Dash-4 or 1/4" NPT?

[Stanley]

Hooking up a new FP gauge. The line has a dash-4 male fitting and the gauge has a 1/4" NPT male fitting. The place that put my hose together gave me a brass female/female dash-4 to 1/4" NPT adapter and said to put the Teflon tape on the NPT side only.

Figured it would be easy but I can't figure out which side of the adapter is which. Everything threads into everything about the same. One end of the adapter is flat and the other end is slightly beveled; also one end of the adapter is slightly (about 1 mm) longer than the other.

Put the male threads together to see how they lined up - they matched pretty good but I could see air between the threads. ?????

[zKars]

Smooth beveled end (37 deg) is -4 AN fitting. Look in the hose and see its mating surface. The seal occurs where the male bevel meets the femal metal, not on the threads, hence teflon tape on those threads does nothing. The NPT threads rely on the tape to seal as the threads interference fit when tightened just right.

Google -4 AN Fittings in Google images to see many many examples. Check out http://www.anplumbing.com as well to see what's available.

Edited July 17, 2013 by zKars

[Stanley]

Dumb me/need my glasses me. As little as I know about hose fittings, I did know about the 37 deg flare. The guys at Mr. Hose wisely put the -4 male to 1/4 npt male adapter on the hose end so it wouldn't get lost. What I was looking at was the 1/4" npt F/F adapter. I looked carefully at the hose end last night and thought it was one piece. Today I used a magnifying glass and saw it was the adapter. Duh....