Another trilam

LittleBen · July 28, 2014, 03:46:00 PM

Ok this one is 60"ntn 1.75" wide tapering to 1/2" nocks, kept wider than pyramidal out to 10" from the tips.

40#@26" 140+fps @ 500gr and 25-26" draw.

Hickory back, maple core, shedua belly.
Used wood database data to estimate proper with by comparison of shedua and ipe.

Anything I missed just ask

Unbraced

Braced

Drawn to 26"

LittleBen · July 28, 2014, 03:53:00 PM

Zradix · July 28, 2014, 04:14:00 PM

Pretty bow Ben.

Still liking this design I see.

Very cool with the shedua!

I've been playing around figuring out a way to easily add a little arc to the riser area. Hard for me to keep the area just a few inches outta the fades from cracking....gotta tiller it perfect which is something I'm struggling with...lol

Sam Harper · July 28, 2014, 04:26:00 PM

That sure is a pretty riser.

monterey · July 28, 2014, 04:51:00 PM

Always enjoy seeing your tri lams!

What is the "wood database"?

Al Dean · July 28, 2014, 05:58:00 PM

I like it.

takefive · July 28, 2014, 06:49:00 PM

Great looking bow. Love the way it bends and the wood combination.

David Flanrey · July 28, 2014, 08:13:00 PM

Trapper Rob · July 28, 2014, 08:24:00 PM

Nice

LittleBen · July 28, 2014, 09:17:00 PM

John, this is the one I was building while you were building yours. Since this I've moved to a similar design but with some deflex out of the riser which seems to help the problem you're talking about. I just today shipped the latest one of the new R/D design to Fujimo so when it lands hopefully he'll post some pics and you can see it.

Mike, wood database is www.wooddatabase.com IIRC and it has some basic mechanical specs on a whole bunch of woods ... Nearly every wood I can think of is listed. And it lists modulus (stiffness) and maximum strength (maximum stress at failure) and basically stress @ failure divided by stiffness is a measure of elasticity, it's not listed but you can calculate it. If you want more details or wanna talk a particular wood shoot me an e-mail.

Thanks for the kind words. It's got a slight whip tiller, or more accurately it's bending most at mid limb, but it's also left extra wide out past mid limb as I mentioned.

snapper1d · July 28, 2014, 10:35:00 PM

I think the only thing you missed was my address to send it to!

fujimo · July 29, 2014, 12:14:00 AM

an' i cant wait.......

PEARL DRUMS · July 29, 2014, 03:56:00 PM

Great looking bow Ben.

Scott E · July 29, 2014, 04:17:00 PM

Love that riser

Roy from Pa · July 29, 2014, 07:01:00 PM

I guess it's ok..

Echatham · July 29, 2014, 07:15:00 PM

I like

LESKEN2011 · July 30, 2014, 07:04:00 AM

Sweet bow, Ben. That is next on my agenda...a trilam. I can only hope it turns out as nice as yours. By the way, you still using about .005-.006 per inch taper?

Zradix · July 30, 2014, 02:53:00 PM

looking forward to your post fujimo...

LittleBen · July 30, 2014, 05:16:00 PM

Kenny,

Yeah I generally use 3 .002" taper lams for a total .006 taper.

Works out pretty close for 1.5" width, probably .005 total taper is better with 1.75" wide limbs. I usually keep mine pretty wide through and slightly past mid limb, or even full width to kid limb on the 1.5" wide bows. If you're going more pyramidal you'll need less taper.

Here's a picture of one strung immediately after coming off of the form, and shaping the front profile to give you an idea of how close .006 gets you. The how in the pic is 1.5" side to 10" for the tips then tapers to 1/2" nocks.

One limb is obviously stiff, but really it only takes very little wood removal to correct that imbalance.

The hinge looks a lot worse than it really is since the limb is still full width there and the form is actually slightly flat there (oops).