Pneumatic Valves and Fittings: More Complicated Than You Might Expect

Today we're taking a closer look at pneumatic valves and fittings. We'll look at different configurations of pneumatic solenoid valves, show how to read valve diagrams, talk about different pneumatic fitting threads, and show how to connect a double-acting cylinder.
Some of the stuff in this video:
*This site contains affiliate links for which I may be compensated
Knipex Pliers Wrench 3-Piece Set (Amazon*): amzn.to/2ruzS8m
Rigol DP832 Triple-Output Power Supply (Amazon*): amzn.to/2FHtSfz
5-Way 2-Position 24V Pneumatic Solenoid Valve (Amazon*): amzn.to/2tQE3ft
1/8" NPT Push-To-Connect Air Fittings (Amazon*): amzn.to/2sLPNj4
1/4" NPT Push-To-Connect Air Fittings (Amazon*): amzn.to/3aARctQ
California Air Tools Ultra Quiet 2HP Compressor (Amazon*): amzn.to/2TQ926q

[@davidpenley6828]

Yes, the wonderful thing about standards is that there are SO MANY OF THEM!!

[@ColtaineCrows]

Just need to add one more to unify them all... Then we have one more.

[@brynyard]

Doesn't help one country clutching to it's ancient measurement units "because freedom".

[@SlamminGraham]

@@brynyard Most scientists, engineers, and industrialists can use both and have tools to do so. It's not us, it's the State.

[@brynyard]

SlamminGraham Not quite, most scientists, industrialists and other professionals just use metric, even in the US. Quite simply because thats the most sensible choice.

[@trondgjeruldsen4291]

Great video as always, thanks from Norway 😀😀

[@bobuk5722]

Hi James. I stand corrected! I was one who (nicely!) said BSPT would not fit into NPTS. Well done with the Fusion model, difficult to argue with that. BobUK

[@xenonram]

Just because they fit, doesn't mean they're made for one another. BSPP will fit NPS because they're both parallel fittings that aren't tapered. The ½" and ¾" both have the same tpi, but other aspects aren't the same. The BSPP/BSPT thread form is 55° Whitworth, and NPT/NPS is standard 60°. They are different for a reason, but you can get them to seal in a pinch.

[@dazaspc]

Exhaust port silencers also serve another purpose and that is to isolate the valve spool from debris. The first valve you showed the drawing for was a mismatch. The drawing was for a Direct Acting valve where the coil acts directly on the valve spool. Often used in low pressure situations and/or situations where a venting of the air/gas/fluid is un desirable. Think a propane/water valve. A suggestion for your spindle project. It appears like you intend to use a 5/2 spring return for the knockout draw bar control. This can cause problems with a tool change if there is an interruption of valve control. this can end with tools being retained in the spindle and damage to tool holders and change gear. At the very least a 5/2 memory valve will hold position until commanded. Ideal for knockout/draw bar applications. This will require a second output to drive the additional coil but in operation will prove it's worth. I would also suggest a Quick exhaust valve be fitted to the return side of the knockout cylinder to allow it to move as quickly as possible when compressing the springs on the draw bar to release the tool from the spindle. These are usually drawn as an OR valve with an attached silencer but not always. In certain markets there are particular definitions of stop states of machinery and occasionally they would require a 5/3 spring center valve or even a 5/3 spring center detent valve used instead depending on machinery state or how the regulation/guideline is written. Not really relevant for a home shop though. Another tip if you use a valve for an air blast in the spindle also use a QEV to prevent valve spool contamination. This is also good practice for coolant/air mixing for spray coolant. Cheers

[@transmitterguy478]

They need to be color coded or some kind of symbol. Threads and fittings are a pain!

[@pravado81]

Thank God you're back. I was having separation anxiety attacks.

[@briturner11]

Fantastic video. Something I appreciated was that you got right into the content. This video is 31 minutes long with 30 minutes of useful information.

[@MyMiniHomeWorkshop]

I had a company in Australia making Brass fittings, there is more to BSP than you may think, Bspp - for free running nuts on Parallel threads, Bsppl - slightly undersized thread for female threaded fittings meant to accept Bspt male threads, Bspt for - male tapered threads

[@shadecreeper1027]

thank you for that video, I'm taking an engineering class and I'm prototyping with a pneumatic cylinder. The cylinder fittings have been so confusing, and when I finally ordered it, I remembered in a video by Fright Props that he used a pressure regulator thing. This video cleared up so much.

