Keeping the Confusion Out of NPT Pipe Thread Dimensions

I recently had the pleasure of helping a caller solve a problem with a Super Air Nozzle.  He had measured the opening on the outlet of his air gun, and ordered accordingly…unfortunately, he didn’t know that 3/8 NPT did NOT correspond to a 3/8″ diameter of a threaded fitting.  I explained the reason for this, a while back, in a blog entitled “When Is A Half Inch Not A Half Inch? When It’s Half Inch Pipe, Of Course!

The ID of a 1/8 NPT threaded fitting is actually pretty close to 3/8". Here's a dimensions table that I reference often.
The ID of a 1/8 NPT threaded fitting is actually pretty close to 3/8″ (left.) Here’s a link to a dimensions table that I reference often to keep this (on right, a 3/8 NPT nozzle with an 1/8 NPT air gun) from happening.

 

As you can see, the Model 1105 3/8 NPT Super Air Nozzle will not fit the 0.405″ (not far at all from 3/8″ if measured with a ruler) ID of a 1/8 NPT threaded connection.  No matter; these are all catalog parts that we have plenty of stock on, so, after a brief discussion of pipe thread sizes, he got a Model 1103 1/8 NPT Super Air Nozzle, and it fits just fine:

IMG_5789
Model 1103 1/8 NPT (male) Super Air Nozzle installed in a 1/8″ NPT air gun.

Sometimes, an adapter is required for air guns that have straight threads.  Two common sizes for these are 5/8″-28 and 3/4″-32 – and we have adapters for both of these (call for details.) Other adapters are readily commercially available…you may find them in the plumbing aisle of your hardware store, or from a local pipe & pipe fitting supplier.  We’ve seen some air guns, though, that have a proprietary thread that doesn’t match up to anything else…in these cases, we have four types of Safety Air Guns on the shelf, ready to ship.

If you’d like to find out more about using quiet and efficient engineered Super Air Nozzles for your air gun applications, give me a call.

Russ Bowman
Application Engineer
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Not All Quick Disconnects Are Equal

Quick disconnect pneumatic fittings have been a staple in any manufacturing facility I have ever visited in my 10+ years as part of the manufacturing world.   The fact is, they have been around for a lot longer than 10 years.   The style we see most often is the 1/4″ Quick Disconnect Fitting, and we are typically troubleshooting a lack of air volume problem because they are not sized properly for the application.  These can be found in any industrial supply companies catalog, your local hardware stores, and even auto parts stores.   Quick Disconnects are even sold with certain EXAIR Industrial Housekeeping products, the key being they are properly sized.

Properly sizing the quick disconnect is a critical step in the process of deciding how to lay out your piping system as well as how to ensure products operate at optimal performance.  As you can see in the picture above, the two quick disconnects on the left are both larger quick disconnects as well as larger NPT thread sizes.   The two on the right are smaller and probably a bit more common to see.  Also notice the thread sizes on each, these are also manufactured in many other NPT thread options.   The through hole on the quick disconnects is decided by the size of the QD, not the thread size on the other end.   The example I am illustrating is comparing the 3/8 NPT and 1/4 NPT quick disconnects: Even though you can have 3/8 NPT threads, your throat diameter of the QD is still restricted to .195″ I.D., the same as the 1/4 NPT.  This can be a large restriction on a product with a 3/8 NPT thread size.

The Inner Diameters of the Quick Disconnects

Also to be noted is that all QD’s of the same size are not made equally, tests have shown that you can lose as much as 20 psi through a quick disconnect and up to 40 psi when not properly matched with the female QD.   This leads to the next step which is to ensure that you are not purchasing a QD on appearance.  MAke sure to choose the QD designed to permit the amount of air you need to operate your point of use product without a volume or pressure loss.

These two points are reasons why quick disconnects can diminish your point of use compressed air product performance.  If you have questions on which size to use with your EXAIR product or need help determining why your point of use product is not performing how you would like, contact us.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

 

EXAIR Now Offers Swivel Fittings Up To 1″ NPT!

Fresh off the production floor is our newly designed 1″ NPT Swivel fitting, model 9204.  This swivel fitting, much like the rest of our swivel offering is, constructed of 303 Stainless Steel, both male and female threads, 25° of adjustment from center line which makes for a total of 50° for adjustment.

 

Model : 9204 1" NPT Swivel
Model : 9204 1″ NPT Swivel

This makes the eighth swivel fitting that has been released from EXAIR.  We now offer swivels that have M4 x 0.5mm thread up to a 1″ NPT thread.   A total of 61 different nozzles from EXAIR can be combined with the swivel fittings we offer to give adjust-ability when installing a Super Air Nozzle into a tight place or within an application that requires slight adjustments to the aiming of the nozzle.

