White oak tri-lam questions

[Josh Leyshon]

I have a mountain of quarter sawn white oak left from a previous job and I want to build a 70" tri-lam reflex deflex with a 60lb draw.No glass.What should my laminate stack be to achieve this? I'm planning on a hill style riser handle as well. Do I need to taper my laminates or can they be parallel? Thanks for any help

[Roy from Pa]

I would say 5/8th stack. I would leave the belly lam parallel and taper the core and backing down 1/16th thinner at the tips than the riser thickness is.

[Josh Leyshon]

Thanks Roy. Do I take the taper out of both sides of the laminate or just one? Also should the core be thicker than the other 2 laminates? Thanks for the advice. I'm really green with bow making

[Roy from Pa]

Just one side. The belly is left parallel and is the thickest, then core thinner then backing about 1/8th thick. Leave the backing 1/8th thick parallel the entire length.

[Josh Leyshon]

OK so only taper the core a 1/16th? Also, should I stay 1.5in till mid limb and then taper to 1/2in?

[Roy from Pa]

Yes on core. I would hold the 1.5" out about 6 inches past the end of riser, then a straight taper to 1/2" wide at the tips.

[Clevelandbowyer88]

Depends on the type of wood your using. My last trilam bow I used a 1/8" hickory backing (parallel) 1/4" ipe (tapered to 1/8 at the tips and 1/8" ipe belly (parallel). Worked out pretty good for me, only had to do minor fine tillering and came just shy of my target weight of 45lbs. White oak take quite a bit of set tho so I'd heat treat it and use it as the core wood since it has pretty good compression strength.

[Clevelandbowyer88]

Also about the taper location that is up to preference. I chose to start my limb taper at the half way point and then straight taper down to 1/2" at the tips. Partly because I was trying to make narrow limbs alltogether and probably went too narrow. The widest part of the limb was only 1", way too narrow for most wood but ipe is super dense and can generally handle slimmer limbs like that.