Hickory Tearout
Hickory is a problematic wood, but spiral tooling helps limit the tearout. May 18, 2010
Question
I'm getting occasional, deep tear-out in hickory while straight knife thickness planing. I plane at about 20% to 25% MC because it is for wood bending. Is tear-out more common in this species than other temperate hardwoods? The same planing conditions do not result in tear-out with hard maple, ash, red oak, white oak, beech, elm, cherry, walnut, black locust or sassafras.
Forum Responses
(Solid Wood Machining Forum)
From contributor J:
I've typically worked with kiln dried hickory rather than the sort-of-dry stuff, but my experience with tearout has been similar. It does not joint/plane well unless it's very straight-grained and the runout is always going the same direction.
From contributor D:
Ditto. If it has any defect or strange grain it will chip out (usually so bad you can't fix it), and if you feed it opposite direction, it takes another chunk.
From contributor S:
Hickory is a stringy grained wood. Being that wet it will tear out more than dried to 7% MC. Also tears out some anyway. Spiral cut heads greatly reduce tearout.
From contributor N:
Ditto what everyone else says. This problem (for us kiln dried hickory) went away long ago after changing to spiral carbide heads. The winter growth rings seem to separate from the summer growth layers pretty easily, so when we have stock to run through a Hussy, it's all vertical grain. Flat sawn stock, even if run very slowly with reduced tearout, had annoying spots at the cathedrals that were peeling up.
From contributor Y:
Hickory is one of the most problematic woods. In order to get a decent result, tooling needs to have a 0 to 5 degree cutting angle. Typical planers have a 20 to 25 degree cutting angle. As suggested above, spiral heads will give a better result, but expect a high defect rate when machining hickory, unless you do enough of it to pay for custom tooling.
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