[@MrPatdeeee]

Great instruction of something that is usually frustrated; when working with these fittings. Thank you so much James. You cleared up a lot when it comes to pneumatic fittings. However, and with NO disrespect at all intended; one NEEDS to understand that there is a "manual" control of these solenoids too. IE: 1. A little colored button can be turned (for air direction) and "pushed" in, to momentarily control air direction. 2. The manufactures ship the electrical connection installed inward of the valve, to protect it and shorten the length of the box. Thus the electrical fitting needs to be re-installed outward of the valve when used; so the electrical connection does not interfere with the button and/or the air fittings. For whatever its worth. Again, no disrespect. You are a genius and helluva an instructor.

[@shaunybonny688]

I appreciate the minutiae of something that can tend to be overlooked and simplified. Thanks

[@mrmiz2547]

Thanks for the follow up! Especially because your doing this all for us and it only slows you down to do a follow up.

[@chiparooo]

Welcome back! Very comprehensive explanation. The mufflers also keep from pulling particulate into the spool and jamming up the valve. Thanks for sharing!

[@haywardhaunter2620]

I just spent two days learning all about fittings for pneumatic solenoids and learning to read the schematic diagrams of these valves. If I had found this video, I could have done all that in half an hour. Thanks!

[@sachinmacwan2780]

You're the MAN for a junior mechanical designer like me! Thank you!!

[@BOBB1947]

I was confused by the tapered-parallel mix up on a Chinese air compressor. Drove me crazy. I really appreciate your timely and very good explanation.

[@squelchstuff]

Welcome back James. Don'tcha just love standards... you know, the different ones that are almost compatible, but never are? Glad to see you again, and please keep on doing what you do.

[@LambertZero]

To add insult to injury, 1/2"NPT and 1/2"BSPP have the same 14TPI pitch so you can't use a thread pitch gauge to quickly distinguish between the two. :-) Fun!

[@xenonram]

That is one of the easiest to distinguish between. BSPP is a parallel thread, and doesn't taper like an NPT thread. You can just lib at them and see they're different. The NPT vs BSP (BSPT) are hard to differentiate; since they're both tapered. Also, NPS vs BSPP are hard to differentiate because they're both parallel.

[@mickyt87]

Quick tip, that blue button on the valves let’s manually actuate the valves without the solenoid. Extremely helpful when troubleshooting pneumatic systems.

[@dasworkshop4967]

As a career EE, I find the electro-mechanical valve schematics possibly the least intuitive of all industry.

[@Paddington2000]

Me too.

[@Factory400]

I will second that.

[@chrisw1462]

Amen!

[@frijoli9579]

lol, EE's....

[@Sevalecan]

EE here too, not sure how much that matters... 😂 . Hydraulic schematics from what I recall are pretty similar to this. Of course once he started talking about it it took me a minute to remember that each block is a different state.

[@FailureIsOptional]

I'm thrilled you decided to post again. Especially this topic. Great to have you back so soon!

[@peterciurea7771]

the main problem i see in air fitting complaints is usually around the taper vs parallel. Parallel requires an o -ring and most users seem to assume a taper and just use teflon tape. That is where the problem comes in. Teflon can accidentally seal a parallel thread, but really it should be sealed by an o-ring and a machined face. The NPT fitting has no o-ring, nor a smooth face to accept an added o-ring. Eventually, it starts to leak.

[@willofscott4611]

Excellent explanation, This makes sense now, having things that have been confusing for so many years, and never really taking the time to get educated on it, your video has educated me in less time then imagined it would take, and the knowledge seems thorough. Thank you

[@ThAtGuY-u9d]

I’m glad you always seem to be working on something that relates to something I’m working on at the moment too. I like how you really get into the technicalities. Thanks for the videos!

[@secondplace]

Good video. I'm trying to part together a tool that I bought from a supplier that went out of business. I got most of the parts and this is helping me put to gather the rest.

[@rbyt2010]

James, I _really_ appreciate the thorough treatment you give your topics. I sure could have used this a year ago when I installed my ATC spindle :-)

[@carlthor91]

Thank you for furthering my education in pneumatics. Cheers

[@junjiecarl6124]

I'm the factory who supplying these air valves and fitting,so I have more experience.Currently we supply all air fittings to US market is NPT thread and UK AUSTRAILIA market IN BSP thread.But we make most valves ports in parallel female,because usually 80% of the customers can't choose a correct fitting type,they just using what they bought and screw in the valve ports.A tapered thread can use onto a paralle female thread if you can accept a bit of leakage but the valves would work normally. Some strict customer will mention thread type when ordering,but if they don't have special requirement,we will make all female threads Parallel.

