NPTF male vs NPSM female fitting

[boatyard]

I am installing a selector valve to borrow the bucket curl lines to angle a snow plow.
The hoses and fittings arrived today. I have male x female 90ｺ elbows to connect the hose to the valve. The hose is NPTF male. It does not thread very far in to the elbow before it bottoms out. I went back to the catalog to double check the specs and noticed that the elbows are NPTF male x NPSM female.
Did I order the wrong fittings? What does NPSM stand for?
The other hydraulic question is how tight should the fittings be? Tight? Very tight? Or really crank on them?

Thanks, Christopher

 

[wdchyd]

You have the right fittings.....the NPSM is just the name for the Pipe Swivel....doesn't need to be too tight...the male mates to the 30 degree chamfer in the pipe swivel.......

 

[milkman636]

Pipe threads are tapered not straight. The taper increases the mating/sealing surface area. Three turns by hand, three turns by wrench, and three threads showing is a rule of thumb that I learned along time ago for good pipe threads. More or less turns is an indication of threads that were over or undercut by the dies. If you can bury the all the threads into a fitting with pipe thread you can expect a leak.

 

[PILOON]

Using pipe thread, you also want to lube or use tape in order to avoid leaks.
Many prefer a pipe dope over tape due to contamination possibilities.
More and more I notice epoxy sealants being used also.

 

[oldnslo]

I am installing a selector valve to borrow the bucket curl lines to angle a snow plow.
The hoses and fittings arrived today. I have male x female 90ｺ elbows to connect the hose to the valve. The hose is NPTF male. It does not thread very far in to the elbow before it bottoms out. I went back to the catalog to double check the specs and noticed that the elbows are NPTF male x NPSM female.
Did I order the wrong fittings? What does NPSM stand for?
The other hydraulic question is how tight should the fittings be? Tight? Very tight? Or really crank on them?

Thanks, Christopher

When using pipe female swivel fittings make sure the mating male nipple has the correct internal sealing face or chamfer. Some fittings do and some do NOT.

Roy

 

[Discount Hydraulic Hose]

Everyone here has it right. The NPSM (National Pipe Straight Mechanical) is a female pipe swivel, and it should seal with your male NPTF (National Pipe Taper Fuel) as long as the male has the internal 30ｰ chamfer. Almost all NPTF fittings I've seen have this chamfer, but some NPT fittings do not.

In case I just confused someone by mentioned NPTF and NPT in the same sentence, here's the deal. NPT and NPTF have the same tapered threads, but NPTF is a dryseal, intended to seal without the need for thread sealant. I'm not sure this matters a lot, since everyone I know still uses the thread sealant anyway.

 

[myyaz33]

Hope this does not break some rules, but this thread is similar to a problem I am having and was hoping to solicit some input from those in this thread who seem knowledgeable.

My thread is here.
leaking NPTF quick connects - TractorByNet.com

 

[Kitz]

Everyone here has it right. The NPSM (National Pipe Straight Mechanical) is a female pipe swivel, and it should seal with your male NPTF (National Pipe Taper Fuel) as long as the male has the internal 30ｰ chamfer. Almost all NPTF fittings I've seen have this chamfer, but some NPT fittings do not.

In case I just confused someone by mentioned NPTF and NPT in the same sentence, here's the deal. NPT and NPTF have the same tapered threads, but NPTF is a dryseal, intended to seal without the need for thread sealant. I'm not sure this matters a lot, since everyone I know still uses the thread sealant anyway.

The nptf also has the 30 degree chamfer in inside of pipe. just alittle more quality work