The job in the shop now is a 6-71 supercharger main shaft. The original broke due to being out of true and made from inferior material. The new one is lighter and features 1045 steel shafting material and 2024 aircraft grade aluminum. What we decided to due was machine a square for the shaft to ride in. After it is pressed together it will not fail. No welds to brake and the assembly spins true. check out the photos. There is more to come.