external pipe threads

[Andy330hp]

I need to call out external pipe threads on a part I am drawing. 1/4" NPT. I've never had to look it up before, so I don't know what the boss outer diameter should be. Does Solidworks have this info? Do any of you? Once I get the boss to the right dia, I was just gonna do cosmetic threads, but I need the boss size!!

 

[meintsi]

From the Machinery's Handbook:
Nominal Perfect External Threads are Ø.49556" x .2907" long with a minor dia. of 0.4329"



Remember...
"If you don't use your head,
your going to have to use your feet."

 

[jbknudsen]

It appears that L5 (Ø.2907)is the nominal length for full thread engagement. The total length of the thread is indicated by L4 which is .5946 for 1/4" npt perfect threads. Don’t forget that the taper ratio is 1 thread height in every 16. This info is from pages 1774 and 1775 of the 24th edition of the machinerys handbook. Let me know if I am reading the table incorrectly.

Additionally I have a lisp routine (yes i said lisp) that will produce a profile of any npt thread sized 1/8 thru 1". I should probabally have the lisp converted to sw api or a vb macro. I have run the lisp and saved the acad drawing and then opened the drawing in sw and used the profile as needed. If any one wants it, let me know and I will give it to ya.

Jesus is the truth, the way, the life.

-Jay

 

[Andy330hp]

I'd like to have that, I think the macro would be better but I'm not an expert at that stuff
ajallen@injectionlogic.com

 

[brengine]

I can never remember the dimensions, and I just never seem to take the time to write them down. Instead, I usually just create a temporary internal npt thread (with the hole wizard), measure the top and bottom diameters and the depth (and/or the taper), and then delete it. Then I apply those dimensions to the external npt thread.
Ken

 

[EdDanzer]

Your best source for this information will be the Machinery’s Handbook by Industrial Press.