The threads do not continue, so even with driving the pin out, you can not unscrew it.
the "cup" is attached and peaned in place
why do you want to take it apart?
The screw and threads are aluminum. Simply unscrew the clamp until it forces the "cup" off the part. When you go to re-assemble it you will need to drill and tap the threaded part to hold the cup on with a screw.because you probably will not be able to re-peen the shaft.