The B500 brake drum lathe uses some commonly available parts so repairing worn and damaged components is fairly straightforward.
The arbor shaft has two major diameters - 11/16” and 1” respectively - of approximately equal lengths. Most brake lathes have a 1” arbor, so many common shaft adapters and spacers will fit.
This particular machine has a bent leadscrew shaft and cracked handwheel boss, most likely from being dropped or mishandled. The leadscrew shaft will need to be straightened or repaired.
This machine ran when I picked it up, meaning the motor powered up, the arbor shaft spun under power and the carriage traversed in gear. However, the ways were exceptionally contaminated with old lubricant and brake dust and shavings; the handwheel spun in a crooked ellipse; the wiring was unsafe; and the gear selector would not engage without some effort jiggling the handwheel and speed selector handle.
This is the carriage and tool post. This machine holds a boring bar in the tool post, and came equipped with an indexable insert tool holder and assorted HSS bits. At this point I tore the carriage down and sandblasted everything but the dovetail ways. The carriage leadscrew was in good shape except for a broken handle on the wheel, so I removed the pressed-in remainder of the old handle and tapped the wheel for a common handle thread size. The carriage is now ready for a coat of epoxy primer!