vj3b.jpg)
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That hickory has something wrong with it, hickory will not break cleanly across the grain like that. It will usually pull up splinters and look like a paintbrush.
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That hickory has something wrong with it, hickory will not break cleanly across the grain like that. It will usually pull up splinters and look like a paintbrush.
Ya, I'm believing that now after two bows failed like this, cept this one failed right off the fade before I got to low brace..the first failed after a couple hundred arrows out at mid-limb. The break looked very similar tho.
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P.S. just did a sacrificial bend test on a strip that I'm 99% positive came from the same batch(2" board re-sawn).
the full length strip bent almost completely double before failing into popped splinters. I had to force it to fold over to separate the two pieces.
So.....I need to examine and test every piece I have to be somewhat sure it is sound I guess. Might even do a hick backed ipe or bloodwood etc. to test it again. I'm still confused by it all.LOL.
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Well thats a clean tension break.
The hickory was the problem.
It's impossible that the osage was at fault. If the osage had some sort of fault it would either have chrysalled or taken set here.
Doing bend tests on thin backing strips is pretty much a waste of time. You need to glue some scrap belly wood onto it so that it's at the same sort of thickness as a limb (back and belly) then bend to the same degree as a bow limb.
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Well thats a clean tension break.
The hickory was the problem.
It's impossible that the osage was at fault. If the osage had some sort of fault it would either have chrysalled or taken set here.
Doing bend tests on thin backing strips is pretty much a waste of time. You need to glue some scrap belly wood onto it so that it's at the same sort of thickness as a limb (back and belly) then bend to the same degree as a bow limb.
OK, thats the next move then.
Set or chrysalis????it never had the chance to get that far. LOL.
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That hickory looks like heartwood, not sapwood. You want the sapwood for backing strips. It should be very white if it's sapwood. I had the same problem with hickory when I tried to use heartwood.
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That hickory looks like heartwood, not sapwood. You want the sapwood for backing strips. It should be very white if it's sapwood. I had the same problem with hickory when I tried to use heartwood.
ADB, this was quite white in colour, mqaybe alittle creamy looking.. the pic may be off...
The bend test strip I used last night in contrast was darker and it bent like crazy! and splintered alot when it failed. I dunno what to do here.
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Looks like the Hickory to me,I do the bend test also and I have found it very useful, :o I just use a short sliver, maybe 5 or 6 inches long and thin it down even so it will bend pretty even,not a long piece and if the Hickory has dry rot it will break across the back just like that one did. :) if it break I scrap the wood that it came from. :)
Pappy
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Breaks on the tension side of the wood break cleanly. The splintering occurs in the neutral plane area.
That limb was overstressed. Try making the limbs wider.
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Breaks on the tension side of the wood break cleanly. The splintering occurs in the neutral plane area.
That limb was overstressed. Try making the limbs wider.
Limbs were 1 7/16" or so already.
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Too narrow. And not because they are 1-7/16 in wide. They are too narrow because the limb broke. If the limb breaks when the limb is 2" wide, then the limb is STILL too narrow. Eventually you will find the width that will work.
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They are too narrow because the limb broke.
I have to disagree with you. There are dozens of reasons why a bow can break. The limbs being too narrow is just one of them. Concluding that a wrong design (limb width) was used, just because the bow broke, is simply wrong.
I've never worked with osage, so I can't say for sure if a width of 1 7/16" was too narrow for the desired draw weight Easternarcher was after. It depends on the length of the bow, the draw weight and the draw length. But I think that width can't be that far off. Judging from the pictures, I'm pretty confident the hickory is the culprit - not the limb width. Yeah, maybe this particular piece of hickory was so lousy that a limb width of 4" may have been enough to give you a bow, but that would have been stupid. Hickory should not break like that, not even if the bow were underbuilt. If it does break like that, there's something wrong with the hickory itself. Don't use any more wood from this particular board. I'm not sure you should blame it on the hickory supplier; it could just be one faulty board in the batch.
