I posted some time ago showcasing a high pressure 'Toolie' style valve I built out of stainless steel. This is the progression of that project. I'm sorry for making a new post, but I figured it'd be easier than modifying my old one. Feel free to move this if needed.
shown below is the valve assembly. The valve is composed of a hammer-needle style valve which actuates the Toolie piston. In total, I'd estimate around 2.5in^3. This was build mostly out of 303 Stainless on my lathe. The sealing faces in the picture are made of brass, which worked great for about 30 shots, but then became problematic (likely due to dust/contaminants). I rebuild the sealing faces out of Delrin, which has worked consistently.
Below you can see the rear of the pin from the hammer-valve.
Below shows the business end of the valve
Here is the gun as it currently sits. All black portions (aside from handle) are 3d printed with Pla Tough. The handle is from an old paintball gun I had, with the sear extended to reach my hammer and re-hardened. The barrel bushings are turned out of Delrin.
Below shows the Barrel in the locked position, and in the Loading position
Below shows the hammer which is mounted in the lower tube of the rifle. I wanted to have as long of a barrel as possible, and didn't want the air to have to work its' way around corners, so this configuration seemed the best. The top piece of steel is what actually makes contact with the pin on the hammer-valve. This was measured to just barely open the valve to its' maximum depth without smashing it into the Piston on the other side. The lower portion of these pictures show the hammers larger mass, as well as the face that presses against the sear.
Below shows the Rifle in the 'Uncocked' position, further shows it in the 'Cocked" position
Below shows the current fill-port. This is a one way valve, so the rifle can be pressurized, then the pump/source removed. The elbow on the opposite side is the exhaust port for the valve.
Inside of the stock is a 1/2" threaded rod that I smoothed down to act as a guide for the main spring
Here is the primary ammunition I shoot. 3d printed Sabot, with a spherical opening in the top for a 1/2" ball bearing to be glued in. Extremely cheap for what it is. Note the rear end has a small protrusion. This protrusion fits as closely to the valve face as possible, to avoid dead space.
Obviously this rifle is not finished yet, but here's where it's at so far. I have yet to hydro-test this valve, so I haven't pushed the system past 1700PSI. Burst calculations show that the materials should be able to handle up to 12000psi, so my eventual use of 4500psi should be safe (once again, pending hydrotesting to a higher level).
At 1700Psi, a very lightweight 3d printed projectile will break the sound barrier (I'm still not completely clear on how an expanding wave of pressure can propel an object faster than that mediums' speed of sound, but it does), and the steel-bearing round will run at something just shy of 800fps.
The gun is LOUD. I am working on a suppressor for it, which is in its beginning stages. This is why the muzzle and front of the lower tube appear as of yet unfinished.
At some point, I'd like to do some longer range testing with this gun. It has a smoothbore barrel as I haven't the want to spend big bucks on a rifled barrel, and haven't used any of the Gun-Drills I won in a machinery auction some time ago (nor a threading broach).
This site is what got me into the hobby somewhere around 16 years ago. Thank you to those of you still around.