[@Clough42]

That's disappointing. If I understand correctly, you're saying that most people don't know how to specify what they need, so in response you use defaults that will fit together, but won't seal properly?

[@stevenafful7377]

Good work James, you have cleared a lot of confusing for me in pneumatics, thanks a lot..

[@stanervin6108]

Might I add that metered ports are a godsend for actuated piston seal, o-ring, and internal 'bumper'/cushion long life.

[@sparky201]

I finally understand air solenoids, thanks

[@cjtroutt8092]

Thank you James for the Video and yes I have found in the past of the different configurations of pipe thread and hyd fitting e.g. ISO or SAE or Sometimes proprietary threads. Keep up with the Gread work here on KZbin channel.

[@scrout]

Good stuff, I am sure you just saved 1000 future headaches !

[@slypig24]

We also used variable exhaust valves, to slow the speed of vale movement, to make it less violent. And think about running your exhaust valves to outside of the enclosure, so it doesn't leave oil from air, inside enclosures, or pressurise inside of enclosure.

[@xenonram]

There aren't any machines that are air tight. (Definitely not air tight enough where venting pressurized air would be of any concern.)

[@frogdavw9699]

Welcome back, missed your KZbin presence , nice video, thanks.

[@tomk2471]

We’ll explained, thank you for all the time spent making and editing this video!

[@notsonominal]

Great to see you back at it, looking forward to the rest of the ATC spindle project.

[@Engineerd3d]

Thank you for covering this. Will store the info for later usage.

[@ElectraFlarefire]

Most of this I knew. The rendering of the tapered British in in american strait hole was really interesting to see just how perfectly they nearly fit.

[@fladder1]

Perfect timing! Welcome back!

[@greybeard3759]

Excellent! I was confident they were G-type fittings but my confidence was ill placed so thanks for the tutorial! Looking forward to the rest of the project.

[@alexforget]

Canadian here, you convince me to build it all in metric like 94.7% of the world’s population.

[@Clough42]

You seem smart. I'm confident if you lived in a place where everything in the local hardware store is imperial and everything metric is special-order and three times as expensive, you could figure it out.

[@lbadten]

First video of yours that I've watched. Subscribed afterwards. Thank you for sharing your time, knowledge and experience in such a clear and concise video. Simply excellent.

[@wirosk2916]

In an application where you might have quite longer connection lines the "mufflers" does make a bit more sense, since there will be a greater volume of air that has to depressurise/flow through the exhaust ports.

[@SuicideNeil]

I like it when the retailers only say 1/8" or 1/4", no other info; you get good at feeling out which actual type it is after a while, a bit like eye-balling Allen-key sizes.

[@Joe_Galaska]

Thank you for your presentation. I enjoyed it and learned from your comments.

[@argonman1]

How can it be called a "standard" when there are so many of them and lots of ways to get it wrong?!! LOL! Great job explaining this confusing topic, super high quality production as always!!

[@hansdietrich83]

A standard only means, that something is officially defined. Not that it should be a simple system

[@sstorholm]

BSP was also defined as the DIN standard at some point, and when ISO came along they also standardized on BSP. So today BSP is the standard “metric” pipe thread. There are also metric pipe threads defined by M and the dimension in mm, so M24 for a 24 mm thread, but they are extremely rare (usually only seen as the nut thread on some oddball compression fittings for pipe work, where they for some reason chose something different than BSPP).

[@jothain]

It's actually really common to see M5 pilot air connection in otherwise inch fittings in European sold pneumaticvalves

[@tverspeelt]

Metric threads are used a lot with hydraulic fittings with compression or conical seal.

[@davidrichardson376]

Great explanation James, as usual. My dream is that in a generation or so, the world will be using ISO standard fittings for everything and that the need for learning this kind of stuff will be history.

[@jamesmauer7398]

Great information on the valves. The fusion360 model was a nice illustration!

[@3dmakerzone75]

Thanks for another very informative video. Over a year ago I was trying to put a valve on my air compressor and couldn't get it to seal well. I finally gave up and it has a small leak still. No I'm going to go back and verify what kind of fittings and threads I have.

[@subuser9627]

Good to know, I keep it to metrics. I like the Knipex Pliers Wrench.

