Primitive Archer
Main Discussion Area => Bows => Topic started by: DC on May 06, 2017, 07:24:35 pm
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Does this dimension matter other than maybe having to use a bridge?
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If it's thick it can be narrow and if thinner it needs to be wider.
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At the moment the limb is 3/4" thick where the "V" joint will be and the siyah is over an inch thick. I think I have lots of wood. I want to narrow the siyah a bit to take that little wiggle out and make it straighter.
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You'll be happier if you make the wide point where the two meet just slightly over half an inch wide.
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I'll try. I think I'll make it. Or be very close. Thanks Oh--- how thick can I get away with on a 40+# bow. I'm using OS so think strong and stiff. :D And heavy :(
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How do these look? Any changes I should make? These are a first for me so I'm groping around in the dark. :D Should the limb come right to the end of the bend?
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Nothing to contribute DC just curious what your making there ?
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That's fine.
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Those look great Dc
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Nothing to contribute DC just curious what your making there ?
A while ago I was trying to bend tight recurves in some Ocean Spray. I failed. I thought I might glue on some recurves (siyahs). I found a natural crook and cut some siyahs. They dried and I found a shortish deflexed OS stave in my stash and thought I would do a practice run on "V" joints and figure some things. The end result will probably not be exciting as I think it's too long but I'm too chicken to make it shorter. The siyahs will probably be too heavy. It is a 2 1/2" dia stave so I'll make the limbs wide and thin. Once it's shooting I can rasp away at the siyahs to bring their weight down. If it shows promise I could move the siyahs inboard a bit. "V" joints are fairly easy to do. If it pops a small splinter maybe I'll decrown and sinew it.
Basically just experimenting and messing about :D
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Looks kinda like a Korean style siyah, like on the warbows which had thicker siyahs, and also pretty wide
Good luck
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That's just the rough shape, the end result will probably look more like a recurve.
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Can the "V" joint bend at all? I'm just trying to maximise the working length.
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Answered my own question :D I "V" jointed a spare decrowned limb I had leaning against the wall. I put the joint right in mid limb, epoxy, heat cured overnight. It took about ten or so good bends before it let go. It broke right at the point first. I just used glue, no wrap.
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;)
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Siyahs and joints should not bend. At the tip, it does not take much to keep them stiff. If you don't make the siyahs too long, they don't even need to be wrapped, especially with modern glues.
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Wait? did it break at the tip or did you also do a v joint mid-limb where it bends too? What glue did you use?
I'm also attempting to do siyahs on my current project. So if that was the tip it would be good to know why it failed.
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Wait? did it break at the tip or did you also do a v joint mid-limb where it bends too? What glue did you use?
I'm also attempting to do siyahs on my current project. So if that was the tip it would be good to know why it failed.
Re-read his post. ;)
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The broken one was a test. I used an old limb(from a broken bow) and spliced it in the middle just to have a worst possible position. I used epoxy. It actually bend far past normal about 10-12 times before it broke. My siyah joints are doing fine.
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You knew how that was gonna end up though didn't you?
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Well, sorta. I did the same kind of test with a piece of lath and it broke beside the joint. It was a crummy piece of wood but it did give me a bit of hope for a little movement in the joint. I still think a little movement is possible but it would be too unpredictable to try it on a bow. A wrap on the pointy end would probably help. It's all moot though, leave joints stiff is what I've gotten out of it.
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I got it tillered to 42#@27" so I started slimming the tips. With the rough tips I shot it through the chrono and got 150fps. I reduced the last 4" by 5 grams each and it chronoed at 157 fps. I reduced the "V" splice area by 10 grams each and it chronoed at 161 fps. The closer to the handle you remove wood the less bang for your buck :D. I'm looking at the "heel" of the siyah. If I remove it I can lose a few more grams but I would be changing the effective angle of the curve. It would also "ease" the string liftoff instead of having it happen abruptly. Do you think I should remove the heel?
I keep looking at that bend. I'n my drag racing days I would be drilling three lightening hole in there ;D ;D ;D
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DC, why are you doing siyahs?
You can easily steam in that statics! Even steeper angles and tighter curves are possible with a natural stave.
