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Jim Wilson
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Default Failure to get sharp

Ed Huntress opined...
I suspect coarse grain. But that's not certain.

Ah, that did not occur to me.

OTOH, W-1 ordinarily has a rather fine grain, doesn't it? And it's quite
a forgiving material to work with. I've made numerous good edge tools
successfully in it with methods just as crude (home-shop G) as those of
the OP. I don't doubt that I have occasionally overheated the steel with
no obvious ill effects.

Of course, I must say that overheating during hardening definitely does
something, and I believe it is what you are talking about. I think I have
witnessed grain growth in particular (ahem), by intentionally breaking
pieces just hardened at various temperatures. The grain pattern at the
fracture looks distinctly coarser or finer, depending on the sample. Am I
really seeing variations in the molecular grain structure, or is that
something that requires magnification or sample preparation techniques.
If that's not what I'm seeing, then what might it be?