Primitive Archer
Main Discussion Area => Bows => Topic started by: J05H on July 31, 2014, 04:40:55 pm
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This is the upper limb from an elm stave I broke about a month ago. I had the back smooth and nick free as far as I could tell. Its probably only my forth or fifth real break ( I've had failures due to splinters and cracks, just few breaks), so I could use a little help as to what kind of break it is. On the others the reason was clear. You can only learn from mistakes if you know why they happened, so I need a little help to keep from making this mistake again.
(http://i879.photobucket.com/albums/ab359/J05H/IMG_20140731_142334290_HDR.jpg)
Thanks in advance for any and all feed back. Josh
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Looks like it was weak in that spot and it just crumpled or the belly was weak.
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Looks just like the break I had on my first elm. It broke at a weak spot from being pulled much further than it should have been at that stage.
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from my experience elm seems to be sensitive to a bad tiller and break easy it looks just like some of the breaks ive had
what part of the bow making process were you in? it doesn't look like the back is clean enough i like to sand it down to 300 grit before i put any pressure on the limbs
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Almost looks like rot to me. How was it harvested and stored?
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Never seen one like that...
Del
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Me neither, Del. My first thought was the stave wasn't handled properly of the stump and it became infected by fungi. Elm is pretty strong and you'd be hard pressed to break an elm stave like this if the wood was sound. IMO! Will you post pics of the break from all sides?
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Looks like it's decayed to me. Was it left as a log for a while in warm conditions before working it down?
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any pictures of tiller....? massive hinge and rot?
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I bought on Ebay from leenterpises and kept it in my house until I was ready to work it. I chased a ring and sanded to 120 grit. This is the last picture I took of the tiller because taking pictures was a pain. I was shooting for a holmie. Its at 18" in the pic, and was out to about 26" of a planned 28" when it broke.
(http://i879.photobucket.com/albums/ab359/J05H/IMG_20140703_153341894_HDR.jpg)
It broke on the left limb in the pic at almost the center of the limb. I'll post pics of the break from more angles as soon as they upload.
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It almost looks like the wood may have been too dry.
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One thing I do know and can see is that it is under designed and had a poor tiller judging by the pic you posted....how wide and long were the working portions only? Regardless of what it is tho your bend needs to be perfect with lever bows otherwise bang!!! And its even more so with Whitewood's....and regardless if it was rot or not try making your limbs wider and distribute the bend better before pulling it that far....if you were pulling it that far like it is in the pic then I am not surprised it broke,and that's even if it was good wood(no rot).
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It is not bending enough out of the fades and it's not Osage.
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I put a red arrow where it broke and blue lines where the levers were intended to start. It was 2" wide in the bending portion and 68" overall. I had evened it out a lot by the time it broke, but looking back I should have had it bending much better by 18".
(http://i879.photobucket.com/albums/ab359/J05H/86e5a6b1-cdec-403f-acaa-310d06861fc3.jpg)
So to recap, it was possibly degraded but definitely overstressed. I should have evened out the tiller far sooner in the process because elm can't take the abuse that osage or hickory can. Thank you all for setting me straight. Hopefully my second elm bow won't suffer the same fate.
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Oh yeah, here are some more pics of the break.
(http://i879.photobucket.com/albums/ab359/J05H/IMG_20140731_162710332.jpg)
(http://i879.photobucket.com/albums/ab359/J05H/IMG_20140731_162931406.jpg)
(http://i879.photobucket.com/albums/ab359/J05H/IMG_20140731_162750551.jpg)
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I just found this. I don't know if it means anything but I thought I'd post it just in case. The earlywood is kind of powdery for some reason.
(http://i879.photobucket.com/albums/ab359/J05H/IMG_20140731_204207997.jpg)
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Definitely decayed. Elm should be able to fold back on itself without breaking in half. I've bend tested a lot of it and never been able to actually snap a piece.
It looks very similar to wood I have cut for firewood that has been fighting Dutch Elm disease for a year and then cut when the leaves have shown it has given up the ghost.
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Well that makes me feel a little better, but I still learned from it. I need to get my tiller right a lot sooner. Thanks everyone for the help.
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I can bend our elm 45 easily and it will not fail in tension. It will crush much more easily
I would want my cash back.
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(http://i121.photobucket.com/albums/o218/dwardo/Bow%20making/IMAG2491_zpsa56d657c.jpg)
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It looks way too dry to me.
Grady
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Elm doesn't really get too dry. It's a lot like sinew that way.
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That is good to know Pat, I have not used Elm yet but I have 3 6-8" Elm trees flagged beside my house that are going to be cut down soon. I keep my wood in my shop that is kept at 40 - 45% RH.
Grady
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It is not bending enough out of the fades and it's not Osage.
Elm is tougher than osage in tension or at least on a par. Elm is almost indestructable in tension......i've tried!
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Just seen your third picture. The earlywood should not look like that.....
Don't worry at 2 inch wide it should have easily held together - I doubt very much wether it was your tiller that was at fault.
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Besides what looks like spalting it also looks like this type of red elm that is extremely light and weak. Can you weight the bow if you still have all the pieces? I know a lot of guys like red elm but I won't even full with it anymore.
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Sorry, I don't have enough of it to weigh, but what I still have does seem kinda light.
Thank you all for helping me figure this one out. I have another elm stave and I now feel much more prepared to tackle it. I'll be able to tell if its degraded like this one before I waste too much time on it. It should be better, because it supposed to have been cut from a different tree at a different time, and I have gotten several other staves from this guy that have all worked out fine.
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Yes do some bend tests on scrap pieces. You can even make a mini bow out of it - like 12 inch long. If you make it to scale it will act exactly the same as a full sized bow.
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Yeah, that's what I was thinking. Mini-bows can be very informative. They are also a lot of fun. Check out this little red oak I made last year.
http://www.primitivearcher.com/smf/index.php/topic,43264.0.html (http://www.primitivearcher.com/smf/index.php/topic,43264.0.html)