I have a deck-mount faucet that has 3/4" non-tapered threading on the shanks below the deck. If it were tapered I could just attach a braided line, but I'm not sure about non-tapered.
The faucet came with a 3/4" nut that theads on to that shank, and the nut has a hole in it slightly larger than 1/2", and a flat washer. It looks like you would use that to connect a 1/2" OD pipe with a flange on the end. Or maybe throw out the flat washer and use a 3/4" cone washer, if such a thing exists.
It would be easier if there were some kind of adapter that goes from 3/4" non-tapered to some kind of pipe thread fitting. I have had no luck finding such a thing online. Any ideas?