SpudFiles

What about building a check valve in a quick connect

Gun freak, no it wouldn't you would be pumping air directly from your hose into your gun, once you disconnect the schrader tool from your gun, it closes the valve and dosen't let air out. Do you understand now?

BTW I edited my older post with pics.

Wait... but if that depresses the pin doesn't it no longer work for a check valve? I'm looking to use a schrader as a check valve on a high-pressure pump.

It would, once you dethread the tool the checkvalve would "close" not allowing air back out, it's simple.

why dont you just make the simple kind in a coupling... pic adding in a minute.

I'm just going to buy one I think... they're about 13 U.S. dollars and rated to 1k psi.

you can make one for under 3 bucks:
gray square things are washers, left one for the spring to hold on and right one to secure the sealer

Will that hold 600+ psi?

Most likely, you can use a rather strong spring and with a metal bearing and an o-ring, I can't see how it wouldn't.

Purely for simplicity's sake I'm using the purchased one for now. Thank you for the plan though.

That plan posted or something similar will hold thousands of pounds of psi. As long as the ball bearing is large enough so there is no way it can pop out the inlet hole it's not going anywhere. It's just like the system used for a beer keg or fountain drinks in restaurants.
The best thing to house the valve is a threaded fitting that steps down a size. There is a perfect ledge for the o-ring and seal surface to rest against.
An 1/8th-1/4 brass male fitting is my standard one way fill valve.

Ahhh I get it now, thanks. A deceptively simple design... just requires an accurately calibrated spring is all.

Why? As soon as the pressure rises the spring basically becomes obsolete. The rise in tank pressure then exerts most of the force holding the valve shut.

Need a spring with a very low spring constant that won't get pushed off its bearing by a pressure spike.