riff raff (you aren't by any chance ex-RRAF, Royal Rhodesian Air Force? Riff-Raff was their sobriquet.) Anyway..............
"While I understand the point you are trying to make about the modest amount of pump driving torque transmitted thru the lower portion of that shaft, in reality the torque transmitted thru the bevel gear mesh is what creates forces and moments on the shaft, housing and bearings.
I'd bet than when this issue if finally resolved, the one-piece welded shaft will be replaced by a two-piece shaft design with no welding. As always, just my humble opinion."
Thanks for perfectly encapsulating the shaft issues for me. I would even venture, now that I slightly better understand things, that if there were no bottom bearing resisting the side loads, then there would be less stress on the weld as a consequence of the flexing/bending happening above the bevel gear between the other two bearings.
Yes. Right on! I vote for a new shaft without any weld, except that it would take years to certify.