Unlike Tagi I'm a firm believer in threading for the 510 in metal. I even thread my 3D prints to avoid leakage; not to say Tagi is wrong but it's just the way I like it, brass nuts just don't give me the confidence I require.
Oh I would much rather have it that way. I have Old Dewalt hand drill, a dying dremel and metal files to work with. I tried to thread the 510 with the hand drill it didn't work that great. But my built mods are what they are . They are more to satisfy my tinkering craving then my nicotine craving. Good practice too for the vapocalypse.
Its funny, the mods I built don't really leave the house while my Tmod and LBC are my daily drivers. You do awesome work, my mod making is stuck in cnc Hammond boxes and a bit o Redneck engineering department, a bit rough but functional.
TLDR - Threading is best, Tight as you can get it brass nut is better, Epoxy - will work but for how long. And when it breaks gotta clean and reglue(while the brass nut just reighten). First two are a bit more serviceable.