conpewter
Well-Known Member
Yup, metal on metal is not good, but take a look at the picture I posted above from the Blichmann manual on how it works. It's not metal on metal:
Maybe it's just me then but I really like the way Blichmann does it as it makes sure you don't overtighter the nut. You could throw an extra washer on the inside but I don't think it's probably needed.
BTW, I emailed John Blichmann last night and I already had an email this morning indicating that he'd update the next print run of their Boilermaker and Brewmometer manuals to include more labels like my Figure 2 above (to make it clearer for people what's what). I've always been impressed with their service. 5 thumbs up!
Kal
A couple thoughts.
I like the above idea not only because it keeps you from squishing the O-ring but also because you can crank down on it and make it really sturdy (My ball valve on the keg is a bit wobbly, but it seals...)
Also Yuri suggested to go with the metric most likely because you don't want NPT, you want a straight threaded (not pipe thread). That way you can screw the nut all the way on to get it tight enough to seal.
Edit: I'm not sure if that bushing will work, it will need to screw down far enough to pull the O-ring taught.
Also I wouldn't use any pipe tape, you arn't making the seal on the pipe threads, it is all up to the O-ring.