"Larry C in Auburn, WA" wrote in message news:bN%Rb.133018$Rc4.1037752@attbi_s54...

They tested two items; hardness and toughness. Hardness is pretty
straightforward using the Rockwell hardness test so they just gave the RC
number for each chisel. Toughness is a little more subjective and this is
where they provided the ranking from 1 to 17. They ran the chisels through
a test then measured the roughness of the edge down to approximately 1
micron (9,500 measurements across 1 inch). From this roughness data they
rated the toughness of the edge.

I remember reading this article and wondering exactly what it hoped
to "prove". To me it seemed to be close to worthless unless you
consider a chisel to be an implement of destruction (or you just use
them to open paint cans or chop through rusty nails).

I'll leave it to the metallurgists to debate this sort of thing,
but isn't the true worth of a chisel found in the fact that it can
hold a decent edge but still be sharpened in a reasonable time?
(Isn't it a compromise?) Doesn't this mean that the "best" chisel in
that test would have a medium/high Rockwell, but a high "toughness"
rating?


Chuck Vance