Harold and Susan Vordos wrote:
"Robin S." wrote in message
.. .

"Peter" aus10n@optusnetdotcomdotau wrote in message
.au...

Used to, but alas not any more,
but ask any toolmaker if they work to tenths of a thou!!

There are over 100 certified Tool and Die Makers where I work and none of
them work to .0001. We do precision grinding with 1/4" die grinders, disc
grinders, polishing stones and sand paper.

You're right, of course. Sometimes the last .0001" *does* matter. As far

as

function is concerned, I'd be surprised if five people reading this group
were actually capable, or had access to facilities capable, of doing that
type of work.

Regards,

Robin



I accepted work with .0001" tolerance in my humble shop when I was actively
machining, and had success. The few times I had a tool returned was not
attributed to having missed a tight tolerance, but to having made a stupid
mistake elsewhere. In part, I was engaged in building tooling for the
manufacture of guidance systems, such as used in military aircraft. Tight
tolerance was the norm, and quickly sorts those that can from those that
can't.

I was called upon on several occasions to quote work with .000050"
tolerance, which I declined. I was (and may still be) capable of working
in such a manner, but without a proper facility, it becomes almost
impossible. My shop left a great deal to be desired in that regard, but in
my youth, I worked where there was a certified secondary standards lab. One
of the jobs I ran with complete success was a set of ring gages with
.000020" tolerance. Someone, somewhere, must be able to produce the
work with tight tolerance demanded of gauging. These people work in a
different manner from others (of necessity), and are often misunderstood.

Harold


My inquiring mind want's to know....

In general, what sort of temperature differentials are acceptable when
working to those tolerances on measurements of a few inches or so with
common metals?

ie, do you have to worry much about the body temperature of your hands
affecting parts or instruments.,

Jeff

--
Jeffry Wisnia

(W1BSV + Brass Rat '57 EE)

"Truth exists; only falsehood has to be invented."