Primitive Archer
Main Discussion Area => Bows => Topic started by: arachnid on October 26, 2016, 05:34:16 am
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Hi guys.
I plan on making myself a new target/field/roving bow but have enough woos for a couple a'bows. So I really want to make an ELB since I never made nor shot on.
I have ipe for the belly. Right now it's not cut or ripped and it's about 20mm thick. I want to rip it to get 2 bows out of it.
Next is maple. My fried can give me a board, 50mm wide and 50mm thick. Haven't seen it yet, only a picture, so I don't know if the grain is as straight to be used as a backing. If it's not, I'll use it as a core and back it with bamboo.
So, I want 2 bows-
a R/D longbow, about 64-62" long (for my 26"draw). I want to use KennyM's form (he's a great guy from Tradgang that has a good r/d form plans).
Ans, as I said- an ELB.
Target weight for both- 45-47#@26". Both out of the same materials (ipe, maple, boo).
So, if you laminated experts can land a hand to fellow bowyer and help me design these bows' it'll be most appropriated. I want to plan and design carfully, for best results and I want get as close as possible to my target weight so I'll have to do as little tillering as I can.
P.s
If I rip the ipe, I'll probably need to make a power-lam ti stiffen the handle. So please consider it in the design (I never made a power lam before)
Thanks in advance
Dor
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You don't learn anything about designing and tillering that way.Doing a search on this site might help.Still I'm sure someone will chime in for ya.I mostly do staves.
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I do mostly wooden lam bows and I have some experience. I've just never done an ELB and never used that particular r/d profile before, so I'm asking those with more experience.
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Wouldn't KennyM be the guy to ask since it's his form?
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Wouldn't KennyM be the guy to ask since it's his form?
It is probably a glass bow form as most of the bows on tradgang are glass
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Wouldn't KennyM be the guy to ask since it's his form?
It is probably a glass bow form as most of the bows on tradgang are glass
Yup, it`s a form for a glass bow. But I`ve seen wooden bows made with similar design. It`s just a r/d longbow form... I just like the shape.
Since I have some experiance making r/d bows (and by "some" I mean "little"), that`s my secondary concern. My main question is the ELB design since I never made one.
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I can't help you on the design or thickness and taper. I would think that you'd want to build up the riser area of that form 1" or 1 1/2" because your wood lam bow is going to take some set, unlike a glass bow. That way, after shooting it in, you'd have a better chance of your tips being forward of the handle or at least even with it.
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elb - cut your ipe to 1 1/8th wide. Cut a backing to suit - hickory,ash,maple,white oak,bamboo etc 3/16th to 1/4 thick. Make a 12 inch powerlam to bring the total thickness at the handle to 1 inch. thickness taper - clamp the bow to a straight form and mark out a straight line taper from edge of handle to 7/16ths thick at the tips.
Width taper - center 12 inches leave 1 inch wide, taper to 3/4 wide 8 inches from the tips then from there into 1/2 wide at the tips.
Tiller for an elliptical tiller. Simply watch the set to show you where is too strained etc. Use the faceting method and only round the belly after fitting horn nocks.
fit horn nocks at about 24 inch draw and narrow the tips to 3/8ths.
Whatever you do don't make the tiller arc of a circle.
As for the Kenny M form just shorten the riser for a wooden version. About 12 inches would be right. Increase the taper rate to around 0.008" per running inch.
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Great info Mike. Thanks a lot.
A few quesitions....
you didn`t mention the total lengh of the bow.... My draw is 26" so I guess 72" is well enough?
you wrote "cut your ipe 1 1/8th wide"... did you mean "thick"?
3/16 and 1/4 is pretty thick for bamboo, is it not? won`t it cause the belly to fret? I know that bambboit usually worked to 1/8 thick.
Do you recomend gluing the lams straight or should I lift the tips to get some reflex?
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I've drawn my 72" hickory bow to 32" and it has a ton of grain violations, also around 40#. it's held together, has 2-3" of set if going that long for that draw and lighter weight, make it whip tillered..
I would just make a 60" bendyish 'ELB' with perry reflex, haha. ipe/maple/bamboo? dunno. since it's perry reflex, may want something harder for the core i.. guess..? but still supple. Still, a long whippy bow should be fun..
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A 26 inch draw would only need a 70 inch bow, even a bit less. I normally made mine 72 inch for a 28 - 30 inch draw.
No I meant 1 1/8th wide for the glue-up then narrow to 1 inch through the center section. 1 inch total thickness is plenty to start tillering.
