Primitive Archer
Main Discussion Area => Bows => Topic started by: juskatla on June 17, 2012, 12:30:39 am
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Hi. I am curious to find some actual examples of finished bow limb thicknesses to compare to.
Right now I have roughed-out two flat bows, both 60 inches long, stiff handles. The Yew one is 1 and 3/4 inches wide - going straight to 3/4 wide tips. The Juniper recurve is 2 and 1/4 inches straight(ish) to 3/4 tips. I'm aiming for 50 pounds.
That's what size I happen to be working on but really, any thickness measurements even of different size/weight bows out there would be very much appreciated.
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Here are som figures.
Hazel primitive with flat limbs.
60.25" ntn 36# @ 28" D cross section with flat belly.
4" from nock the limb is 20mm wide and 10.3 thick.
27" from nock the limb is 42mm wide 14.1mm thick.
'Twister' Yew bow
http://www.primitivearcher.com/smf/index.php/topic,28324.msg376265.html#msg376265 (http://www.primitivearcher.com/smf/index.php/topic,28324.msg376265.html#msg376265)
Top limb 6" down from nock 24.6mm wide 13mm thick.
29" down from nock 43.4mm wide 15.9mm thick.
Hope this helps
Del
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A friend of mine is composing a library with all kinds of bows, including detailed measurements and statistics for each design and wood. Take a look in this library. (http://library.orionbows.nl/) There's many examples of great bows, with detailed width and thicknesses listed.
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They are all within a 1/16" of each other. No matter the style, length or wood species.
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I am curios to see what the replies will be on this topic. Rich tried to set up such a "library" of different bow styles and was shot to pieces by others because there would be too many "variences". I think mine would fall into the same description as what Pearl came up with.
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They are all within a 1/16" of each other. No matter the style, length or wood species.
That's why it is so easy to go from a 50# bow to a 30# bow if you don't pay attention while tillering.
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Thanks to all for the help. I did do a lot of looking before I posted the question but didn't find much about bow thickness. That's a really interesting statement from Pearl Drums. I am wending my way through that bowyers library as my primitive internet connection permits.
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So, if you guys were to pick up a piece of wood, reguardless of species, what thickness would you reduce it to before you started thinking about tillering?
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The thickness where the bow limb started to flex as I ran the draw knife.
George
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So, if you guys were to pick up a piece of wood, reguardless of species, what thickness would you reduce it to before you started thinking about tillering?
I am afraid that question cannot be answered without considering the species of wood. And even within the same species there is signifiecant variation. That's why you floor tiller - when you feel the limbs start to give way, that's when you begin to get serious.
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I usually draw taper lines on both sides of the limbs from 5/8" thick at the fades to 1/2" thick at the tips and then work the sides down to the lines, after that I start working down the crown thats left in the middle using the ring lines as a thickness guide. Length, weight, limb width and type of wood make a big difference on limb thickness.
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Gordon you make exquisite bows so I am not challenging your skills.With that being said are you saying you would tell someone new to bow making that their roughed out bow should be two inches thick? I think probably not. IMO there is nothing wrong with giving a person a suggested starting limb thickness. 5/8" is a good start for any type of wood considered to be of bow making quality. Roughing out a bow is not rocket science. If it were I would have to find another hobby :)
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Jon, 5/8" might be ok with osage, but if you started there with a piece of yew, juniper or cascara, you would end up with a 20# bow. I am not saying always start out with 2" of thickness. What I am saying is that the thickness at which tillering begins is dependant on the species, variation between individual staves, and also the bow design. One simply cannot state a value that will work for all species (and designs) as the previous poster requested. It is just not possible.
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They are all within a 1/16" of each other. No matter the style, length or wood species.
Okay, but if the above is true, then if follows that you could rapidly reduce any stave down to a certain dimension, which would be a great place to start if you were a fledgling bowyer. I don't have the experience to know if all bows end up within 1/16" of each other, but if it is true, then that's some pretty useful information for the beginner.
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Another way to pose my question would be: what is the thickest bow that we have on record? Come up with that number, and you can tell any new bowyer to remove wood (without worry) down to that line.
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They are all within a 1/16" of each other. No matter the style, length or wood species.
That is simply not true. I measured some of my bows and got a spread of 3/8".
If you want to be safe, rough out your limbs to 1" thickness and then hog off wood until the bow just barely starts to bend - then slow down.
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I was just curious to find a few actual examples from finished bows. That was the only question, no hidden agenda. I'm not actually expecting to be able to cut corners or tiller these two much differently with the info. For example - given the thickness of a 100 or even a half dozen finished bows of the same species I think I'd learn something- but certainly don't have that experience myself.
