Homebrew PCBs

On Wed, 26 Apr 2006 06:00:35 +0200, Herbert E. Plett <cachureos@...>  
wrote:

> deep wrong!
>
> a mm is one thousands of a meter - an internationally defined and fixed  
> length.
>
> one inch is defined as 25.4 mm or 0.0254 m -> there is no standard for  
> it!
>
> and what about 17/32" ? crazy! industrial specs now are all required in  
> decimal
>
> notation and therefore the importance of 0.001" or mil or, better yet,  
> mm!
>
> ...and please keep off terms like ounces, pints and the like... the  
> world IS
>
> metric and not owned by the Empire!
>


Even the use of the mil or thou shows clearly the superiority of a decimal  
system (as opposed to the fractional nonsense i really can not bend my  
brain around, who can imagine 17/32" in his head??).

But fact is, independently of the silly resistance to converting to SI,  
components will still be in mil spacings for many years before they are  
all replaced by metric. So we do have to deal with it. Luckily it there is  
a key in my PCB software that switches all measurements between  
mm/mil/inch/um, so i don't have to do any conversions.

Another thing is drill size numbers. I will never understand why those are  
not simply labeled in diameter, like it is in mm here, but instead in some  
random number...

ST