Tri-lam stack thickness

[Michael Pfander]

I want to build a tri-lam as my winter project.  I need some help on the taper and stack thickness for 55# @ 28" 66" bow.  I am planning on .002 taper on the core, parallel on back and belly.  The riser will be 18" fade to fade.
MAP

[Bowjunkie]

We need more information. What materials will be used? What kind of side profile? Straight, d/r, semi or full recurve?

[Michael Pfander]

I plan on using bamboo for the back, yew for the core, and osage for the belly.  It will have a mild r/d proflie.
MAP

[mikkekeswick]

Use more taper for sure. R/d bows like to have parallel width limbs out to about 10 inches from the tips. This really helps maintain the reflex in the mid to outers and also helps with limb stability.
I use 0.005 taper.
you can't really use accurate stack info on a wooden bow because the materials aren't homogeneous. Aim for your stack to add up to 1/2 inch at the fades and you should be ok.

[LittleBen]

X2 what Mike said.
Definately use more taper. It'll mean less tillering in the end. And take his advice on he width taper ... This guys knows this type of bow.


FWIW
Only time I've had luck with stack is making multiple bows for the same ipe board, and even then it was maybe within 10%. Change boards, and everything changes.