Primitive Archer
Main Discussion Area => Bows => Topic started by: JPF on April 01, 2018, 03:00:01 am
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Hi everyone,
I'm doing my first board bow from red oak, a Mollegabet design.
Now I've already cut the shape added rawhide(from dog bones) and started the tillering of the active limbs, the width is 5.5cm(2.16 inch) and the thickness i got so far is 7mm(9/32 ") (Including the raw hide thickness), now the problem is that its hardly bending so my questions are the following:
1-Can i make the active limbs thinner without risking a permanent bend or breaking?
2-Or can i narrow them (but i have rawhide on the side)?
3-Is the rawhide on the side necessary or can i remove it to show the wood?
I've attached a picture showing a 5kg (11 pound) weight attached to the string.
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The rawhide doesn't need to be on the sides. I cant tell you if the rawhide is necessary having never seen the board you're using. You should leave it on the bow since it is already in place. You will want to shorten the levers up and make the limbs bend farther out, you don't have enough working limb to get much draw length from.
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What weight bow are you trying to make? I think it is already too weak. I would straighten up the tiller and get as much as you can from what you have left. You said it is hardly bending. I bet if you pulled 30# instead of 11 pounds it would be bending a lot.
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I'm looking for a Draw weight of 30# max.
Now regarding the weight attached 11 pound,I feel like it's going to break if i pull more or add weight.
As for the design i took it from BoarriorBows and i think it should work, but he uses maple instead of red oak.
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Unfortunately, you took approx 1/2" thickness from the belly and now have just approx 1/4" remaining. Should have taken just 1/4" from belly and, thus, would have 1/2" remaining. Boarrior's vid wasn't clear about this.
Good news is you've learned much that can be applied to next project.
Molle was my 1st attempt too. Imo, not a design for newbies. Pyramid design would provide better odds of success.
Good luck next time!!
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If you would post the layout dimensions we could offer more help. This design is not the best for a first bow. Give width and length of working limbs, length of levers, and overall length.
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This is the design I've made
I understand regarding the thickness, but will it break if i try to add more weight? it does feel hard, at 1/2 " it was impossible to bend
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You are way too wide for such a low weight bow, and the limbs are pretty thin. I suggest you narrow the limbs to 1-3/4" wide and see what you get, I would not remove any more belly wood.
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Actually my limbs are 5.3cm (2.08"), this is the part I've modified before because it was too large.
And I've made a mistake regarding the thickness it's actually 9mm (23/64") at the thinnest and 1cm(25/64) on the edge.
Now i'm thinking about thinning the levers to 1.3cm instead of 1.9 for look and make it more flexible, is it risky, can it break?
I've attached the new design.
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Without risk there is no reward. With natural materials there is always the chance it will blow up on ya. Narrow it down like mentioned and see how much it wants to bend, and build one of Eric's tillering gizmos, he has a video up on YouTube
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build one of Eric's tillering gizmos, he has a video up on YouTube.
https://www.youtube.com/watch?v=KqvwUqn-EFQ
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Ok thank you for your help.
Will build one then.
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build one of Eric's tillering gizmos, he has a video up on YouTube.
https://www.youtube.com/watch?v=KqvwUqn-EFQ
Yes. Do that. Very simple and will make the difference between a well tillered bow and one with hinges if you are having a hard time eyeballing the bend.
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This is My personal opinion and only that, I think that a bow with levers aren’t the best for someone very new at making bows. There is little working limb and imo the less working limb = more chance of failure. Personally, I think a good starting point would be a parallel limb bow with last third of limb tapering to tips, or a pyramid bow. Bow length as long as distance from your eyeball to the ground if you have 8” of non working handle or chin to ground if it bend through the handle. Start with floor tillering, then move to the tree. Once on the tree put a belly tight string on it and pull to your desired draw weight. You won’t get a whole lot of bend most likely. Note the stiff and weak areas. Scrape wood from stiff areas. Brace the bow as soon as your bend will allow it at your desired draw weight and continue drawing and removing wood till you are at your draw length.
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I said the same a ways back Morgan, but all said he has it cut out so might as well make a bow😉
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Thank you for your feedbacks, will keep them in mind, but since I've already started this design might as well continue on it, and see how it goes. So far so good.
Will go step by step.
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1-Can i make the active limbs thinner without risking a permanent bend or breaking?
First, a lot of new guys get this misconception that a thin bow is going to break, or even that some thickness resists set. This is backward! You MUST make limbs thinner to avoid set (permanent bend) and the thinner a limb is, the less likely it is to break. BUT!!!!!!! A very thin limb like this IS at risk. NOT because it is thin, but because it is UNEVEN in either thickness or strain.
Right now you are worried that if you pull it more it will break. It probably would, but not because it is thin. The real reason is that some places are too thick, and others are thinner. So, the bend will find the thin places. They will bend too much, too far and could break there.
The solution is to watch that video about the gizmo. Do not pull the bow any farther yet, keep using the same 11 lb weight on the string and make the curve better. More even. Already we can see some places bending and some places not at all. Slowly scrape away wood where it isn't bending and you want it to bend.
2-Or can i narrow them (but i have rawhide on the side)?
Yes, you can narrow, but you will still need to fix thickness in some places. You can also taper the active limbs side to side if you want. There is no rule against it. The sides don't have to be parallel. maybe by thhe handle you leave it 2" wide like you have and maybe at the shoulders 1-1/2" wide. Then work on the bend again. Slowly.
3-Is the rawhide on the side necessary or can i remove it to show the wood?
Since the rawhide is on now, leave it on. Once the bend is better, you should work down the levers, too. They are too thick and heavy, more than you need.
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Thank you for your detailed answer, I've already run through some modifications, I've reduced the thickness of the levers, and started to remove the rawhide on the sides (mostly for look, to show the wood), now i'm going to even the whole limb, to get a better curve overall, I've noticed the parts that needs working on.
I"ll post a picture once i get a better shape.