Zebra wood twisty lams!

[Appalachian Hillbilly]

I have some real nice zebra wood that has made some beautiful risers. Decided to cut some lams for limbs. Cut one way so that the grain and stripes are parallel, the bend real nice.
 
Cut the other way so that the stripes are really wild and swirly... you try to bend one of the lambs and it will propeller in as much as 3 different directions! That is with a 50 thousandth lam! May try  to do it as a veneer backed with maple.

[kennym]

Yep it is terrible about that.  Even as veneers.

I now make sure even with veneers, the twist is opposite on back and belly to equalize the torsion. Like, if you could xray the limb the grain would make an x of the 2 veneers grain. I've had it ruin a bow because of limb twist...

[Jon Lipovac]

Wow Kenny.  I would not have  thought thin veneers would have that much effect on limb twist. How thin are your veneers? You’ve got me thinking I need the pay attention to this.

[Appalachian Hillbilly]

I was amazed at how strong the twist was. I spent some time Saturday with bowyer Mike Treadway and he warned me of it. I would intentionally try to keep it from twisting and it would propeller back and forth throughout the lam. And that was just at .050

[kennym]

Mine were .030 and I ended up pitching that bow...

I even tried narrowing it up and moving the center toward the twist, but no dice.

I didn't think it could matter either, but you have .060 trying to twist with both veneers twisting the same way.

[Stagmitis]

You would think with all that pressure and glue in the form it would behave but it still rears its ugly head- Kenny good job figuring that out after one bow-Im a slow learner 

[Longcruise]

I've only done one with zebra veneers and had no problems.   This thread is making me feel lucky.  Probably won't do another.  Too many other choices to borrow trouble!

[kennym]

You would think with all that pressure and glue in the form it would behave but it still rears its ugly head- Kenny good job figuring that out after one bow-Im a slow learner 

Ummmm, I just didn't mention the other one... 

[Kirkll]

The sawdust makes me sneeze... I don't work with zebra wood if  i can help it any more.

But......Nice straight vertical grained Zebra wood can make a great hot rod bow if you are so inclined. Mix it with some Paduke in the core and use real thin glass.....it's unreal what type of performance gains you can get with it.... They say "Cores don't matter" ....  Horse feathers i say... It all works together as a matrix assembly.
Light weight , stiff material makes a big difference.

[Appalachian Hillbilly]

The two on the right are the lams I ground from Zebra Wood. One set vertical, one flat grain. Looks like I will be using the nice straight grain....

That's maple, bamboo, straight zebra, crazy Zebra  in the pic.

[Kirkll]

I’ve had good luck grinding those wild flat grain zebra veneers down to about .020 and using a booked matched pair belly and back by flipping the grain to balance it out.
No twist issues at all…. I used 36-40 grit paper in my drum sander to get them down to .020…. It’s tricky…. But can be done if you are patient.

Kirk

[Jon Lipovac]

But......Nice straight vertical grained Zebra wood can make a great hot rod bow if you are so inclined. Mix it with some Paduke in the core and use real thin glass.....it's unreal what type of performance gains you can get with it.... They say "Cores don't matter" ....  Horse feathers i say... It all works together as a matrix assembly.
Light weight , stiff material makes a big difference.

Kirk. When you have built these limbs. Do you like the zebra on the compression on tension side and why? Trying to learn which wood characteristics are better or worse on compression/tension side and why.
Thanks