The first, and most important, phase of upgrading and restoring this table saw is to remove the arbor, and machine a replacement with the common 5/8" shaft size which will accommodate modern blades.
I began by removing the motor, belts, blade, and bearing retainer clips. I soaked everything in PB Blaster for a couple of days, then I drank a few brews and bashed the shaft out with a hammer and draft punch.
With the old arbor removed and (mostly) disassembled, I moved on to modeling up a replacement shaft that could be machined to fit the existing sheave (what most people might call a "v-belt pulley").
The required bearings don't seem to be available anymore, but the replacements are not hard to find in the right dimensions. I have no idea if it will even be possible or sensible to cut a snap ring groove in a bearing.
Of course, I'll need a new set of arbor spacers to go with the 5/8" shaft size. Maybe I could purchase these parts, but I would prefer to make them (or have them made).
I have a feeling I may need to modify this design after I remove the other bearing and sheave.