[@HanstheTraffer]

Until recently, Factories, ships, even nuclear reactors were regulated with pneumatic systems. When one studied "Instrumentation and Control technology" You studied pneumatic control systems. And yes it can get VERY complicated.

[@Th3Su8]

The reason only one side of the diagram is labeled is to show its "normal" state, the position in which the valve is in with no external forces. In the case of your valves it shows the state where the solenoid is in the off state and the spring is pressed against the spool.

[@dholzric1]

thanks. great info. I could have used it a few years ago when I was converting my machine

[@johnspathonis1078]

Great video. There should be more like this. May I add a few comments that may help your viewers. All circuits ( pneumatic and hydraulic) should be drawn in the deactivated state with no electric, hydraulic or pneumatic power applied. Adding the hoses to your diagrams would help greatly and be less confusing to some. BSP is often referred to as G (gas). The term Teflon tape should not be used. The word Teflon is a trade name of the DuPont Company. It should be referred to as PTFE (polytetrafluoroethylene). You would not want to get sued by DuPont. Also hydraulic circuits and pneumatic circuits can look almost identical. Can you point out how to differentiate the two as pneumatic and hydraulics can be used in the same circuit. Cheers.

[@johnmiddleditch3656]

Excellent, tapered thread in a tapered hole :-) A well made and superb training video, thank you.

[@jasonh3109]

Wow!!! Such a great introduction to the topic! I’ve always wanted a simple breakdown like this, but still so rich with info. Woo hoo. Thank you Sir!!

[@x_ph1l]

Very helpful explanation, thank you! That shed light on many things about threads for me.

[@jaimeandrade9973]

Estoy maravillado con sus videos y ,me asombra su capacidad en multiples areas (Diseño, Electricidad, electronica, metalmecanica, CNC, neumatica y quien sabe cuantas mas) Felicitaciones.

[@Know-Way]

Thanks for the video! Your content and production is top notch. I always enjoy watching your videos.

[@pavankumarpaila8848]

Very nice And very very interested Good job sir ...🤝🤝🤝 Thanks for the teaching

[@andrewwilgress4100]

All your videos, Well done.

[@chrisj4570g]

Glad to see you back. 👍

[@luis0mlg871]

Thanks for the great video!!! God bless you

[@darren92redrum67]

U can definitely mix bsp with np threads, I am in UK alot of air tools are made for American Market and are 1/4" NPT female. The quick fittings I use are euro style, I don't think it's possible to get euro style quick fittings with np threads.

[@Neptune730]

Yes, The "P" port needs to go OUT. LOL Sorry couldn't resist. Love the vids James. Keep them coming.

[@albertlee638]

Excellent tutorial! Please keep it coming.

[@brukernavnfettsjit]

This video is a real skill builder, THANK YOU! Well laid out- lit and shot and very thorough. This is a great starting point and opens new doors in the world of mechanics and electronics for me. How did you shoot this between the two cameras and the audio? It's very seamless and nice. Did you have two cameras running at the same time, and one of them on your chest or something?

[@Clough42]

I generally roll three or four cameras simultaneously I shot this particular video with two GoPro cameras, one on each side, and a Sony a7iii overhead with a 90mm macro lens, pointing straight down. Audio comes from a Sennheiser wireless lav and is recorded on a Zoom H4n audio recorder. Everything is synchronized and edited together in post, with color correction to match the cameras and basic dynamic compression to smooth out the audio. Sometimes it's just simple cutting between angles, but sometimes I end up overlapping audio and video out of sequence when it makes things clearer.

[@metricdeep8856]

Teflon is a lubricant not a sealant. Teflon tape reduces the friction and therefore heat while (tapered) fittings are driven together. I do agree that it will prevent low pressure leaks if you overwrap fittings to fill the unsealed space.....but that's a hack job.

[@Tracks777]

awesome video

[@Tracks777]

amazing content

[@Paddington2000]

Well I didn't see the first video but this was interesting and very helpful. Thank's.

[@nikhilpmankar]

Nice and clear explanation. I am subscribing to your channel

[@ChristopherGoggans]

Thanks for the fantastic video and thorough explanation!

[@EverettsWorkshop]

The crazy thing is that the 1/8-27 NPT will almost go into a 1/8-28 BSP hole, but will screw up the threads. When I worked at a Chrysler dealer there were issues with techs using the wrong oil pressure gauge fittings during testing on some of the internationally-designed engines and damaging cylinder heads in the process. Thankfully I was not one of them.

