My first QEV

[Hrawk]

Hi all,

I seen these valves in another thread and just had to have a go.

(http://www.spudfiles.com/forums/ebay-pn ... 23241.html)

This is what I came up with using parts lying around. 7mm OD barrel with 6mm ID.

I have made a separate tank using 2" pipe, 80cm long connected to a cheap regulator. I charge the tank to 115psi with the reg set to 90psi. I get about 15-20 shots before the pressure starts to drop below 90.

I diddnt really do any calculations on it, just started throwing everything together.

Love to hear any thoughts or comments on this.

Cheers

Hrawk

[jhalek90]

im confused, because i dont see an end cap on your chamber.... and how is the chamber connected to the QEV?

[Hrawk]

I found that the brass end caps for the smaller size tubing fit perfectly inside this size tubing. I soldered them in place.

At the QEV end, I drilled and tapped for 1/4" BSPT and used a male-male connector into the QEV.

Ill see if I can get a few more pics to help explain.

[jor2daje]

looks nice but your chamber is large enough to throw a much longer barrel on you will see increased performance.

[daniel0663]

I saw this in the Slingshot forum not to long ago....

Looks like a fun plinker to have, and oviously beats the commercial BB guns in power wise...

Have you thought of adding a longer barrel?

other than that, looks fun..

[jhalek90]

Be carefull, your end plug is waiting to blow off.

you can solder copper. but brass must be brazed.
Brazing requires much hotter temperatures, and a different type of solder.

Copper to brass "solder" joints seem like a bad day waiting to happen.

EDIT:
Although, you are only shooting this at 90 psi.... i would still consider soldering a proper copper end cap... just leave the brass plug there... and put the new end cap over it.

[Hrawk]

Cheers man, I figured as much.

This was more an experiment than anything else.

To be honest, when the valve arrived, I was a little confused as to how to use it, but luckily there are 1 or 2 guns here using QEV's that I could learn from.

I tried to make everything I could threaded so I can change things when necessary. The chamber is just a piece of pipe and an elbow I had laying around.

As for the barrel, I thought I was very lucky finding a piece of tube that fit perfectly inside the 3/8 barb adapter. At present the barrel is not glued or soldered, but with the nice friction fit it has, it stays in place perfectly.

Now that I know it works, I will look around for some other tubing, would love to find something with a 3/8" ID so I can use the thousands of rounds of steel BB I have for slingshot shooting. These weigh in at 3.5gm.

I really like the idea of having a screw in barrel so I can have multiple sizes ready to go.


EDIT:

@ Daniel0663 - Hey man, who are you over at SSF ? I posted the pic up earlier to show a mate what I had made. I'll prob delete the pic from there, not being slingshot related.

@ Jhalek90 - Thankyou for the advice. Much appreciated. Do you think I could get away with drilling it through and placing a pin through the cap and tube ? It's no problem putting a cap on, I was just trying to keep it neat.

@ Jackssmirkingrevenge - I didn't even know that was possible, thanks so much for the great idea. I assume I need to depress the trigger when filling ? or is the incoming pressure enough to open the valve ?

Thanks again everyone, much appreciated.

[jackssmirkingrevenge]

You can fill through the blowgun, thus eliminating the ball valve, this will cut down on dead space and improve performance, as well as making it simpler and lighter.

[Hrawk]

Hmmm just a though, If I was to fill through the blowgun, I'm guessing I would need to remove the air source before firing ?

I'm very happy with the way it works so far, turn the ball valve to charge, fire, rince, repeat.

I see you are an 'aspiring machinist', I have a Sieg C6 lathe and X2 mill on order, they should be here next month. If you don't mind, I might be hitting you up with a few questions. Mainly on what tooling to use. I love the idea of using indexable tooling, but I have heard that HSS is a better way to go for aluminium, brass and plastics.

I will also be working on hardened steels and still looking for the best tooling option for that.

Any advice greatly appreciated.

[jackssmirkingrevenge]

Hmmm just a thought, If I was to fill through the blowgun, I'm guessing I would need to remove the air source before firing ?

I'm very happy with the way it works so far, turn the ball valve to charge, fire, rince, repeat.

What you'd need to do is hold the blowgun open while filling, let go, remove the air source then fire.

If you're interested in true semi-auto while connected to your air source, replace the ball valve/blowgun setup with a slide valve - it automatically shuts off the air supply and pilots the valve every time it's pulled.

I see you are an 'aspiring machinist', I have a Sieg C6 lathe and X2 mill on order, they should be here next month. If you don't mind, I might be hitting you up with a few questions. Mainly on what tooling to use. I love the idea of using indexable tooling, but I have heard that HSS is a better way to go for aluminium, brass and plastics.

I will also be working on hardened steels and still looking for the best tooling option for that.

Any advice greatly appreciated.

I'm fairly new to the game myself, only recently invested in a Sherline setup. I have more goodies on the way shortly, mainly a dedicated table and motor for the mill column and assorted goodies and accessories.

I recommend reading through this thread, LeMaudit provides a fantastic series of video tutorials covering basic techniques that will also make you a neat little pen gun

[pneumaticcannons]

nice photoshop skillz jsr..
Depending on the type of blowgun you have, it might leak if you fill it through the blowgun. i suggest you test this and if it doesn't leak, scrap the ball valve as jsr said