Had a boiler inspector call me out on my tube rolling technique

I've been doing boiler tube repairs for 12 years now and thought I had it down perfect. Last week this old inspector named Frank watched me work and said I was over-rolling my tubes by about 0.005 inches. I almost laughed at him but he pulled out his gauge and showed me the difference. He explained how that tiny extra expansion causes stress cracks down the line, usually around the 5 year mark. Now I'm second guessing every job I've done this past decade. Has anyone else had an old timer point out something small that totally changed your approach?

2 comments

2 Comments

sarah_hart2d ago

Oh man, Frank sounds like a legend. Had a similar thing happen with an old millwright who showed me how I was setting my expansion readings wrong on a firetube job. He pulled out this beat up notebook from the 80s with hand drawn diagrams showing how the tube sheet thickness changes the whole calculation. I had been going by a half inch rule of thumb for years and turns out I was off by almost a full turn on some really thick sheets. Still think about that guy every time I set my torque.

kaib181d ago

Man, that notebook story hits hard. Did he ever explain why tube sheet thickness throws the standard formula off so much? I always figured it was just about wall reduction but he must've had a whole different way of looking at it. Those old guys had tricks you just don't see in the modern manuals, its crazy how much gets lost.