I followed this thread with interest. However I can only agree about metric
and imperial measurements for science/technology, I find micro inches,
pounds per gallon (US not Imperial) and so on totally anachronistic and
confusing. Having said that I prefer Imperial measures in daily life, Having
a "pint" does not mean visiting the pub to consume 0.5682 litres of beer.
ps. Those wishing to preserve the full oddities of decimalised Imperial
measures may also like to know that an old measure for 100 pounds weight is
... a cental.
No wonder we dropped that one, far too logical.
pps. For those wishing to know: a rod, pole or perch is 5.5 yards.
Regards
Mike
-----Original Message-----
From: TechNet [mailto:[log in to unmask]]On Behalf Of Brian Ellis
Sent: Monday, June 02, 2003 1:03 PM
To: [log in to unmask]
Subject: Re: [TN] Micro-inch to copper weight conversion...
But the Imperial system is so logical. Let's take linear distance for
example.
12 inches = 1 foot
3 feet = 1 yard
22 yards = 1 chain
10 chains = 1 furlong
8 furlongs = 1 mile
Therefore, in one mile, there are 80 chains, 1,760 yards, 5,280 feet and
63,360 inches. I think I've missed out the rod, pole or perch somewhere
along the line, though. Then, for nautical use, there is the fathom,
which is 2 yards and the nautical mile, which is a lot longer than the
terrestial one.
Isn't this much more interesting than the boring metric system, where
only 10 and exponents thereof are used as multipliers? :-)
Of course, in our industry, we also bastardise things even farther, by
the league (3 miles). For example, we may measure (in backward
countries) ionic contamination in micrograms per square inch. This is
akin to speaking alternate words in a sentence in two different
languages. It would be much more logical to use apothecaries' drams per
rood, even if nobody knew what the hell you were talking about, but then
they don't anyway, when metric and imperial are mixed so haphazardly.
Reminds me of an exhibition I was attending in England. The day before
opening, I decided I needed another MDF laminate panel, because the
stands were so many feet wide, instead of the usual 5 metres. I beetled
along to the carpenters' shop and explained our problem. I asked the guy
what were the standard panel sizes. He replied 48" by 2 metres. Ugh! :-(
Brian
Steve Gregory wrote:
> Hi All,
>
> I got my boards back from our fab vendor (the ones that had the trace
> thickness problem), and they sent the XRF measurements that they took.
> But they're in microinches, is there some conversion that you do to
> convert that to copper weight?
>
> Here's the measurements that I got:
>
> µin Cu
> 1. 170.9
> 2. 173.0
> 3. 170.1
> 4. 170.6
>
> Thanks in advance!
>
> -Steve Gregory- ---------------------------------------------------
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