Question on Tri-lam

[Kevinnator11]

I'm planning to start a tri-lam soon and was wondering which would be the best way of doing it.  Osage core with a hickory belly or the other way around?  And if I recall correctly the starting thickness would roughly be 1/4 for the core and 3/8 for the belly.  Is this correct?  Boo backed of course.

[Bowjunkie]

I would do osage on the belly.

I think unless you're looking for a really heavy bow, the thicknesses you mentioned are going to require you to remove quite a bit from the belly. Of course, it depends largely on your width, cross section shape, length, and other specs.

Ultimately, a goal with tri-lams is to have very accurate tapering prior to glue up, and have the thickness put you slightly over target weight before you remove any wood from the belly. If this is accomplished, you won't need to do much tillering or weight reduction, so don't need much extra wood.

Keep notes. They'll help with future bows.

I'd give you some exact numbers from my bows but I won't be home til late tonight.

If memory serves, most all of my bamboo/osage/osage tri's used osage 3/16 - 1/4" for both the core and the belly lams. This would be for bows in the neighborhood of 58-62" ntn, about 1 1/8 to 1 1/4" wide,  moderate to highly d/r or recurved, and about 60# @ 28"...

If you're making a longer bow, shorter draw, don't have a means to precisely taper, etc... you may want to leave a little more meat on the bone.

I've yet to use hickory between the boo and hedge... so you may want to add a tiny bit of thickness for that as well.

[Kevinnator11]

That answers a lot of questions.  I'm shooting for around #55 @ 29".  Probably around 64-66 ntn 1 1/4" wide.  I'll shoot for 1/4" thick as a start.  Thanks for the info.