I have decided to manufacture the diff tubes from Stainless Steel. I bought 3†schedule 80 tube and got two pieces of 3/8†plate profile cut for the inside flanges. I used ¼†plates to make the outside flanges. I machined the ends to fit the bearing inside, then tig welded the flanges inside and outside to the tube. I have used ½†grade 8.8 S/Steel bolts and doweled the top for alignment. I think I have gone overboard on strength once more.
These should polish up very nicely. Merry Christmas to all.