ok . open any electronics component catalog.  ( digikey , mouser , avnet 
, farnell ,newark arrow )and look at parts

you fill find things like 50 mils 25 mils 100 mils for lead pitch and 
widths. and then look at the equivalent in millimeters. Which numbers 
would you rather key in to create a new footprint ? Sure there are 
metric parts but we don't use them ( yet ) . Ribbon cable is still a 100 
mil pitch , Smd components ares still 50 mil pitch ( some tqfp and bga's 
are in millimeters true )  and i'd rather key in 25 mils when creating a 
part then a crazy value like 0.62954 millimeter.

i think we will only be successful in switching to millimeter when there 
are no more parts made using imperial pitches. and that is not going to 
happen for a long time.

And believe me i know what a pain converting is , I am from belgium and 
have grown up with the metric system , after 2 years in the usa using 
inches , and feet and pound and gallon that heve no linear relationship 
to them is still a nightmare. But for board layout i translates in nice 
round numbers.

> In a global economy standardisation is essential, do you really think 
> that inches have a future?
> The IPC recognises this, which being American based is very 
> surprising, but encouraging.
> Even Britain the bastion of Imperial is slowly but inexorably moving 
> towards metrication.
> I was brought up on imperial and pounds and shillings, so I'm fairly 
> understanding.
> As far as I'm aware the USA is the only country that doesn't have a 
> metrication programme in effect


>
> Chris Mogford.
> ************************************************************************
> * Tracking #: E7E9D6B0EAA28E45B0C48EF8E6F4E50D563153A1
> *
> ************************************************************************
>


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