Air line coupler compatibility

[Jehannum]

I've got a nice new to me compressor, and I'm standardizing to tru-flate type couplers with 3/8" fitting-side to 1/4" NPT tool-side fittings.

It was nice and convenient with the Lowe's T-type 2 male/male, 1 female/male, 1 quick disconnect female fitting pack, but they don't sell the 3/8 to 1/4 male/male adapters in bulk (or by themselves at all).

I went over to Napa to have a look, and found a Type "G" that looks fairly similar by eyeball (and is marked "Automotive" on the packaging, same as the Lowe's package, which indicates a Tru-flate style connector to me), but before I go downtown and buy a bunch of 'em in bulk, I was wondering if anyone knew off hand whether the T and G types were interchangeable or compatible?

I've had a hodgepodge of fittings before, and nothing quite worked right, but now that I've got the 5HP compressor, I want to do it right out of the gate.

Thanks for your help!

 

[Schurkey]

I keep meaning to re-pose this photo to include the Aro "A" style coupler, but I haven't (yet).

For the record, I converted FROM "T" Tru-Flate (Automotive Interchange) TO Milton "V" high-flow, interchangeable with "Euro High-Flow". Note the much-larger air passage in the V-style fitting. Tools using a lot of air flow work better with the V-style fittings. The actual coupler body can be had from many suppliers--mine are Milton, if I were doing it again, I might have gone with Prevost Safety Couplers.

Milton "M" is also known as "Industrial Interchange", and is probably the most popular style.

The NAPA "G" is a 3/8 coupler body, uses different plugs than 1/4" coupler bodies. Far as I can tell, the G is a larger version of the T, both seem to be "Automotive Interchange" style, but in different sizes.

Don't confuse the THREAD size with the BODY size. A 1/4" body might have 1/4" or 3/8 pipe threads on it, male or female.

I think the middle one is equivalent to a NAPA "G".

 

[Jehannum]

For the record, G and T don't interchange (my female quick disconnect wouldn't set the ball bearings in the groove). It was about a $3 lesson to learn.

So, unlike Gin and Tonic, this G&T doesn't go together.

I'm just going to go down to my local hydraulic supplier today and buy a bunch of T-type fittings on their own instead.

It works out well, because I also have to go get a bulkhead fitting for my new sandblast cabinet, and nobody carries bulkhead fittings locally but them anyhow.

 

[Jehannum]

I keep meaning to re-pose this photo to include the Aro "A" style coupler, but I haven't (yet).

For the record, I converted FROM "T" Tru-Flate (Automotive Interchange) TO Milton "V" high-flow, interchangeable with "Euro High-Flow". Note the much-larger air passage in the V-style fitting. Tools using a lot of air flow work better with the V-style fittings. The actual coupler body can be had from many suppliers--mine are Milton, if I were doing it again, I might have gone with Prevost Safety Couplers.

Milton "M" is also known as "Industrial Interchange", and is probably the most popular style.

The NAPA "G" is a 3/8 coupler body, uses different plugs than 1/4" coupler bodies. Far as I can tell, the G is a larger version of the T, both seem to be "Automotive Interchange" style, but in different sizes.

Don't confuse the THREAD size with the BODY size. A 1/4" body might have 1/4" or 3/8 pipe threads on it, male or female.

I think the middle one is equivalent to a NAPA "G".

Thanks!

I'm going 3/8" bodies to 1/4" NPT threads, FWIW. Makes my ancient and puny Craftsman 1/2" impact feel mighty again.

 

[Schurkey]

For the record, G and T don't interchange (my female quick disconnect wouldn't set the ball bearings in the groove). It was about a $3 lesson to learn.

So, unlike Gin and Tonic, this G&T doesn't go together.

I'm just going to go down to my local hydraulic supplier today and buy a bunch of T-type fittings on their own instead.

I'm going 3/8" bodies to 1/4" NPT threads, FWIW. Makes my ancient and puny Craftsman 1/2" impact feel mighty again.

If you have 3/8" bodies, you need G coupler plugs.

If you have 1/4" bodies, you need T coupler plugs.

If the T coupler plugs fit your coupler, you have 1/4"-body couplers. Within the 1/4" world, the V style will give you best air flow and tool power.

 

[ZipSnafu]

Are "V" and "M" interchangeable?

 

[Schurkey]

Are "V" and "M" interchangeable?

No. A "V" plug cannot be crammed into an M coupler. However, an M plug can "sort-of" work with a V coupler. It leaks, but it'll lock in and transmit air.

 

[Jehannum]

If you have 3/8" bodies, you need G coupler plugs.

If you have 1/4" bodies, you need T coupler plugs.

If the T coupler plugs fit your coupler, you have 1/4"-body couplers. Within the 1/4" world, the V style will give you best air flow and tool power.

I have T-marked plugs that have 3/8" bodies.

 

[plinker]

FWIW, Napa does (or did) refer to the I/M couplers & plugs as "type D".

 

[Schurkey]

I have T-marked plugs that have 3/8" bodies.

Unlikely. Far as I know, the T style is uniquely 1/4".

https://www.miltonindustries.com/couplers-and-plugs/t-style/1-4-mnpt-t-style-plug.html

https://www.miltonindustries.com/
click on "COUPLERS & PLUGS" near the upper left corner.

