kicad-developers team mailing list archive

[Karl Schmidt <karl@xxxxxxxxxxxx>]

On 10/13/2010 01:17 AM, Dick Hollenbeck wrote:

> > I wonder if it occurred to others - if the inch had been defined as 25.6 instead of 25.4/mm this
> > problem would have been quite different.
>
> I thought the inch was defined first.

MANY various inch standards existed, but once the Canada inch was defined as 25.4mm  the others 
followed.

Wiki has a fair writeup http://en.wikipedia.org/wiki/Inch#Historical_origin

The evolution of measures is fascinating - worth a read:

The Science of Measurement; A Historical Survey  by Herbert Arthur Klein

Years ago I wrote up a fun bit on volume measures:

http://wiki.xtronics.com/index.php/Jack_and_Jill


> That's what they said in here in the USA in the 1960's.  And then Dr.
> Spock came along and the world got soft, teachers got a break, kids got
> a break.  In the 1960's I remember there being a commitment to learn
> metric, then that commitment went away, because it meant, ahem, work and
> study and teaching. Not just for kids in school but also for adults out
> of school.

I remember that all to well and it seems like we are reaping the economic consequences of always 
taking the path of least resistance as we speak.

> It might have been a nice thing to do with the Y2K initiative.  You
> know, declare the inch dead.  The problem obviously is the machine
> tools, tools, etc.  But if we simply started measuring everything in
> metric, the 2.54 that we would see everywhere would eventually get
> tiresome and the machines would eventually get made in metric.

The movement of manufacturing to Asia, will continue to push us in to a metric only world.

That being said - I can visualize 10 mils, I have a great feel for a quarter inch, but I have to 
work hard to keep my metric case sizes visulized.

http://wiki.xtronics.com/index.php/SMT_Case_Size_Codes

I hate using fractional inches so much, that I carry a decimal-inch tape measure for carpentry 
work... Stanley 33-272  - Starts out in 1/100th of inch..

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Karl Schmidt                                  EMail Karl@xxxxxxxxxxxx
Transtronics, Inc.                              WEB http://xtronics.com
3209 West 9th Street                             Ph (785) 841-3089
Lawrence, KS 66049                              FAX (785) 841-0434

They can print money; they cannot print wealth.
Wealth only comes from productive behavior.
Printing money only destroys the ability of wealth
producers to produce more wealth. KPS

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