Have You Ever Worked With Koa?

[Julie Moriarty]

I bought some koa, my first experience with the wood. I had to plane pieces flat and square. I don't have a power jointer, only planes. The irons are very sharp. But whatever I tried to do, I could not prevent tear out. I changed directions. I ran the plane at an angle. I set the iron to take whisper thin shavings. And I closed the mouth as much as I could. But nothing I did stopped the tear out. The only thing I didn't do was wet the wood.

Is this the nature of the wood or am I missing something?

[Chris Padilla]

Figured, curly, interlocked grain can make planing this wood painful. You need excruciatingly sharp tools and light cuts. However, it sands very nicely and takes most finishes very well.

[Loren Woirhaye]

Focus on scraping cuts. A no. 80 cabinet scraper is a most useful tool. You can also explore double-bevel sharpening in order to raise the effective pitch angle of the plane you are using. German horned smoothers are often bedded at 50 degrees. I would guess you need to get close to 60 degrees to address the interlocked grain. Steve Knight used to make high angle smooth planes but I don't think he's doing it anymore. You may be able to locate a used one.

[John Bare]

Chris is correct about figured, curly, interlocked grain woods. Try a scraper to smooth it down. Get a good burr on the scraper and it should work without any tear out.

[Julie Moriarty]

For just finishing purposes, I understand using a scraper. But if you're trying to flatten a board or joint an edge (I needed to do both), then what? The wood isn't highly figured but it may have interlocking grain and that's what is giving me problems. I just sharpened the plane irons a couple of weeks ago and haven't used them that much but maybe I need to sharpen them again.

[John Downey]

I've had similar problems hand planing mesquite. It can take a very long time to plane, due to light cut and frequent sharpening. I'm usually smoothing though, not dimensioning.

For mesquite, I like to hollow grind the blade and buff the edge on a hand crank felt wheel with some fine polishing compound - stuff I have is for stainless steel, any very fine polish would do for charging the wheel. Needs touch up often, maybe after 30 minutes of use.

[Chris Padilla]

I don't know how much flattening you need to do, Julie, but a router floating above the koa riding on parallel/coplanar rails might be another way to flatten it.

Or, God forbid, a handheld belt sander might work.

I'd start with a resharpening and trying again.

[Loren Woirhaye]

Polish and set the chipbreaker about 1/32" from the edge. Set up right, it can manage tearout... not as well as double-bevel sharpening I think but nearly as well. Read up on chipbreaker tuning if you want to get your bench plane performing as well as possible.

[Julie Moriarty]

Thanks guys! I'll give conventional methods another try before I take out the belt sander

[Bruce Page]

I made a mantel clock for my sister out of Koa. As mentioned the figured grain can be challenging but doable with sharp tools. I ended up sizing everything with my drum sander, it was a lot easier than changing blades on my jointer & planer.

clock.jpg

[Chris Padilla]

Nice work there, Mr. Page! Yep, I ended up doing A LOT of sanding to tame tear-out on koa. A beautiful wood but I'm not sure I'd work with it again.

[Bruce Mack]

Beautiful piece.

[Chris Fournier]

Using a scraper on curly woods tends to leave a washboard surface that follows the end grain/tangential grain of the wood. Try wetting down the koa with a rag, let it sit for a minute and as you see the moisture wick off begin to plane with your sharpest plane. Never fails. Ever.

[Julie Moriarty]

Using a scraper on curly woods tends to leave a washboard surface that follows the end grain/tangential grain of the wood. Try wetting down the koa with a rag, let it sit for a minute and as you see the moisture wick off begin to plane with your sharpest plane. Never fails. Ever.

Thanks Chris. I'll have to try that next time.

I ended up doing the drum sander method. Koa is so beautiful when planed I just kept trying. It would go fine for a bit then tear out. I saw nothing in the grain indicating that would happen. It's not figured like Bruce's clock so I kept thinking it was me. But it kept happening. Anyway, I got the boards flat and edges straight for gluing using just sanding. I ended up using a beam sander for the glue edges.

Thanks everyone for your help!

[Chuck Darney]

And I'll assume the plane(s) you're using have a good high angle? I tried flattening some Big Leaf Quilted Maple with ~38* angle (25+the bed on my LV BUJ). The tearout was way bad. I put a 50* micro bevel on another blade (for 62*) and had no problem with tearout.

...Chuck