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I have to disagree with you. There are dozens of reasons why a bow can break. The limbs being too narrow is just one of them. Concluding that a wrong design (limb width) was used, just because the bow broke, is simply wrong.
I've never worked with osage, so I can't say for sure if a width of 1 7/16" was too narrow for the desired draw weight Easternarcher was after. It depends on the length of the bow, the draw weight and the draw length. But I think that width can't be that far off. Judging from the pictures, I'm pretty confident the hickory is the culprit - not the limb width. Yeah, maybe this particular piece of hickory was so lousy that a limb width of 4" may have been enough to give you a bow, but that would have been stupid. Hickory should not break like that, not even if the bow were underbuilt. If it does break like that, there's something wrong with the hickory itself. Don't use any more wood from this particular board. I'm not sure you should blame it on the hickory supplier; it could just be one faulty board in the batch.
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I agree wholeheartedly.
This hickory board came from the only local supplier that carries it. Can't blame them....the osage came from a bowyer supply place.
As for the design, I actually build most of my osage bows to around 1 3/8" width and 62-66" length...this one was at 68" overall. the osage was overly thick, maybe 9/16", the hickory was 3/16" thick. I planned on having lots of room to play with tiller etc. I was only shooting for a 40-45lb bow in the end. When it blew at only about 4" flex on the tree.
Did I overstress the limbs in exercizing them in floor tiller?....man if I did, it was doomed to fail anyhow in my opinion.
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If the limbs need to be 4" wide when using this batch of wood, then you know for sure that the wood is brittle. But brittle wood is not the problem. The problem is that the design you are using does not match the material. If you want to keep trying until the material you obtain works well with your design, then expect to keep breaking bows. It's not a bad approach, just and expensive one.
I'll be interested in seeing the final verdict. :)
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Rubbish. Sorry... I have to disagree too. 1 7/16" wide hickory backed osage will give you whatever weight you want in a flatbow. That is PLENTY wide for this wood combo. I've made 100# hickory backed osage warbows, and 80# flatbows which were narrower. But yes, the tiller needs to match the design.
It's either the wood, or the tiller job. I seriously doubt this is purely a design flaw.
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It's either the wood, or the tiller job.
Which one do you think it is? What method would you use to find out?
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No idea without seeing the bow or the tiller. If I had to guess... I'd say it's faulty wood. Making the limbs wider would not change the result IMHO.
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If a new guy wanted to make a flat bow, what would you recommend?
Make the bow 1" wide and if it breaks make the next one wider.
Or, make the bow 2" wide and if it doesn't take any set, make it more narrow until you start getting a little set, and then stop.
Or, make the bow as wide as I make mine, and get some new wood if it breaks.
>:D
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Eastern, this banter is for your benefit. Personally, I like a good argument. But the decision is up to you.
I don't disagree with the idea that your tillering or the wood may be preventing you from making a bow with the wood you have.... so if you take that advice, you will be fine.
Of course, if you take my advice, you'll break fewer bows. IMHO. ;)
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Dang boys...didn't mean to start a feud! O:)
I've made several which and boo backed osage bows that were narrowed, like 1 3/8".
Ipe bows down to 1 1/8th. got a which/ipe elb thats a hair less than 1 inch wide too...lighter draw of course.
I dunno...it just seems like there was bad wood to start since the bow was barely bending at the failure moment. I actually was happy with the curves at that point....didn't see anything wrong. and like I said, I've made a few already, so I've been down the road before.....I wasn't expecting catastrophic failure at 4 inches of bend!
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If a new guy wanted to make a flat bow, what would you recommend?
Make the bow 1" wide and if it breaks make the next one wider.
Or, make the bow 2" wide and if it doesn't take any set, make it more narrow until you start getting a little set, and then stop.
Or, make the bow as wide as I make mine, and get some new wood if it breaks.
>:D
Your simple 'solution' of "just make it wider" is rubbish. Bit more to it than that. Design, wood and tiller must all match... not just make it wider if it breaks. General statements like this rarely solve problems.
