Primitive Archer
Main Discussion Area => Bows => Topic started by: NorthHeart on December 26, 2017, 11:28:19 pm
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So i have another stave ive been kinda putting off. I wanted to sinew it, but impatience and this new fondness to explore Yews capacities has me wondering if i can get away with rawhide only. Allow me to describe the stave. 62" OAL 1-1/4" wide. The gnarly limb with a knot in the belly removed thus leaving a hump, has plenty of sapwood...but on the straight limb i got the sapwood too thin. So thin that in the center of the outer limb you can see heartwood peaking through. Id like to try for a bow thats 50-55# @ 24-25". Do yall think that rawhide will suffice or is this stave gonna need a sinew backing?
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more pics....
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A little bit of heartwood peeking through was pretty common in many of the yew bows from the 1930's and 40's. I think you will be fine.60" btwn nocks is plenty of length for a 25" draw. Even more do able if the handle flexes a bit.
A thin rawhide backing wood be good for protection from dings if you use this one for hunting, even if the back doesn't technically need it.
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No need to waste good sinew if your goal is to protect the back at that bow and draw length. Tthere are other natural materials that are much easier to obtain and apply and which will protect that back.
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Thanks Hamish, that gives me more confidence!
So with yew, a very thin layer of sapwood like this is sufficient enough to keep the back from lifting a splinter or breaking the bow altogether? Keep in mind all my experience is with Osage and working a ring down.
Joa-id like to make sure i understand your reply. My goal with sinew is always to protect the back of the bow by moving it inwards towards the neutral plane, so that under tension the back doesnt splinter, crack, or break. Is there another benefit to sinew that im unaware of? Truth be told i find it messy as hell and waiting months for it to dry sucks lol. Plus its more added mass and im still not sure if it helps speed or actually slows the bow down. Also what other natural materials other than rawhide would you suggest. Im open to the idea of trying new things.
One more thing, can sinew be applied to the sapwood and it still stick fine? Something about the sap wood seems smoother and less porus than the heartwood is why i ask. Almost like its greasy or something.
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Sinew definitely protects the back but like you said it's a pain in the butt and adds mass. I think for a bow to truly benefit from having sinew it should be pushing the limits of what the wood itself can handle so that the sinew takes over and really gets a work out. Otherwise you're just gluing dead weight on the bow. This usually means that the bow should be relatively short and often induced into reflex while the sinew is drying. This really gets the sinew stretching when you get out to full draw. I agree that rawhide would be the right insurance for this bow. In my opinion, a bow should be specifically designed to benefit from sinew. The sinew would stick to the sap wood just fine. A few years back, Gordon made a beautiful sinew backed yew bow with the sap wood still on. It turned out great.
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Like Weylin said, rawhide would be the way to go on this. Get the lightest rawhide available. 60" is not short by any means and won't be pushing the limits of a yew stave with violation, even if it was heartwood, particularly with only a 25" draw.
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Weylin and high desert, thanks for your advice fellas.
After rawhide how long do yall typically wait to start bending it? Ive been giving mine 7-10 days, but with no real guidance as to if i should allow more time, or if i can get away with less.
Also, im running a bit low on rawhide and have never tried to splice it. Will that serve as a weak spot in the rawhide backing where it comes together? What if i over lapped it a 1/4" or so?
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What are you using to glue the rawhide down? I've typicallybuse Titebond II, and I usually wait two days. If using hide glue, the 7-10 days may be necessary depending on your climate, longer if more humid, but I'm sure someone here has more experience with the rawhide hideglue combo.
If your handle isn't bending, butting the rawhide will work fine, you can thin it out a bit and overlap if you want. Definitely overlap if a bending handle bow. This may not be necessary,and probably overkill, but for protection, I run a bead of superglue at the end where the two overlap, on the piece that is on top.
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I use Titebond III for my rawhide.
It sounds like your referring to splicing the rawhide at the handle. I should have been more specific. I have one 19" piece and one 43" piece left. So the splice would be on one limb.
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Titebond III works awesome too, just waterproof.
If doing a splice midlimb, then tapering each end for about 2", and overlapping should work just fine. I've never done it midlimb, but on a bending handle bow, and it worked with no problems.
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For such bows I like stiff plant fiber backings like flax or sisal, or linen cloth.
See for example http://www.primitivearcher.com/smf/index.php/topic,56612.msg777777.html#msg777777
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joa- I took a look at the link you provided, pretty interesting. Unfortunately the hay bales where i live use synthetic cord for binding, so that might be something id have to special order. When would one use Sisal as opposed to rawhide or sinew?
Here are some current pics. The rawhide is on now, i thinned it down to a smooth transition at the handle and towards the tips. I didnt have to splice the rawhide since i ended up cutting strips from another hide that i was actually planning to use for a quiver(bows are funner to build anyway:)) I also got the antler tips epoxied on and worked down a bit. Suppose its time to start working it to brace height on the long string.
