Re: Hardness tester wanted


"Sevenhundred Elves" <sevenhundred@xxxxxxxxxxxxx> wrote in message
news:kfd0i.40426$E02.16242@xxxxxxxxxxxxxxxxxx
Harold and Susan Vordos wrote:


<clutch@xxxxxxxxx> wrote in message
news:133jqh3hp6eh47c@xxxxxxxxxxxxxxxxxxxxx
"Tom Gardner" <tom(nospam)@ohiobrush.com> wrote:

Does anybody have a hardness tester laying around? Gunner has five or
six
I'd bet! (encased with rust maybe, but...)


Enco has a new one for 800 bucks iirc.

Wes

That's why I bought the old Wilson. They're quite proud of those things
when
they're new. I always wanted one, but couldn't justify the cost.
Getting one cheaply from ebay made it a reasonable acquisition. I
didn't
mind the rebuild, and had more than enough material on hand to make the
components. Truth be known, it was a fun job. I rarely comment on
machining being fun. The shine went off that for me years ago.

Harold

I have been thinking of making (or rather applying, for there is no
actual "making" involved) my own hardness tester for a cost of something
like zero.

This is how I figure:

IIRC, at least one of the different hardness tests is designed around
measuring the size of the impression made by a sphere, (help me with
their names please).

Instead of applying a precise force for a precise length of time, my
idea is that if I have a piece of steel with known hardness, and another
that is unknown, I put them both in a vise with a ball bearing between
them. Then squeeze hard. Now the pieces obviously get indented with the
same force and for the same length of time.

So I have get impressions, one in the unknown material, and one in the
known. Now I reason that the relative sizes of the impressions must
surely be proportional to the relative hardnesses of the materials.

Do you think this idea would work as I think it might? If it does, what
should I measure, the areas or the diameters of the circular indents?

S

In a sense, that's how a hardness tester works, but in the case of the
Wilson, it measures the depth of penetration, not the diameter.

Yeah, your idea would work, but I have serious doubts about the ability to
read the results and translate them to useful information with a reliable
degree of precision.

Harold


.

Relevant Pages

  • Re: Hardness tester wanted
    ... Harold and Susan Vordos wrote: ... Enco has a new one for 800 bucks iirc. ... at least one of the different hardness tests is designed around ... So I have get impressions, one in the unknown material, and one in the ...
    (rec.crafts.metalworking)
  • Re: Hardness tester wanted
    ... Enco has a new one for 800 bucks iirc. ... So I have get impressions, one in the unknown material, and one in the ... surely be proportional to the relative hardnesses of the materials. ... In a sense, that's how a hardness tester works, but in the case of the ...
    (rec.crafts.metalworking)
  • Re: Hardness tester wanted
    ... Enco has a new one for 800 bucks iirc. ... So I have get impressions, one in the unknown material, and one in the ... surely be proportional to the relative hardnesses of the materials. ... In a sense, that's how a hardness tester works, but in the case of the ...
    (rec.crafts.metalworking)
  • Re: Hardness tester wanted
    ... at least one of the different hardness tests is designed around ... surely be proportional to the relative hardnesses of the materials. ... Wilson, it measures the depth of penetration, not the diameter. ... Measure the diameter of ball bearing. ...
    (rec.crafts.metalworking)
  • Re: Changing over to ceramic bearings.
    ... "Materials Science and Engineering." ... and I get the concepts of hardness and fracture toughness. ... modulus, the "height" of the line, the strength. ... Callister also says that yield and hardness are related in metals, but says nothing of the sort for ceramics. ...
    (rec.bicycles.tech)