servo motor shaft 5/8 to 1/4...best way??

Hello,

I am considering some servo motors which have a 5/8 shaft, but I
need to couple to 1/4 shaft couplers. I cannot open the couplers
up enough, so I am trying to figure out the best way reduce the
shaft diameter, or maybe attach a 1/4" adapter endpiece.

My question: Can the shafts be easily removed from a servo motor
to be chucked up in a lathe? Will I never get the thing
re-assembled properly? Maybe even chuck the motor in the lathe
and power it up!!??

All suggestions appreciated.

Thanks,

Eric