Primitive Archer
Main Discussion Area => Bows => Topic started by: rcoen2 on May 09, 2021, 09:17:10 pm
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Hi all,
Ive been working away the last couple months on my first bow. Its inspired by Paul Comstocks overbuilt whitewood bows. So its 2" well past midlimb. Oregon ash.
So yeah, I just started to get a little overwhelmed with tillering, and am hoping to get a little guidance and support. I'm seeing that there may be a hinge I'm dealing with on the bottom side. But I don't know if its actually a hinge, or if the mid to end of the bottom limb just needs to bend more for it to be a proper arc.
I'm still on the long string, and so I'm hoping to get guidance on how to get the arcs right so that I can get off the long string and onto an actual bow string for the next stage of tillering.
Thanks!
(https://live.staticflickr.com/65535/51168831241_0d3f6f0046_z.jpg) (https://flic.kr/p/2kXBCQi)Bottom-Top (https://flic.kr/p/2kXBCQi) by Ryder Coen (https://www.flickr.com/photos/192969628@N04/), on Flickr
(Bottom limb is on left, and Top is on right)
(https://live.staticflickr.com/65535/51169925500_3b7a3f68c5_z.jpg) (https://flic.kr/p/2kXHf7Q)Top-Bottom (https://flic.kr/p/2kXHf7Q) by Ryder Coen (https://www.flickr.com/photos/192969628@N04/), on Flickr
(Top limb is on left and Bottom limb is on right)
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We need unbraced profile ;)
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Like this?
(https://live.staticflickr.com/65535/51169976805_db468a8a60_z.jpg) (https://flic.kr/p/2kXHvnp)unbraced-bottom-top (https://flic.kr/p/2kXHvnp) by Ryder Coen (https://www.flickr.com/photos/192969628@N04/), on Flickr
(https://live.staticflickr.com/65535/51169982535_f03e79fcf0_z.jpg) (https://flic.kr/p/2kXHx5c)unbraced (https://flic.kr/p/2kXHx5c) by Ryder Coen (https://www.flickr.com/photos/192969628@N04/), on Flickr
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Definitely too much bend in the inner limb on both sides. Left worse than right. Avoid that area for the rest of the tillering process. Likely already bending a bit more than it should even if the bow were fully tillered.
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Definitely too much bend in the inner limb on both sides. Left worse than right. Avoid that area for the rest of the tillering process. Likely already bending a bit more than it should even if the bow were fully tillered.
Got it. Thanks. I guess I removed too much in the fades (?). along those lines should I take a bit more off of the inner on the right/top limb to balance out the overbend?
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I wouldn’t touch either inner limb till you get the rest of the limbs bending. Leave that part uneven for now or you’ll drop too much draw weight.
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Look at lots of pictures of straight limbed bows. Study the pics as to what they look like drawn. As a beginner, it is easy to “think” you know what you are after, but not really be able to articulate what it should look like (I speak from experience on this). First, know what you want the tiller profile to look like. Just out of the fades, mid inners, mid limb, mid outers, and the tips. Break it down in pieces, and then tie it all back together, in your minds eye. Now tiller each part shooting for that shape. Yes, the limbs are bending too much at the fades. That is the last step. Finish with the fades. Get the the rest looking like you want it, and then get the fades moving. It’s salvageable, it may just be a lighter draw than you were shooting for.
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Look at lots of pictures of straight limbed bows. Study the pics as to what they look like drawn. As a beginner, it is easy to “think” you know what you are after, but not really be able to articulate what it should look like (I speak from experience on this). First, know what you want the tiller profile to look like. Just out of the fades, mid inners, mid limb, mid outers, and the tips. Break it down in pieces, and then tie it all back together, in your minds eye. Now tiller each part shooting for that shape. Yes, the limbs are bending too much at the fades. That is the last step. Finish with the fades. Get the the rest looking like you want it, and then get the fades moving. It’s salvageable, it may just be a lighter draw than you were shooting for.
does it work to just focus on getting one limb right and then the other, or should I be trying to hone in both simultaneously?
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Both at the same time. Don’t rush it. Go for a couple of inches, no more, and get each limb the right shape and equal to its partner. When it’s right at 2 inches, go to 3, and get it right. Then 4,5 and so on. Use a gizmo or a straight edge to help the eye get it right.
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one last question is how far into the limbs are they already bending too much? In other words how long should I make the 'do not remove more wood' zone on each limb?
