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Stuck NPT fittings

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Stuck NPT fittings

Unread postAuthor: snowjack » Mon Jan 22, 2007 8:44 pm

Probably a noob question. I'm almost done building my first gun, but I'm having trouble with the threaded fittings. The male fitting is NPT Sch80 PVC, and the female fitting is NPT Sch40 PVC (this is for a combustion gun, I couldn't find the male fitting I needed in Sch40). Anyway, I can't get the male fitting to go in all the way. It gets tighter as it goes and gets stuck about 2/3rds of the way in. Both the male and female are supposed to be tapered threads according to McMaster (straight is NPS instead of NPT, right?). On Burnt Latke's site he recommeded filing down the little imperfections in the thread seams, but that doesn't seem to have helped. I also tried lubricating the threads with a little WD-40 but that didn't help either. Any suggestions?
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Unread postAuthor: squeaks » Mon Jan 22, 2007 8:48 pm

hahahahaha............sorry, had to laugh at this one.
NPT fittings are supposed to get tight until the point where you can't turn them anymore. This is so that a proper seal can be acquired. It's perfectly fine to have some of the threads not being used. Just remember to teflon the threads.
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Unread postAuthor: Bluetooth » Mon Jan 22, 2007 8:54 pm

Yeah, if you get it all the way in your not getting it back out. Lol
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Unread postAuthor: garrettee » Mon Jan 22, 2007 8:57 pm

Take it easy squeaks, If you knew it all when you started you wouldn't be here right now. That's what this forum is for, right?
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Unread postAuthor: MrCrowley » Mon Jan 22, 2007 8:59 pm

2/3rds aint bad, if it blows off dont blame us :P
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Unread postAuthor: squeaks » Mon Jan 22, 2007 9:24 pm

I was taking it easy. That's why I was enjoying this moment for some comic releif. Yeah, I knew about just as much when I first started. Then I discovered the joy of the forum search key and spudwiki. Two lifesavers.
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Unread postAuthor: snowjack » Mon Jan 22, 2007 11:34 pm

squeaks wrote:I was taking it easy. That's why I was enjoying this moment for some comic releif. Yeah, I knew about just as much when I first started. Then I discovered the joy of the forum search key and spudwiki. Two lifesavers.


No harm, no foul. But just for the record I did spend about an hour searching the forums, reading, and going through the Wiki, and didn't see anything mentioned about stuck threaded fittings.

Actually, all together I've probably spent three or four hours reading through the forums here, and I think I saw more posts about forum etiquette, grammar, and spelling than about spudguns... :-)

Anyway, thanks for the sanity check, everybody. :D
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Unread postAuthor: squeaks » Mon Jan 22, 2007 11:45 pm

Yeah, we are a bit nutz here about grammar and whatnot. In fact, just by typing this message someone will proofread me and fix any and all spelling/grammar errors. That or they will make fun of me for whatever dumb reason I'm posting this message. That's half of the fun of the forum.
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Unread postAuthor: A-98 » Tue Jan 23, 2007 12:07 am

ugh. you spelled "nuts" wrong!!!

lol, jk

ya, when i first started i thought that you had to get them almost all the way in...but then i realised that that wast possible.lol.
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Unread postAuthor: Pete Zaria » Tue Jan 23, 2007 12:16 am

Snowjack,
Two strap wrenches (like these: Image ) work wonders on stuck threaded fittings.

I don't know if they'd shrink at all if you put them in the freezer to get them cold - it might help, and I don't think it could hurt them...

Peace,
Pete Zaria.
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Unread postAuthor: snowjack » Tue Jan 23, 2007 11:32 am

That should work. Thanks, Pete!
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Unread postAuthor: jrrdw » Tue Jan 23, 2007 2:00 pm

Helpfull hint --
After you get it out of the freezer, try a hair dryer on the out side of the female fitting, that will make it even easier to unscrew.
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