Help With Fittings???

OK,

I want to use push-in fittings on my DIY water cooled rig (still working on it). The problem is i know nothing about piping. I see a lot of sites that have readinds like this...

3/8" O.D. x 1/4" MNPT

I know that the O.D. = Outter Diameter and the MNPT stands for Male National Thread Point. What I don't know is does the tube O.D. is 3/8" and the MNPT refer to how deep the threads will go, or does it mean that the thread of the tubdings diameter is 1/4". will this reduce my flow rate at all?

Please only reply if you know and don't guess. I have asked alot of people and gotten some great advice however it just didn't make sense. Thanks t all who reply!

Any facts and or links you can post here will be appreciated by me as well as many others!

I am unfamiliar w/ push-in fittings. But generaly for your example: 3/8" is the OD of the barbed end (or whatever end it has). And the 1/4" is the ID of the threaded end.

I am using 5/8" (OD of barb) X 1/2" (ID of threaded end). The ID of the barbed end is just under 1/2". And the OD of the threaded end is about 3/4". (I will be streaching 1/2" ID tubing over 5/8" so it dosn't restrict flow.)

If you using 3/8" tubing, use 3/8" MNPT (so it won't restrict flow). 3/8" wil be fine for the other end as long as the walls aren't too thick. If they are the ID might end up being 1/4", and you should see if you can streach your tubing over something bigger. Just remember the first measurement is for the OD.

I have no idea if this answers your question(s). So I kinda covered some of everthing. But it was hard to pin-point what your actual questions was. I think it was what does 1/4" MNPT refer to. But maybe I'm wrong.

If you worried about threading, I would just wait till you have the fittings to find out. Mine have 14 threads per inch. Uhh.. yeah I'll stop typing.

Thanks DeathONator,

Sorry if the question seems confusing. My actual question was does the second measurement (MNPT) represent the barbs O.D. or I.D. or does the it represent how deep the the bard can be screwed in. Hope this clarifies all questions.

BTW I replied to your pm, slyy.

Mike,

No disrespect on your input. Infact the comment wasn't even meant to be rude. I had spoken with numerous people before you who were giving me info that didn't even come close to making sense. Your reply was helpful but it still didn't quite answer my question.

Ok,

I think I have even managed to confuse myself the way i worded my first post. All I need to know is what does the MNPT represent. Is it how deep the threads on a fitting or barb will go or does it have to do with the diameter of the barb end threads. Hope this clears things up a bit!

The dimention before MNPT is the inside diameter of the threaded end. The letters MNPT just basically let you know it is the male end.

Thanks for all the replies,

Death your the man. Through all my confusion you figured it all out and finally I got the answer I've been looking for!!!

Thanks again.