I'm going to slice my 67 prop valve in half to find out what's inside so I can make more unless someone has sucessfully disassembled one. Can't get the little piston with the hole in it out. Back threads got "over bored" by the vertical mill in an attempt to get the nipple that had gone Zen (became one with) the valve. Yeah, pass the doofus... The machine shop guy said "Oh yeah, that's 1/2 inch" despite my protests. Besides, those little buggers are hard to find!