I meant that thickness if using a wood backing but if using bamboo then keep it thin (1/16th - 1/8th). The thickness of a backing doesn't really affect its 'ability' to chrysal a belly. If a backing is overly resistant to tension for the belly I would trap it not make it thinner. Most of the 'work' done in a bow is by the outer few mm only therefore width has more of an effect on evening out tension/compression properties of different woods. IMO....;)
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A 26 inch draw would only need a 70 inch bow, even a bit less. I normally made mine 72 inch for a 28 - 30 inch draw.
No I meant 1 1/8th wide for the glue-up then narrow to 1 inch through the center section. 1 inch total thickness is plenty to start tillering.
I meant that thickness if using a wood backing but if using bamboo then keep it thin (1/16th - 1/8th). The thickness of a backing doesn't really affect its 'ability' to chrysal a belly. If a backing is overly resistant to tension for the belly I would trap it not make it thinner. Most of the 'work' done in a bow is by the outer few mm only therefore width has more of an effect on evening out tension/compression properties of different woods. IMO....;)
Thanks for the explanation. I guess you learn something new every day... never knew that evening out tension/compression is done by adjusting the width.
So, if I use bamboo backing, I should start with a 1/8" thick boo and 7/8" ipe? currect?
What if I want to use maple core to make a tri-lam, how thick should I keep it?
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Yes that is correct and if using a maple core I would make it an 1/8th thick and remove that thickness from the ipe.
Good luck.
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For the boo thickness I thin it to near knife edge then cut the profile and again thin to near knife edge this basically gives you a tapered boo backer
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I wonder, black locust vs maple for the core? Someone used black locust for the core of a hornbow & it worked great..
if you wanna do tri-lam, perry reflex, sounds more annoying than just 2 lams.;.
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Ok, I got both boo backing strips flatten and thinned down to 1/8"..... with no belt sander. All I used are a plane, a spoke-shave and a lot of sweat. Took about and hour to do both.
I do vace a question about tillering the ELB. Do I leave the few outer inchs of the limbs stiff or do I make it a bit whippy?
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Eliptical tiller and not whippy
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Yes :) elliptical but definitely not whippy!
simply trace the side profile before bending it and then everytime you unbrace it compare it to the unbent side profile. Set will start to show at about 20 inches. From there out use the set as your guide. you want none at all inner limb, a fraction mid limb then the rest out to the tips. I used to glue mine up with 1 1/2 inch of eflex and most would still hold some when tillered and shot in.
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Ok got it. Thanks.
One more thing.... As I said, I flattened the boo but it looks so narrow! A bit unsafe even.... You told me to start at 1" thick, in the end, how thick is it going to be approximately? It just lpoks so slim, I'm not used to it....
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When I made my boo backed yew the largest bamboo I could get at a reasonable price was 3". I planned and sanded it down to 1/8 tapering to 1/16". It was only about 1 1/8" wide at the wide end. I just made the bow match the dimensions of the boo and it turned into one of the best bows I have. Right around 40# @ 28" but I could have gotten 50-55# no sweat. It's a bit late now but when you are splitting the boo check to see if it's oval shaped and split so you get the flattish side. You are probably better to try and get a 4" dia boo but over here there seems to be a price break at 3". 3" was $40 and 4" was $80.
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Ok got it. Thanks.
One more thing.... As I said, I flattened the boo but it looks so narrow! A bit unsafe even.... You told me to start at 1" thick, in the end, how thick is it going to be approximately? It just lpoks so slim, I'm not used to it....
a 40# bow would be around 7/8th at center, 50# maybe 15/16ths and above 60# don't alter the center thickness.
Anyway leave the center full thickness to establish the belly thickness taper. Then as you tiller you can finesse the bend towards the handle. You can even leave the center full 1 inch thickness and reduce the work it will do there.
Get it roughed out and I can help you with the tiller if you want.
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Ok thanks Mike. I'll get the lams ready and keep you posted
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Sooooo... I got a piece of hard maple. long and thick. I plan to rip it to 1/8" strips.
Here are some pics.
Face- near perfect grain (look at the angle of the end grain):
(https://scontent.fhfa2-1.fna.fbcdn.net/v/l/t1.0-9/14956470_1138283342928055_863822355459292264_n.jpg?oh=9f08252ab206e15aa3bee309cbd66750&oe=58A29A3E)
Sides- Well, the grain sucks at the sides...
(https://scontent.fhfa2-1.fna.fbcdn.net/v/t1.0-9/14962794_1138283336261389_7297145096033883787_n.jpg?oh=ff244595cea0b0f5fbb6f532e0c456ac&oe=589B75FA)
Now, I plan to use it as a core and back the whole think with bamboo.
My question is, can I use it as backing strips? the grain on the face side is one of the straightest I`ve seen but the side grain concernes me.
Your thoughts please.