I have noticed in several posts that makers split their bearings or eccentrics after shaping them. Two problems with this method, holding an odd shape part also being delicate very light cuts required with the slitting saw.
Earlier practice was to face the two mating surfaces then solder together, bore the shaft hole, then drill clamping holes, separate the parts and mount on a slightly oversize mandrill then finish shape. This allows the mandrill to be held in a lathe chuck for tuning or fixed to a rotary table to be shaped.
Given that there are more than one way to skin a cat, you have a choice
Mike