I don't mind you questioning what I wrote, getting accurate info is more
important. Besides, I question people all the time so it's about time I get
questioned back. g

I don't think I said what I wanted to say very clearly. Let me try again.
They didn't come up with an overall rating of the chisels. What they did
was measure two things. Hardness and toughness. Hardness is an objective
measurement so they just provided the RC number. Toughness is more
subjective so after testing the tools they measured the roughness of the
edge and then provided a ranking of the chisels by roughness (i.e. their
definition of toughness). It was left to the reader to balance the two
measurements (actual harness measurement and the roughness ranking). They
made 9,500 (9 thousand 5 hundred, not 9 point 5) measurements across a 1/2"
chisel so I think that works out to about 1.3 microns. I earlier said it
was 9,500 measurements across a 1" chisel, but it was actually across a 1/2"
chisel.

Most of the chisels were close in hardness so that wasn't a determining
factor in my opinion. Ignoring the ergonomics of the various brands for a
minute leaves us with these two measurements to evaluate. Given a
particular hardness number (over 1/2 the chisels had an RC number between 59
and 61) then the FWW hardness factor would seem to be the determining
measurement. I understand your point that the two factors (hardness &
toughness) fight against each other. A kitchen spatula would rank very high
on the FWW toughness scale, but still couldn't cut anything, OTOH a ceramic
chisel might be hard but wouldn't be very tough. This is why they gave both
numbers. However, since the chisels scored roughly in the same hardness
band we're talking about similar materials.

As a point of interest (maybe?), the softest chisel only ranked 8th for
toughness rather than 1st as might be expected and the hardest chisel scored
second for toughness rather than last.

Now factor in cost, ease of sharpening and I give up, I'm just going to stic
k to the coolest looking chisels... At least THAT I can figure out.
--
Larry C in Auburn, WA

"Jim Wilson" wrote in message
k.net...
Larry C in Auburn, WA wrote...

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.

Wow. By that measure, a CSO (chisel-shaped-object) made of mild steel
would have rated highly, as it is extremely tough, although not at all
hard, being typically HRC35 or below. Of course, the edge would fail by
bending despite the toughness, so I am being a little facetious.

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.

Wow, again. Those are some mighty big microns! (G) They're even bigger
than tenths! Most microns, properly "micrometers," are about 0.00003937";
25,400 of 'em fit in an inch.

Seemed to be something of a crap shoot to find the "right" chisel.

IME, that's exactly how it is "in real life." Thanks for the information
on the article, Larry. I haven't seen it and wondered how they would
compare the tools quantitatively. Please forgive me for picking on it a
little bit. I don't mean to be giving you a hard time at all.

Cheers!

Jim