EXAIR's Swivel Fitting Family
EXAIR’s Swivel Fitting Family

If you have any questions on which swivel fitting will best suit your application, or which of the 61 different nozzles should be installed onto a swivel for your application, let us know.

Brian Farno
Application Engineer Manager
BrianFarno@EXAIR.com
@EXAIR_BF

 

Quick Disconnects & Why Not To Use Them

Quick Disconnects are a quick and easy solution to hook up devices to your compressed air system.  These units can be found in quite a few factories and are more often than not being used incorrectly.  I know that on the air compressor in my garage, the only way to hook anything up to it was to use 1/4″ quick disconnects.  Chances are they are even a few of them within your facility, assuming you have compressed air available.

1/4" Quick Disconnect male and female.
1/4″ Quick Disconnect male and female.

When you really look at a quick disconnect though you start to see why it shouldn’t be used to install every compressed air driven device there is.   You can see in the pictures below that a 1/4″ quick disconnect that goes to a 3/8″ NPT adapter has a .192″ opening at the small end.  A 3/8″ Schedule 40 iron pipe will actually carry a .493″ inner diameter.   If you were to use this quick disconnect on something like a 2″ Heavy Duty Line Vac, you will starve it for air due to the limited ability of the small diameter to carry enough air volume. This, in turn, will limit the performance of the Line Vac.  This is because the through hole on the quick disconnect cannot pass enough air to feed through to the Line Vac.

Inner Diameter of 1/4" quick disconnect.
Inner Diameter of 1/4″ quick disconnect.

On the 1/4″ quick disconnect to a 3/8″ NPT this may not be as large as a problem as the next picture.  Below you can see a 1/2″ quick disconnect that is going up to a 3/4″ NPT.  a 3/4″NPT Schedule 40 iron pipe is actually a .824″ inner diameter.  The quick disconnect at most has a .401″ inner diameter.

IMG_4614
1/2″ quick disconnects

 

Inner diameter of 1/2" quick disconnect.
Inner diameter of 1/2″ quick disconnect.

Even though you are providing the correct thread size for your connection (a 3/8 MNPT and a 3/4 FNPT respectively in our example) the quick disconnect’s small inside diameter could be too much of a restriction for the volume demanded by an end use product. Due to this restriction point you will see pressure drops in your system when using a device with a properly sized inlet for its demand of compressed air being fed with an improperly sized quick disconnect.  This is one of the main reasons one of our first questions in troubleshooting an EXAIR products performance with a customer is whether or not they are using quick disconnects.

If you would like to learn more about how to properly plumb your EXAIR Intelligent Compressed Air Product, feel free to contact us, or take a look around our Knowledge Base.

Brian Farno
Application Engineer
BrianFarno@EXAIR.com
@EXAIR_BF

 

 

 

Just My Size

So, I was spending some daddy/son time with my 5 year old this past weekend, (5 and a HALF if you ask him), when he asked me about my new job and what kind of “stuff” I helped our customers with. So we got on our tablet and I showed him our website, EXAIR.com. I decided to start off with our Super Air Nozzles because I thought he might be able to relate a little after seeing me use my portable compressor to blow off my workbench, sawdust, etc. in our garage.

As we scrolled through the section we came upon our Atto Super Air Nozzles. Well, that was the ONE for him! He was so excited that we had nozzles that were, per his words, “just my size” and he wanted to know when I was going to bring him one home.

Of course, as with most children, I could see his wheels turning as he was trying to come up with ways that he could use these to push his cars around or blow the dirt out of his Power Wheels dune buggy or maybe just blow some air at our dog, you know, just for fun. (By no means would I condone this behavior.)

Boxer

Since we offer the Atto Super Air Nozzle in both 316SS and PEEK material, I asked him which one he thought he would want…… BIG decision for a 5 year old! (Well, 5 and a HALF). Of course the answer was, “just get me both daddy because they are little, just my size”.

1108SS

Take a look at our extensive Super Air Nozzle selection.  The fact is that we fit any “size” from 4x.05 metric to 1-1/4″ NPT and almost every size in between, as well as multiple material options.   No matter what your applications size, or environment, chances are we will have a Super Air Nozzle that will fit it, if not then we have twelve other product lines that might just fit the need.  Feel free to check the website, EXAIR.com, and check out our Super Air Nozzles. I can guarantee there will be something to fit your application, or “just your size”, if not we’ll take it back under our 30 day guarantee.

Nozzle Lineup

Justin Nicholl
Application Engineer
justinnicholl@EXAIR.com
@EXAIR_JN