Primitive Archer
Main Discussion Area => Bows => Topic started by: Wooden Spring on January 30, 2015, 09:37:30 am
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I currently make backed flatbows, but I've been wanting to experiment with some basic siyahs. Can anyone post some pictures of theirs so I can get an idea of what it "done right" is supposed to look like before I goof up a few bows figuring it out?
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(http://i399.photobucket.com/albums/pp78/pat_05/IMG_1972_zps84d5d103.jpg)
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_1949_zps635f3e8f.jpg)
(http://i399.photobucket.com/albums/pp78/pat_05/IMG_1974_zpsbdc58a24.jpg)
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AWESOME!!!! Just for that, take the next two days off of work!
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Really cool Pat. Thanks for sharing
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What type of wood are you working with in these pictures Pat?
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I haven't had my coffee yet, but I thought I was looking at a bunch of hockey sticks :-[ :-[
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Looks like hickory and jatoba?
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Ash siyahs, Elm, Bulletwood for working part of bows.
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PatM, I don't have access to bulletwood, but I do have access to Ipe. How does Ipe compare to it?
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PatM, also, it looks like your overlap is 3" with a 4" siyah angled at 30 degrees. It appears to be 3/8" consistent thickness and 1/2" at the overlap. Is that about right?
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Something like this???
Sorry for the crude sketch, but I have to draw something in order to understand it...
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You should just pick a length of splice and siyah length that fits your design. Plenty of room for experimentation. The picture I posted is actually a four inch splice and a 7 inch siyah.
The thickness of the splice will be dependent on what it takes to keep that area stiff relative to the draw weight.
Ipe is better in compression but also harder on the backing.
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Wood, I have only worked with bulletwood maybe 3 times. In my opinion it is just like working with osage but a bit stiffer. Great wood. It is also called beefwood because when you work it it looks like raw beef until the color fades out in a few hours. It doesn't chrysal like jatoba and seems a little more elastic than ipe.
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Awesome, thanks PatM and Badger. I can't wait to start experimenting!
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Badger: I had it in my head that you used to make a l;ot of bamboo-backed massaranduba bows.
But yeah, ipe is a bit stiffer than bulletwood, but if you haven't used either, bulletwood is PLENTY stiff and strong. I love it, but can't buy it readily, and tho I have gotten some great stuff off of Ebay, you can't see the grain at all in pics. Ipe is the same way. Trouble getting wood without serious grain run-off back to front is what got me making more selfbows. I used to lust after beautiful tropicals, but had too many bows slip-fracture on the belly under compression.
Pat does cool work. I have never splices a siyah like this, and I want to try it, too. I usually thin the tip of the bow by tapering and then reinforce the belly side with overlaid slats.
Pat: How is that elm backing made? Did you actually slice the top layer off a log, leaving the back just like a self bow back, or is it from a board?
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Pat,
where are the pics of the finished backed flat bows? I thought I saw them a while ago.
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Here's a thought... If you cross pinned the siyah in place with, say, hickory dowels, would you still have to sinew wrap the joint?
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Here's a thought... If you cross pinned the siyah in place with, say, hickory dowels, would you still have to sinew wrap the joint?
I've wondered about this many times - but I've come to think about it differently than I first did. I think a large part of the strength of the wrapped joints comes from the glued surface area involved. The the amount of glue holding surface area on a length of thread or sinew wrapping is very very high when compared to the very limited surface area of the pegs run thru the joint. The crush-resistance and shear-resistance strength of the pegs themselves is very little engaged in this application. ...or at least I've deluded myself into thinking that these excuses explain the physics involved better. ::)
BTW - Your 'crude drawings' are anything but! I save them regularly to work with...
OneBow
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There wouldn't be enough thickness to support all but the thinnest of pins. Wrapping is a far better solution.
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Here's a thought... If you cross pinned the siyah in place with, say, hickory dowels, would you still have to sinew wrap the joint?
You'd have to thicken it substantially. I'm with OneBow. Modern glues are actually stronger than the wood, so the magic is in getting a nicely fitted glue joint. The wrapping is there to help out, and keep it together if a ghlue joint fails, as well as making it look nice.
BTW, I just remembered that I have spliced a recurve onto a core, and then backed that with hickory or bamboo.
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Splicing into the core and then running the backing up the splice is the best option but that works better when just gluing in a typical recurved piece.
(http://i399.photobucket.com/albums/pp78/pat_05/aug2012019.jpg)
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Rats... I was really hoping that pinning it would work. I had ideas of making the splice REALLY decorative, like the dragon's tail shown below. I can do wonders with a bandsaw, and I'd love to give that a go!
