Pre tillering Boo?

[nyamazan]

So I made my first all boo bow, came out better than I though but worse than I expected.

Trouble I had was with the tillering as I couldn't take any wood off the front and back of the limbs and ended up with taking off so much on the sides I ended up with it being 3/8" at the tips. It was hinging pretty bad at the fades!

I thought I had pre tillered it correctly but two errors;
The belly limb I tillered  with the boo the wrong way round i.e the belly limb bending the the same way as the back limb.

The other mistake I think I made was not allowing for the riser portion  to not bend as I had a 1" thick riser sandwiched between the limbs.

Do you reckon I should pre tiller the next one without the riser portion bending by clamping a solid piece of wood on both the center portions of both the limbs?

Sorry for what may be a stupid question but I'm new to all this.

Thanks all.

[LittleBen]

That sounds reasonable. Let me say this though, it seems like these bows tend to end up bending more at the fades than along the rest of the limb. In the images I've seen and build alongs this is what I've seen.

I would consider putting a tapered actionboo core lam in between the back and belly lams to help with the tiller. Just a thought. Nothing crazy just maybe .001"/" or .002"/" taper.

Was the bow 3/8" thick at the tips or 3/8" wide? Pics would help.

[nyamazan]

The bow was 3/8 wide and 5/16 thick.
It was a sort of test with local bamboo that grows here. 56" long and came out at 40#@28". No pictures as I put it to the test and drew it to 31" before it failed, not at the fades but at a node that I had sanded down to much on the belly.
I am pretty inpressed with this local wood.
I don't have access to action boo. What about a ground boo tapered lam?

[Roy from Pa]

The tapered lam should work.

[nyamazan]

Thank you.

[Sam Harper]

It wouldn't hurt to put a power lam in there, too, to strength those fades.  Just make it about 1/8" thick, just a couple of inches longer than the riser on each end, and tapered to paper thinness.

[nyamazan]

Do you mean to put a power lam and the tapered lam in?

I have made a longer riser that is 15" as opposed to the other one that was 12". The new one has much more gradual fades than the other.

Would the longer riser not take the place of a power lam, or do you need the power lam to be of boo so it would flex more than the hard wood riser?