[time-nuts] Standards for units
Brooke Clarke
brooke at pacific.net
Wed Apr 4 02:21:29 UTC 2007
Hi:
There was a recent incident when a passenger aircraft (maybe Canada) had
to make an emergency landing because of a wrong metric - English
conversion resulted in not enough fuel to get to the destination.
Are there metric equivalents to different series of English threads.
For example I recently purchased a tap for 8-40 threads after mistakenly
purchasing a 6-40 tap. Most good hardware stores in the US have 4-40
taps, dies, various lengths screws and nuts. Although 6-40 and 8-40 are
standard sizes they are not commonly stocked. Are there a a number of
alternative combinations of root diameter and pitch in the metric system?
Have Fun,
Brooke Clarke
w/Java http://www.PRC68.com
w/o Java http://www.pacificsites.com/~brooke/PRC68COM.shtml
http://www.precisionclock.com
Magnus Danielson wrote:
>From: Hal Murray <hmurray at megapathdsl.net>
>Subject: Re: [time-nuts] Standards for units
>Date: Tue, 03 Apr 2007 17:14:50 -0700
>Message-ID: <20070404001451.A4954BE06 at ip-64-139-1-69.sjc.megapath.net>
>
>
>
>>>The US has been metric since 1988, however the continued use of
>>>customary units during the indefinitely long transition time is the
>>>problem. Fundamentally it seems there is a lack of political will to
>>>place a definite cutoff date on the use of customary units.
>>>
>>>
>>I have friends who work in the auto industry. They reported (over 10 years
>>ago?) that all new designs are metric.
>>
>>I wonder how much it would help if GSA gave a serious preference to things
>>that were metric?
>>
>>What's 8.5x11 in metric?
>>
>>
>
>An odd-shaped A4ish paper for which there is no propper envelope.
>
>This fact I had to learn from an American professor that was enligthened when
>he came to Sweden. Since then he converted to A4 even in his NYC flat where his
>wife mostly lives (there is a downside to being professors at different
>universities divided by the atlantic).
>
>
>
>>Do we have to convert to A4 too?
>>
>>
>
>Preferably. :)
>
>
>
>>For real fun, look at bicycle parts. I remember seeing one part that had
>>25.4 threads per inch.
>>
>>
>
>:)
>
>
>
>>What fraction of the military is metric? Do they buy potatoes in kilos or
>>pounds?
>>
>>
>
>The aviation side certainly have alot of imperial measures. Figures.
>
>Look at GPS. Certainly metric all the way as far as I have seen. Like all
>aviation stuff that part may ofcourse use a mixture. Wonder what nice orbit
>errors they would have if they used metric and survey inches as basis.
>Hmm.... 2 ppm would be some 50 m or so.
>
>
>
>>>One would have thought that with the advent of computers using the
>>>"survey inch" and related units for new surveys would have vanished by
>>>now.
>>>
>>>
>>There is probably a lot of legal baggage there. I'll bet they will be one of
>>the last holdouts.
>>
>>
>
>I wonder just how many metric related laws they would have to write before
>all things is metric. There is already a few to go around you know.
>
>Cheers,
>Magnus
>
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