A 30 year boilermaker in Gary told me my tube rolling was too fast, and he was right
Last Tuesday I was rolling tubes on a small firetube job in Gary and an old hand named Ray watched me for about 10 minutes, then said I was spinning the expander way too quick and would egg the holes. I slowed my drill down to about half speed and went past the point where it felt tight, just like he showed me, and the tubes sealed clean with no weeping on the hydro. How do you all figure out when a tube is rolled enough without going too far and cracking the sheet?
That old guy probably saved you a leaky sheet. I was taught to watch for the tube wall to just kiss the hole, then maybe a quarter turn more and stop. Every size and gauge rolls different so there is no set number of turns. Feel and sound tell you more than a torque spec ever will. You did the right thing slowing down, fast spinning is how you gall the seat and thin the wall.