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Not sure with yew, as I don't work with it, but it's my understanding that it can go thicker and narrower than most anything else. With most woods, you will end up somewhere in the half inch range, so your pretty safe starting rough at 5/8-11/16 and slowly tapering out to the tips. If you go pyramid style, you will remove wood evenly, no thickness taper, to get within target weight range, and adjust the tiller with the width taper. With other styles, you will keep the front profile set, and taper the thickness out to the outer limbs. Paddle bows are a bit weird to tiller; they taper in thickness to mid-limb and then not so much in the outer limbs. In all, I would start at 11/16 for anything but yew, and would wait for someone who works with it more (Del, Gordon...) to chime in on what they typically see for thickness with yew. The major difference between other woods is not so much in the thickness, but in the width of the limbs. You can even make a bow out of white pine, the limbs will still be about a half inch thick, but will be around 3 inches wide.
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Jon, 5/8" might be ok with osage, but if you started there with a piece of yew, juniper or cascara, you would end up with a 20# bow. I am not saying always start out with 2" of thickness. What I am saying is that the thickness at which tillering begins is dependant on the species, variation between individual staves, and also the bow design. One simply cannot state a value that will work for all species (and designs) as the previous poster requested. It is just not possible.
Agree 100%
Bow making is way more about feel than it is about numbers. Learning 'the feel' is the bit that takes a while and if you get stuck on figures you will find it harder to learn. Listen to the wood and not the ruler:)
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They are all within a 1/16" of each other. No matter the style, length or wood species.
That is simply not true. I measured some of my bows and got a spread of 3/8".
Really Gordon?
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Yes. really.
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I am still pretty new at this stuff - I have about ten hunting weight bows behind me so far. I build my bows from trees that I cut and split. It may be different for people who work with boards. I have found that I have more success if I draw the front profile and let the wood tell me the required thickness. I remove wood till it bends like I want it to - I don't think I measure thickness at all.
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How do you know Gordon? Did you go measure all of Pearl Drums bows?
He simply stated what all HIS bows were,and that statement is true for him and from his experience and point of view. To say its untrue is incorrect unless you have personally measured his bows.
And your statement of what your bows is true too,that they vary to the measurement you posted.
Numbers mean nothing as far as thickness at finish tiller,and while tillering...like mike said its a "feeling" that must be learned. .....but there are good rules of thumb numbers for each wood,and its intended design and specs to reduce to to get to floor tillering in a quick n easy manner..it just depends on wood,design,and intended weight and learning where a good place to start is for it to reduce the meat off quickly to get it to a floor tillerable stage...and i think the original poster is just asking whats a good starting dimension to reduce to to get the unwanted meat off to start tillering.
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Is this the right room for an argument?
I've told you before!
No you haven't!
Hang on is this the 5minute argument or the full half hour?
The full half hour.
Right time's up.
No it isn't.
I'm afraid it is.
No it isn't, anyhow, you're not arguing, you are merely conradicting everything I say.
No I'm not.
There you go again.
etc...
Del
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Heres a good starting point for the dimensions and intended poundage you listed...
For the yew i wood facet a line down the side starting at 3/4" at the fade and taper down to 5/8" at the tips...that should get you into floor tillering,and make the belly slightly crowned....and i wood only tiller that one out to 26".
The juniper i would start a facet line 7/8" on the side at the fade and taper down to 3/4"...again make a slightly crowned belly with this design as well...and i wood only tiller it to 26" max as well...and are you going to back the juniper? I wood..sinew is best,and rawhide the very least.
These starting numbers could be less or more pending on how dense each piece is
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I thought Pearl Drums was making a statement about wood bows in general. My appologies for the misunderstanding.
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A friend of mine is composing a library with all kinds of bows, including detailed measurements and statistics for each design and wood. Take a look in this library. (http://library.orionbows.nl/) There's many examples of great bows, with detailed width and thicknesses listed.
I'm off topic a little, but thanks VERY much for that link, DarkSoul. Excellent reference for lots of different bows and woods, with great pictures from many different angles on completed bows. I'm going to eat that site up like it's a spaghetti buffet.
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Yes thanks for that bowyers library link. I hope it only grows. And thanks for all the help as always - didn't mean to get people arguing...
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"and i think the original poster is just asking whats a good starting dimension to reduce to to get the unwanted meat off to start tillering"
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Blackhawk. Thanks- I actually was just curious about those finished measurements, not starting. Just curiosity mostly I guess. I know how to rough out a bow more or less, but do appreciate all the helpful info. I am going to sinew the juniper, and hopefully can draw it to 28 inches with the sinew.
I guess I get a couple things from this- maybe people don't usually bother measuring that finished thickness- especially after gaining a lot of experience - rough it out- tiller it to best suit the wood, and why would you bother to go back with the calipers afterwards? Anyway- it's not information that seems to be floating around much.
And perhaps- without getting into too many of the variables - if there is a really general ballpark mid-limb thickness for a flatbow like these two I mentioned I think we're looking at "about" 1/2 inch thick for most bows give or take 1/16 or 1/8? (???) ok maybe not 1/8.
Still- next time I visit someone with a large collection of bows I'm taking my calipers...