I don't really agree with the comment about "relative hardnesses". Most of
the higher alloy materials have a pretty narrow range for a really good heat
treatment, and you want to know that you have hit within the range. Example
is the "twin peaks" in the torsional impact curve for tempering A2. You want
to hit one of the peaks, you definitely want to stay out of the valleys. I
paid pretty good money for the first tester, at a time when I wasn't all
that flush (much more than the prices I see now on ebay), never regretted
the purchase. Fine knives deserve fine heat treatment, and if there is any
appreciable alloy content, you want to be able to test the outcome. (These
comments are not as true for lower alloy steels: working with W2 or O1 the
ranges of acceptable results are much wider than they are for more
hardenable materials).

Adam Smith
Midland ON



"Proctologically Violated©®" wrote in message
...
Do you have a local heat treater by you, to check out theirs? Or school?

I don't know how expensive these things are, but I imagine they ain't
cheap.
I think, tho, that unless you really want to calibrate your stuff against
laboratory standards, *relative* hardnesses are about as useful ito of
effectivenss of heat-treating processes. You could maybe make an
air/blowgun w/ shop air and a carbide/diamond ball, or a ball cemented to
the tip of a suitable projectile.
Might do you while yer hunting for the real thing at a good price.
Might find use in neighbor control, as well.

Also, they make (and I have one!) an air-operated arbor press/punch ditty,
which might could be calibrated. It's a small benchtop jobby, weighs
about 75 lbs, packs a helluva wallop, very fast. Iffin yer innerested,
I'll dust off the nameplate.
I fire it up once in a blue moon, when I'm bored, or if I just wanna scare
the cats.

Knife-making is da bomb. I'm going to a good show here in Manhattan
tomorrow.
There's a guy from LI who found a way to bond/melt titanium onto steel, w/
a mother-of-pearl effect. Incredible, as is the price--about $5K for a
blade w/ a so-so handle!
----------------------------
Mr. P.V.'d
formerly Droll Troll
"Al MacDonald" wrote in message
news:QeJcf.118841$yS6.90917@clgrps12...
Greetings,

A friend and I are building a heat treating oven for his knife making
hobby and my general home machine shop. He wants to be able to test the
hardness of his knife before and after heat treating (C50-C55 range) and
I am interested in being able to test metal in general (anneal, machine,
reharden to Cxx various sized items that may surface to be worked on) so
we are looking at buying some kind of harness tester. I see lots of
larger Wilson and similar models on ebay but there are many different
models (3JR, 1JS, 3JS, 5JR, 12A, and huge variations on prices. Most
come with weights and some come with diamond and different sized ball
indenters, which I assume are all changeable for A/B/C scales. I haven't
run one of these machines before, and while the idea of various weights
vs. various sizes of penetrators makes sense, I'm assuming the plug in
cord and remarks of motors may be to raise and lower the penetrator
gently onto/into the test surface.

I also see some smaller portable models, but I have no idea on whether
they would work well enough to be worth buying.

My question is this: does anyone have any comments on specific
makes/models which would do what we want, or anything I should be looking
for (or looking out for) when buying a used tester? Thanks.

Al MacDonald