Primitive Archer
Main Discussion Area => Bows => Topic started by: Elktracker on August 04, 2011, 09:30:03 pm
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I just finished a sinew backed Yew short bow for my grandma (this is my first sinew backed bow) and while shapeing it for sinew I made the back flat and the belly rounded, the rough bow had about 2" of reflex before applying the sinew and after applying the sinew and letting that dry and cure it now has about 1/2" deflex. I tillered the bow out to a short draw length about 15" as its just a wall hanger and about 43" long end to end. So my question is next time I attemp one of these bows would I be safe to assume that I should round out the back of the bow and keep the belly mostly flat?? Any info would be appretiated, thanks.
Josh
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I am thinking you may have mixed up your belly and back. The belly is closest to you when you are aiming the bow and the back is away from you. The sinew goes on the back. Sinew will increase reflex not reduce it. Something wrong in your explanation that doesn't make sense. Maybe try and explain again, learning the terms can be a little tricky at first. Steve
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Lol Thanks badger I know the difference between the belly and back ;D I sinewed the back of the bow and it was flat before sinew was applied, the belly was rounded. And yes it whent from reflexed wood to deflexed wood when the sinew dried.
Josh
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Josh, the sinew should have at least held the reflex the bow already had or drawn it into more reflex. I can't imagine why it would draw it into deflex. :o :-\
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Ya thats what I thought?? I was thinking maybe the back being wider (flat) than the belly maybe it just went toward the side with less wood.
Josh
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sinew shrinks as it dries. That would pull on the back. It doesn't work the other way. Are you in a parrallel universe or something, Josh? ;D
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The bow I tried to replicate was the Pit River or Achumawi sinew backed yew, its in the TBB 1 on page 176 and in the pic of the side view it appears that the back is rounded and the belly flat, that is why I thought I got that part backwards???
Josh
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Hey Josh...maybe you used erectile tissue and you rubbed it too long while sanding? >:D >:D >:D
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How bout some pictures Josh? How long did the sinew dry/cure? Almost all my sinew backed bows were flat back/rounded belly bows. That design is fine. Usually the sinew pulled the bow into more reflex as it dried. I was able to tiller one badly enough for it to take some set, but never got deflexed tips. I'm baffled.
Lee... :o :o
George
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Im uploading a video of the bow on my photobucket for my grandpa ill post a shortcut when its up here shortly.
Josh
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O ya and it cured for just shy of two weeks before doing any bending, I didnt put much stress on the bow at all as it was a short draw low weight bow. It showed no set from start of tiller to finish
Josh
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Ok dont make fun of me to bad here I use photobucket to send my grandpa videos of my bow progress and different projects so all the videos in my album are for him lol. You can get a pretty good look at the bow in this video, and as for the explination for the sinew causing deflex, that was just what I thought it was when I made the video but its still a mystery to me ;D http://s1019.photobucket.com/albums/af314/mandoman1540/?action=view¤t=110804-153741.mp4
Josh
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Was your wood totally seasoned and down to proper mc? Maybe there was still some moisture in it and it deflexed from the loss of moisture out the belly side causing it to deflex cause the back was sealed with glue n sinew? I know yew can move if its not totally dry. Just a guess.
But sometimes wood reacts funny when removing wood and releiving a funky stress in the wood. Maybe it was reaction wood? Weird man.
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I dont actually check moisture content with a moisture meter but it was cut over a year ago and has been in my house roughed out. As far as the reaction wood, that very well could be a possiblity with this piece being a big limb.
Anyway thank you all for giving this a read I may try the more rounded back on my next one.
Josh
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Josh, I don't remember reading it. What glue did you use on the sinew? I watched your video and nothing jumped out as a problem. It looked like a nice little bow to me.
George
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I don't see why you could'nt tiller it on out if you wish to.
I never heard of your problem, never add sinew or heard of it not adding it'd own reflex.
Everytime I sinewed a bow I perpeared the back as if I was'nt adding sinew (CHASED A RING). And the shape of the back as what I added the sinew to. I realize you don't chase a ring with YEW. On these types of woods I use the back right under the bark. No need to file it flat to add siinew just add like it is.
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George I used Tb hide glue
crook I just didnt see any reason to get it bending to much as it will be a wall hanger but as is she can display it braced or unbraced, also not sure why I flatened the back, just seemed like the thing to do at the time. Thanks again guys for the info. Even though I dont know exsactly why or how this was caused I am guessing it was a freak accident and hope it wont happen on the next one I attemp. Thanks again!
Josh
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nice looking bow im sure you grandpa will be very proud of you. Did you pre bend the wood before sinewing to add reflex ? The only possibilty I could think of is the wood was pre bent before sinewing and then went back to its original shape in the 2 weeks you let it dry
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I think it is awsome pure and simple. Enjoyed the video ;) the arrows were cool as well.im shure that they will be desplayd with much pride!!!it would be sweet to make meat with them first >:D