Planer Chipping, Flaking, Tearout
Possible causes - and solutions - for a poor surfacing result with ash. February 27, 2005
I'm having quite a hard time surfacing ash. I'm getting a lot of chipping or flaking. I expect a little around knotty areas, but even in harder areas, I'm getting flaky tearout. I'm running a 36" Whitney. Could this be a blade angle problem?
From Dave Rankin, forum technical advisor:
This could be the angle of the tool, the dullness of the blades, or the material itself.
One way to correct this is to use a spiral designed head. This will help break up the cut.
I don't how old the knives are, but here are a couple of other suggestions before you try changing the blade angles. Make sure you are feeding the ash with the grain. Run your hand carefully down the board to be sure it doesn't snag, then feed it through. Also, take a spray mist bottle and lightly mist the board with water. It can help with other hardwoods like birdseye maple to minimize tearout. Also, you may want to consider using a drum sander for really dense pieces to avoid chewing up your planer blades.
Here are a couple pages with some Basic Tooling Guidelines that might help.