SpudFiles

My goal is to make a portable semi-auto bb thingy.
The mechanism i want to make is like a paintball marker.
I want my air resevoir to hold about 300 psi.
and i want to be able to control the amount of air that loads the double hammer valve.

If there are any helpfull tips you no of please let me know,
also im not sure how to make the trigger mechanism and what kind of air container i can use.

The above picture is missing the hammer spring.
This is the good one with the spring in the back

it seems overly complicated
there are such small parts here... this will be PITA to build even in large caliber

it seems possible, do you have access to the tools need to make the precision parts?

yeah a friend of mine has hight tech tools at his school we can use but i want to make as much as posible without any fancy tools. The only thing i need is high variation of tube diameter then i can make the mechanism.

Simulating a Tippmann valve, especially one from a Pro-Lite is going to be difficult at best. The hardest part, as you have already figured out, is the trigger/sear/hammer spring mechanism.

I have pictures of a valve that will do exactly what you want without all the extra pieces. I'm putting it together in a flash animation so that it can be easily understood. I'll edit this post when it is finished.

What calibre and power levels did you have in mind?

sorry I don't want to bring you down but that will be very difficult to build... with or without 'fancy' tools... not in this caliber
6mm is really small and there are lots of smallish parts on it.. lots of o-ring grooves and so on

well i want to be able to play small airsoft skirmish with friends an i want to shoot with high velocity, there for i want the hammerspring an the air flow to be adjustable. calibre will be 6mm.

I think that if your trying to make something like this them you should have machine knowledge, i have my own lathe and im in the process of making a semi-auto bb gun and without my lathe it would be almost impossible. ive seen people make simple hammer valves from plumbing parts so i would try and make one of them first and then progress from that. I have also seen someone make a semi-auto system from a syringe and a bit of glue, that may be a good starter for you.

If you dont have the right tools or knowledge then just buy a powerful bb gun

Here is the animation I spoke of.



This particular valve is a type of spool valve similar in function to Tech's QDV. Obviously, this is just a very rough sketch of the valve, as other pieces are going to be needed, especially at the pressures you spoke of.

As far as its hookup, the main chamber is hooked up to the tee. A regulated air source (automatically refilling the main chamber to the right pressure) is ideal. The air also flows into the secondary (firing chamber). When the trigger is pulled, which is connected to the rod, it closes off the primary chamber and only allows the secondary chamber to fire.

As far as controlling the velocity, this can be done one of two ways. First way is the same way Tippmann (the maker of the valve you posted) does it, which is to induce turbulence at the breech. The second way (and easier) is to use the regulator to turn the pressure up or down.

Please note that this valve design is not mine (it belongs to Dr Nerf from, well, somewhere else), but is a design I have been toying with for a while now.

@hubb: MM this is indeed less complicated thanks.
you said that you have been experimenting with this, what were your findings?
and what material did you use?
im not sure what to use jet. alu abs or steel.

The couple of prototypes I've used were small and made of PVC. I've never taken any of them past about 30psi.

but the problem with this valve is that it wont be able to seal of the magazine

By adding a bolt in front of the barrel plug, the problem would be solved.