Primitive Archer
Main Discussion Area => Bows => Topic started by: missilemaster on February 26, 2013, 10:34:21 pm
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Hey guys,
I am in the middle of finishing a buckthorn bow( 61" ntn, 50# @ 26", 1 1/4" fade to mid limb, heat tempered), and I noticed this on the belly near a hole. At first I thought "oh great, a crysal" but as I looked at it closer I noticed some things about it. First, I dont think it is a hinge per-say, because I left extra wood around the knot. The rest of the bow's belly is nice and clear, nothing wrong. I noticed also that it followed the growth ring on the belly and didn"t wander off. Also, it doesn't appear that it is a pucker in the wood so much as it is a step, like one ring were sliding under the other, you can even feel it.
I was just wondering if you guys had experienced this with any other wood? Would there be any way to patch it? Thanks,
Cody
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Had something simular on a highly stressed bbo and it eventually fretted out right almost to the back.had I tried a belly lam when I first noticed it I might have been able to save it.now it's in the corner of shame!
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Hmmm? Red flag for me.....that last buckthorn I did had that same exact ring step at a quirky knot...and when it failed ,it failed at that knot and that island step ring popped cleanly off....not saying yours will do the same....but I did question whether that lil island ring step was faulty and not bonded well enough to the next ring up in the bow.....if you can feel that step id say its not bonded well to the next ring up,and id put a wrap around the whole island ring covering it up to err on the side of caution.
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Looks to me like a knot divot, a big one. I've only made two buckthorn bows, but on one of them I was whittling down the tips in the vicinity of a knot with a formation like that, and my knife caught the grain and it popped right out, leaving a nice bowl. From your pics it looks like you've only uncovered the top half. If you can remove it, that would be the best thing, but if not, I guess take blackhawk's advice.
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Basically the same as glue creep except in this case it's the natural glue between layers.
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I'd say your bow doesn't like those two rings and is trying to get shed of them. Can you remove the remainder of that ring without causing a hinge?
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I'd say your bow doesn't like those two rings and is trying to get shed of them. Can you remove the remainder of that ring without causing a hinge?
My thoughts as well.
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Hmmm, if you remove any wood it's bound to make it weaker, but if you plugged the hole and then took off the ring it might be ok... If you want to retain the look of the hole, maybe plug it with horn...
Maybe a daft idea, just tryin' to think outside the bow.
Del
Alternatively replace it with hole grown at high altitude, they are much tougher O:).
JW sent me some special holes last year, heck of a job getting them through customs ;)
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Alternatively replace it with hole grown at high altitude, they are much tougher O:).
JW sent me some special holes last year, heck of a job getting them through customs ;)
When Customs opened they box the dummies thought it was empty!
I just bought a dry oilwell in North Dakota and I am going to saw the sections of hole into 18" pieces and sell them as "pre-dug post holes", dollar each and I will cover shipping.
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Sounds like a sweet deal to me JW. I hate diggin' post holes! ;). Judging by what you read in the papers, there's a growing number of people in your target market! Btw misslemaster, I second ,third whatever the other guys said about your island wanting to pop off.It's trying to bend under that bit, and spit out the piece of wood.This will then give you a hinge where you will now have less wood.
Might have to pop it off and fix the tiller . Lower weight , but still functional. Might only loose a couple of pounds if you're lucky. With your superior skills and intellect ,I'm sure you will pull it off just fine. Be sure to post the results .
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Thanks for the info guys. I guess the lesson is, try not to have ring islands on the belly.
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Not necessarily, Cody. I think your limb is bending up to where the ring lifted but is stiff behind that(left thick for the knot) causing the ring to seperate as the limb bent. Sort a hinge but the ring was preventing the hinge...til it poped.
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I see, that makes sense Hopefully I will be able to fix her.
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Not necessarily, Cody. I think your limb is bending up to where the ring lifted but is stiff behind that(left thick for the knot) causing the ring to seperate as the limb bent. Sort a hinge but the ring was preventing the hinge...til it poped.
+1
If I were you and wanted to keep the draw-weight I would use the same technique for patching a chrysal. Look on Dean Torges website for a great description of how and why it works. This bow is toast if you don't fix it.
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Cody
Looks like what we call a fischer .
They show up from time to time in boards that have not been bent so I don't think it is some thing you necessarily did !
I would try to remove and patch it in or maybe as Dell suggested ,it sounds good and would look better !
Have fun !
Guy
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I always tiller knotted areas to appear slightly flat. Knots are weak spots. Jawge
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Some sort of a stress crack where you left the exture rings. If it stops between the rings that likely what it is. leave built up wood around knots. Quit doing that long ago. No need to plus it afects tillering some what.
