Re: gm-cm to oz/inches conversion?

This is correct. on the surface of this planet (I am asuming we are
all on the planet earth) the standard sea-level pressure is 29.92 mm
of mercury.

A perfect vaccummee means no particles of anything. no gas, nada.

All pressure mesurements are either from absolute, or differential.
When you check you tires, you are measuring the differential between
the inside of the tire and the atsmospere it is in. If you are
pumping down to vacuume your reference (atsmosphere) will be higher,
but no higher than 29.92 +/- changes in the barometric pressure
casued by weather or altitude.

An yes Dave, you did well to eschew the the obsfuscation.

Dave

--- In CAD_CAM_EDM_DRO@y..., dave engvall <dengvall@e...> wrote:
>
>
> e.heritage@b... wrote:
>
> > Seeing as we're on this metric / imperial debate I have to ask,
how do I
> > convert inches of mercury or water into microns of vacuum?
> >
> > John
>
> John, et al
> I may be all wet but think of this as a reverse system. i.e a
perfect vacuum would be draw a column of Hg equivalent to the
> atmospheric pressure. Vacuum then is expressed (?) as the
difference between this and what you achieve. (in mm of Hg or microns
> (micrometers) of Hg. multiply by the sp. gr. of Hg to get the
measurement in H2O.
> In the real world, as you pump down, you watch the gage go from 980
mm or so to a mm or so. You turn on the diffusion pump, wait a
> little bit, turn on the ionization gage and go on down. Been 40
years since I've done this so it is a little fuzzy.
>
> Did I obfuscate the issue sucessfully?
>
> Dave
>
>
> [Non-text portions of this message have been removed]