On 2008-01-15, Stealth Pilot wrote:
On 15 Jan 2008 04:58:17 GMT, "DoN. Nichols"
wrote:

On 2008-01-14, Stealth Pilot wrote:

[ ... ]

why what's the problem? I read the details from my mullins thread wall
chart. it lists the 18 pitch threads exactly as quoted.

Out of curiosity -- what does the mullins thread wall chart say
is the OD of the thread. IIRC, the original question said that the
actual measured OD was 1/4", while any pipe thread would normally be
named for something closer to the bore size, thus requiring a much
larger diameter for the threaded part.

the post answers the last two sentences of the question.
a. what's it used for? - pipe thread.

Not clear -- until you can tell us that your chart shows the OD
as 1/4". It could easily be some other thread with the same pitch, but
a smaller OD, for a different function.

b. his suspicion that it was a mistake is probably wrong since there
is a listed application for the thread size.

Again -- are you sure about the OD?

[ ... ]

I wonder what that glow is around here?
11mm tapping drill for both.

11mm divided by 25.4 mm per inch gives a diameter of 0.4331",
and the actual tap diameter would have to be a bit over the tap drill
size, while the original poster said that *his* tap was measured at 1/4"
(that is 0.250" so these are *very* different taps.

oh I get it. the light's on.

Where? Not in your head, yet, apparently.

Enjoy,
DoN.

--
Email: | Voice (all times): (703) 938-4564
(too) near Washington D.C. | http://www.d-and-d.com/dnichols/DoN.html
--- Black Holes are where God is dividing by zero ---