Primitive Archer
Main Discussion Area => Bows => Topic started by: Matt Heppe on September 04, 2012, 11:41:17 pm
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This is my first effort at a recurve. It is red oak backed with hickory with red oak siyahs. Tip to tip it is 64". This image is 45# @ 27". I'm planning on tillering it to draw to 30". Are there any tillering corrections that you think I need to make?
(https://lh5.googleusercontent.com/-vyuMHwS-HHE/UEatI5KfQoI/AAAAAAAAA1s/MtjTGzSvrqw/s800/Bow%25203%2520Tiller.JPG)
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There are(to my eyes) a few very minor stiff spots, not sure if im right but IMO it looks that way.
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This looks pretty darn good to me. I might scrape (very gently) just of the right fade. But you're doing great. An unbraced pic would be helpful.
Gabe
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looks pretty good to me, if i was bein picky :) i would say the left limb is a hair stiff about mid limb . look forward to seeing it done those syiahs look good too.
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Rigid or bendy handle? Either way I would work the right fade a tad to even her up. How close to draw weight are you?
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I see a little but of a hatf bend 6" from the left fade, and a flat spot for 8" just past that. Hard to know wthout seeing the unstrung profile though. Nice job, interesting design.
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The right limb looks pretty good but it looks like the left has a couple of potential hinges with a flat spot mid limb
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I'm with Marc. I see that potential hinge about 6-8" towards the Fades from the Siyah with flat spots on each side of it.
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I´m with Marc and mullet and maybe 30" draw is a bit too much for a 64" bow...
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Not much I can say to improve what has already been said by some really fine Bowyers except i hope that red oak holds up for ya. I've got a feelin though that if it holds up that set will be hard to avoid. Danny
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Two pics to add. One unbraced and one braced. You can see that it has taken some set, but that's ok. I built this bow because I really wanted to try out two things I'd never done before: 1) I wanted to put siyahs on a bow, and 2) I wanted to do a lamination. I chose hickory because it is a great backing wood and red oak because I had some in the workshop. I'll have to find some better belly wood for the next one.
Tillering this bow was much different than for my flatbow/longbows. The bow was very stiff at first (the added lamination made it very thick. I had the long tillering string on with a goal of reaching 10" of movement. I had to take a lot of wood off with the rasp, but got my 10" of movement @ 50# (with a goal of 55# for the finished bow).
After 10" I gave the bow a light sanding to get the rasp marks out of it and put a low brace on it. The bow immediately pulled 47# @ 27". The caught me very off guard. After so much work to get just 10" of movement with the long tiller string, the braced bow went almost to my draw length underweight. What could be the cause of this? Did the leverage of the siyahs affect the draw weight, making it draw easier as the string was pulled back? Or am I imagining things and should be more careful next time?
I have some room to play and hope to end up at 28" @ 45#. I should be able to work out the tillering flaws. I really like the bow and will repeat the design again. I'll have finished pics by the weekend (I hope). I haven't decided how I want to finish it.
(https://lh5.googleusercontent.com/-f69-p1GfMA8/UEfmKXT1PxI/AAAAAAAAA2A/bQ8qUR-yDvU/s821/3+unbraced.JPG)
(https://lh4.googleusercontent.com/-tJl7YJJk9VY/UEfmLVqg02I/AAAAAAAAA2E/JwxjKxTTgys/s821/3+braced.JPG)
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Recurves have a high pre-load, so to speak.
Or higher early draw weight.
So the bow seems much heavier, at brace, than it actually is.
An easy mistake with reflexed designs.
I often second guess when to put it on the short string.
I tend to short string fairly early, spending alot of time getting the thickness dialed in first.
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What sharpend said,very easy to miss judge the weight on a highly re flexed bow,I try and get it braced as soon as possible. I use a tiller stick on my bows instead of a tiller tree until I get them ready for brace so as soon as I can stretch a string across tip to tip and all looks even I will brace it to a low brace especially if it has a lot of reflex. That one is really looking good. :)
Pappy
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It's all been said already pretty much.
if you insist on going to 30" I'd suggest making it bend through the handle a tad.
Or maybe put some slightly longer siyahs on it. (25" siyahs will get you there no prob >:D )
Del
(Looks V nice btw)
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Thanks for all the tips and info. I did some scraping and sanding and the bow ended up at 46# @ 28" with 1.75 inches of set. It is under the goal weight of 50-55# but I now have a better understanding of how to work with a recurved bow. I decided not to go for 30" draw as it is not a good length for me.
