Hard Walnut?

[Wally Crawford]

I don't often get a chance to turn Walnut as it is like finding gold around here. My question concerns how quickly it dulls my tools. If I look at the Janka scale, it is not as hard as Hickory or Pecan, and I turn quite a bit of those species, but this Walnut is dulling my tools as quickly if not more quickly than those two species.

I am using 5/8" gouge primarily an Ellsworth grind with a 55* bevel sharpened on a CBN wheel, but I don't see where any of that should make the difference.

What am I missing here? Does Walnut contain a lot of silica or something that is causing this or do I just accept it and keep sharpening?

[Mel Fulks]

It is rated as having a lot of silica. Air dried walnut is usually easier to work than kiln dried.

[Peter Blair]

Mike you nailed it. I do think the amount of silica is related to the area and soil the tree is grown in. I too find air dried wood of any kind is easier to turn than kiln dried.

[Reed Gray]

I don't know how much silica it has in it around here, but walnut seems to dull all tools more than other woods, well, except for Ipe.... Chainsaw, handsaw, chisels of both turning and flat work, bandsaw, it just dulls everything.

robo hippy

[Mel Fulks]

The answer is ….a lot of silica.

[Wally Crawford]

Thanks guys. That's probably what is going on and why I am sharpening so often. I am working green walnut and twice turning my bowls ( twice the fun:-) )but the walnut I was gifted, although green, is fairly dry for green wood.

Thanks again for the feedback.