Gene, Rev. Ron and Galoots,

>Gotta ask: three whacks at one sample or tests on three samples?

3 whacks at 1 spot on 1 sample. Average the 3 tests and that's
1 reading. Then we took other readings on different areas of the
sample. Eliminated highest and lowest, averaged the rest and that
is the number given on the list.

For the thin saw material, we did a Superficial N test. It still
uses a diamond point but loads to 15 kg instead of 150. I gives
the hardness only at the surface. A chart converts the N numbers
to HRC. On thick saw blades (7, D8) there is no difference between
HRC and N. On the thinner material HRC tends to be inconsistent.

On the laminated plane blades, the readings were consistent over
the lenght of the hardened steel. Elsewhere it fell to 15 HRC
(or lower) which is considered unreliable and off the scale.

The saws had an even hardness. 3 tests on one spot done on 4
different areas of the same sample. The average of the 3 tests
varied only by 0.3 HRC from one area to the other. The D8 had
higher variance but I don't have the numbers here.

Hardness on the chisels usually went down to 50 HRC about 1 3/4
in. from the tip and then even lower.

>be bend with out breaking when the metal had a hardness of 48-52...
>I couldn't alter the set of any tooth in that #12 blade without
>hearing that sickening little *snap* sound.

I took out some set on the bow saw blades at 52 HRC by pressing the
blades in a steel vise. It responded well without any snaps. After
sharpening, the resulting set was sufficient. I'll see when I have
to set the teeth again...

>Also, please note that hardness alone does not a good tool make. There
>are several other constituents that can make or break (literally) a
>tool. Alloy, hardening process, hardness, sharpness all have to be right
>for the thing to work.
>
>The Never-Wrong Reverend Ron

I did these tests only to get a general idea of the hardness for
different tools/application. I don't consider an HRC number to
indicate a quality scale. Hardness is only -1- parameter.
I also hoped to get feedback on the variability just for the fun
of comparing.

Bon rabotage,
Louis Michaud