A guy I used to work for bought an old lathe that's capable of turning 4' diameter stainless tubing 12' long with 6' diameter flanges welded at each end to build the vacuum enclosure for the UT Rail Gun research project. He used it to turn and face the end flanges and cut o-ring grooves. It's totally awesome and scary to watch at the same time. It takes a real man to crank those two handed handles on it because it's all old technology, but at least there's a crane for work piece handling.