SpudFiles

Piston Valve piloted by a QEV. Golf Ball Sized Barrel. So far all aluminum but we shall see what happens when I get to the chamber.











































Lots more work to go. I have roughly 8 hours into machining so far. Stay tuned folks

Great work, lucky you have access to tools to make that!

Very clean work too BTW

You've made my Sherline feel very small

Excellent work, please tell me this is destined for HPA!

nice work sure will be a performer!

jackssmirkingrevenge wrote:You've made my Sherline feel very small

I went to an engineering expo last thursday there was a lathe on show that had 17 meters between centers and 3.5meter swing no tail sock had two spindles and 3 steady rests! yet made no more noise at 3000 rpm then the 40'' 120'' at work.

A man can dream

hahah lol once you're in canada you can just print your own

That is some nice aluminum work .

I almost said a "non-forum approved word". Nice work and looking forward to the finished product.

The chamber would be good in aluminum too. What other materials are you considering?

I'm considering 304 Stainless Steel or 6160 Aluminum for the Chamber. The valve body is 6160 Aluminum. I may consider Mild Steel for the chamber if I can find a nice enough prebuilt air peg. Modify with larger ports. Everything must look Pretty

I made a piston out of Acetal but it's pretty heavy. I might make the piston from Aluminum, hollow it out, weld a cap on one end.

gyrotech,
Absolutely beautiful work! What operating pressure do you plan to use? What are you using for a piston / barrel seal?

That does look amazing. How long did it take you to bore the thin walled piece on the lathe? Or did you use a very large drill bit to take it most of the way?

velocity3x wrote:gyrotech,
Absolutely beautiful work! What operating pressure do you plan to use? What are you using for a piston / barrel seal?

Not to concerned about higher pressures. I have a Viair 450c air compressor, setup to use in my truck. Top's about 150psi. I'm planning a long barrel, 6 or 7 feet. With a C:B ratio of 3:1.

The piston was going to be a piece of machined Acetal, which is a hard plastic basically. I'm switching that up for hollow aluminum. Should be very light. It is barrel seal. Most people use rubber for the seal? I have some nice gasket material at work. Might try that. I'm also planning on a rubber bumper for the piston to slam into. I imagine it would take quite a hit without one.

I do plan to water pressure test the unit. This gun will be used around family, friends. I plan to test at 300psi maybe more for a very large safety factor.

If your familiar with water pressure testing, basically you fill with water, then add air pressure. Water being virtually incompressible, not much can go wrong if it fails on testing. Also leaks are easily spotted. Although I doubt I'll have any leaks.

ramses wrote:That does look amazing. How long did it take you to bore the thin walled piece on the lathe? Or did you use a very large drill bit to take it most of the way?

The third picture shows the holes I drilled. I used a boring bar to then enlarge the holes. I started with a 1.5" drill bit. Generally I did 0.200"-0.300" passes for rough cuts and 0.050" for final cuts. I would not call myself a machinist. I did not go to school for machining. I am a welder, a fitter, a lead hand. I build food handling equipment and have picked up a fair bit of skills along the way. I do not know how to calculate proper travel speeds for cutting...however I do understand whats to fast, to slow, I can make a slip fit accurate to a few thousandths of an inch or a nice press fit.

I have about 8 hours of machining into the project so far. To me, that's working pretty fast.

Thanks for the possitive comments guys

jackssmirkingrevenge wrote:You've made my Sherline feel very small

Excellent work, please tell me this is destined for HPA!

Not sure what HPA is?