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I tried to bend the OS into a tight curve and failed miserably. I used steam, boiled and dry heat and just couldn't get it to bend very far. The belly would crack. I was trying for close to 90 degrees. So I came up with the idea of using siyahs. I went looking for natural crooks to use. Guess what, OS doesn't bend like that. But by now my brain was in siyah mode and I wanted to try it. I got the best crook I could find and started out. I realized halfway through that I probably could have bent the bow as tight as these siyahs were. Anyway I have learned a lot messing with this "waste of time ;D". I'm going to try bending green OS to see how that works.
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At least you seen what reducing weight on the tips can do for performance and you got a good hang for how to do siyah glue ups.It's all done in little bits here and there and your right the more weight reduction farther out from the handle the better.It's interesting to some of us anyway.
I can see steam bending pin knotty wood can be frustrating but doing it green might be the ticket.I would maybe let a layer of shellack dry on that wood before steaming too.It could'nt hurt any.
A pic of the bow would be nice and at full draw too.After you dress it up of course.
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Do you think I should remove the heel?
I definitely would reduce it but not remove it.
I add siyahs when the stave is not long enough.
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Interesting thread I have a bow setting in a box that I never found the time to put together from Dave Mead but on his siyas he shapes the siyas in a fat knife edge and drills 3 holes in them when I get back in town I will see if I can take a pic for you, they are amazingly thin !
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You can probably reduce those tips by half. Make them narrower and taper to a knife edge. Use a long loop that straddles the knife edge.
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The knife edge would end at the bridge?
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Yes. Then have it flare out abruptly so that there is a wider spot for a tracking groove. You can make your taper outside your v splice less bulging.
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Where the limb meets the siyah you can taper the limb quite a bit, along the splice narrow the width so by the time the limb ends it blends seamlessly into the siyah.
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Back at this again. Building new stairs up to the deck got in the way :D.
More questions. At "a" the limb is .4" thick. At "b" it's .6" thick. How much do you think I can thin out around "b" and still keep it from bending? The point of the "v" joint is about 2" to the right of "a". Urufu, in your last post you said I can thin the taper, should it blend smoothly at "c", like remove those shoulders completely?
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Back to the drag racing days comment, you could probably succeed in drilling holes to lighten the Siyahs by lining the holes with thin wall aluminum tubing. It would be a little less traditional , but it would help in lightening towards the end of the limbs. The thin wall aluminum would allow structure to prevent breakage, I would imagine.
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Simson: "DC, why are you doing siyahs? You can easily steam in that statics! Even steeper angles and tighter curves are possible with a natural stave."
I don't know why HE'S doing siyahs, but when I did them it was either to stretch my wood budget by using something too short otherwise, OR, just to see if I could do it that way. I did recurves THIS way, let's see if I can do it this OTHER way.
PatM is all over this. A triangle cross section is about 88% as stiff and strong as a square cross section the same biggest dimension, but something like 40% lighter.
I even make Mollie levers either a pretty skinny trapezoid or Gothic arch cross section.
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It's also virtually the only way to make a really sharp static with a wood like Ipe. Just added short sharp statics to an Ipe flight bow using this method.
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Simson: "DC, why are you doing siyahs? You can easily steam in that statics! Even steeper angles and tighter curves are possible with a natural stave."
I don't know why HE'S doing siyahs, but when I did them it was either to stretch my wood budget by using something too short otherwise, OR, just to see if I could do it that way. I did recurves THIS way, let's see if I can do it this OTHER way.
PatM is all over this. A triangle cross section is about 88% as stiff and strong as a square cross section the same biggest dimension, but something like 40% lighter.
I even make Mollie levers either a pretty skinny trapezoid or Gothic arch cross section.
Tangential, but I'm planning to thin my molle levers into a an arch cross section as well. Wish I had a chronograph so I could see what kind of difference it might make.
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Anyone remember David Brunetta's Skeletip bow? One of the prettiest flight bows I ever saw, no siyahs but it had some holes in the outers:
(http://davidbrunetta.com/img/art_bows/SKELETIP-BOW.jpg)
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Wow that's a stunner. Wonder if you could do something like that on a mollie. Probably not.
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Those are siyahs on the ends, lust really low angle and sandwiched in.
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Anyone remember David Brunetta's Skeletip bow? One of the prettiest flight bows I ever saw, no siyahs but it had some holes in the outers:
(http://davidbrunetta.com/img/art_bows/SKELETIP-BOW.jpg)
WOW!! just WOW