Connecting water lines to a faucet with a non-tapered thread

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?

Think of that fitting as a water hose to hose bib...the threads and sealant (pipe dope or tape) don't make the thing waterproof, it's the washer being compressed that does. Without seeing it, I'm guessing here, but they do make supply lines with a flat washer attached to the end. You'd thread that through the hole in the nut, put the washer on it, then tighten that down to the shank to make that waterproof. Doesn't the installation instructions give you a hint?

Because it is NOT tapered, that is why you CAN use a braided line. You thread is probably 1/2" ips, because I have never seen a sink faucet with a 3/4" shank.