How to measure NPT Fittings and pipe sizes 

Informative. Thanks. I've always known that NPT measurement was different from other things, like fasteners, etc., but I didn't know exactly why until just now.

just started a job doing compressor service calls. i asked my service manager how to measure pipe threads and he couldn't tell me. thanks man.

Short, sweet, informative, basics.

When I am at the Pearly gates, I was only gonna ask to see the one who invented email to beat up, but now I have to add the one who did the subtract 1/4 inch to the list too ;) Thanks much for the simple and quick lesson.

I've lost my mind on this several times. Thank you.

Excellent straight forward no nonsense professional explanation.

One could fill volumes of what "teachers" don't teach young men who want to be plumbers...Thanks for the informative tutorial!

Master Tool; Thank you, easy to see-hear and understand! Bravo!

Dang good video by a pro's pro. I'm an old man who was taught steam pipe-stuff by WWII guys. Not being too educated I have to use memory tricks. NPT I think of as NOMINAL pipe. Putting the words "pipe" and "tube" next to each other reveals that the 2nd letter "i" means pipe is measured by its INSIDE diameter. And the 2nd letter "u" in tubing is bc it's measured by the "OUTside" diameter. Nominal is an important characteristic because even tho 100% of home owners see is Schedule 40 there are thicker schedules of pipe. Example; 1" Schedule 40 has a nominal inside diameter of 1". A 1" Schedule 80 has a nominal inside diameter of much less. (My Pipefitter's Manual isn't handy.). Another example; when holding a length of 1" pipe the threaded end inside diameter will measure less than its non-threaded end inside diameter. Hence, nominal. Dang good video-this guy is a pro's pro.

Short sweet and too the point, excellent video!

Thank you for so clearly explaining at the beginning of this video the pipe fitting measurements, and how and why typical measurements of diameter and circumference differ from NPT. VERY HELPFUL!

THANK YOU for explaining why the heck NPT sizes are all 1/4 inch off. Unfortunately, even the inside diameter isn't actually very close to the measurement in the name

Perfect. Thank you very much. 1 quick question, what about when it comes to sizing up a high pressure nipple, like when the sidewalls of the nipple are larger? I have a bunch of nipple in the tool room that the measurements are worn off from pipewrench marks. Thanks again.

Thank you, you did a very very good job at explaining that. Good job

Excellent presentation and thank you!

You explained in 4 minutes something that has confused me for many years! lol. Can't thank you enough.

I really appreciate your explanation!

Your the best , thank you for saving me multiple trips to home depo

Thank you for the explanation. As a machinist, I was throughly confused why my “5/8” pipe cap wouldn’t fit lol.. I’m about 1\4 off lol…

This is awesome info. I wish I watched your video before I ordered mine. Lol But at least I know I made the mistake and not the supplier.

Can you identify a SAE fitting just by spotting an O-ring below the threads? Or would you have to determine if it's tapered to decide if it's a SAE fitting?

I have a keg cylinder with 33.5 mm inner thread led, i want remove led and i install convertor like metal water pipe , which size thread should I choose ? Its make me sick to think about it ;)

Finally! Thanks for this.

hi there, Im changing out a little section in my water pipe installationz 1inch pipe.. how to join two pipes if they can not move. both sides threaded and they can touch when i finish. how to connect them. thinking about making a longer thread and move over the coupling all way then just move coupling over to the other one when i finish the rebuild..

Great video, just wondering why you always subtract a 1/4 inch on almost all the fittings

Okay, let me see if I have this right... I have a 1/8" o.d. tube that I need to connect to a male thread that measures about 3/8. I've found a push connector that fits 1/8" o.d. tube to 1/8" NPT female thread. So the connector will work, right?

BSP pipe also comes tapered, like NPT. And some conduits have a different taper and some straight an some the same taper as NPT. Pipes 2" and larger have almost exactly the same size inside diameter as the nominal pipe size for SCH 40. Taking a quarter inch off the OD of a 1.5" pipe will yield 1-3/4". The rule of thumb won't work there. The rule of thumb here ONLY works for little pipes, then doesn't work for 1.5, does work almost for 2, 2.5, doesn't work again for 3 and gets worse and worse bigger than that. Best to use the chart, look it up or find someone that knows. I frequently ask for second opinion when 'eyeballing' threaded pipes and I have been doing it for 35 years....usually the 1.25 and 1.5 sizes are mis-estimated--especially when they are up high and can't be inspected closely. For 2" versus 2.5 ", the thread pitch gives it away....2" is the biggest with 'fine looking (11.5 tpi)' threads and 2.5 is coarse like 3, 3.5, 4, 5-inch and all the larger pipes up to giant sizes (8 tpi).

for smaller pipe fittings, do you you subtract 1/8" from the inside measurement rather than 1/4"?

Awesome bro

What is the paper/plastic size chart guide you have on our workbench? looked for it using the words "pipe size chart" and nothing came up. Great video. Thanks!

Well done!

Very informative

Great break down 5 star ⭐⭐⭐⭐⭐

thank you sir for sharing that knowledge is really awesome!.

Thank you

Can I use my measuring tape for this ?

What if the g.i pipes don't have thread because you just cut it?

National pipe taper

Try this theory with sched xxs pipe

You were holding a plug, not as you stated, a "cap". Sorry, it's the hydraulic and pneumatic repairman training in me.

That check valve isn’t a 3/4” npt . It’s a 3/4” inverted flared fitting. 😮 Don’t ask me how I know it is. .

There is no good reason that i can find why they dont use Od for male parts like every other industry. We can still determine flow with different schedules it doesn't make any sense to use Id for anything female fittings where the I'd determine the od of the pipe to CV connect. Like oh I have a 1/2 hole in this fitting so let's use a 1/4 pipe yeah that sounds right.

NPT - National Pipe Tapered NPS - National Pipe Straight

Of no use to me. Camera is positioned wrong for what you are trying to show the viewer. All that I can see is your thumb & not exactly where you are positioning the rule, leading to confusion at best. Overhead shot is only way to go. Otherwise your heart is in the right place.