NPT Vs NPTF

[lahane1443]

I have supplied 10 pressure components on which 1" NPTF thredolet was required by drawing.
Test certificate for thredolet shows 1"NPT & hense customer has rejected all the components.
What is the difference in above two threading.
Is there any chance that above material will get accepted?
I need to reply to customer on above mess.

 

[looslib]

Check out this webpage, it explains the diference and why one is preferred over the other.

http://www.cutting-tool-supply.com/TechTips/Tapping/NPTvsNPTF/NPTVsNPTF.htm

"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[hydtools]

Is the test certificate incorrect about the thread?

Ted

 

[lahane1443]

TC is correct .

 

[looslib]

If the TC is correct, then you used the wrong thredolet and the customer is correct in rejecting them.


"Wildfires are dangerous, hard to control, and economically catastrophic."

Ben Loosli

 

[rmw]

A thredolet is by definition a branch fitting with a female NPT thread in it. There is a male threaded "Olet" and I can't think what it is called right off (don't use them - rarely see them).

So on that basis, listing a thredolet with a FNPT thread is superfolous. If you said thredolet, you said female threads, and the only thing to determine then is if they are NPT or BST or some other standard.

Google the word "olet" and see what pops up.

rmw

 

[MikeHalloran]

The 'F' suffix does NOT refer to female threads but to the 'dryseal' thread form. I have no idea why the character 'F' was chosen, but given your confusion about it (you are not alone), it seems an unfortunate choice.

http://www.asme.org/products/codes---standards/dryseal-pipe-threads,inch

Mike Halloran
Pembroke Pines, FL, USA

 

[MikeHalloran]

My current operating hypothesis about the reason for using 'F' as a suffix to denote 'dryseal' is that it's somebody's subtle joke, and means 'fantasy'.

.... because I have never seen one actually seal without some kind of thread sealant applied.



Mike Halloran
Pembroke Pines, FL, USA

 

[hydtools]

I believe the 'F' was to indicate fuel service.

Ted

 

[engineer4fun]

I agree the TC seems to be correct

Designer and <a href="

http://www.coilingtech.com/compression-springs.html">compressing

springs</a> enthusiast