Hi GeoffS

I am of no use to you at all but I suppose one of us has to pop his head up over the parapet and risk getting it shot off :heehee:

Welcome to the forum :wave:

I know National and British Standard pipe threads but never heard of 1/2 G.

What's this wire size thingy?

Perhaps tolerances are't specified, especially if the male and female thread forms differ.

Presume you are either only doing one side of the thread so you can't cut to fit, or, you cut to size and it didn't fit and you find yourself in a wrangle with the customer?

Either way, good luck

Robin