Hi krv,
Just been thru the same exercise! I have one of the little tools to install / remove the valve it also cleans & cuts thread. I tried & couldn't get a seal. More googling & I found that you also need a taper or the seal to work!! So I cleaned the rubber off a tire valve stem, drilled out my home made fitting & loctited the stem in, works just great!
After doing this I found out that you can buy a fitting with the valve in it!

check out your local hydraulic or phenumatic supply shop.
Cheers Kerrin