Submarine torpedo tube distortion control

Tom's first student at Electric Boat developed an in-process distortion-monitoring technique using feeler gauges, allowing real-time compensation by adjusting weld sequence and grinding-and-reweld corrections. Reduced finishing pass from quarter-inch machining to skin pass.

Thank you. Let me tell about some other submarine stories. Are you familiar with the torpedo tubes? They have to be very straight. They're pretty long — longer than the torpedo. The tolerances are something like a millimeter. They used to weld them up, and of course you get distortion from welding, and then they would machine them with a great big boring machine that would go the length of one of these things. I'm not sure how long they are, but probably 40, 50 feet long. My first student, who went to work for Electric Boat — he's now retired, I'm still working — he figured out how to do it so they would not have to straighten them. When they put the welds in, going around the circumference, they actually had something automated. He put some feeler gauges on the end, measuring distance a couple of feet away, and he could see the angular distortion. What he would do is compensate with the weld. He would stop the continuous weld and go on the other side to pull it back the other way. Or he would actually grind out the weld and put another weld in to cause more distortion in that direction. So he monitored in-process the distortion and corrected for it in this cylindrical joint. And all of a sudden, all they had to do was just a skin pass down the bore, as opposed to taking a quarter inch off.