Zebra wood problem, chunks coming out.

[Bill Huber]

I was given some Zebra wood last spring and was just not getting around to working with it. I have never worked with it before so this is all new to me.

The boards were 4/4 and I re-sawed one and then was planning it down to 3/8 to make a box. I was taking very light cuts with the planner and on the second cut I heard funny noises coming from the planner.

I ran it though again with the same setting on the planner and it took out some more. I checked my knives and they are fine, I ran some red oak though and it did just fine, smooth and clean like normal.

This is what came out the other side.
What am I doing wrong or is Zebra wood a good wood to work that thin?
Big chunks were missing and had been just pulled out.

99510 99511

[Peter Quinn]

Bill, do not fire your shot gun into the planner when working zebra wood!:D

Wow. I have worked some Zebra wood, but never that thin and always on a spiral head planer. We did have cracks and strange checks present themselves after fabrication in the middle of boards that had appeared sound during milling. I'm told they are there but hard to see and are the result of these massive trees being felled without enough brush cushion to absorb their fall to the ground, causing the very dense brittle wood to shatter on impact. It often doesn't show these defects until after you glue it up.

I don't know if this has any bearing on your situation. My only suggestion or question would be are you orienting the grain correctly when planing? Any quarter sawn material is going to get a bit weak when it gets that thin, so I would think it essential on a straight knife planer to orient the grain correctly. I have blown up QSWO going to thin in my home shop planer, looked just like that picture of yours but in oak.

[Bill Huber]

Bill, do not fire your shot gun into the planner when working zebra wood!:D

Wow. I have worked some Zebra wood, but never that thin and always on a spiral head planer. We did have cracks and strange checks present themselves after fabrication in the middle of boards that had appeared sound during milling. I'm told they are there but hard to see and are the result of these massive trees being felled without enough brush cushion to absorb their fall to the ground, causing the very dense brittle wood to shatter on impact. It often doesn't show these defects until after you glue it up.

I don't know if this has any bearing on your situation. My only suggestion or question would be are you orienting the grain correctly when planing? Any quarter sawn material is going to get a bit weak when it gets that thin, so I would think it essential on a straight knife planer to orient the grain correctly. I have blown up QSWO going to thin in my home shop planer, looked just like that picture of yours but in oak.


Peter I think you nailed it, I was not watching the grain. Looking at the wood now I see the grain and I should have been feeding it in the other direction.
Now that these boards are screwed up I will try and see how it goes feeding it in the other direction.

Thanks

[David DeCristoforo]

Peter nailed it. "Bass akwards" feed direction. The grain is almost straight up and down in that area. Not unusual for Zebra which is also very open pored and somewhat soft. Feed direction would be critical here, esp. with very thing stock. What you have is the ultimate example of "tear out".

[John Michaels]

Zebrawood can be unpredictable. If the tree was felled improperly, there can be hidden (and visible) cracks as mentioned in the above post. You might have had problems regardless of how you fed the wood into the planer. I made some table legs out of 8/4 zebrawood and everything seem fine. The legs had been planed and a taper was cut on the table saw. Not until I was using a random orbit sander did huge chunks of the wood break off. I went through 7 legs to get 4. When buying zebrawood if there are any visible cracks at all in the wood, you might want to pass on that board because that can mean hidden ones as well. Hope this helps.

[Ken Fitzgerald]

BIll,

I've turned some pens and bottle stoppers out of zebra wood and have mixed success. It seems like it can be extremely brittle to me.

[Vinny Miseo]

Hi Bill,

I am going to second what John Michaels said. I had the same problem last week. It did not matter which direction the wood was fed, it would blow out. Luckily we have a drum sander that helped to acomplish the task.

We also bought some chinese zebrawood ply for super cheap, and warped like crazy once we cut it. My first experiance with the wood has not been a pleasent one... and the project just started.