SpudFiles

Then you'll have to use a giant pilot valve. Or a metal ball valve, which you dont want to do.

Well Ill see, i probably will though

A very close tolerance fit on a non ringed piston may still require an eq hole. Look at the size of the EQ port in a sprinkler valve diaphragm. Only a very tiny one is required. My Mouse Musket did not use o rings on the piston, but still required an EQ hole because the grease would seal it. That valve was hand lapped for a close fit. Most pistons have the opposite problem, the piston is way too loose with lots of blow by space.

Ok, so or the EQ. hole did you drill a hole through the top or cut a groove along the side

*cough* 1/4" qev *cough*

I would go with that but I don't want to spend more money on the pilot valve than the rest of the gun

I'd probably spring load a ball valve. Better than a modden blowgun and more accurate. Depressing a normal blowgun will throw of your aim unless you swap the lever from a linear extension trigger. Basically just a bolt (or longer) that when depressed acts directly on the blowgun poppet.
That would probably be more accurate than a spring loaded ball valve but you might miss out on performace a little bit.

Or you could go with a 3/2 valve, make it semi-auto while you're at it.

Maybe since I'm finally getting a compressor, how would a push button like you had on your 6mm work, didn't it have better performance than your blowgun

If you do get a good piston seal with very little to no leakage, the size of the pilot hole should be very tiny. In regular bits, I used the smallest 1/16th inch on both the Mouse Musket (lapped piston) and on the Dragon (o ringed piston).

Edit; located photo of the EQ hole being drilled in my piston.

clemsonguy1125 wrote:Ok, so or the EQ. hole did you drill a hole through the top or cut a groove along the side

On mine I drilled a hole. This piston was made with a center hole that did not go all the way through. This was used for a bolt to chuck this into a drill press. I slowly turned it down until it just fit in the Mouse Musket. Grease sealed the piston completely so a EQ hole was required in order to pressurise the chamber ( it would open the valve ). A small hole was drilled from right behind the face of the piston (chamber area) to the center channel to the pilot area. In this one a 1/16th inch bit was used. I have sounds of this working posted online.


Here is the piston screwed onto a bolt that is chucked in the drill press.


The piston before it became round on the drill press. A bolt was screwed into the hole.

you can make the sealing face teh check valve like the Brass Harpoon gun