Im having a bit of a mental block regarding the hump on one limb where the knot was. My brain sees it as a "kink" and wants to flatten it with heat. Not only are we past the stage of doing any of that, but i would like to become a better bowyer and learn to work less than perfectly symetrical wood. So when i start bending the limbs and my eye catches this "kink" or imperfection what am i looking for as it flexes? Do i just want to sort of ignore the actual hump and draw an imaginary line through that area in my mind, or what should my mental process be...
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Heres where i am on the Yew bow. Im using the long string to get it to brace. At the current distance its pulled in the pics its at 95#. What do yall think about the bend so far? That kink on the left limb is playing tricks on my mind ??? I think its already taken just a tad bit of set on the outter limbs too.
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If you're shooting for 50-55# you shouldn't be pulling it to 95#. Don't pull beyond your final draw weight.
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Thanks DC, i got a bit carried away and didnt realize till i took that pic where i was at. So my thought process should be to keep removing material until the limbs bend evenly, reach brace, and never so over 55#? I guess my fear is that thats a lot of material to remove in order to do that. If i make a mistake in the removal of wood will i be able to correct it by then. I suppose this is the live and learn part.
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Remove a bit, put it back on the tree, repeat. Sometimes you'll think that you're going to wear a path in the concrete back and forth. I use a fine rasp just to put marks on the stave and then use a scraper to take off the marks then back to the tree to check how you're doing. Stop often, go read PA and then go back to it.
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Thanks man. The way you you worded that was exactly how i needed to hear it ;)
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Got it to 4.5" brace and pulled it to 16". One thing thats throwing me off is that the limb with the hump required way more thinning to get it to bend similar to the straight one. On the outer third its less than 1/2" thick, where as the straight limb is well over 1/2". Do yall pay any attention to thickness or just do what ever is necessary to make the bend do what you wish?
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Is the width the same at 6" intervals along the limbs?
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DC-on the straight limb yes, on the limb in question the thickness about the same on the inner third, but just after the humpis when it reduces down pretty thin for about 6" until it runs into the stiff tip.
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Width, not thickness.
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I should really learn to read more closely. Yes its pretty much parallel from the fades till about 6" from the tip. There is a very slight taper throughout the limb but barely noticeable.
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Now, do they match each other? What I'm getting at is if one limb is narrower it will bend more. Is the limb with the hump wider anywhere?
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Width wise both limbs are almost identical. Short of checking it with a micrometer, but visually they appear the same.
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OK, just had to check that. I did that once, forgot to check the width and ended up with one thin limb and one thick one. Sometimes wood is denser in one limb and you do end up like you. As long as they are bending evenly, that's what you're after.
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When you're saying kink are you talking about the little thing mid limb or the bigger one at the fade. Both are on the left limb.
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Good question. I am referring to that little hump mid limb. Though that raised up area near the fade is bugging me too, making it hard to determine if its bending evenly considering it starts out forward (higher) on the tree.
Also there is some twist in the limb in question, and when viewed from above with the bow sitting on its belly (unbraced) it leans the wrong direction, as in back towards the direction of the other limb, if thats not too confusing. I could elect to heat the handle and try to add pressure from the side but am afraid i might possibly scorch the rawhide and glue near the handle area, so im thinking of just letting it go and see what happens. Once its braced it doesnt seem as bad and the string isnt actually that far off from the center of the handle.
Thanks for helping DC, looks like its just you and me on this on HAHA!
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It looks like the little mid limb lump is just a wiggle in the grain. As long as there is no knot I would just treat it as part of the limb. Don't leave it stiffer there, keep the thickness taper constant along the limb. Maybe squint a little to almost try to ignore it. The left limb looks a little stiff so take 5 or 6 scrapes put it back on the tree. Try to get it looking like the right limb.The big lump at the fade is going to mess with your eyes a bit.
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Took more wood off the left limb and especially in the wave at the center of the limb. Got her back to 17" with only a 4.5" brace. Still taking more set, maybe i shoulda removed more off the outter part of that right limb sooner? We will see if i can make anything decent outta this one.
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That looks better, I think. That hump in the fades is messing with my head though.
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Heres how she turned out. Drawing 47# @ 24". 500gr arrow(cut down the 555 gr to an easier number to work with) at around 142fps. I might add some copperhead skins to just the last 6" of the tips and add some artwork, and a shelf.
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Looks good :D
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Time for some proper pics ladies and gents.
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more.........
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more..........
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Ohhh, you done that up proud :D
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Nice job , looks to me like the outer thirds could use a little more bend,still looks good.
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Thanks DC, appreciate you sticking with me till the end on this one. )P(
Bob W i think your right. I got aggressive with the rasp and target weight came in a bit shy so i left it. I think when i built my first bows the whole "leave the tips non working for speed" theory became a little too engrained in my head. While tillering my following bows i will chant the mantra, "let the outter thirds bend, let the outer thirds bend". Lol. Its still probably gonna take some more "reminders" from you guys for it to stick.
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She’s a thing of beauty! Nice job