Ex: if I'm making a 72" ntn hickory backed osage ELB, with grip 1.25" wide tapering evenly to 1/2" tips, and I tiller it full compass and it breaks, making it wider will not help. The wood combo is sound, the design is good, and the tiller would be correct. Fault can only be with the wood itself, or the tillering.
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If I'm making a 72" ntn hickory backed osage ELB, with grip 1.25" wide tapering evenly to 1/2" tips, and I tiller it full compass and it breaks, making it wider will not help.
If you say so. ::)
No point in arguing the particulars when basic concepts are in question here.
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You missed the important sentences in the post. Taking one part of a response out of context may work to suit your purpose, but it doesn't tell the whole story.
My point exactly... no point in arguing the particulars when basic concepts are in question.
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Fault can only be with the wood itself, or the tillering.
This part is wrong, obviously. Fault can also be with the design. Fault can also be with the glue. Fault can also be with an excessive difference in the compression and tension values of the different woods, e.g. the hickory may be fine and have average strength but the osage is especially strong in compression. I could go on, but let's take one thing at a time. Talking about width opens up the discussion to possible changes in the design in order to prevent breakage. The idea of trying to fit the wood to the design is the reverse of what I would do. That's my position.
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There again, you're taking a single sentence out of context. The bow I gave as an example is of sound design. Agreed? (and glue-up is part of the design). Hickory and osage are one of the best matched woods there is. It's just one example, and there are obviously many many more.
If the bow fails (and the wood and design are compatible as in this case), it's either a fault in the material, or a mistake by the maker... period.
Your generalised statement of 'just make it wider' is not good advice. I think we basically agree... design, material and manufacture are ALL vital.
I don't know about you, but I pick a piece of wood(s) and then match the design to it, optimising it's best qualities. It's bad practice to force wood into designs it does not excel at. That is a design failure.
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The bow I gave as an example is of sound design. Agreed?
Well no, not agreed. We are talking about a flat bow. The ELB design is not relevant to this discussion and therefore not sound on that basis. (Sorry, for those who think I've taken the sentence out of context, please scroll up to see the sentence in context... and look at all the other things we've discussed as well. ;))
Hickory and osage are one of the best matched woods there is.
Yes, I agree. But I must also mention that this combination didn't work well for Easternarcher in this case.
Your generalised statement of 'just make it wider' is not good advice.
Show me where I said "Just make it wider". You didn't take that one out of context, I'll give you that. You made it up.
I don't know about you, but I pick a piece of wood(s) and then match the design to it, optimising it's best qualities.
Where do you think designs come from? They come from taking the piece of wood and then shaping it so it performs well. Then the maker stands back and says, "This is a good design for this wood". Then the next guy takes the design and says, "I have some of that wood, if I choose that design I will be optimizing the wood's properties!". Then proceeds to break the bow because the wood is not exaclty the same as the first piece of wood.
(If you read that, I admire your patience).
I think we basically agree... design, material and manufacture are ALL vital.
Yes, we agree on that. Drat.
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Good grief.
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Breaks on the tension side of the wood break cleanly. The splintering occurs in the neutral plane area.
That limb was overstressed. Try making the limbs wider.
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;D ;D ;D ;D ;) ;) Don't know if making it wider would have helped,maybe :-\ but I still say in this case it was dry rotted wood. :)
Pappy
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agree with pappy here that wood sure looks suspicous to me, to dry almost pithy looking.
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"Try making it wider" is not "Just make it wider".
And, since I'm outnumbered, I'll say this: now it's a fair fight. ;D
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This is fun but I will bow out now. I'll switch to lurker mode. Keep us posted on your next attempt, Eastern.
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Someone above mentioned the hickory looked "pithy". I agree...it has the appearance of almost being crumbly even tho it looked sound when sawn - plained and glued up...That says dry-rot to me.
Shall we leave this discussion there.
I will glue another one soon enough and yes, I will post results then.
Wish me luck.