@Pᴀᴜʟsᴛᴇʀ2 I do have welding equipment (in fact the best stick machine) that is pretty good at my disposal. I have a larger fitting that in 1 inch. And I'm thinking I can drill a hole big enough for that little 1 inch thing to go in then weld it. Then use tape to seal the threads I showed you. And screw it on.

@Pᴀᴜʟsᴛᴇʀ2 I did get an 11/16-18 UN-2B tap and the threads are perfect but a tiny bit too big. And I tried to get it to thread and it just acted like a drill bit