[sdiy] Metric vs imperial, was: My new Moog 960 sequencer clone module project.. slowly but surely ..

[Tom Ivar Helbekkmo]

Donald Tillman <don at till.com> writes:

> Of course I recognize and appreciate the advantages of the metric
> system.  It's great for scientific work.  But for everything else;
> engineering, design, culture, regular life... the metric system
> becomes a serious disadvantage.

It depends.  You mention engineering.  Talk to a machinist, working in
the United States, and he'll tell you that while material stock comes in
Imperial units, fastener sizes are specified in standard fractions of
inches, and so forth, all his actual machining work is done with the
"thou" as the base unit.  A thou is 1/1000 of an inch.  A milli-inch,
that is, but it's pronounced "thou".  (For real precision work, it's
necessary to consider "tenths" as well, where a tenth is 1/10000 of an
inch.)  A machinist will say things like "this needs to be 500 wide",
not "half an inch wide".

(As an example of an engineering advantage of metric standards, if
you're drilling a hole that's to be tapped for a standard #8-32 screw
thread, you need to use a .136 drill (also known as a #29 drill).  There
are tables to look this up.  For a metric M4x0.5 screw (very close to an
#8-32 in size), I don't need a table to know to use a 3.5mm drill.)

Also: "serious disadvantage"?  Only to the extent that you're either
working with tools and material that are in Imperial units, or you've
grown up with Imperial units, and have no intuition for the metric.
That's just saying that trying to change confers disadvantage, which of
course it does.  It's not an inherent problem with the metric system.

You sound like one of those people who go "Metric? Hah! When people ask
me how far it is to the post office, I say 'about a mile'.  I don't say
'about 1.609 kilometers'", and think they've made a valid argument.

-tih
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