Jim --
Yes, the US sure knows how to foul up measurements.
We are officially a metric country.
But we really use Olde English measurements, at least some of them.
Except that most of industry, where it isn't using metric measurements,
actually uses decimal inches. Most American parts are dimensioned in
inches with decimals carried to the thousandths place (mil), depending on
tolerance.
So, 0.312 is 5/16, rounded to the nearest mil. 0.625 is 5/8, etc.
The electronics industry is really messed up. Since the US invented it,
most dimensions are decimal inches, but the Japanese gained lots of ground,
and started using metric values. However, the standard sizes didn't
change, so the pin spacing on a DIP package is now 2.54 mm, same as the old
0.1 inch. Unless, of course, it did change. The standard connector on a
3.5" hard drive uses 0.1" pin spacing. The 2.5" hard drive used in laptop
computers uses the same signals but a connector with 2mm spacing!
Yike!
Extra credit question: Which measurement standard is the original 38
Special designed to, and why does this affect the NATO alliance? Answers
involving Badgers will not be accepted. When you have finished your essay,
turn in your blue book at the front of the room.
Mike K1MG
> ....Hi gang, I know I'm gonna take a beating on this, but
> here goes (hangs his head in shame)
> Ready to build my ZM-1 now and have drill bits, but
> mine are labeled 1/16,1/8,1/4 etc...the pattern shows holes
> with drill sizes of .125
> .250
> .312 ?
> .625 ? I guess the .125 is 1/8", and also
> the .250=1/4 " but how bout the rest?
> ....
Jim kw3u
[
QRP-L Archive |
]
[
1993 |
1994 |
1995 |
1996 |
1997 |
1998 |
1999 |
2000
]