[amluto]

> ALSO, helpful hint: If you are mixing plastic pipe (like schedule 40/80) and metal pipe, always have metal female couplings and plastic male couplings. A metal male going into a plastic female is one tighten away from cracking the plastic.

Or buy transition fittings or "special reinforced" fittings. Or, if you trust them, use push-to-connect fittings -- SharkBite, John Guest, ProLock, etc. (ProLock appears to be a John Guest product that is also sold by SharkBite.)

I've seen plenty of female plastic threaded fittings break even when connected to male plastic threaded fittings. They're just not that strong under circumferential tension.