Primitive Archer
Main Discussion Area => Bows => Topic started by: Knoll on July 29, 2014, 11:03:28 am
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Picked up an osage board at MOJam ... 1" x 1.5 x 72, quarter sawn. Am relatively new to bow-building and 0 experience w/ backings.
Looking to be 'bout 40-45 lb @ 26".
Seeking conservative layout/design suggestions appropriate to this board and newbie bow builder.
Hope to hear from a bunch of ya!
Michael
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Hickory backed osage makes a good bow from what I've read. Pyramid design is simplistic for beginners.
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Michael, IMO a hickory backing(or bamboo but hickory is a simpler process)would be in order for an osage board bow and it will make a fine bow. I'd go 66", 1 1/2" at the fades and out to mid limb with a straight taper to 1/2" tips(for now). A 4" handle placed in the center of the bow with 2" fades. This will give you a bow of almost any weight you want. The hickory backing should be about 1/8" thick and the bow glued up with about 3" of Perry reflex. TB glue will work just fine for this bow.
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Pat, what is Perry reflex?
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You are 1/2 way to a breath takingly awesome bow.
I think as far as backings go Bamboo is king, but I've read great stuff about rawhide (assuming you aren't up for sinewing). I'm out of bamboo or i'd offer to prep one for you and trade you something for it.
Do a youtube search for "bow aragon" and you'll see one of Konrad voegelle's bows. That is almost exactly what Pat B is describing above.
You can glue it with TB@ or TB3 if you don't wrap it in celephane. The deflex can be clamped in but you don't need much.
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Sorry. Perry reflex is adding reflex as you glue the back to the belly. Basically you lift the tips up on blocks(about 3" to 4") and pulling the handle down to the table. You will want to pre-tiller the belly so you get a nice even bend at glue-up.
This method was popularized by Dan Perry of Utah. He is a flight shooter so he was trying to get the best performance out of his bows.
There might even be a write up in the" How To" section by Dan Perry.
Boo is pretty finicky to prep and I have had more bad luck with boo than hickory witch is pretty fool proof. Rawhide only adds insurance but not performance.
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Perry reflex is reflex glued in while attaching the back. Its under "pressure" even after the clamps are released. That can make a bow hold the same reflex it started with, sometimes. Id suggest hickory. You can look at hickory most often and know just how healthy it is, boo not so much. Hickory is more reliable and 10x easier to prep and finish. Ive made plenty from both hickory and boo and will never use boo again. Id suggest, for a 28" draw, a 64-65" ntn flat bow. Start with 1 3/8" fades and carry that out 16-18", then straight taper to 1/2" wide tips. TB3 works fine, but you better have your ducks in a row and do a dry run prior to using glue. TB3 sets fast and if you are fiddling with 65" of bow you don't have much time. Drill a pair of toothpick sized holes dead center of the handle, through both the back and into the osage about 3/8". When you glue up you lay the back on, insert toothpicks and then clamp out to each tip. The toothpicks keep the whole sha-bang lined up and it cant slip and slide at all. If you glue a back on that gets twisted, it will result in a twisted bow with no way to fix it. If you decide to use c clamps, I do, then be sure you just nudge them tight and don't squeeze all your glue out. Also, alternate which side of the limb as you place clamps so you don't have all the clamp weight pulling to one side. That's about all I know about glue ups.
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Ok, got it.
Pearl- that's a great idea using the toothpicks as guides.
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Not mine Falcon. Like 99.9% of what I know, I learned form others by reading here. This place is loaded like no book or books you can buy.
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I totally agree Pearl, That's why I keep coming back. Well that and the people on here are like no other kind of forum I've ever been a part of. So quick to offer advice, positive and constructive criticism, and never expect anything in return. A great bunch of misfits is what y'all are!
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Pearlie gave me the idea about the tooth picks when I was gluing up the "Classic" hickory backed lemonwood I donated to Twin Oaks for the raffle table. It is a trick that will keep you from loosing your mind at glue up time.
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So much help/info. But if others wish to chime in, don't be bashful. Thanks, guys!
One other question . . . well, one at the moment. Board is full 1" thick. So if I setup my table saw JUST right and do some test cuts, could split that board into 2 @ 7/16" thickness. Am I pushing my luck for 40-45# @ 26"??
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Leave that thickness at the handle so you have good, solid fades. If you rip it in half you will have to build a power lam in order to keep the handle on. That's no fun.
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Leave that thickness at the handle so you have good, solid fades. If you rip it in half you will have to build a power lam in order to keep the handle on. That's no fun.
Duhhhhh, really thought that through!
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Slow her down big guy! Easy there! Follow the same basic rules of any bow build. Proper length, proper fades and a proper tiller, and don't forget a proper tiller.
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I would cut a small slat and do a bend test on any store bought hardwood ,be it hickory or not!the wood may look fine but may be damaged by fungus.
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I prefer to use the full thickness when working with board bows so, like Pearlie suggested, you can make good solid fades and won't have to use a power lam. Actually at 1" of thickness you don't need to add a riser at all. You might just add a back lam to the handle area to fill out the back of the handle for a better fit in your hand. I use thick leather for this but cork will work or even a short(4") piece of wood.
