The two most common taper pipe threads used in the United States are NPT and NPTF. Applications range from electrical conduits and hand railings to high-pressure pipe lines that carry gas or caustic fluids. NPT threads are for mechanical or low-pressure air or fluid applications and require the use of sealing compounds like Teflon tape, […]

Oct 11, 2002 · How does the difference in thread forms effect the tooling used to produce NPT and NPTF threads? Taps are available for both NPT and NPTF threads having the appropriate form to produce each type of thread. Since NPT threaded parts require sealing compounds, it is acceptable to use an NPTF tap for NPT applications. However, NPT taps cannot be ...

Nov 2, 2011 · They are changing the 1/8"-27 npt to nptf and using an nptf fitting. I get different drill sizes depending on whose charts I use. C or D for 1/16", R or Q for 1/8" npt(f). ANSI chart says R for 1/8" npt. They wanted to try the 1/16" npt in an nptf hole. The bushing in my jig is for an R(The current size for npt before the change they want to nptf).

Mar 22, 2011 · 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.

Oct 11, 2003 · "A variation of the NPT thread that is used for hydraulic purposes is the Dryseal ANSI Standard Taper Pipe Thread (NPTF). This thread has the same form and dimensions as the NPT thread, except that the truncation of the crests and roots is changed to ensure that the spiral clearance around the thread is eliminated.

Jan 10, 2008 · If you you only need NPT threads and not ANPT or NPTF, then have engineering stand behind their knowledge of the proper thread form for the intended use. Run a few calcs on time/cost estimates of increasing the gaging required to reduce the rejects to an acceptable level (we all here know the high spec stuff can be done, it just takes more time ...

Jan 18, 2009 · What about NPT vs NPTF vs NPT dryseal. My understanding is that NPTF and NPT dryseal are the same thread. They have a deeper "V" on the thread vs a standard NPT which is more blunt. Yes? If so, I'd assume an external NPTF (or dryseal) thread can accept a standard NPT fine? It seems difficult (impossible) to find a Mil-Std Hex seal flush plug in ...

Jan 20, 2011 · Where I would see a concern the risk runs using and NPTF (major diameter larger the NPT) if one would inspect it with an NPT there would a difference gage stand-off. 2”-11 ½ NPT L1 Plug Gage Plane OD 2.35418 -.001 Small end OD 2.32693 2”-11 ½ NPTF L1 Plug Gage Plane OD 2.35593 -.0015 Small end OD 2.32868

Feb 9, 2006 · NPTF is the designation for Dry Seal (SAE standard J476) pipe threads. They have the same pitch and taper as NPT threads, but the thread form is modified to seal better. A NPTF should mate with a regular NPT, and 11-1/2 is the correct pitch for 1" pipe.

Aug 1, 2003 · NPT and NPTF threads of the same size will go together. NPTF threads are NPT threads with the tops and bottoms ounded off so they interfere at assembly. The intent of NPTF threads are that they can seal without using thread sealent (teflon tape or Loctite PST), hence they are also called "dryseal type".