Re: OK what is the diferance between carbide and powdered metal ?


"BottleBob" <bottlbob@xxxxxxxxxxxxx> wrote in message
news:43D1BD71.4E14B985@xxxxxxxxxxxxxxxx
> Dixon wrote:
>>
>
>> Congrats to Polymer Man. You fit into my 100 to 1 theory. It is
>> surprising
>> how few people know you can't change stiffness (modulus of elasticity) by
>> heat treat or alloy.
>
> Dixon:
>
> A personal anecdote may be apropos here. Decades ago when I was a Tool
> & Die apprentice my boss (an old English die maker - well maybe not so
> old since I'm older now than he was then) told me that the stiffness of
> steel is not affected by heat treating. My immediate reaction was to
> say: "No Way", since it seemed so obviously counter-intuitive to me. I
> then went about doing some experiments to prove him wrong. I got some
> hardened drill rod, some soft cold rolled rod, some A2 rod, all of the
> same identical dia. and took them to the lathe and extended them out of
> the chuck the same distance. Put an indicator on the end to measure the
> deflection and hung some weight on the end of the rods. To my surprise
> and chagrin, my boss was correct! They all deflected about the same
> amount.
> I learned an important lesson that day. Experimental evidence takes
> precedence over speculation, logical seeming deduction, or unsupported
> biases.
>
>
> --
> BottleBob
> http://home.earthlink.net/~bottlbob

Bob,
In a similar vein. I had hired a young engineer fresh out of school. One
of his first tasks was to design an aluminum C shaped frame to hold an air
cylinder. It deflected too much so I told him it needed to be redesigned.
He suggested a stronger alloy of aluminum, and said he'd run the
calculations. He had trouble finding the Modulus of Elasticity for the
stronger grade of aluminum, but said he new a professor that would know.
The next morning he came in and said "You knew didn't you? Why didn't you
tell me?" I said that he had learned this in school but the lesson didn't
stick. I'll bet it did this time!

Gary H. Lucas


.

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