Would it work?

[Kegan]

With bamboo back and belly (the outside-forget what it's called- outermost on both), could I use a tapered red oak lam on the inside to give it proper bend, tillering it like a semi-pyramid afterwards? It would be a straight longbow, nothing fancy. Red oak boards are justt the cheapest and easiest I have access to, and wondered if they'd work with the boo being the main working parts?

And if so, anybody know if boo is like yew and cedar, and has to be veyr thick and wide to reach weight?

[Pat B]

I've been thinking about a boo backed/boo belly bow with a riser added between the two at the handle and out a bit. I don't Know what weight to expect but was thinking about a simple design.
   I don't know how thicker boo will effect the pull or the durability.   Red oak should work OK because the boo will be taking most of the compression on the belly and tension on the back. Also, added reflex or R/D would add to it also.    Pat

[GraemeK]

Using a central red oak lam will not overcome the tillering difficulties of a back and bellied boo bow -- it will just make the core of the bow heavier than necessary and the bow slow. If your design needs more thickness than the walls of the boo allow you should use something light like spruce or cedar since it is only holding the surfaces apart and taking no significant tension or compression loads. The only way to get the all boo bow tillered is to pre tiller the parts then glue them together -- you can then refine the shape with a little side tillering and perhaps some heat tempering of the belly if the glue you used can stand the heat.

Graeme

[Kegan]

Thanks guys! I've just been thinking of some way to make an "assmeble" bow, and solid red oak board bows have given me trouble in the past. This seemed like a plausible means.

GraemeK-I don't mind a heavy core, for at 75-85# a little extra mass doesn't become as apparent . But tillering seems to be a problem? Why wouldn't the solid tapered core (the point of using it at all) help refine the bend for tillering?

[GraemeK]

Hi Kegan

The problem with stiff heavy cores is that it makes the bow slow not that it is heavy to hold -- The place to have lots of mass to make the bow nice to shoot is in the handle not the limbs.
The reason the oak core will not give the bow good tiller is because it does not affect the tiller much -- the thing that changes tiller is the thickness of the limb at any particular point ( reduce the thickness by an eight and half the strength ) this is why bamboo is such a challenge -- you can not scrape away the surface without ruining it and the outer surface  dips and wallows up and down at the nodes which gives you thickness differences.

Graeme

[Kegan]

Hi Kegan

The problem with stiff heavy cores is that it makes the bow slow not that it is heavy to hold -- The place to have lots of mass to make the bow nice to shoot is in the handle not the limbs.
The reason the oak core will not give the bow good tiller is because it does not affect the tiller much -- the thing that changes tiller is the thickness of the limb at any particular point ( reduce the thickness by an eight and half the strength ) this is why bamboo is such a challenge -- you can not scrape away the surface without ruining it and the outer surface  dips and wallows up and down at the nodes which gives you thickness differences.

Graeme

Okay, I think I'm getting what you're saying! When I mentioned red oak, I was thinking that at about .55-.6 SG, it wouldn't cost me too much speed (I'm not after speed so much as a feliable weapon), the boo doing all the work (the red oak being a thickener). The boo lams would both be parallel, untapered, with the center lam of oak (the cheapest "bow wood" I can find) being nothing more than a spacer between the lams (tapering from say, 1/2" to 1/8") to give the bow a good "pretaper" like fiberglass bows.

From what you say though, it sounds like it's a bit of a long shot at best. So maybe I'll jsut set that idea aside for now?

[1/2primitive]

I think it would work.
Here's my brainstorming since I've been writing this post---I wonder if a center laminating of a lighter wood such as Poplar would give a spacing between bamboo layers, and save weight, making the bow less massive for a given draw weight. The wood in the middle wouldnlt be doing any work, so I think it'll be fine. Just brainstorming, what do you think, guys?
     Sean

[stiknstring]

Why not drop Vinson Miner an email and ask if he will divulge his secret for his cane dragon bows...boo backed and bellied.  There was someone who recently won BOM on this very site that made boo backed and bellied bows....i would ask his opinion rather than conjecture on whether or not it could be done. It obviously has and there is no sense in reinventing the wheel ya know...I believe it was robustus that built the bow so why dont you PM him to see what he says...??  Just a thought

[Pat B]

I have one of Vinson's Cane Dragons. The center lams of these are a multi lam in themself. Mine has either 3 or 5 lams of maple and the 2 outside are osage. These lams are laid up on a horizontal plain. I believe this is a Japanese, possibly Yumi design.  James Parker(Robustus) is who posted the boo back and belly bows. James makes incredible bows...and RyanO's brother makes beautiful boo backed and bellied bows also.   
   I believe this is more than what Kegan(and I) is talking about.  I am thinking about only a riser in between the back and belly at the handle with the limbs being only 2 bamboo strips.

[Ryano]

Kegan, My brother does make bows exactly how your talking about. He uses a tapered core and two parallel bamboo strips on the outside. They are glued up pre-tillered so to speak. The only tillering he does to them is done from scraping the edges. Oak will make a fine core, and actualy I'd stay away from some of the lighter woods like mentioned above. Medium light woods seem to make the best core. My brother uses a lot of black walnut, maple and Cherry.

[Ryano]

Here's a link to one of the bows my brother posted a while back.
http://www.primitivearcher.com/smf/index.php/topic,1925.0.html

[Kegan]

Thanks everyone! Pat was right, that was what I was talking about. Simple and to the point as far as boo bows go.

Thanks Ryano, glad to see the finished product works

Now just to get the amteirals and start assembling ("m getting excited about this project )