High pressure NPT question

[Munch]

Is there any play with a NPT fitting or does it have to be tightened all the way even if you put some red loctite on the threads?

I have a T fitting that goes in the bottom of my N2o solenoid but if I bottom it out it's pointing the wrong way so I need to back it off about an 1/8 - 1/4 of a turn to make it fit.

[Y2Kvert4me]

Did these fittings both come in a kit, or are you mixing stuff here?

Unlike flare or compression fittings, NPT (tapered pipe thread) fittings seal via the threads themselves.

If you are actually bottoming this tee out (running out of thread) without significant resistance, that is cause for concern right there, telling me it probably wouldn't seal anyways, as you should never be able to reach that point (without stripping the threads). There are some (NPS, BPS) straight thread fittings available, which may thread together, but those are usually designed to seal with an O-ring or compression ferrule as opposed to the threads.

Usually when a NPT connection gets tight you'll be several (visible) threads away from it actually bottoming out. Yes you can go +/- from that "tight" point for alignment purposes (go whichever direction is closest).

And it's better to use a thread sealant, not Loctite on NPT fittings. Loctite does work, but is not really it's intended purpose. A tapered pipe fitting is not prone to vibration-loosening.

[Munch]

The pieces came together in a kit and I'm not technically bottoming it out, I meant turning it until it won't turn any more and still has threads showing.

As far as backing it off a bit once it's tight, it's either tight or pretty loose so that's why I was thinking loctite to kind of hold it in place.

[Y2Kvert4me]

Originally Posted by Munch

The pieces came together in a kit and I'm not technically bottoming it out, I meant turning it until it won't turn any more and still has threads showing.

As far as backing it off a bit once it's tight, it's either tight or pretty loose so that's why I was thinking loctite to kind of hold it in place.

OK, that sounds better.

If you only need a 1/4 turn more at the tight point to reach desired alignment, assuming you have a good means of getting a wrench on it (and holding the solenoid), you should be able to muscle it there. In fact the liquid on the threads (Loctite or sealant) may actually aid you in getting there from the thread lubrication (until it cures).

[Sneaks]

No Locktite or tape on those fittings Munchers. Use only teflon paste for your sealant.
And yes, you can turn that fitting up to a 1/4 turn more with no damage. I turned mine about that far and everything is fine. It was just a bit un-nerving wrenching that fitting like a gorilla to get it where I wanted it.

[Munch]

I used some thread sealant, put a wrench on it and got it right where I wanted it.