Since there have been no replys I will give it a try. Looks like the left end of the shaft is setup for a pair of anglual contact bearings at locatin "C". It looks like a collar/spacer goes on next followed by a nut with an M20x1 thread. The nut is tightened on the spacer which clamps the bearing inner race to the setp on the lead screw. The right end looks like it's set up for a plain bearing as the journal is much shorter. It also has a spacer then a nut but I would bet the bearing if semi floating in the bearing block to allow for thermal expansion.
This is exactly how my Bridgeport is setup.