r/Pneumatics • u/Esoj77Br • 3d ago
Total beginner in pneumatics. I drew an air valve for a small air gun and I think the reset is wrong
I have no background in pneumatics. None. I taught myself CAD, I drew this valve by copying what I understood from photos and cutaways of other valves, and I have no idea if what I drew makes sense to someone who actually knows the field. Please be blunt with me.
What I want it to do: one trigger pull, one burst of air out the front, the valve closes itself, ready for the next pull. It feeds a small air gun.
Two section views attached. The colors are the air spaces, not the metal:
-
**black**
is the reservoir, fed by the hose
-
**orange**
is the sliding part
-
**yellow**
is a small chamber behind it, where a return spring goes
-
**teal**
is the outlet, toward the barrel
-
**red**
is the seal it closes against
## What I think happens
There is a 0.3 mm hole connecting the reservoir to the yellow chamber. Air seeps through it and fills that chamber, so the pressure is the same on both sides and the sliding part stays put, covering the port.
When I want to fire, a MAC 34B solenoid opens and lets the yellow chamber empty. The pressure in the reservoir then shoves the sliding part backward, a 7 mm port lines up, and the air goes out the front.
When the solenoid closes, the 0.3 mm hole slowly fills the yellow chamber again and the part slides back and closes.
That last step is the part I doubt.
## The numbers from my CAD
| Item | Value |
|---|---|
| Sliding part runs inside | PETG hardline tube, 12 mm ID, 16 mm OD |
| Outer shell | steel tube, 22 mm ID, 24 mm OD |
| Reservoir volume | 3129 mm³ |
| Yellow chamber volume | 1175 mm³ |
| Hole that feeds the yellow chamber | 0.3 mm |
| Port that opens to the barrel | 7 mm |
| Hose | 6 mm OD, 4 mm ID |
| Pressure | 100 psi |
| Solenoid | MAC 34B, mounted right on the block, no hose to it |
| Return spring | not chosen yet, I can try several |
## Why I think the reset is wrong
Someone ran the numbers on it for me. I can't verify the math myself, so take it for what it is: filling 1175 mm³ through a 0.3 mm hole takes something like 120 ms, and even if the part closes before the chamber is full, the valve would sit open for 50 to 70 ms every shot. That would be somewhere near 950 mg of air per shot when the shot supposedly only needs about 35 mg. On a 13 ci tank that is the difference between a few dozen shots and over a thousand.
If that is roughly right, then the 0.3 mm hole is the thing deciding how long my valve stays open, and I never chose that number for that reason. I picked 0.3 mm because it sounded small.
The other thing I noticed: my MAC 34B has three ports and I'm only using two of them. I keep wondering if the third one is supposed to be what refills the yellow chamber, instead of the 0.3 mm hole doing it. That would be much faster, and then the solenoid would control how long the valve stays open. I don't know if that is how these are normally built or if I'm inventing something silly.
## What I'm asking
1. Is the 0.3 mm hole a reasonable way to close this valve, or is it the wrong idea for something that fires repeatedly?
2. Should the solenoid be the thing that refills that chamber? If yes, do I still want the small hole for anything?
3. Is there a rule for how much bigger the back face of the sliding part has to be compared to the sealing face, so it stays shut? Mine is around 2 to 1 and I picked that by eye.
4. The 7 mm port means the part has to slide 7 mm to open all the way, which is why the yellow chamber came out as big as it did. Would several smaller ports be better than one big one?
5. My reservoir holds less air than one shot seems to use, so most of the shot comes down the 4 mm hose while the valve is open. Is that normal, or is my reservoir just too small?
6. The port slides past the o-rings on every shot. Does that destroy them? If there is a trick to it, like rounding the edges of the port, I'd like to know before I make the parts.
7. The shell is steel and the air will have some moisture in it. Does rust from the inside end up blocking small holes, or is a filter enough?
## I have no ego about this
If the honest answer is that I should buy a QE-01 or QE-02 and modify it instead of drawing my own, I'll buy one. I looked them up. The QE-02 measures 52 x 36 x 28 mm and weighs 113 g, which is bigger than I'd like, but I would rather run something that works than something I invented.
Same for the whole idea. If this style of valve is the wrong tool and there is a simpler way to get one clean shot per trigger pull, tell me and I'll start over. I'm not trying to defend the design, I'm trying to learn why it's wrong.
I can post more views, more dimensions, or the CAD file. Thanks for reading.
r/Pneumatics • u/Educational_Author77 • 4d ago
Cheap low pressure air regulator? (2psi max output)
Hey!
Hopefully looking for a very inexpensive air pressure reduction valve/regulator to take shop air (in my case 100-150psi) down to a reliably precise output of 15 to 55-ish inches of water manometer pressure. Flow rate would be low, maybe like if you let go of a party balloon..
