Primitive Archer
Main Discussion Area => Bows => Topic started by: Dustinhill on September 03, 2016, 09:16:11 pm
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here's a hickory shortbow I've been working on and I wanted some input before I finished it. Initially I drew in the thickness and width tapers from the Oneida bow on p 57 of "the encyclopedia of native bows arrows and quivers vol. 1" because my last few attempts came in under weight. I was surprised that once I had roughed it out to the exact dimensions, the bow only bent in the handle and I could barely pull it back. Not sure why that would be, any ideas there and about the method of drawing a thickness taper would be appreciated. After that, I just eyeballed it to #48 @ 18". The bow is 46 nock to nock, I'll add more pictures once it's finished. Any tiller advice would be appreciated because there's some humps in the bow that are making it a little hard. As always, I appreciate all the advice ive gotten from everyone and this site! Also please excuse my lack of shirt, it was super hot in the shop.
Thanks,
Dustin
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Your fingers are the best thing to use for a thickness taper. Run the limb between your thumb and finger. You should be able to notice where it's thick and thin. Looks like you have a potential hinge below the handle/fade on bottom.
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Thanks Jon, i didn't see that. Would the best course of action be to remove some wood below the area where it's hinging?
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Good advice From JonW. I also see the slight weak spot on the lower limb near the handle area. Lower limb is also bending a bit more than the upper limb from my eyes. Not by a whole lot though. I'd scrape the entire upper limb a bit to weaken it and don't touch the area near the handle on the bottom limb again. Maybe give it a few scrapes at mid-limb. What draw weight and draw length are you going for? You could get maybe 22 or 23 inches if you get the handle/center bending a bit.
Kudos to you guys making short bows. Can't see myself doing it!
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Thanks dictionary, it's funny I can't see myself making a long one! Too much debarking for me ;) and I was playing it safe and going by the "draw length x2 + .25 of that = bow length"
Also, 18 is pretty comfortable for me because I have a chronically torn rotator cuff. I could go a little longer but my goal was for longevity. I'm trying to spend more time shooting to get ready for squirrel season (October) then making another bow. And I was going for 45 at 18. I tried to keep the handle a little stiffer, but its definitely not rigid. Should I have it bend more?
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Thanks dictionary, it's funny I can't see myself making a long one! Too much debarking for me ;) and I was playing it safe and going by the "draw length x2 + .25 of that = bow length"
Also, 18 is pretty comfortable for me because I have a chronically torn rotator cuff. I could go a little longer but my goal was for longevity. I'm trying to spend more time shooting to get ready for squirrel season (October) then making another bow. And I was going for 45 at 18. I tried to keep the handle a little stiffer, but its definitely not rigid. Should I have it bend more?
You probably don't need the handle bending if you're shooting for an 18" draw length. Has the bow taken much set? You should be able to correct these small things and be around 40-45# at your draw length.
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It's taken some set, I think a lot of it was a bad floor tiller. So the things to do are, scrape mid limb on lower, whole upper limb, and a little bit on the handle area?
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I'd scrape midlimb to the tips on the bottom limb then scrape the upper limb until it bends evenly with the lower. I wouldn't touch the handle at this point if I were you.
You using a tillering tree or stick to tiller? I've found the tillering stick with a straight edge is a very easy way to find where it's bending too much or too little. Our eyes can fool us, but a straight edge is very precise.
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I'd scrape midlimb to the tips on the bottom limb then scrape the upper limb until it bends evenly with the lower. I wouldn't touch the handle at this point if I were you.
You using a tillering tree or stick to tiller? I've found the tillering stick with a straight edge is a very easy way to find where it's bending too much or too little. Our eyes can fool us, but a straight edge is very precise.
...just like a ruler?
how about a tillering gizmo?
Nice job Dustinhill!!
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I've been mostly using a camera to tiller so that I don't have to hold it at full draw. Am I correct that a tillering stick would require that? And would the straight edge be placed horizontally above the bow? And thanks loon, I thought about making a tillering gizmo but the bow has some humps so I figured it wouldn't work very well. Maybe making a smaller one could work?
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https://www.youtube.com/watch?v=K3P2hyEN4qA
Go to 9:00.
It's just a straight block of wood, or hell you could use a credit card, ruler, etc. Anything with a straight flat edge. Have the bow drawn on the stick then run the block down a limb on the belly of the bow. If the gap between the wood and the block or whatever straight edge is wider in one area than another, you know it's bending too much at that point. You'll want to leave that area alone. If one part of the limb, the gap is very small or nonexistant, you will want to take wood from that stiff spot. Ideally the gap on the entire length of the limb should be exactly the same. This is essentially what the tillering gizmo does, but it uses a pencil to mark the spot instead(making it even more foolproof). I just never cared to take the time to make one, as these are much simpler. It really takes a lot of the human error side of bowmaking out of the equation. Does not work for the fades at the handle of the bow though, only the working limb.
Also I never draw a bow to full draw on a stick. My full draw is 28". I may draw it to around 20-22" on the stick using the straight edge. If it's pulling good at that draw length, it will be pulling good at your full draw most likely. I also use a mirror to verify this.
