Heavy Tri-Lam Flatbow/Warbow

[familyfriendlyname]

Hello!

I am also posting here to see what I can do...(I posted on the Warbow section as well.)

Basically, I have boards of purpleheart (which will be spliced/scarfed together), hard maple and white oak.

I was told that the only way I could get a heavy bow out of this combo of woods would be to make a large and thick flatbow. Apparently maple doesn't like a D shaped belly like a typical warbow. I am going for a white oak back, purpleheart core and a maple belly, and well over 100#, hopefully 130#.

The least wide board I have is about 3" wide. All the boards are an inch thick, and have straight grain, and quarter sawn, the rings are 30-45°. What dimension should the purpleheart core be if the belly and back are shaved down to .125"?

[Badger]

     In all honest if I was starting a project like this I would make the small investment in better lumber. For any given design with any given wood you have only once correct thickness regardless of weight. The with is actually what allows you to have specific draw weights. The white oak can make a good backing if it has flawless straight grain, the purple heart is very heavy for a core wood and the maple likes to be wide and flat.

    You could use the maple for the core and use something like ipe or osage for the belly and wind up with a reasonable width maybe 1 1/2" or even less.

   

[familyfriendlyname]

Thanks for the fast reply man!

I don't mind if it turns into a pyramid/flat bow, so long as I can use the woods I have with me, and have a decent poundage.

[Marc St Louis]

I would shift those around a bit.  Use the Maple for the backing and the Oak for the belly

[familyfriendlyname]

I would shift those around a bit.  Use the Maple for the backing and the Oak for the belly

Hm. Then what would the dimensions be? B/c the boards are all an inch thick, would it be better to go the boardbow route then back/belly it to make a hybrid board/war bow?

[J05H]

Regardless of what order you laminate them in, your going to have to do work all three pieces down to much smaller thicknesses. The best way I know to do that is with a band saw. Do you have access to one? By the way, clever screen name

[bowandarrow473]

I'm with Badger on this one.  And that is a very clever scene name indeed!

[bubby]

I rip most of mine down on the tablesaw then thickness planer then hit it with a beltsander

[familyfriendlyname]

I think I may have access to a bandsaw, if for a limited time- we have contractors working on our apartments.

My other idea was, what if I made a 80" boardbow from the purpleheart, then back and belly it with the other wood?

[mikekeswick]

Honestly if you need to ask these questions chances of hitting 130# are slim  I'm not meaning to put a downer on your project but a 130# bow of any design is hard to come by. How many bows have you made upto this point?
What weight are you comfortable shooting?

[familyfriendlyname]

Honestly if you need to ask these questions chances of hitting 130# are slim  I'm not meaning to put a downer on your project but a 130# bow of any design is hard to come by. How many bows have you made upto this point?
What weight are you comfortable shooting?

No, I like the honesty.

I have made a couple board bows, Red Oak ofc. One was Boo backed.

As a frame of reference, I comfortable with the 90# fiberglass Mongol bow I have, but I tried a 100# fiberglass horsebow (Hungarian?) and it wasn't too bad.

[Marc St Louis]

And that is a very clever scene name indeed!

It is indeed.  It would be a pity if this was a previously banned member that would just have to be banned again once found out

[Wooden Spring]

Oh, I would steer away from using quarter sawn white oak as a backing. Due to the ray fleck found in both white and red oak, these are MUCH more pronounced in quarter sawn lumber, and I've had quarter sawn white oak snap at very low poundages. But, where it fails in backing, it EXCELLS as belly wood.

If it were me, I would just reverse your order - Hard Maple back, Purpleheart core, and White Oak belly.

I'm not sure about the dimensions to get that high of a poundage, but when it comes to bowyery, it's all about EXPERIMENTATION... Start with one set up, if it blows up, or comes in at a different weight, try something different.

There CAN be a lot of math involved to try to figure this stuff out, but my methodology involved sawdust and splinters.

Start with 1/8" Hard Maple backing, 1/8" Purpleheart core, and 1/2" White Oak Belly.
Make your glue up 2" wide and glue in about 3" of reflex.
When that's dry, cut it at 1-1/2" wide until about midlimb, then taper to 1/2" nocks.

[familyfriendlyname]

Nah, I just got my name from Bart Simpson.

Either ways, thanks for the rough dimensions wooden spring! I may have to bump the maple and pplhrt to 1/4, I don't think the contractor's bandsaw can make stuff that thin...

The belly is then tapered from grip to nock then I presume?

[Wooden Spring]

Nah, I just got my name from Bart Simpson.

Either ways, thanks for the rough dimensions wooden spring! I may have to bump the maple and pplhrt to 1/4, I don't think the contractor's bandsaw can make stuff that thin...

The belly is then tapered from grip to nock then I presume?

What I normally do is to first cut an even thickness of 5/8" along the length of both limbs, this usually gets the bow bending just a tad. Then, use the "One, Two, Three" tillering method outlined in Stim Wilcox's book "The Art of Making Selfbows" (great book by the way). What this means is that you get the middle of the limb to bend first, then nearest the handle, and lastly at the tips.

It took me forever to realize that you can't really go by dimensions on the thickness - you have to sand, shave, scrape, or cut what the bow wants.

It's like riding a motorcycle. Let the engine tell you when to shift, not the owner's manual. That right there is the best advice I can give you.