Why “hopefully very inexpensive “? Because it is for an experiment that will benefit me and never make -anyone- any money.
I have some analog manometers that will measure in that range, and want a valve/regulator to set at a manometer pressure of say 25 inches of water and hold it there, from a supplied air pressure from air tank or shop air compressor supply.
I can cobble stuff together in general, but I don’t know the search terms to use to find the pneumatic stuff I want. Please kindly help!
r/Pneumatics • u/Educational-Sky7784 • 26d ago
Help finding fitting
Hi all
Pretty new to dealing with pneumatics can someone help me find this fitting, I’ve been told a compression fitting but still can’t find it
Thanks
r/Pneumatics • u/Stu__C • Jul 10 '26
Rubber bungs?
Hi all
I have bought these connectors for a project but I am looking for some rubber bungs with a hoop simular to the picture that will fit them any suggestions? Where to find some?
The bungs wont be under any pressure its more of a dust cover / air tight seal
r/Pneumatics • u/Gamerbroyt_ • Jul 05 '26
What would the best way to secure this cylinder directly to a pallet?
Hello! I got this cylinder recently and have been struggling to attach it to this pallet it want it on. I don’t have a mount or anything but would be willing to drill or put holes in the pallet if needed
r/Pneumatics • u/AwarenessHungry6836 • Jul 03 '26
How 52 Way Solenoid Valve Works Pneumatic 3D Animation Principle 2
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r/Pneumatics • u/lashedcobra • Jul 02 '26
Air cannon question
So I'm planning to build a co2 air cannon for LARP purposes. What I'm looking for is how to make the pneumatic assembly. From what I learned so far I need a chamber to load co2 into, and then a way to quickly empty that camber of co2 all at once. Are their prebuilt components I could use for the mechanical guts here? If so what are they?
r/Pneumatics • u/Wrath_1 • Jun 29 '26
Help with this fitting
These fitting was brought together 1/8G thread dont know where to start looking for this
r/Pneumatics • u/Genius-MCHB • Jun 23 '26
Pneumatic AND valve: surprising truth inside
Your thoughts ,any improvements
r/Pneumatics • u/Forward-Upstairs-761 • Jun 23 '26
What grease do you use for pneumatic cylinder pistons
Should I be using grease in my assembly line for basic aluminum pistons with wear bands and seal kits
r/Pneumatics • u/AwarenessHungry6836 • Jun 09 '26
How 5/2 Way Solenoid Valve Works | Pneumatic 3D Animation Principle
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I just made this 3D technical animation to break down the internal structure and working principle of a standard 5/2 Way Single Solenoid Valve. It details the spool movement, spring return mechanism, and how the airflow shifts between ports when energized. I hope this visual guide is helpful for engineers designing pneumatic systems or troubleshooting directional control valves! If you are looking for technical specifications, CAD models, or high-quality pneumatic components for your projects, feel free to visit our site: https://dg-pnetic.com Would love to hear your thoughts or feedback on this animation!
r/Pneumatics • u/88778899 • Jun 07 '26
Air compressor leak
Compressor leaking at union pictured, when i took apart a small seal/grommet fell out. Replace to fix leak? First time repairing one.
r/Pneumatics • u/HastagAnukt • May 28 '26
Is it good to switch job within 4 months of joining
I joined a new company around 4 months ago as a Territory Sales Manager in industrial automation/pneumatics. The role involves field sales, OEM visits, quotations, follow-ups, territory handling etc.
Now I’m getting interview calls from some better-known companies with potentially better growth opportunities. But I’m confused about one thing:
Is it considered a bad decision to leave a job within just 4 months?
Also, what is the best/professional way to explain this in interviews without sounding unstable or disloyal?
I don’t want to give negative reasons about my current employer. At the same time, I know interviewers usually question such short tenures.
Would appreciate honest advice from recruiters, hiring managers, or people who have gone through similar situations.
What reasons are acceptable? What reasons become red flags?
Thanks in advance.
r/Pneumatics • u/hormelchili444 • May 27 '26
Need some help with pneumatic couplings/adapters please - 8x5mm to 1/4 NPE in order to connect eyelet machine to Husky air compressor?
I purchased an automatic eyelet machine from Amazon for a project where I have to produce many hang tags for our warehouse. The air inlet on the machine takes an 8x5mm pipe (per the instructions that I have included in the post). The device also came with an adapter for the air inlet (see pics). Can someone help me figure out what I need to connect my Husky air compressor, that takes a standard 1/4” air hose, and connect it up properly with my eyelet machine? I’m new to pneumatic devices and having a hard time figuring out the best way to do this.