Now I need to find a string. With the siyahs I need much larger loops than you have for a longbow. Hopefully I can communicate what I'm looking for with a string maker.
I saw a beautiful black and gold Turkish bow on paleoplanet. If I get my courage up I might try a poor man's copy. I'll post it when it's do e.
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Making strings is a cinch. I recommend learning how to do a flemish loop and making your own out of fastflight. I got a 1/4# spool online for about $25 but I'll be able to make a bajillion strings from it. check out poorfolkbows.com for a tutorial on how to make a jig and a string. He explains it really well. You'll save a ton of money making your own strings.
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Making strings is a cinch. I recommend learning how to do a flemish loop and making your own out of fastflight. I got a 1/4# spool online for about $25 but I'll be able to make a bajillion strings from it. check out poorfolkbows.com for a tutorial on how to make a jig and a string. He explains it really well. You'll save a ton of money making your own strings.
Plus, it's really fun to mix and match colors and try different combos. One of my favorite parts of making the bow is twisting a string. :)
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Dangit! Chrysals!
The red oak just couldn't take the pressure. I'm going to save the siyahs and use them on my next bow. I was still in the breaking-in phase and hadn't finished the bow, so am not too upset at the development. The whole purpose behind this bow was to try out siyahs and to do a lamination. Both were successful. I just made a bad wood selection and misjudged the tillering due to the unexpectedly high initial load of a recurve.
I am going to do another bow with siyahs. I am thinking of going non-laminated and using hickory.
Is there a North American hardwood that handles compression well? Something I could have paired up with hickory? I chose hickory backing because I knew the bow was going to have a pretty big bend to it.
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How about hickory backed osage with hickory siyas? Make the handle bend a scoosh (nice technical term, eh?) and otherwise match the last design fairly closely.
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Shame about the chrysals... I hate thos suckers >:(.
Still its all part of the game when trying to push wood to the limit.
Del
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Is there a North American hardwood that handles compression well? Something I could have paired up with hickory? I chose hickory backing because I knew the bow was going to have a pretty big bend to it.
That is a good way of thinking, but not only must the backing be able to take the bend, the belly must also be able to withstand the compression. Red oak is pretty poor in compression, so the powerful hickory is likely to overpower the belly with such a sharp bend.
You could have trapped the back, making it about 2/3 the width of the red oak belly. That would have helped a lot. A longer bow length is also a good method, but that is probably not what you wanted.
Hickory on its own would have been great for a design such as this one. It might have gotten some set, (but no chrysals) which could have been avoided by - again - trapping the back.
Elm would have been good as well (no hickory needed on the back). And of course hickory backed osage or maybe even hickory backed hornbeam.
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if your gonna try a selfbow go with hickory or white oak, both will take the bend, Bub
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You know you're an addict when it is going to drive you nuts all day long that the sawmill is closed on Fridays. I can see the hickory and elm on their shelves. I'm dying to ask Mr. Spacht if he's cut any Osage.
My name is Matt Heppe, and I am an addict.
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;D ;D ;) to bad about the chrysals. :( It was looking good. :)
Pappy
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Matt, you might be able to save it with some belly lams like I did here...
http://www.primitivearcher.com/smf/index.php/topic,34403.msg455218.html#msg455218
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I came up with a solution and the bow will come back from the dead better than before. Pics coming soon....
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I have made a number of Elm and HHB bows of this design with no chrysals and a long draw.
While you can just make it in recurve form there is just something about the angled glued in siyahs that "make" the design.
The best option is really a wider shorter limb and a longer lower angled siyah. 35 degrees is best. Basically a pumped up mollie.
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You didn't say where the chrysals are or I missed it. My guess is they are spread out over the entire limb? Both sides? That indicates a design flaw. Just a guess but it is too short. Drawing it any further may be dire. Jawge
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George,
The chrysals were all on the left limb where several people spotted a flat spot and a two potential hinges.
I won't use a chrysaled bow. Too much risk, I think.
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A chrysaled limb that is corrected is actually less likely to break if the back of the limb is sound and tension strong. The belly wood is "getting out of the way" so the back has less pressure on it.