OK that worked. I made 2 cuts with the dremel , using the 1/16" cutter disk. Cut as deep as I dared, and whacked it with the cold chisel. No effect the first try, so I cut a
little bit deeper, then hit it again and it cracked. I nicked the shaft with the dremel, ever so slightly. But at least the bearing is off.
Fabricator, you're right, I could have prepared a lot more before starting. Serves me right! Would have spent 15 minutes with sandpaper, scotchbrite, and a check with a micrometer, rather than 4 hours cranking, cursing and almost breaking the rotor.
By the way, while trying to look for ideas on other websites like "practical machinist" I found lots of advice that made no sense, like running a weld bead around the inner race. For the record, that sounds like a bad idea to me. They seemed to think that the post-weld contraction would made the bearing race bigger...
The other advice about heating it up with an oxyacetylene torch sounds like inviting disaster, warping the shaft. Then the craziest folks say they put the
cutting torch on and remove the race with that!!
You guys are the best. Thanks!