I'm guessing you have a 1/4" female quick-coupler that happens to have 3/8 pipe thread. But it's still a 1/4" coupler, which is why it fits the T coupler plugs.

Is this the part number? https://www.lowes.com/pd/Kobalt-3-8-in-Auto-Coupler-Plug-Kit/3414260
Not a lot of info on-line. The reviews seem to confirm that it's a 3/8 body, not just 3/8 threads, but nowhere does it say that it takes the T style plugs.

FWIW, Napa does (or did) refer to the I/M couplers & plugs as "type D".

Yes. NAPA "D" is a 1/4" Industrial Interchange coupler plug. Milton calls it the "M" style.

https://www.napaonline.com/en/p/NTH90674SS

 

[Jehannum]

Unlikely. Far as I know, the T style is uniquely 1/4".

https://www.miltonindustries.com/couplers-and-plugs/t-style/1-4-mnpt-t-style-plug.html

https://www.miltonindustries.com/
click on "COUPLERS & PLUGS" near the upper left corner.

I'm guessing you have a 1/4" female quick-coupler that happens to have 3/8 pipe thread. But it's still a 1/4" coupler, which is why it fits the T coupler plugs.

Is this the part number? https://www.lowes.com/pd/Kobalt-3-8-in-Auto-Coupler-Plug-Kit/3414260
Not a lot of info on-line. The reviews seem to confirm that it's a 3/8 body, not just 3/8 threads, but nowhere does it say that it takes the T style plugs.


Yes. NAPA "D" is a 1/4" Industrial Interchange coupler plug. Milton calls it the "M" style.

https://www.napaonline.com/en/p/NTH90674SS

You can argue with me if you want, but I've got what I've got. They say "3/8 T" on the side. I can give you a pic if you don't believe me, but what incentive do I have to lie?

I bought a Napa "G" female quick disconnect and it chucks up the 3/8" T's from Lowes with no leaks. So, I went and bought a bunch of G hardware and I'll make do with that.

The upshot is that Napa's male G's (and my local hydraulic shop's amflo CP7s, which Amflo calls "TF" type) don't interchange with Lowes' 3/8" T female disconnect, but the Lowe's 3/8" T male fittings interchange just fine with G-type female disconnects.

 

[Pontiac787]

How much do you guys think the Milton V couplers impede the airflow? I am adding a longer hose to my trusty old 30 gallon oil-less compressor. I'm trying to decide if I should put a coupler onto the output of the built-in regulator or attach the hose directly.

The reason that I'm thinking about putting the coupler first is that it would make it easy to switch between a hose that terminates with a type V coupler and one that terminates in a type M coupler. The downfall would be that this setup would have two couplers on it.

As an alternative I could connect the hose that terminates with the type V coupler directly to the regulator and then use the second hose to go from the type V coupler to a type M.

I guess as a third option I could just go with the type V coupler and live with the residual blow by from using the type M fittings.

 

[Jehannum]

How much do you guys think the Milton V couplers impede the airflow? I am adding a longer hose to my trusty old 30 gallon oil-less compressor. I'm trying to decide if I should put a coupler onto the output of the built-in regulator or attach the hose directly.

The reason that I'm thinking about putting the coupler first is that it would make it easy to switch between a hose that terminates with a type V coupler and one that terminates in a type M coupler. The downfall would be that this setup would have two couplers on it.

As an alternative I could connect the hose that terminates with the type V coupler directly to the regulator and then use the second hose to go from the type V coupler to a type M.

I guess as a third option I could just go with the type V coupler and live with the residual blow by from using the type M fittings.

I will always add a coupler between the compressor and any flexible line. That way, if the line fails, you'll have less time between it starting to flail around the work area and when you get it off the air supply.

 

[hd54kh]

No love for the L type fittings?

Almost all mine are L and I have a few adapters to go to M.

I worked in a body shop in the 70/80s and this is what we used and I just stuck with them.

Now in the new garage I am building I have a 80 6HP 2 stage compressor already purchased and am thinking of revamping my connector inventory.

I do use my old Tip Sandblaster and will be getting a larger bead blast cabinet. They will consume some air.

Also thinking of replacing all my old sparay guns with HVLP type.

Any advice of my best choice for fitting style? From the visual only here the Type V looks to be the highest flow.

Terry

 

[ItsNemo]

No. A "V" plug cannot be crammed into an M coupler. However, an M plug can "sort-of" work with a V coupler. It leaks, but it'll lock in and transmit air.

I primarily use V's on everything but have a few M's that came on tools (mostly nailers and other low volume tools) and haven't had issues with the M fittings in the V couplers.

I noticed a significant difference going from M to V and it's worth the cost. Standardizing on V for everything is the way to go if you're doing it right for the first time. I keep a couple other style fittings around and some short whips if I ever need to worry about adapting to some other sort of air system if my tools go elsewhere and/or someone brings tools over. I really hate disassembling my fittings if I can avoid it.

 

[Lonnies Performance]

I am devising a new layout for my garage...

All my mains are 3/4" & hose reels will be 1/2" hose with "G" series industrial couplers to get enough air for my 1" impact.

For lighter weight & ease of use, I'm making up an adapter to connect normal 3/8" line to these reels for use at the bench or for normal activity.

Just bought a bunch of Prevost Euro series couplers which are "V style" to use on my common equipment.

 

[ed howell]

I changed out all my M style to V style and you can hear the impacts spinning faster.