I gave up trying to tiller intuitively a long time ago. My eyes and brain are subject to making false judgements, so I like to rely upon these simple tools to counteract that.
Dic
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It's too hard to judge tiller without the unbraced and front profile.
A natural deflexed kink can look like a hinge to us.
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Thanks guys I'll try that! And I'll post front profile and unbraced pictures tomorrow when I'm back home.
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Here's the unbraced picture and front profile. I tried feeling it with my fingers and didnt notice any spots that seemed too thick or thin near where it's hinging. In the unbraced picture I did see some deflex near that area, but not that much. It's definitely taken some set, the left limb in the picture is the top. I wanted to check in before i removed any more wood. Thanks everyone!
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Here's the pictures
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I'd scrape midlimb to the tips on the bottom limb then scrape the upper limb until it bends evenly with the lower. I wouldn't touch the handle at this point if I were you.
I agree.
Once limbs get closer to equal bend, consider turning it upside down just to see if it looks and feels right that way.
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Thanks Dubois! I'll do that
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Unbraced your top limb has more deflex, so it should appear slightly weaker braced and drawn, but it doesn't, your bottom limb looks weak. Stay away from the bottom limb for a while, especially right out the handle. When you sort out your top limb, your bottom can use some scraping midway and out, but not until you even up your top. Your top limb should be coming around a little more, so on these tricky staves I rely mostly on thickness taper. Try to find some thick spots on that top limb, if you use a caliper I bet you will find some, especially when comparing the thickness to your bottom limb at the same distances from your handle.
With this type of front profile it always takes a bit of patience and scrapin to get your mid-outer limbs to come around. Go slow and steady, so far so good
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Somehow it hinged in the top limb after I thought i had worked out the hinge in the bottom. Now it seems like I didn't work out that either. I think it might be toast or at least end up way under weight. I've been scraping the inner part of the top limb but it doesn't seem to be helping. What's the best way to remove the hinge? It's really asymmetrical now I don't know what happened. It seemed like it only has minor issues then after one round of scraping it all fell apart. I can usually see where it's going wrong, I think my problem is that I can't fix it. Any help is appreciated
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I guess on looking at it again, it seems like the hinge is out of the top limb, but they're just bending very differently. Is that what's happening?
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I would say you have the arrow knocked low. Just a bit, but low. That is throwing off your tiller, dragging the front limb to far. Straighten that out and try again and see what that does first.
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Dustin you are seeing first hand the difficulty of tillering short bows, very small mistakes in tillering are amplified. the best way to remove a hinge is to avoid them altogether. A small amount of scraping on small bows can get quick results when your that far along, that's why I said to only scrape the thick parts you find, not the entire limb.
What you did here now is weakened your top limb to the point that your bottom limb is now stiffer.
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Wizardgoat - I had already done this by the time I read your post. Thanks for the advice, every time I learn a little more. So should I now try to scrape only the thicker spots on the bottom limb, then maybe heat treat to see if I can increase the weight a little? And slimbob I'll try that thanks
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That's what it's all about man, I've messed up my fair share of short bows. By the time a short bow is braced I'm only scraping small 1-2" areas. Your bow should have a steady thickness taper from handle to tips, so yes, remove any thick spots. Don't worry so much about weight at this point, youll learn more from a well tillered 20# bow than a 40# hingey bow, and your next bow will be better.
Heat can work to up your weight
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Thanks! I'm going to try and just make it a little better every time i work on it. Should I just try to get the bottom one even with the top now?
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Yea you're teeter tottering a little, Dustin. Now the bottom limb is stiffer than the top. As Goat said, it doesn't take much to change the tiller on a shorty. I'd take some off mid-limb to tip on the bottom now, slowly of course.
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Will do guys, I'm probably going to take a break and hit it tomorrow so I keep working slowly. Thanks for all the help!
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Thanks for the help everyone! Here's the progress I've made on the bow. I used calipers like wizardgoat suggested and got the limbs even. There is a .5mm difference between the limbs at one or two places but other than that they both tend to taper at 2mm every 6 inches. I also got he handle working a little more and heat treated the top third of the top limb. I think that the full draw still looks un even but with the limbs being the same can I assume it's just the extra set the top limb took? Right now the bow is #36 @18, if it's 46 nock to nock do I have any room to draw further?
Thanks everyone, I've already learned a lot from making this bow and I appreciate you all taking the time to help me out!
-Dustin
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Pics
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* I mad a photography mistake, in the braces picture the top limb is on the right and in the unbraced it's on the left
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I took it to 19" today and it was #40. I'm going to leave it there and not try for 20 unless anyone has any final thoughts about the tiller and I have to change it. 40 is my target weight (doesn't hurt my shoulder and should be good for small game at least) and I hope to put some finish on and make a string soon. Any final tips are appreciated.
Thanks,
Dustin
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Tiller has improved from before. The top limb looks like it could have bent a bit more closer towards the handle. However, I'd probably leave it as is if it is at your weight and draw and you like the way it shoots.
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Thanks dictionary now that you say that I can see it but if it's ok I'll leave it alone. Thanks for all the advice everyone, I have a lot more information for the next time around!