SpudFiles

Hello folks. Just started my first serious airgun build with the end goal of a nice handy, slim, and portable gun to trek around the woods and plink cans with. I was inspired by some of Brian the Brain's creations here on Spudfiles, such as his coaxial pirate pistol and hammer valve flintlock designs, I'm also a huge fan of the buttstock reservoir airguns our ancestors used, such as the Lukens, and of course, the Girandoni, so I would love to end up with something reminiscent of these airguns, not in complexity but maybe in looks...from a squinting distance.

I realize ball valve launcher's are relatively poor performers. At first I was aiming for a coaxial piston pnuematic as they're far more compact than even a ball valve, however I opted for a ball valve simply because I wanted the ability to disassemble and modify the chamber, plus they seem to be far less finicky.

Anyway, simple design with only 4 vital components

-36" long, .56 cal barrel
-13" long, 1/2" copper reservoir
-3/8" ball valve
-Lock aka mechanism which will allow the ball valve to snap open with the pull of a trigger I don't know if this is the optimal barrel/chamber ratio, however I want to keep the chamber on the small side while still using the long barrel to it's fullest. I've tested it already and the results are very exciting, I used an old bike pump and with just 2 good pumps (and using my hands to open the valve) I was able to shoot a 1/2" ball bearing faster than a slingshot with powerful flat bands.

What I have so far, chamber, valve, and barrel. The barrel is seamless steel pipe I found online, with a 1/2" steel ball bearing the fit is so exact it has an almost air tight fit in the barrel. Even the thinnest of patching will cause it to be very difficult to get down the barrel. Nice slippers eh?

Today's challenge was trying to turn the ball valve handle into a faux flintlock frizzen Which is supposed to emulate the flat L-shaped piece here

The purpose of the frizzen on a real gun is to give the flint a steel surface to scrape and spark against, the purpose of my frizzen is to be a surface for the hammer to collide with at high speed which will turn the valve faster than a spring alone, it's comparable to pushing a door open vs kicking it open. Right now it's just epoxied together, I don't expect the epoxy to hold, especially since this piece will be subject to a lot of stress, I will braze or solder this eventually.

This looks awesome, awaiting results!

Things are starting to slowly move onward again, I put the project on the shelf for half a year, but now I've got all the parts I need and I'm optimistically hoping to get this functionally finished by June.

Here's layout of the mechanism and chamber. Stock is in blue, lock is red (lighter red is internal parts), barrel and chamber is black, the circle under the ball valve handle = schrader valve.

I've yet to figure out a safety for the ball valve, without one there's a good risk of knocking the valve handle and discharging the gun. I'll probably just slap a rotating knob under the handle which can be rotated up to lock the handle in place.

What's a safety

farcticox1 wrote:What's a safety

That big thing we promote heavily here!

SAFETY FIRST! :bom:

Nice project! Interesting way of knocking a ball valve open, and you have centuries of flintlock design for inspiration!

What's a safety

Thanks Jack, yes, the inspiration is boundless with all of the unique designs of airguns and flintlocks of that time. I think it's a funny coincidence that the action of the flintlock design seems to be perfectly adaptable to a ball valve opening mechanism.

Got this nice little high-pressure gauge I plan on inletting into the stock with the face on the underside of the stock. Got my pressure chamber to where I can unscrew this and pop it out if it needs replacing (epoxy threads are cool).


Here's one of the laminations being cut to profile, it will be two 3/4" cherry pieces and a 1/4" walnut core lam, should contrast nicely.


Currently getting the lock plate shaped out and a new air chamber assembled.

Good job. It looks old enough that is what I like about the appearance, and will surely fire with enough energy, when the weapon is finished.
On the other hand, the small manometers of which you have this super good! I pay to see his gun firing. regards

Thanks Hectmarr. I already knows it shoots great, but it will shoot even better with a proper trigger mechanism and something to kick the valve open.

This is a car seat support frame I'm cutting some of the parts from, including the lock plate.

The section that is to be the lock plate

Much filing and hacking later...
One lock plate, undrilled.

Much filing and hacking later...

Bartholomäus Girardoni would be proud!

All three laminations finally come together as one.


Inletting areas for the air chamber and trigger mech


A rough trigger


Amidst a cloud of sawdust and metal chippings something vaguely gun-shaped begins to appear.

This is just the barrel thrown onto the stock, I've yet to inlet the barrel channel. Still so much to do: hammer, hammer spring, trigger housing, inletting the lock plate, inletting the barrel, inletting the ramrod channel, drilling and tapping the lock plate, and that is just to get it functional!

jackssmirkingrevenge wrote:

Much filing and hacking later...

Bartholomäus Girardoni would be proud!

Hehe, thanks.

Coming along very nicely, kudos!

Here's the progress from last week

Barrel fully inletted, this was a pain and I didn't get a tight fit because I got lazy and accidentally rounded off the edge with sandpaper, no fixing that, live and learn.


Sawblade makes good mainspring material


Trigger and trigger housing


trigger seated in stock