First of all, thanks to everyone who offered advice. It was very much appreciated.
As it turns out, I had another, broken, 700E eccentric that I happened to find in my junk box. As I looked at it, I wondered just how tough the steel casing was around the cast metal tube. So, I got a pair of side cutters and the thing collapsed pretty easily. SOOOOOOO, being very careful, I just sort of started to nip away at the one in the photo. I’d grab a bit of the thin steel, pull it and sort of curl it—all the time being very careful not to put too much stress on the wheel—and as I did this, the cast inner tube sort of crumbled. It took some time and patience, but I finally got her off clean, with no damage to the wheel or the pin. By the way, I did try WD40 and 3 in 1 penetrating oil, all to no avail, as it was really stuck in there and did not come loose until I had virtually all of it cut away.
