Re: Slightly off-topic : History behind lettered drills

--- In CAD_CAM_EDM_DRO@egroups.com, dave engvall <dengvall@n...>
wrote:

> > hence our manufacturing proceeds with imperial.
> > Measurement is an exact science but boring !
> > Steve Roberts
> > Professional Engineer (Canada & UK)
> >
>
> Mixed measurement systems are a problem.
> IMHO if we had put Km on our interstate hwy system and sold

gasoline in liters we would be metric now.

> Most of the international manufacturing concerns (car companies)

have gone metric. Too many inch tools are coming out of Boeing to

> convince me they do much in metric except the military stuff.
> Getting standards in the early 19th century when the US started to

convert to interchangable parts must have been interesting.

> <ugh>
>
> dave

+- 0.001" or +-.003" tolerance is much easyer to keep than the
standar metric of +-.01mm(0.0004").that's why the U.S. don't want to
give up on standar "inch".
metric system is much easyer to work than "inch".it's all multiples
of ten,just like working with money,if you can manage your budget you
can do metric.(well...,maybe it is not that easy :-)