NavList:

Gary LaPook added:


And our army and marines use "mils" as a unit of angular measurement and of direction. There are 6400 mils in a circle, 17.77777 to a degree and 3.375 minutes to a mil. East is 1600, south is 3200 west 4800 and north 6400. This comes as an approximation of a miliradian, there are  2000 pi miliradians in a circle,  approximately 6283.1853, so the approximation by using 6400 comes within 1.8%. These are useful units as they are approximately the sine or tan values when used for small angles and can be used for estimating distances and for adjusting artillery fire. Interestingly, the communist block uses a similar approximation by using 6000 mils in a circle which comes within 4%.


Red wrote:

Zed, in the States you have to be careful when you talk about "mils". They are
our smallest unit of currency (thousandth of the dollar, which has never been
coined as far as I know, but is used in commercial bulk trade) and they are also
"thousandths of an inch". If you go to a machine shop and ask them to take eight
mils off an engine block, they will shave it down eight thousandths of an inch.
We also measure polyester films (recording tapes, transparent overlays,etc.) and
paper stocks in the same mils, thousandths of an inch. IIRC "post card stock"
must be at least seven mils thick by government requirement and matchbook covers
were 32 mils thick, although the memory is faded and probably a bit off. (I
don't plan to get my calipers out to confirm that.<G>) Printers use their own
odd paper weight system but still used mils for the jobs that required it.

----- Original Message -----
From: "Zed" <packeteer@gmail.com>
To: <NavList@fer3.com>
Sent: Tuesday, July 18, 2006 4:47 AM
Subject: [NavList 811] Re: Units and area. was: gipsy moth iv


  

fyi: for 60 cm most people I know of would say 600 mil (short for millimeters)

I think that way of describing length comes from the construction
industry. And I think they use mil because its shorter than saying
centimeter.


    

And here you have a system which, in its usual nomenclature and usage,
      

doesn't
  

allow for a simple TWO feet, but forces users into SIXTY centimeters? Sorry,
George, but that's simply trying to enforce a system onto organisms that
      

don't
  

have a natural inclination to use it.

      

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