Originally Posted by super_stanchy
They were the new ones they brought to make 2 nuclear sub prop shafts
2ft dia and 80 feet long. 9 months work 24/7 at a cost of 2 million pounds each. If the dockyard made them not an outside contractor the navy would save 4 million pounds and the was back in the 80's.
They were to be made from drop forged stainless steel and they were not very round to start off, They thing was to get under that hard skin in the first cut or you could say goodbye to any tool life so they used a very high temperature gas torch to heat the metal in front of the tool to red hot then start turning. It was like fireworks all night long as they would only do this on the night shift less chance of anyone getting burnt.
The old 80 footer used to cut a 0.005 taper every foot so the operator who had been operating the lathe for 20 yrs used to sit on the cross slide and adjust as it went along and he would cut the bearing surface which was about 3 feet long parallel to 0.0002"