Primitive Archer
Main Discussion Area => Bows => Topic started by: medicinewheel on December 10, 2010, 01:14:10 pm
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Hey guys, tillered this little elm recurve today, 58" ntn, 35#@24". upper limb wouldn't want to come around really for a while, and now I'm afraid I overdid. Tiller blind by now...
Have a look. Any coments welcome (as long as they remain family friendly 8) 8) 8) )
Thanks.
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I took the liberty of grabbing the last photo and taking the bottom limb, flipping it and putting it side by side to the upper limp. Does this help? I would aggree that tye upper is bending more...
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WOW, I really have to learn photoshop - great thanks!!!
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I use a program called GIMP. does the same stuff as photoshop but is a free download.
http://www.gimp.org/
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Ya, I'd stay away from that section starting about 2 or 3 inches out from the fade on the upper limb until you get the lower one caught up a bit.
The upper limb is definitely bending more.
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Nice looking bow can't to see the finished product
Thanks Leroy
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Then again you may want to stop right there if you are happy with it. Recurves have a tendency for the bottom limb to stress more than the top limb and this may help cancel that out. Just a thought.
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I think at the first stepp working on jut the upper limb from midd. Now that limb working too much at inner limb after the fade.
Than will see the bottom limb need some more work or not.
I would use some heat treat too.
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To draw the bow actually feels pretty good, nice balance. I left the tillering alone for now and toasted the belly to gain back some of the reflex; now I leave it sitting for a few days. 30 to 35#@24" is my desired draw weight for this one, so if I'd gain some pounds from toasting, I would scrape it some more.
@Bevan: actually I use GIMP; just have to learn to do that sort of legerdemain with it! Thanks again...
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i see nothing wrong with that
that bottom limb is just a tad stronger,nothing qrong with a little positive tiller
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I'd say the bottom limb is stiffer.
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Dont mind the hasty photoshop job. I have marked with arrows on the picture were I would remove some wood:
(http://i995.photobucket.com/albums/af73/Holten101/Tillerkopi-1.jpg)
Green is the upper limb and red is the lower (I hope I didnt switch them around;-)
Cheers
Btw: Very inspiring work....I hope I have a suitable piece of wood in the workshop:-)
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Frank
Recurves of that style need to be exercised a lot more than other bows after wood removal. Also the tiller can shift overnight after resting as you work on the bow
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The thickness taper of the upper limb does not look right to me. It should taper evenly from thicker at the fades to thinner as you approach the recurve, and it seems to be doing the opposite.
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@adb, sailordad: yes the bottom limb is stiffer, and the tiller is ~3/8" positive at the deepest point of the curve, which may be a bit too much, since the upper limb is also ~3/4" longer. It does balance nicely when pulled, though, thats why I'm insecure!
@Holton: It's great to see it pictured like that: That's exactly where I thought it doesn't want to come around.
@Mark: I have worked it slowly and I have worked it a lot, but maybe not enough. I'll do that some more when it has gained a normal moisture content after the toasting; it's fairly humid around here right now, would you say 4 days, 5 days would be enough?
@Gordon: you are right, it appears to look like that on the pictures, but I just gave it a close inspection, and it tapers the way it should except for several bumps due to some pin knots which may have cause the imagination.
@everybody: whenever I asked a question here in the past I was given answers that helped me solve the problem, this time is no exception. Thanks for that!
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Its a really cool looking bow. If this one doesn't come around I hope you are willing to try another one. Jim
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Frank
If it's really humid then a couple days would be enough
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It looks to me like the upper limb is bending to much near the fade. Actually both limbs are in my opinion, but the top limb is worse. I'd get the mid to outer limbs bending some more or that bow is going to take quite a bit of set right off the fades if it hasn't already. It would also help though if you showed a front profile of the limbs.... and a unstrung profile.
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Think you are right; the tips had moved from 4 inches in front to be in line with the back of the handle. I did not take a picture of the unstrung profile when I made that series, so now it's toasted and the tips are in front again. I'll take a front profile later today.
So I really think I should perform some more tillering.
In case I would lose to much draw weight, would it make sense to back it with a sinew layer or two, or would that cause even more set??
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You can always add sinew after it's fished to bump up the draw weight a little. I'd continue tillering and see what it comes out at first. You could always cut it a little shorter too for the draw length/weight your shooting for it should be ok.
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Here's a full draw picture of one of my all time favorite bows of that style. See how round the tiller shape of the limbs are right up to the base of the recurves. IMO this is the fulll draw shape you should be shooting for on this bow.
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Actually....that IS the tillershape I am shooting for!
Thanx Ryan!
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@Marc: My experience with toasted bellies (...and with bow building in general ... ;D ) is marginal; I'm totally surprised that my little bow now reaches 35# long before I'm at brace height. Is that normal, will that stay? - If so I could easily get a better arc and still have my desired weight.
@Gordon: It's the angle of the picture and a bit of a twist in the upper limb that makes it look as if tapering wrong way round.
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@Ryan: here is the front profile; further tapering on upper limb is limited due to a pin knot right on the edge where circled.
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Heat-treating does wonders with Elm. The limb profile looks good. Ryan has a good tiller on his bow. If you tiller yours the same then it will turn out good. Here is another picture you can go by
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Exploded right through one of the pin knots on upper limb before I reached brace hight. To bad...
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That's to bad Frank. Did you let it rehydrate after heat treating it? Elm almost never fails in tension.
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I guess this particular pin knot suffered damage from the heating actually; looks as if the heat had crawled through there to the back of the bow.
PS: probably would have helped to wait a few days longer, too...
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If you waited a couple days then that should have been enough. I've started working a bow in as little as 1 day after tempering without any trouble. Did this Elm have fine growth rings by chance?
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Too bad Frank. :( That is my favorite style of recurve.
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Tempered it last friday, and it was not too dry around here. The rings where sort of fine, yes.
I have a better piece of elm and I'll soon start another one!