Thread: Rotten wood...silica

I posted a week or so ago about a piece of rosewood that destroys plane irons.

Well, here's what it does to a high hardness chinese steel iron with the "unicorn" applied to the lower bevel (which is a drastic improvement in damage prevention). Softer irons don't do better, they do a little worse (this is expected - a much harder iron would tend to fare worse if you did something like dropping it or running it into a giant nail, but even maybe not for the latter).

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I found about where the iron would hold up - a 15 degree back bevel plus unicorn. This is an enormous amount of edge protection and the result is that it will still slowly take damage (the lines shown above come in fewer than ten strokes). Needless to say, setting up a plane iron at 60 degrees effective isn't a great way to plane stiff end grain.

But you get this with the very steep plane iron after miserable planing. Miserable can't be overstated.

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Well, I finished the paring chisels for George W. over here, former toolmaker at Williamsburg and I figured I'd blow up my confidence and see what they would do (how long before they leave lines all over everything).

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Nothing, no problem. These are "unicorn" treated, and may take damage without it. The chisel being used is one of two rejects that I made during the "george chisel" process. See the narrower of the two with handles in this picture.

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The rejects both warped some and got re-heated and re-cycled and I fought my forge before I made the "tailpipe" forge (which made things easier), so they should be plenty hard (they are), but slightly less fine grained (i'm sure they are due to frustration with heating and letting them get a little too orange before getting them evenly heated).

There's something in this for people who want to heat treat things (even though I wasn't able to give the "rejects" as good of care as they should've gotten, they work great. The steel they're made of is fine grained, so even if the grain grows a little, it's still a lot finer than XHP/V11 or A2 would be, and they're probably at the hardness limit for both of those types untempered. 26c3 makes a better chisel without the chisel being perfect than V11 or A2 would be capable of (and probably better than O1. An O1 chisel given the same thermal cycling as these chisels would easily match anything you could do with V11, but there's not much incentive to do it - it takes time, and people view "O1 as a low technology steel".

What did I learn here? well, straight in paring of this wood is pretty miserable just because it's on the harder side for rosewood - but if you were ever going to use it to build something, you would want a wide long paring chisel with good edge strength and supplemental support from the sides that you could use as a guide to pare to and pare with a slicing motion. Then, it's fairly pleasant. But it's not pleasant like working a typical US hardwood.

There would be no great reason to use a volume of this rosewood to make furniture, but you can get past the silica for small stuff like guitar necks and tools.

(carbide sawblades don't mind the silica, so getting close with a chop saw and then paring or scraping is the way to go).