Robatoy wrote:
On Sep 8, 9:04 am, "Leon" wrote:
"Robatoy" wrote in message
...
I now make parts for different people who e-mail/fax me drawings
so I can quote on them.
Some parts are such that I can't tell what they are or what
they're the purpose of them are.
Sometimes I see dimensions as obviously imperial ones, sometime
it is hard to tell, especially when I have NO clue what these
parts are. Personally, I don't give a rat's ass what system is
used as I work in both metric and imperial.
But what seems to be the reason for the US hold-out to stay with
an archaic system?
http://img200.imageshack.us/img200/9974/metricmap.jpg
Ok, What ia half of 5.3 mm?
That'd be 0.1043307", Leon. (BTW, I do get your point. )G
I used to design business forms. Most typewriters (remember those) and
computer printers were based on the inch systems but used many strange
scales. I ended up having to work with line spacing of 1/8", 1/4", 1/3" and
1/2", character spacing varied from 1/12", 1/10", 1/8", 1/6" and up to
5/32". The biggest problem is that the typesetting equipment all ran on
another scale traditionally used by typesetters and printers, picas and
points. While conversion is not precise, a pica is very close to 1/6" and
there are 12 points to a pica which works out to about 72 points to the
inch.
When you work in all these scales for many years it becomes natural to you
and you can convert back and forth in your head easily. I still have
stainless steel rulers in all these spacings and scales, and often use them
when one of them will work better for me. When it works correctly I will
even use metric.
One of the reasons that the old Imperial system is dying is that different
countries used different standards. I learned many years ago that Imperial
measurements are useless in precision work because England, Canada,
Australia and the US all had different lengths of inches. Granted this was
at the 5th or 6th decimal but it was unuseable. Another example is the
gallon. Do you prefer it to liters? But which gallon? In the printing
business we had to mix photo chemicals for our litho camera film. You would
have to check where the Kodak chemicals were made because if they said add
30 ounces of concentrate to a gallon of water, you needed to know which
ounces and which gallon. A US Gallon contains 128 ounces which is 4 quarts
of 32 ounces each, a Canadian Gallon contains 160 ounces which is 4 quarts
of 40 ounces each. Even the ounces were slightly different. In this regard
metric is much easier.