Primitive Archer
Main Discussion Area => Bows => Topic started by: Mesophilic on August 26, 2020, 02:44:16 pm
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I've got a bit of propeller twist on one tip of this bow I'm working on. I get confused on which side is strong vs weak.
This is 52" sinew backed with slightly flipped static tips.
Please disregard the the marks from the bandage wrap in the sinew, not trying for BOM contest. There's a whole chapter in Mesophillic's book on How Not to Make a Bow that covers why I'm stuck with this method for now ;D
Anyway, what do you guys think? To straighten out this limb tip a little, should I remove material from the A side or the B side of the belly?
(https://64.media.tumblr.com/a595533e99ebbb4734a5d7957434855e/35c159a8d6f0dc8a-95/s1280x1920/89e8d21c077e132f648f9c067175bf00b70b505a.jpg)
(https://64.media.tumblr.com/14948db96cdbceaa249e2496138bba5c/2bd02d5beca0a9bc-84/s2048x3072/f74372ddccfd4da7e94ddc62d66f751b2038f2b4.jpg)
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(https://64.media.tumblr.com/832f3e34b9a36c74540e69f573337916/55a632c0834602e3-24/s1280x1920/1b94f7f808471237461010d38ab3a08983462571.jpg)
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Wait and see how it looks braced. You may not have to do anything. A little twist isn't necessarily a bad thing in a selfbow or sinew backed bow. Once braced you can see how the string tracks and adjust accordingly.
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Wait and see how it looks braced. You may not have to do anything. A little twist isn't necessarily a bad thing in a selfbow or sinew backed bow. Once braced you can see how the string tracks and adjust accordingly.
These pics are braced.
Didn't even realize it but my string is the exact same color as the arrows I drew to show the twist. (R
The tips aren't highly reflexed so I don't think the twist will affect it too much, but I still need to drop about 10 pounds off the draw weight, so I figure maybe I could take some twist out while I'm at it.
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What twist?? :D :D :D
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looks straight enough to me haha, I get concerned if I have a bow that doesn't have at least that much prop twist :BB
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You could reduce the "A" side a little at that hump to straighten it out but other than that I wouldn't mess with it. If the tiller is good at full draw take long even scrapes from each limb to reduce the weight without affecting the tiller.
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Thanks guys.
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I'd leave it. Doesn't look like much to me. Jawge
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+1 what Jawge said.
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well I think you got good advice,,a little off the A side would make it look lined up a bit,, but dont think is necessary as others have stated,,
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A heat gun tweak would take care of it in minutes.
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A heat gun tweak would take care of it in minutes.
Oh no, this would be asking for a whole new chapter in my previously mentioned book on How Not to Make a Bow :D
I have to swear off of electricity at a certain point in the bow making process or I end up screwing things up. Partially from anger management issues :-K )-w( :-T
Thanks again, guys. After all the work and waiting through the dry time for the sinew, I can sleep better now.
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How does it shoot?
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How does it shoot?
Haven't tried yet, and may not get much chance.
I've got two chrysals starting on the side, a couple of inches out of the fade on one limb. Doesn't surprise me, this wood is only 3 to 4% moisure content per my moisture meter (and that's with being stored indoors with a swamp cooler running!!!)
Wood is very unforgiving here.
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I thought damp wood chrysaled more, not being as hard as very dry wood.
Personally, I would be quite concerned if chrysaling happened before the bow was even shot, but I don't use sinew.
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I'm don't know about damp vs dry wood when it comes to chrysals. But wood in general here is so dry it just cracks, splinters, and checks just by thinking about putting stress on it. So nothing surprises me anymore.
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What's the RH in your house? Wood and sinew/hide glue will find moisture equilibrium with it environment. So at 50% RH there will be a M/C value for the wood at a specific temp.
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Sorry, I don't have anything to measure RH in the house, just my mositure meter for objects.
But if this gives you any idea how dry we get, the weather currently says it's 24% RH outaide right now, but that's with a 60% chance of rain.
Around noon, with low chance of rain, it's generally single digits with temps in the upper 80's to mid 90's.
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You might have to store your bows near the swamp cooler. ;D
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please show us the checks
sinew bow usually fair will in dry climate,,
maybe the bow was over stressed before the sinew was appied??
I did blow up a bow a few days ago,, and am sure RH was a factor ,, but other factors were
over stressing the design
too thin on the sinew layer,,
really just not enough wood for the weight I was pulling, or the draw length,,
but the bow did not have any chrysals,, and I have not had a problem with that,
I did have a friend that chrysaled his bow ,,when first bracing and had a weak spot,,that caused the problem,,
it is really dry here in Santa Fe, New Mexico,,
I guess my point is, other factors may be an issue as well as the RH,, you should be able to get a good stable sinew bow,,
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Sorry, I've already destroyed it to reclaim the sinew, and didn't bother taking any pictures.
What cued me in, was finding what looked linitially ike scratches that wouldn't sand out.
In reflection, I'm pretty sure this is entirely my fault, just don't have enough experience and about to throw in the towel anyway. The learning curve is too steep when you don't have access to bow woods. This is probably the last $100+ bill I'm adding to the wood pile. Could've bought a real nice bow from a reputable maker for all the $100 bills I've burned up in the wood stove the last few years.
Anyway when the sinew dried and I started working on the long string, the inner limbs were bending too much and the outer limbs not enough. I think working it on the pulleys to check the limbs put too much stress there. I personally feel that the lack wood mositure content contributes to a very unforgiving situation based on the wetter climates I've lived in. Didn't have one tenth of the problems I have compared to when I lived in Ohio.