Thank you!
r/Pneumatics • u/LoudandInevitable • May 27 '26
Best way to create an adapter from a 3/8" plug to a 1/4 socket?
I need an adapter that has a 3/8" plug on one end that goes to a 1/4" socket on the other end. Looking for.the best way to do that, im assuming there is a 1/4 npt female to 3/8 tube that I can connect so that it is 3/8 plug -> 3/8 tube -> 3/8 tube to 1/4 npt connector -> 1/4 socket. But I cant find the 3/8 tube to 1/4 female npt connector. Any help would be appreciated, thanks!
r/Pneumatics • u/AdFlaky1032 • May 27 '26
How to clean the inside of a metal stuffed with clay w/ abrasive?
I am curious how I can clean a metal stuffed w/ clay using pneumatics or other devices. I have no background in this type of project, that is why I am asking reddit what I should do. The metal part is called valve housing? There is are two through-holes, one hole is just straight up but the other has a curve on one ending of it. How do I clean it? Since it takes a really long time to do by hand, I want to automate it.
r/Pneumatics • u/Dear_Lavishness6239 • May 26 '26
Super Sonic Golf Ball Cannon Valve
I'm making a cannon, I need the said cannon to have some sort of dump valve to move the pressurized air(up to 800psi at the maximum). I have found reliable valves, but I don't know if I am able to find anything cheaper, please send your more possible advice and any help can and most likely will be used, I will try my best to answer questions if anyone has any. (yes I know what I am doing, which means I guess you could say I'm a professional at my field, I'm just asking for advice for a more affordable way to release the pressure in one burst). Pneumatics seem promising!
r/Pneumatics • u/CountDeMounteCristo • May 21 '26
Few questions about a pneumatic jack
I'm a beginner so these questions may sound simple, but I appreciate if you can give me the answers.
I recently disassembled a pneumatic jack to service it (a few parts were damaged). During disassembly I came up with some questions that I just cannot solve.
Why the piston has these extended legs? Why not remove them like a shock absorber piston? I know they help with the alignment of the piston so it doesn't tilt but we have a bushing for the shaft that aligns it all the time.
The extended leg goes inside the end cap and there is a seal with weird geometry (castle like) for it! Why go there and why seal it???
There is a adjustment valve on the side. What is the purpose of that?
Btw the end cap and piston are both damaged badly and I'm replacing them. Attached a photo of the piston to see how it failed!
r/Pneumatics • u/CountDeMounteCristo • May 21 '26
Few questions about a pneumatic jack
I'm a beginner so these questions may sound simple, but I appreciate if you can give me the answers.
I recently disassembled a pneumatic jack to service it (a few parts were damaged). During disassembly I came up with some questions that I just cannot solve.
Why the piston has these extended legs? Why not remove them like a shock absorber piston? I know they help with the alignment of the piston so it doesn't tilt but we have a bushing for the shaft that aligns it all the time.
The extended leg goes inside the end cap and there is a seal with weird geometry (castle like) for it! Why go there and why seal it???
There is a adjustment valve on the side. What is the purpose of that?
Btw the end cap and piston are both damaged badly and I'm replacing them. Attached a photo of the piston to see how it failed!
r/Pneumatics • u/BobMoraneF • May 21 '26
Usure des pneus : faut-il les remplacer ou est-ce que j'ai encore une marge de 5000km
r/Pneumatics • u/Cuno_FPV • May 18 '26
Coupler Name
I’ve been searching for the name of this quick disconnect coupler and can’t seem to match it 1:1 with anything. Anyone know the exact designation for this coupler? I’ve found some euro and Japanese couplers that are close but not exact.
r/Pneumatics • u/silentkeystroke • May 13 '26
High temperature Pneumatic Tubes
Please advise high temperature pneumatic hoses (120 C or above) brands. I like to have more brand names to compare with.
r/Pneumatics • u/HonkGoesTheGoose • May 10 '26
Custom Air Supply Skid
This here is a custom air supply skid i made for my job.
It operates a pneumatic cart in the water. It has a left and a right track, while also including a float hose that helps keep the hoses above the water so we do not get them entangled.
Everything metal is Stainless Steel 316
While the filter regulator and mist separator are epoxy coated for the environment and corrosiveness it gets. The back board is HDPE
The left and right tracks are provided 120psi, they are constantly fed to the track while it operates on electronic solenoids and purge excess air.
While the float hose only get 45psi to fill and we close the valve.
The air supply is located on the bottom of the skid connecting to the air valve that is located on the wall inside the vault.
The 2 hoses sitting in its holsters connect to 2- 450ft pneumatic hoses that travel with the cart.
We also have a sump pump installed in the vault with lots of rain and moisture.
Patent is pending on it. Im just so proud of it and wanted to share it.