NPT Gaging question. 1

[doohicky]

Is there anybody that deals with castings and can answer me a question on the proper use of a NPT ring gage on a pipe plug?

I know that when gaging pipe, flush would be the end of the pipe(according to B1.20.1), but would the same hold true for a plug? The cast plug does in fact have a cast in radius on the end of the plug and this makes the first thread incidental.

What I am looking for is any published criteria that specifically spells this out. Opinions are also welcome.

Thank you for the clarification.

Mike

 

[EagleKnee]

I believe the best way to "check" NPT plug to ring gauge is to calculate the number of turns in.

(3 to 5) turns in/out 1/8"to 2" NPt
(5 to 7) for 3"...up...

some gauges come with milled calibration edges that line up flush to calibrate.(mostly LP style)

plz correct me if this is not right.

hope this helps.