Plumbing - NPSM

[Donald]

I bought a 1/2" water filter to use in the softwash system I am assembling. The inlet and outlet are NPSM. Not NPT. NPSM is a straight thread, not tapered. I thought piping was either NPT or if not tapered it's sealed with a gasket or O-ring. This is just a female threaded opening with no way to deal with an O-ring.

So how does NPSM seal if not tapered or an O-ring?

 

[BigCahuna]

Rubber gasket maybe ?.,,

 

[tom slick]

You’ll need adapters to change thread type

 

[mk378]

It's the same thread as on sink faucets. The female fittings have a rubber gasket in the base. This is also used on RV water pumps.