Hi Rich, I used to work in a cycle shop, Russells of York, before I joined the Navy and if I remember correctly , 14gauge equals 2mm...
13 gauge = 2.3mm
14 gauge = 2.0mm
15 gauge = 1.8mm
16 gauge = 1.6mm
I'm blowed if I can remember what the thread was, mind I have that problem all the time.
I seem to remember that there were some nuts that could be used instead of the nipples, ( sorry moderater) that are normally used..
Hope it is of some help.....

....Smudge