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You're not thinking what you are doing with the grain of your outer limb.... I would keep your decoration to surface adornments rather than structural.
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You're not thinking what you are doing with the grain of your outer limb.... I would keep your decoration to surface adornments rather than structural.
No doubt you're right. I'm just weird like that. :laugh:
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You're not thinking what you are doing with the grain of your outer limb.... I would keep your decoration to surface adornments rather than structural.
I agree with him.
See, I think this would be POSSIBLE but the whole area, all the way down a couple inches below the splice at least would have to not bend AT ALL, costing you a huge amount of working limb length. Same principle we tell new guys when they glue a handle on a board bow. That handle can not bend, or it will pop off. You can get away with murder if it is really stiff, but any flex will have that lifting splinters, etc.... When you splice two woods with different stiffnesses, their different resistance to flexing cna cause failure, too (one wants to flex a bit, and the other doesn't).
Use your skills to make a fancy overlay for the front and back of the siyah, or something. You could even do the belly splice with the backing over the whole deal like that. I made some belly splices with a finger-joiner on a router once that were pretty cool, but a lot of set up and planning.
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10-4, no decorative attempt in the mating joint.
So, I think two more questions and I'll be ready to give it a go.
1) How do they affect the overal length of the bow, assuming a 28" draw? (my normal flat bows are 68" ntn)
> Should I keep the bow the same length to start with, and essentially stick the siyah on the end? Then gradually start making shorter bows?
2) Since I don't have easy access to sinew, could I wrap the joint in cotton cord soaked in Titebond 3?
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Again that will depend on your choice of wood and width of limb/siyah length. I prefer about 60"-64" for this type of bow when using a strong belly wood. You're really just making a mollie with the levers set back a bit.
Linen is the best natural choice for wrapping. Preferable to sinew in fact.
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Linen? Awesome, that's easy since my wife is a seamstress.
Thanks dude!
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Silk is good, ...and is readily available, ...and has a bit of tradition to it, if that sort of thing matters to you.
OneBow
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Pat
spring buck asked eariler
Pat: How is that elm backing made? Did you actually slice the top layer off a log, leaving the back just like a self bow back, or is it from a board
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and I have been hoping you might comment, as you usually seem quite generous sharing your methods
willie
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That is just the outside of a stave reduced in thickness. It's hard to beat a single unbroken ring for a back.
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PatM- This may be a dumb question so excuse my ignorance.
Is a spliced in siyah the same in performance as a static recurve of the same dimensions,
Or is there noticeable higher performance because a lighter wood can be used?
Aside from looking real cool, and being able to get longer bows from shorter staves, is there more advantages? Just a style preference?
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You can't really compare them directly since they won't be the same dimensions.
Studies have shown that sharper statics store more energy but lower angled levers are more efficient.
Seems to work out about the same.
You'll have to make one and see what advantages you find but better use of short staves and smoothness of draw are definitely pluses.
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thanks pat
there are some good questions here, and some excellent answers.
this thread will get bookmarked for when my Siyahed project get started
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Yeah, Willie, I used to mess around a lot with recurves of all types looking for that perfect, secret, stiff but weightless, high energy storing recurve. Styles are fun to mess with because they teach you things, and I have made some fast recurves, but basically, if I execute ANY style well, they all shoot about the same speed. Maybe that is just me. Go do it, it's fun and you'll make some cool bows.
But, don't get me started on all the stuff I mean to do someday! :P The hollow recurves. The cable-backed Arctic-style hinged recurves. The linen-backed bamboo longbows. The multi-pyramid loose laminate bows. The double cable Mollie. So many crazy ideas in my head.
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That is just the outside of a stave reduced in thickness. It's hard to beat a single unbroken ring for a back.
Does this just take forever, or do you have a cool method?
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That is just the outside of a stave reduced in thickness. It's hard to beat a single unbroken ring for a back.
Does this just take forever, or do you have a cool method?
I have a cool method involving a very sharp hatchet, a farriers rasp and a board with coarse sandpaper stuck to it.
Doesn't take that long with practice. The hard part is you basically sacrifice a perfect self stave to use only the outside 3/16.
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Pat, I have a 40ish inch long piece of yew, is it realistic if I splice on syhias to reach a 28" draw?
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How clean is it?
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It's perrt much perfect.
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It's japanese yew, so ring count isn't as high. Just dunno what to do with the little feller
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Cool, Pat. That's how I used to do bamboo! I think most of my elm is oo wayy to try it, but if I ever get a short, fat chunk, maybe I'll do this instead of billets and splicing.