Re: [CAD_CAM_EDM_DRO] rant

I heard a story about the 2,54 conversion factor. At the beginning
of WWII there were three different conversions in use; the US used
2,54 plus a few millionths, the British used 2.54 minus a few millionths,
and the Canadians used exactly 2.54.

Since this could cause a problem with making machinery compatible
for the war effort they called a conference to settle the issue. This
level of difference did not matter to most industries since it was beyond
where they worked or could even measure. It did matter to the national
labs and the few manufacturers making the most precise equipment.

At the conference they quickly agreed to 2.54, the Canadian standard.
The US representative commented that the difficulty of recalibrating
the measurement equipment at all the large US corporations would be
a huge effort and would take some time.

The representative from Moore Special Tool said that there was actually no
problem! Moore Special Tool made all of the calibration equipment used at
all
of the top calibration labs at the time. They had independently decided
that
the conversion standard should be 2.54. All of the equipment that they
sold and the calibration services that they provided reflected the 2.54 and
not the official US standard. Since no private calibration lab could
measure
to this level without using Moore instruments they, in effect, were using
the 2.54 conversion already.

ps:
I don't know if this is true or if I have all the facts straight but it is a
great story.
I could not find any references on line. It is touched on in "Foundations
of
Mechanical Accuracy" by Wayne R. Moore, possibly the greatest coffee table
book of all time (for machinists ;-}).

Pete.

----- Original Message -----
From: stan
To: CAD_CAM_EDM_DRO@yahoogroups.com
Sent: Sunday, April 06, 2008 5:20 AM
Subject: [CAD_CAM_EDM_DRO] rant


Anyone else think the inch could be adjusted a bit? I mean 25.4, what kind
of
a figure is that? Some sod in history must have said '25.6? bugger that lets
make it 25.4, that will really mess them up when they start messing around
with binary'. Will anyone notice if the inch grows a little bit? Its based
on
the average thumb after all, we could just say the average thumb has got a
bit bigger. Could have a go at the mm either. There's a bit of bar in Paris
that says what a meter looks like, a quick rub with a file on the end of it
and life would be a whole lot simpler. Or how about calling it a metric
inch?
Blame the Japanese for it and make a 16 inch metric foot so it looks
convincing....anyone?....please?...pretty please?...