Male NPT into a Female NPSM

[flexiblegoat]

Does anyone know how far a 1/2" MNPT will thread into a 1/2 FNPSM when it is hand tight? (note: this arrangement is typical of bi-metal thermometers threaded into thermowells.) I can't find a chart/table which shows this information. I could just try it, but I do not have the parts.

 

[hydtools]

Figure it out from the taper. Calculate the distance to equal diameters, female ID to male minor where interference begins.

Ted

 

[ports394]

http://www.mcmaster.com/#straight-thread-pipe-adapters/=exjh0n

try looking at these adapters.

I used to use some Ingold fittings that are 1 1/4" NPS threads male, and I just use 1 1/4" NPT caps to close them. Ended up getting about 1.5-2 turns on it. But that was enough, with some teflon tape, to seal them.