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That’s a question the strait edge will better answer. Take a 4 inch...block (2x2 works well, but nearly anything with a straight edge on it). Run it along the belly with the bow drawn as you have it in the pics. Look at the gap between the belly and the block as you slide it from fade to tip. You will see that the gap on this bow is greater near the fades and there will be no gap as you move out toward the tips. Wide gap, followed by thin or no gap...the no gap spot is not bending enough. Get the gap equal along the limb. A little common sense here. The fade won’t bend much at all, nor the tips. Aside from those two areas, everything else should be the same gap. So how far out the limb should you get it to bend more? Let the straight edge tell you that. Easy peasy.
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okay, thanks for the advice and guidance. I shall carry on!
Hopefully it turns out decent, but the learnings what's most important I guess for my first one. Thinking of the quote in tbb v1 "The best way to go about making your first bow is without hope, but with persistence." Haha, Its hard to not get too attached though!
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Haha yep.... post more pics as you start getting closer to FD :OK :BB
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Having crazy wide limbs won't help you one bit. Very wide limbs also need to be thinner than 'normal' for the draw weight to be manageable....When the limbs start getting thin tillering becomes much harder.
My first bit of advice would be to narrow the limbs to no more than 1 3/4" for the widest sections. Then assess your tiller again. Post more photos when you get there :)
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Having crazy wide limbs won't help you one bit. Very wide limbs also need to be thinner than 'normal' for the draw weight to be manageable....When the limbs start getting thin tillering becomes much harder.
My first bit of advice would be to narrow the limbs to no more than 1 3/4" for the widest sections. Then assess your tiller again. Post more photos when you get there :)
Thanks for your suggestion. I think at this point I feel most drawn to keeping them wide to try and preserve a higherish draw weight. If it wasn't for having too much bend in the inner limbs then I would likely feel more open to reducing the limb thickness
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I can see a need for a tillering gizmo, here is a how to link;
http://www.primitivearcher.com/smf/index.php/topic,61422.0.html
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I personally think your ok with 2 inches wide. If it is parallel limb to mid limb, meaning 2” wide at the fade, and holding that 2 inches to mid limb before it tapers...if it were mine, I would slightly taper, maybe 1/8 or 1/4 inch from fade to mid-limb. It will be a bit more efficient I believe. But that is your call.
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Slimbob!!! its been a while!! Its good to see you!!!
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the wider limbs do become more sensative to wood removal,, and can make tillering more challenging,, you should be able to get plenty of weight with 1 3/4 wide limbs,,
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The dimensions are dependent on multiple factors. If you make two bows of the same species, length, draw length, draw weight, and they only differ in width, then the wider one will be thinner. If you have two bows of the same species, length, draw length, and you want a higher draw weight in one then thickness will (or can) be the same for both but the heavier one will need to be wider (all things optimized). 2" wide may or may not be wide depending on the wood species or design. For good performance, generally speaking, we want our bows to be as thick as possible without taking set as this will result in the lowest mass cross section. Even across most wood species, if built to the same working limb length, draw length, and limb taper style, the thicknesses will be very close. Exceptions would be more elastic woods like yew or ERC.
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Hey Deerhunter! Been around, just busy. Good to hear from you.
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getting the limbs to work evenly,, is more important than how wide it is,, especially on his first bow,
you can see the inners are taking set,, possibly that is how the stave was shaped, but it seems like that,,
tapering the limbs would help get the limbs bending,,the Paul model is great, just a bit more challenging for a first bow,,
also I would not worry about trying to get a specific weight on your first bow,, just get one that is bending even and shoots well,, you can get more specific on your design as your experience level increases,, make a bow that shoots, then proceed,,with more specific intent,,
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I agree with all of that.
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So, I will assume you are putting in to action some of the things discussed earlier. Or perhaps you have left it all in the shop and decided to just think about things for a bit. I find the latter really beneficial, in that after a pause, I come back to the problem with a refreshed set of eyes, and a renewed spirit. Either way, I have a suggestion or two. Take a heat gun, and temper the belly. Before you do that, straighten out the set in the inner limbs, and toast it with it just past straight. Just a tad of set back. That should give you back a little muscle on this one. Do that before you put much more stress on the inner limbs. Once done, shorten your long string up snug to the belly. You have “0” inch brace height, with a tighter string. Your tiller profile will read more true. Tug on it an inch or so and use the straight edge to determine where to remove wood. Now just keep tightening the string up as you progress. 1 inch BH, 2 inch Bh etc.. don’t touch the inner limbs at all for a good while! Brad was right. The draw weight at this point should be of secondary concern. Perfect tiller is the goal, and the weight is what it is. The tempering and straightening will help with that.
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Looks like mid limb and toward the nocks needs to bend. Remove wood and test on the long string.
Let the stave tell you the width needed. So what I do is if I find the limbs do not respond to wood removal I begin to slowly narrow them especially for the mid limb toward the nocks area.
Jawge