[@EyeMWing]

Re: mismatched threads. Yeah, that happens. It's always counterintuitive and surprising. Lets talk about automotive brake line fittings. You've got the line size, which is both imperial and metric - the two are essentially cross compatible, you can essentially only buy imperial in the US and metric in the rest of the world. It's fine, because the lines get flared and the flares are standardized (well, there are two standards, but that's another thing entirely). The *fittings* on the end also come in both imperial and metric. For awhile during the changeover to metric in the US auto industry (so, the entirety of the 80's, 90's, and well into the 00's for some parts on some cars), it was not uncommon for this to cause situations where the component on one end of a line took a metric thread, and the other end took an imperial thread. Cool and good. So you can have a 3/8ths brake line with a 3/8ths fitting at one end, and a 10mm at the other. And then lets say you're replacing that line and don't carefully check both fittings and decide it's 3/8ths at both ends. The 3/8ths fitting will *absolutely* thread into the 10mm end. It will even tighten up a little. It will *never* tighten enough to actually seal the flare properly - in an absolutely safety-critical application.

[@MegaAndroyd]

I always thought npt stood for national pipe thread and not tapered. Now I know. Thanks!

[@perspectivex]

I think you were right before en.wikipedia.org/wiki/National_pipe_thread, www.usplastic.com/knowledgebase/article.aspx?contentkey=998, but NPT is anyway tapered.

[@dicelabiblia7461]

Great video, thank you so much

[@sbirdranch]

....And he smacks the trolls down hard! Bam! People driving a couch. Just ignore them.

[@keithmonarch447]

Hello James. This video is dated 2yrs. Yep Keith from Michigan and I worked with valve logic systems. My gosh I hated to have to trouble shoot them. Versus electrical controls. As making a service call. The very first question I asked (I was darn frank) Why did you move ANY pneumatic tubing from its original location????

[@donmittlestaedt1117]

Thanks James. Well explained.

[@paultrgnp]

Hey James great to see you back. I am glad you decided to "take the bull by the horns" on this matter as we are all better informed by you doing so. Incidentally, are you an Aluminium or Aluminum sort of guy, not to mention Magnesium vs Magnesum or Potassum vs Potassium. 😁🍻

[@Clough42]

Sometimes I say 'alubidub' because it makes me feel clever.

[@TAWPTool]

Yet another great video. Thanks for sharing!

[@cyberzoom0]

Thank you!

[@AmateurRedneckWorkshop]

Very informative video and very well done. Thanks.

[@TrPrecisionMachining]

very good video..thanks for your time

[@trentcox5024]

Another great video and very informative

[@bhoiiii]

New subscriber. Great explanation. Thanks for your work and time.

[@20796mayur]

awesome video, thank you 👌👌👍

[@RaymundoGabriel]

Thank you so much!

[@bekindalways7629]

Very important concept thank you

[@charles1379]

keep up the good work

[@russellhayward2359]

Very educational. Thank you 🙂

[@richardclark375]

Good job. Thanks

[@easyboy1950]

Great video

[@bobuk5722]

Hi James. Difficult to judge sound over KZbin but to me it sounded like some of the high frequencies had been supressed, which is a GOOD THING as they can over time damage the ability to hear higher frequency sound. In the extreme (I'm an ex telcom engineer) you can understand what is being said but not recognise who is saying it. Cheers. BobUK.

[@Clough42]

Yeah, the compressor also evens it out some. It definitely takes the sharp edge off the high frequencies.

[@Clough42]

@@SystemsPlanet audio compressor. The biggest difference is that the diffusers cut the high frequencies. The audio compressor then gains up the remaining sounds.

[@pankiltripathi5590]

Thank you! : )

[@cadewey6181]

And NPT will never seal in BSPT. The Japanese, German and Italian machinery fittings will be BSPT. Use teflon tape carefully. If the tape extends beyond the male thread, it can be cut off and will flow downstream and work into downstream devices. At the crane company, hydraulic pump shafts broke due to teflon tape in the bearing area, making them seize up.

[@laframe1016]

Thank you!!!!

[@TylerHarney]

Lets see the connection between the air compressor and the pneumatic hose. Searched all of youtube and can't find the right components to couple my 6mm PU hose to the air compressor.

[@incubatork]

Worthy video to send to "How it works" very understandable. Its a shame they do not use the coloured plastic inserts to denominate the actual size, my Reverse osmosis system for example uses all 1/4" tube but has connectors with 4 different colours to supposedly help instalation.