Blowback Hammer valve : Build log

[Leonard]

Hello Guys!

Im opening this thread as a build log for a blowback hammer valve launcher. The design is pretty straight forward but as much as i know i have never seen it done without a lathe or machinery. I will be building this without any special tools (but with a lot of Epoxy!).

Here's the final design, to scale : 10 pixels = 1mm. Caliber of ammo will be 10mm. The grey in the drawing are areas that will never be pressurized at any point in the shooting process. Trigger not pictured.

<a href="http://s342.photobucket.com/albums/o434 ... esign1.gif" target="_blank"><img src="http://i342.photobucket.com/albums/o434 ... esign1.gif" border="0" alt="Photobucket"></a>

I am waiting for parts from RCwings.com to come tru mail, more precisly the brass tubes needed to build the hammer valve. I have started to build the hammer, it is currently curing in my room. It might take a few days for me to update since im waiting for parts. Like JSR says : Watch this space.

[POLAND_SPUD]

wow you are the first person who draw their diagrams trying to keep everything up to scale

hope it will work... I am not sure if there would be enough pressure to reset the hammer... I am not into this kind of guns but it goes without saying that this is essential in order to make it work properly (maybe there should be some flow restriction for the first 1 or 2 cm of the hammer reseting movement after hitting the valve just in order to let it get more momentum... obviously the fact that you are using epoxy doesn't help here as this might require some serious tweaking


JSR posting in 5.... 4.... 3.... 2.... (naaaaaah he is sleeping in his bat cave... but if you manage to get it to work fine I am sure he will hug you long time )

[jackssmirkingrevenge]

JSR posting in 5.... 4.... 3.... 2.... (naaaaaah he is sleeping in his bat cave... but if you manage to get it to work fine I am sure he will hug you long time )

He was actually out getting hammered on Guinness, I'm as Irish as Mother Theresa but any excuse to drink

People have made auto hammer valves but yes, hugs are on offer

One thing which bothers me about this design is that the air pushing back the bolt is wasted, I would rather have a system that exhausts only through the barrel.

On that note, I've started on a tiny hammer valve auto myself that will look more like this, and in untypical style, will make extensive use of threaded fittings to be *gasp* serviceable

Bit of a tight schedule at the moment though, ah well.

[psycix]

Blowbacks and hammer valves are quite the hype these days aren't they?

Not to discourage you, but I have the feeling that the hammer will not be pushed back enough.
And as this requires tweaking, tweaking and more tweaking, a threaded fitting to make things serviceable may come in handy.

[Leonard]

Dont worry, ALL moving parts will be serviceable. I know i'll have a lot of tweaking to do, so i prepared myself for this. I got a bunch of different springs ^_^. Also, the holes in the back of the hammer shaft (in wich air that push the hammer back goes tru) will be hand drilled, so i will be able to adjust the airflow until i get what i need.

Thanks for the comments!

As for this thread : I have not received the parts for the valve yet, but the hammer is finnished. I'll post the pics as soon as i can.

[jackssmirkingrevenge]

And as this requires tweaking, tweaking and more tweaking, a threaded fitting to make things serviceable may come in handy.

Even I have understoon the importance of this, y'all are going to be so proud