NPT fittings ???'s

[PRyker]

Where is the best place to buy NPT fittings and such. I have tried locally and cannot find anyone who sells any. Everyone looks at me funny when I ask if they sell them. Is there a good online supplier??



Thanks



Phil

 

[SRadke]

NPT is THE most common fitting there is. What are you working on... . plumbing? ... . fuel system?... . hydraulic?... . They are used for everything.



-Scott

 

[Fireman Dave]

Our local Ace Hardware carries a lot of them.

 

[Rman]

I goto a local hydraulics shop, I know most hardware stores have the common fittings. The reducers and what not might be hard to find, I have to use the hyrdraulic shop for those. Generally you don't see more than a one size drop in a reducer at the local hardware store. I was able to find a 3/4 o 1/8 reducer at the hydro shop.



Online, Grainger will have it, they have everything.

 

[grfraz]

They are looking at you like that because they probably don't even know what they sell, just ask them for the size fitting you would like, i. e. 1/2" elbow or 3/4" tee. If you go and ask them a question like this, then they all get that confused look on their face, NPT is a standard pipe thread here in the good ole USA it only means that the threads on the fitting/pipe are tapered to achieve a better seal. Just about every hardware store that sells plumbing and/or gas fittings sell these fittings, but if you ask the clerks, they ain't goin' to know what you just said. :-laf



So you need to figure out what size you need and go to you local hardware store find the plumbing section of the store and get for them yourself.





fyi- NPT - National Pipe Taper Thread



the link : NPT- National Pipe Taper Threads - ANSI B1. 20. 1



Note! Pipe sizes do not refer to any physical dimensions. The outside diameter of a pipe or fitting must be measured and compared to a table for size identification. A 3/4" NPT pipe thread has an outside diameter - OD - of 1. 050 inches. The pipe size generally refers to the inside diameter.



Each thread size has a defined number of threads per inch - TPI, or pitch. The 3/4" NPT pipe thread has 14 threads per inch. Both the TPI and OD of the thread are required for positive identification of thread size because more than one size have the same TPI.

 

[PSU-CE]

Between Lowes and Home Depot you can find alot of smaller size stuff.

 

[BV]

Sad but true that more and more people don't know what some of these basics are but they know what all the bulletin board acronyms are - ROFLMA

 

[Jumbo Jet]

When all of us baby boomers die off, the only information available will be on the Internet and computers. There are a few of us that have tried to pass the knowledge on to our kids, but not very many.



I hate to go to an automotive parts store and ask for a part for a vintage automobile that is not in their computer. Blows them away. Now if I need an adjustable wing or a under carriage lighting kit for a 1994 Honda Accord - shoot - they can slap that on the counter as soon as the English to Spanish interpreter finishes interpreting!!

 

[PRyker]

Thanks for the info guys.



When using pipe fittings is there a point where they can be over tightened? I ask this because logic would dictate that if the threads taper to a larger size the further the fitting is tightened I would assume there is a point where it would be too tight? Or should I simply tighten until I can no longer see the threads?



Seems like a silly question but I want to do thing right the first time and hate to learn through breaking stuff.



Thanks



Phil

 

[PRyker]

Also,



When sealing these fittings do you use thread tape of thread sealant in a tube? I am always worried about getting pieces of tape or thread sealant into the oil system or fuel system.



Thanks



Phil

 

[SRadke]

You basically tighten until they feel tight. There's no rule of thumb, just not tight enough to break them I always use some sort of sealant on the threads, they don't seal good otherwise. Teflon tape works well on small pieces and it's clean. For the larger, dirtier applications I use a product called "Rectorseal", good stuff for plumbing, hydraulics etc. but a bit messy. Loctite also make a brush on product that is teflon paste or something like that, it seals really well but you have to wait for it to cure before putting pressure agenst it.



-Scott

 

[rbattelle]

Just my opinion

In my *opinion* the finest pipe fittings money can buy are made by a company called Swagelok (www.swagelok.com). From their website you can download complete specifications (including torque requirements) and you can find the local distributor. You can then order your parts online (with complete pictures, CAD drawings, and layouts for almost all the parts) and have them shipped from the local dealer. I do this for every pipe fitting I buy (I buy a few hundred $ worth every year for my various projects).



I usually use Teflon tape, but am evaluating an anerobic sealant made by Swagelok called "Swak". As others have said, don't overtighten or you can warp the parts and then they'll never seal right. I usually "snug" them up then run the assembly and retighten a little at a time if there's any leaks.



This is just my opinion... don't mean to step on anyone's toes.



-Ryan

 

[PRyker]

I would assume then that you guys do not tighten until you can no longer see the threads. I ask because I have had some get pretty tight when only 1/4 of the way screwed in and others go all the way down and bottom out. Does it matter where they tighten and how much thread I leave exposed?



Thanks



Phil

 

[lmills]

I was told by a good friend that did sprinkler fitting for years that he prefers to get a minimum of 4 turns into the fitting.

 

[Proram]

lLoyd, Would that be the same guy who said" you don't need anti seeze on that fitting???" LOL



Scott

 

[lmills]

OMG. thats hilarious that you remembered that, but yes

 

[rbattelle]

More Opinions

I would assume then that you guys do not tighten until you can no longer see the threads. I ask because I have had some get pretty tight when only 1/4 of the way screwed in and others go all the way down and bottom out. Does it matter where they tighten and how much thread I leave exposed?



Thanks



Phil

No way!! If you can't see any threads, and assuming the hole was properly drilled and tapped, you've way overtightened the assembly. When you tap an NPT hole the farther in you go with the tap the wider the hole is and the deeper your fitting will be able to be screwed in before it gets tight. When I tap an NPT hole I go slowly and tap just until I can start a fitting into it for a couple revolutions before it begins to tighten up. If you tap too far the fitting will go all the way in and not get tight enough to seal.



Lloyd's rule of thumb of 4-turns minimum is one I've never heard, but it sounds pretty reasonable.



-Ryan

 

[PRyker]

Anti seize? Should I use it? Also, is it recommended to use an assembly lubricant? Do AN fittings require teflon tape? I would think they do not as the compression fitting is what seals the fitting closed?



Thanks



Phil

 

[rbattelle]

Anti seize? Should I use it? Also, is it recommended to use an assembly lubricant? Do AN fittings require teflon tape? I would think they do not as the compression fitting is what seals the fitting closed?



Thanks



Phil

I don't think there's any need for anti-seize on NPT fittings. At least, I've never used any but maybe there's some reason it should be used that I don't know about.



Excellent question about AN fittings. I don't *think* they require any Teflon tape or thread sealant. I've got a few on my truck and I didn't use any thread sealant and they've never leaked. A good friend is a certified aircraft mechanic (they use all AN fittings) and he never used any. I worked on a GE F-100-229 engine (F-16) once and none of the AN fittings on it used any thread sealant.



-Ryan

 

[PRyker]

Thanks for the info guys. I will use teflon tape on NPT's and probably a light assembly grease for the compression fittings. I have learned a lot about fittings now and feel better equiped to properly install them. The TDR does it again!



Phil