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I recently had that happen on a black locust bow, except it was on the back. It's as if the "island" of growth rings there around the knot started to seperate. I gave it a thick sinew patch because I could not stomach trashing it. It is good so far. Will it last? Who knows.
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Never leave an island on the back of a bow. Generally speaking it is OK to leave an island on the belly but I guess this was the exception.
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I know what you're saying Pat, and I agree. I've had those layers in the built -up wood around knots seperate more than once. The problem is, the only reason I ever did it was because all the books advise to do it. Was this bad advice on the author's part? It seems so in my experience. Am I wrong that the books advise to leave islands around knots?
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Jimmy, lots of changes have ben made in bow making from when I first started back in the 1980s. Back then only osage, yew or lemonwood and maybe hickory were acceptable for bows. ::) We've learned a lot since then. If you read TBBI then read TBBIV you will see that the guys that were the experts back then learned from everyone else that what they had to say in the former had been disputed and viligent experimentation opened more doors for budding bowyers. Not that they were wrong in those days but all avenues had not been examined yet.
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Like Pat says...
And remember one of the first points made in TBB1 is "don't always believe the received wisdom!" It's discussing 'stacking'.
Yes read and listen, but do you own experiments, become your own 'expert'.
Same as all the stuff about 'never violate a ring on the back'... I think that comes from working Osage. The sky doesn't fall in if you do it (with sensitivity) with Yew.
Del
And another thing!
TBB is wrong about the Mary Rose.....
The Mary Rose was pulled up from off Portsmouth.. not Plymouth grrrrr Fttzzzz Hissss ;)
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Hey Cody, you jinxed me! >:( ;) This is an osage bow I'm just finishing up. I went out to put a few more arrows through her and after about 20 or so I noticed this. I think it is similar to your situation. The bottom ring of the riser started lifting right where it feathers to the limb. There is a whoop-te-doo right below the handle and a knot at the fade. I guess I remove too much at the whoop-te-doo so it bends just enough to cause the grain to lift. I think I can add a sinew wrap on this and it should be a pretty simple fix. Hope yours works out for you too. ;)
(http://i5.photobucket.com/albums/y199/PatBNC/crack002_zps7de4fa7a.jpg)
(http://i5.photobucket.com/albums/y199/PatBNC/crack001_zpsb234d761.jpg)
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OK,
So I thought about patching it, but I decided to remove just a hair more to see if I could create an island where the pull up was happening, since I had left extra wood anyway. Well, I didn't have to go deep at all to get an island, then I took my draw knife and...POP.. out it came, barely 1/16" deep. At this point I could still patch it, maybe with an ipe lamination, But if it isnt a hinge, would sawdust and glue work as well?
Thanks for the help, Cody
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one more
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Yep, on my last bow... i shoulda' just left it in a corner but I tried to use it and it cracked in half. :( if you think you can save it, by all means go for it. good luck to ya.
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It wasn't doing anything there anyway. If you have a spot where there is nothing but air supporting it a slight scoop isn't going to make much difference.
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Looks good to me the way it is !
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I think I can still see the chrysal at the bottom of that scoop :o... faint pale hair line?.
I'd go a bit longer and deeper on any patch. belt and braces, no point doing it and then thinking wish I'd gone deeper and longer.
Del
IMO a scoop like that is asking to collapse, it's a bit like the string angle thing.... if you take a bit of card and push edge on it's quite rigid, but you put a slight curve in and whoops it collapses, once the force isn't straight down the length of the wood /card whatever, once it has an angle of leverage... it will bend more. Put a U bend in the middle of a long strip of steel and then push on the ends... guess where it bends, yet the steel is the same thickness all along.
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It is of course very hard to tell from the pictures.
I would be able to give a definative answer if the bow was in my hands! ;)
First thing I would do is sand it smooth and then string it and check if the balance between the limbs has been affected. eg. is this limb weaker? At all? Even just a fraction? If not then I would start drawing it slowly, again just looking to see if that limb is acting weaker than it was before. If the tiller hasn't changed then take it gradually to full draw. Then i'd be looking to see if there was any damage to the belly there. If mot you've got your answer!
If this areqa does at anytime start to look weaker then it will require a little bit of tillering to bring it back into balance.
If worst case scenario a chrysal starts here or it looks hingy (unlikely) and you don't want to lose any weight then doing what I suggested earlier is really the only way to go (that will last!).
Did you look on Dean Torges site?
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Is it just me or do you guys see it... I've put a red line just right of the line.
You can see how they match up book fashion...
I don't think it is ring as the bit that popped would be following a ring.
Chrysals do go remarkably deep.
Del
BTW:_ I just checked out Dean Torges site (thanks Mike) and found the article, excellent read:-
http://www.bowyersedge.com/patch.html (http://www.bowyersedge.com/patch.html)
The link is here for those too lazy insufficiently meticulous to find it themselves ;)