Re: [VAL] copper?!

[Rob Super <robsuper@xxxxxxxxxxx>]

Sorry to re-open a thread that seems to have petered out (just picked 
up several days' msgs), but re:

>  copper appears
> to be neither 1/2" or 3/4". It actually measures 5/8" O.D. Neither I,
> nor any of the assorted hardware stores I've visited between Dallas and
> our current location (Galveston Island) have ever heard of 5/8". One
> hardware guy insisted that it must have been 1/2",

Nominal 1/2" copper pipe measures 5/8" OD.

"Nominal" means what it's called, not what it may actually measure. 
Thus, e.g., a (nominal) "2x4" wooden stud actually measures 1.5" x 
3.5". In the case of copper pipe, when the effective ID is ~1/2" it's 
called "1/2 inch" . Bottom line: if it measures 5/8" on the outside 
it's "1/2-inch" copper pipe and you want to use what the catalogs and 
packages call "1/2-inch" fittings. Similarly, if it measures 1/2" OD 
it's nominal "3/8-inch" copper pipe, etc.

And, just because the guilds like to keep things as mysterious as 
possible, the nomenclature for copper refrigeration tubing is 
different: their nominal "1/2-inch" tubing actually measures 1/2" OD, 
their "5/8-inch" actually measures 5/8" OD, etc. --you really have to 
make sure you and the hardware clerk (or the catalog) are speaking the 
same language!

Rob