Originally Posted by Supergyro
I got hold of a caliper today. The point my reg won't go past is .687. The reg head that fits is .685. The reg head that doesn't fit is .692. < That's the problem. I may try to use some 1,000 grit sand paper to diameter down. I should be okay as far as o-rings go because it's regular tank o-rings. Might just have to do that.
I know that the sanding worked, but in case anybody was wondering, it is the VASA at fault here. The ASTM standard for an ASA (CGA-320) has a range of .685-.694 inches for the flange past the o-ring on the male part (regulator end) and a bore of .694 - .703 inches for the female ASA where the o-ring makes the seal. The VASA was made 7 thousandths undersized.