According to JR North :
Sure there are. I made a 4" dia low speed ball bearing for a project a
few years ago. Used 1/8" balls, and had an inside diameter of 3.25" Be
aware that clamping the races in a chuck will distort them, causing
uneven drag when finished.

If you've got two-piece jaws, make some "Pie" jaws to fit on the
chuck, and turn them in place to the intended OD of the race. Then, you
have support the whole way around. (Better with a 6-jaw chuck to start
with, of course.)

I doubt you can make a good, high speed, high
load ball bearing on a lathe.

Agreed -- but you can do better if you use a toolpost grinder
with a wheel dressed to the right profile to make that ball race, and
grind after turning to just a bit short of the final size. (Actually,
you should also harden the steel between the turning operation and the
grinding operation.

Of course, using a toolpost grinder on a good lathe is always
fraught with worry about damage from the abrasive thrown by the grinding
operation.

Good Luck,
DoN.
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