Steve,
Take the bearing off the end of the shaft .....
Mount between your chuck and a centre in the tail stock.....
Now with a hacksaw, saw thru the windings just after the rotor stampings.

You then need to remove the wire in between the 'ears' ....you can just cut thru with a saw blade down to towards the centre..and remove the wire as you go.....the rotor stampings will eventually come free...there's a plastic 'stamping' at each end of the rotor that has a sleeve extension that the shaft passes thru. You can pull the plastic off from the shaft..
Once the wire is removed and the plastic stamping you should be able to remove the shaft without any damage....the rotor stampings will be free....
Slowly slowly catchy monkey......

Out of curiosity, what diameter is the rotor? And how many copper segments are there on the commutator? ( might make a nice brushless motor if it's 12.....

)