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Main Boards => The Bowyer's Bench => Topic started by: LittleBen on July 28, 2014, 03:46:00 PM

Title: Another trilam
Post by: LittleBen on 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
   (http://i1212.photobucket.com/albums/cc450/Benjaminklein/Mobile%20Uploads/photo-50.jpg) (http://s1212.photobucket.com/user/Benjaminklein/media/Mobile%20Uploads/photo-50.jpg.html)

Braced
  (http://i1212.photobucket.com/albums/cc450/Benjaminklein/Mobile%20Uploads/photo-48.jpg) (http://s1212.photobucket.com/user/Benjaminklein/media/Mobile%20Uploads/photo-48.jpg.html)

Drawn to 26"
  (http://i1212.photobucket.com/albums/cc450/Benjaminklein/Mobile%20Uploads/photo-49.jpg) (http://s1212.photobucket.com/user/Benjaminklein/media/Mobile%20Uploads/photo-49.jpg.html)
Title: Re: Another trilam
Post by: LittleBen on July 28, 2014, 03:53:00 PM
 (http://i1212.photobucket.com/albums/cc450/Benjaminklein/Mobile%20Uploads/photo-52.jpg) (http://s1212.photobucket.com/user/Benjaminklein/media/Mobile%20Uploads/photo-52.jpg.html)

 (http://i1212.photobucket.com/albums/cc450/Benjaminklein/Mobile%20Uploads/photo-53.jpg) (http://s1212.photobucket.com/user/Benjaminklein/media/Mobile%20Uploads/photo-53.jpg.html)
Title: Re: Another trilam
Post by: Zradix on 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
Title: Re: Another trilam
Post by: Sam Harper on July 28, 2014, 04:26:00 PM
That sure is a pretty riser.
Title: Re: Another trilam
Post by: monterey on July 28, 2014, 04:51:00 PM
Always enjoy seeing your tri lams!

What is the "wood database"?
Title: Re: Another trilam
Post by: Al Dean on July 28, 2014, 05:58:00 PM
I like it.
Title: Re: Another trilam
Post by: takefive on July 28, 2014, 06:49:00 PM
Great looking bow.  Love the way it bends and the wood combination.
Title: Re: Another trilam
Post by: David Flanrey on July 28, 2014, 08:13:00 PM
:thumbsup:     :thumbsup:
Title: Re: Another trilam
Post by: Trapper Rob on July 28, 2014, 08:24:00 PM
Nice
Title: Re: Another trilam
Post by: LittleBen on 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 (http://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.
Title: Re: Another trilam
Post by: snapper1d on July 28, 2014, 10:35:00 PM
I think the only thing you missed was my address to send it to!
Title: Re: Another trilam
Post by: fujimo on July 29, 2014, 12:14:00 AM
an' i cant wait.......  :bigsmyl:    :bigsmyl:    :bigsmyl:
Title: Re: Another trilam
Post by: PEARL DRUMS on July 29, 2014, 03:56:00 PM
Great looking bow Ben.
Title: Re: Another trilam
Post by: Scott E on July 29, 2014, 04:17:00 PM
Love that riser
Title: Re: Another trilam
Post by: Roy from Pa on July 29, 2014, 07:01:00 PM
I guess it's ok..  :)
Title: Re: Another trilam
Post by: Echatham on July 29, 2014, 07:15:00 PM
I like
Title: Re: Another trilam
Post by: LESKEN2011 on 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?
Title: Re: Another trilam
Post by: Zradix on July 30, 2014, 02:53:00 PM
looking forward to your post fujimo...   :bigsmyl:
Title: Re: Another trilam
Post by: LittleBen on 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.

 (http://i1212.photobucket.com/albums/cc450/Benjaminklein/Mobile%20Uploads/photo-51.jpg) (http://s1212.photobucket.com/user/Benjaminklein/media/Mobile%20Uploads/photo-51.jpg.html)

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).