I switched out my tanks. I had a small swage with square shoulders set up in the treadle hammer. I clamped the torch in the vice so I wouldn't have to fiddle with it. I did a trial run with a piece of scrap and it worked perfectly. So with the tang screwed into the barrel, I heated the end of the tang bright orange, stuck it in the swage and tapped it lightly. It sure cooled off fast. I had to take about 3 heats to get it drawn out. Of course it didn't center itself on the real deal like it did on the scrap piece. I was able to pretty much correct this on the anvil. I let it cool in a bucket of ashes.
After cooling, I scribed a center line and filed the sides of the tang smooth and evened up the shoulders. I ended up gaining about 1/2 " even after filing the end square. I think it went pretty well. The heat colors never went past the lug on the tang. No apparent damage or scaling to the threads at all.