Hand Tools

Subject:
Re: Hardness Data for Chisels

Warren in Lancaster, PA
Moxon says that edge tools should be tempered to a "dark goldish colour", which I think would be about 60 Rc. (He predates the Rockwell scale by three centuries). He mentions that files and punches should be tempered to a "light goldish colour", which might be more like Rc 62.

There has certainly been a notion afloat that the harder the better for chisels and plane irons. For some tool makers, a high hardness number might be more of a marketing decision than a tool performance decision. As an example Hock plane irons are hardness 62. But when he says "The extra thickness of our blades offers superior stability, precise adjustment, and easier honing.", he seems to be playing to his customers prejudices rather than making a real performance decision. Does he really have experience using planes that informed his decision on hardness? I don't know.

All of my chisels seemed to outperform the "5 steels" mentioned above, for hickory, persimmon, and jarrah, but as you have noted, tester technique plays a big role in the outcome.

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