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with a pyramid bow you can get a rough pre tiller using the method in this build a long if you want to induce some reflex at glue up, I would think limb thickness on the belly wood should be about 3/8", that would give you 1/2" to start, just another option good luck and post pics http://www.primitivearcher.com/smf/index.php/topic,35312.0.html
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RE backing, here's my plan . . .
Went down to my local hardwood dealer and found straight grained pc of hickory, 13/16 thick.
Plan is to rip width to 1 1/2, which is same as my osage board. Don't have a bandsaw, so will resaw to 1/8" using the table saw.
Then glue that 1/8" hickory (as backing) to the osage board.
Then layout the bow and get to work . . . . . .
OK plan?
Thanks, in advance
Michael
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Good plan. Are you gluing it up flat, or adding reflex?
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Good plan. Are you gluing it up flat, or adding reflex?
Intrigued by the Perry reflex approach. Have done just the glued-on reflex tips so far, so Perry reflex would be new territory. So, would need to do the reflex thingy at time of gluing backing on, correct?
Thanks to all who've chimed in. Got lotsa options for this board or futures!
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Yes, you'll be bending the reflex into your bow on a form before glueing it up. The form I use is really basic; just a 6 foot long 2 X 4 with a couple of pillars on each end and one in the middle, 'tho I've since removed the center one. The bow next to it is hickory backed osage that I made last year. Don't remember how much reflex I put in it, but I'm sure it was 3" or less. It holds 1 1/2" now. Pretty sure if you do a search you'll find a post with exact dimensions for a form and how to do the glue up.
I don't have a band saw either. I either use my table saw or hand held jig saw. Pat and Pearl Drum's advise about working the osage board down before trying to bend it on the form is key. Make sure you leave enough thickness in the handle area, though.
(http://i376.photobucket.com/albums/oo207/okdoak/Wooden%20bows/ocherrybow1_zpse42625c4.png)
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Actually, to clarify, you'll bend it on the form and clamp it right after glueing the slats together ::) I always do a dry run first just to make sure that I have the belly wood thin enough to get the bend I want. On the bow I posted, I ripped the osage board 5/16" at the tips tapering to its full thickness of 5/8" at the fades. Still had plenty of wood left for a 45# bow.
Geez, must be time for bed...starting to ramble here. :) Good luck!
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Make something like GB has, minus the inner uprights. It will keep the tip lifted as the glue dries, you would probably get about 2.5"*3" off the form.
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Here's my el cheapo form in action. That's about 3" of reflex (easily done when the wood is only 1/4" thick ;)) Like Pearl said, you can just go with the uprights at the ends or space the inner ones so you get an even bend from tip to fade if that's what you're aiming for. If you really get into making backed board bows, you should check out Dean Torges' Hunting the Bamboo Backed Bow DVD. Lots of good info in it, and while he uses bamboo, it works the same with hickory.
(http://i376.photobucket.com/albums/oo207/okdoak/Wooden%20bows/RDform_zpse1cdca0a.png)
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So, if fade width is extended to mid-limb or thereabouts before tapering to 1/2" at tip, do I need to do elliptical tiller or is circular tiller still appropriate?
Reason for asking is that all my bows, to this point, have been tapered from end of fade to tip and circular tillered. Elliptical tiller would be yet more "new ground".
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Yes, tiller would be elliptical.
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So, if fade width is extended to mid-limb or thereabouts before tapering to 1/2" at tip, do I need to do elliptical tiller or is circular tiller still appropriate?
Reason for asking is that all my bows, to this point, have been tapered from end of fade to tip and circular tillered. Elliptical tiller would be yet more "new ground".
The following is just my opinion and I've only ever done one DR bow and that exploded, others may well disagree.
Come to think of it, if I were you, I wouldn't read this post ;)
It depends what you mean by elliptical... if you mean more bend near the tips and less near the grip then No!
The way to look at it is... it should be tillered the way you'd have tillered it if it was straight BUT the tips should flex less, by the same amount as they are reflexed (make a similar allowance for deflex on the inner limb). EG, the unbraced shape should be sort of subtracted from the usual tiller.
I usually do arc of a circle. So if I had 2" reflex , I could draw the arc of a circle, add 2" of reflex to that shape at the tips and there's the tiller shape ;D
Probably an oversimplification, but hey... sue me!
A full deflexed reflex bow has a huge reflex which at full draw uncoils to give a virtually straight limb which is angled towards the archer by the deflex near the grip.
Del
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My suggestion is to forget all that tiller shape confusing talk, your building a staright bow with a stiff handle. Regardless of width profile. Use your scraper on edge and run it from from fade to 8" short of the tip, bow drawn to say 12-16" and held static while you do this. Mark the flat spots and make that gap between the scrapers edge and the belly of your bow the same and you will have a lovely tillered, butt kickin' good shooting bow. Promise. If it doesn't balance just right after several full draws, simply pick the strong limb and give it 10 full scrapes. It will balance and shoot like a pro Joe made it.