Opinel natural stones?

I used one once, small pocket stone sized, reminded me of an Arkansas stone.
 
Any natural stone would be a bad choice for modern alloys.
 
felizalde55 said:
Just for my knowledge, why?
Thanks a lot.
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Becsuse modern steels have very hard alloy elements that are harder than the stones abrasive. Technically, the steel starts grinding away the stone more than the stones grinds away the steel.

It's elements like Chromium and more so Vanadium that give the steel lots of wear resistance which it too much for any natural stone to handle.
 
Yep. Doesn't take much additional chromium or carbon, in common stainless steels with carbon @ around 0.6% or better, to start really slowing down the effectiveness of an Arkansas stone, for any heavy grinding at all. I've been tinkering with a couple of my Arkansas stones lately, and there's a noticeable threshold in working speed, when switching between honing on something like 420HC (0.5% carbon, ~13% chromium or so) to a steel like AUS-8 or equivalent (such as 8Cr13MoV) with 0.7-0.8% carbon and 13-14.5% chromium. The carbon and chromium form hard carbides (chromium carbides) that are harder than the natural novaculite abrasive in the stones. 420HC seems to respond OK, or even well, on such stones; but that's what I consider to be about the upper threshold before I select a different stone/abrasive, like AlOx or SiC. This isn't to say an Arkansas can't work at all with such steels, but it'll get very slow. And, as Jason mentioned, the carbides in the steel will begin to wear down the stones themselves; and that's not good for them in the long run (think: glazing, which makes them even slower).


David
 
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Jason B. said:
Any natural stone would be a bad choice for modern alloys.
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Would be like trying to shape granite by grinding it on the side walk. :D

Every once in awhile I do it just for a laugh to remind myself how far we have come.

As the edge just skids across the stone like sliding on ice. :D
 
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