Building a Modern Pneumatic Airgun

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Stot:
I bought plans for a pump gun ages ago. 3 pumps 12ft.lbf But I'd love to try a single stroke up to that power. I would go steel for a pump up as the thinner wall would allow for a larger swept volume in a less bulky rifle.

Cheers
Stot

Stot:
The breech needs to be dished out to sit on the hammer tube and valve properly. With a mill and a ball nosed bit, easy but an 1 1/4" ball nosed mill end isnt cheap and I didnt have one. :scratch:

An alternative is to set the mill up like a horizontal mill with a boring bar ( the type that takes HSS square tool steel ) in the chuck supported by a center at the other end and the bit set to 1 1/4" diameter, mount the breech on the toolpost and take passes. I tried this on some scrap and it just didnt have the rigidity and chattered a lot no matter what I did.

Looking through my mill bits collection I found a normal 1 1/4" mill end so I ended up turning my angle plate through 90 degrees so that I could clamp the breech in the vise, bring it to center and take passes at the base to dish it out. I could only get just over 1/2 way down the breech this way but thats fine because then I can flip it around and do the other side. :ddb:

I also picked up this week an Ultrasonic cleaner from Maplins only £25 reduced from £45. This is great for cleaning parts before assembley especially where you really dont want swarf clogging anything up. It does wonders on brass. :clap:

SO. This time round I...

* Milled trigger and bolt slots in the hammer tubes before I changed the lathe configuration.
* Turned the angle plate 90 degrees and mounted the breech in the clamp.
* Took passes at the base until I reached the desired depth.
* Turned the breech around and milled in from the other side to the desired depth.
* Used some spare tube and some wet'n'dry to finish the base to an exact fit to the tube.
* Polished out most of the machine marks to a matt finish.
* Cleaned in an ultrasonic cleaner.

Cheers
Stot

cfellows:
Hey Stot,

Thought you might be interested in this video. I'm firing .22 caliber pellets through my home made air gun and it is using High Pressure Air instead of CO2. Noisy as the dickens and it sure does shoot hard!

http://www.youtube.com/watch?v=nYMU_6GhOCw

Chuck

Stot:
Nice Chuck. Is the air regulated at 850psi?

I have a feeling these two guns will be quite a handful if allowed to go to full power so I'm trying really weak hammer springs to start off. Havent really done much on them over the Christmas period but ill have an update soon.

Cheers
Stot

cfellows:

--- Quote from: Stot on January 06, 2011, 03:02:29 PM ---Nice Chuck. Is the air regulated at 850psi?

I have a feeling these two guns will be quite a handful if allowed to go to full power so I'm trying really weak hammer springs to start off. Havent really done much on them over the Christmas period but ill have an update soon.

Cheers
Stot

--- End quote ---

No, it's not regulated. I've now got a slow leak around the release valve that I need to fix.

Chuck

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