[SEL] OT - what is NPT REALLY..........

[James Mackessy]

The NPTF threads have a taper of 7/8" per foot, something I did not know
until recently. Now I'm trying to figure out, if the "F" does not stand for
fine, as in
screw thread sizes, what does it stand for? "Dryseal"? Now I'll be up all
night!;-)
Best Regards;
Jim Mackessy
Syracuse, New York, USA
----- Original Message ----- 
From: "William Olson" <weolson at wiktel.com>
To: "The SEL email discussion list" <sel at lists.stationary-engine.com>
Sent: Tuesday, February 01, 2005 6:55 PM
Subject: Re: [SEL] OT - what is NPT REALLY..........


> Just to add some confusion to the thread, no pun intended, I'll add the
> following info:  I am a licensed electrician and looking in the National
> Electrical Code book under IMC or Rigid conduit about threading pipe
> (conduit), it states the following.  "Where conduit is threaded in the
> field, a standard cutting die with a taper of 1 in 16 (3/4 inch per
> foot) shall be used.  Fine Print Note: See ANSI/ASME B.1.20..1-1983,
> Standard for Pipe Threads, General Purpose (Inch)."
>    I don't know if this helps or hinders the ongoing diolog, but I give
> it for what it's worth.
> William Olson, Roosevelt, MN
>
> diesel at easynet.co.uk wrote:
>
> >Quoting James Yost <jnyost at yahoo.com>:
> >
> >>Bill,
> >>
> >>Both are correct. I do not think you could win or
> >>loose on trying to see who is right or wrong.
> >>Engineers sometime refer it as taper but us common
> >>folk say thread.
> >>
> >>Jim
> >>
> >
> >I'd say National Pipe Thread is the correct term, as the thread comes (as
does
> >the British Standard Pipe thread) in both taper and parallel forms. Both
are
> >listed in the SAE handbooks that we have.
> >
> >Peter
> >
>
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