SpudFiles

Found this at the local hardware store for $3.50 "Fymspray major atomiser W.S. 18".

The brass part has an O.D. of about 28mm while the o-ring has an O.D. of about 31mm so it probably could fit Type K copper pipe and Type L and Type M if you use teflon tape around the brass fitting to push out the o-ring. Threaded centre seems to be 5mm metric.

With built in grooves, it would be perfect for a homemade pump (I imagine it was for some sort of manual garden sprayer). Unfortunately, it seems these parts are from the '70s-'80s and I've only found NZ web pages for them but perhaps something similar can be found in the U.S./Europe or Aussie.

Interesting. I wouldn't trust brass as piston material, it is a rather soft metal. Never seen anything like it at my hardware stores.

Building a hybrid or something?

I think this kind of piston would be a pump piston, not necessarily a valve piston although I'm sure it could be used as one. As long as you had a decent bumper or put a thick washer on the end of a threaded rod that's threaded inside this piston, the brass will hold up in most pneumatics and hybrids.

Just realised JSR could machine something like this in a few hours, damn you and your mini lathe!

Nah 8)

Yeah, it could be used on a pump I guess.

Brass is the standard valve or piston material despite its "softness".
You could lathe that out with a drill and a file.
A chainsaw file and a drill goes a long way for making o-ring grooves.

MrCrowley wrote:Just realised JSR could machine something like this in a few hours, damn you and your mini lathe!

A few minutes actually