Think I posted having problems getting one of the gearbox bearings out, in a blind hole. The bearing is conical, and a small amount of leverage popped out the balls and carrier leaving a conical internal surface and no space behind to get anything substantial in to grip:

So I ended up grinding it out (no damage to the case

A less traumatic way to do that job is to use a stick welder to run a weld bead around the inside of the bearing outer. When this cools the weld shrinks the bearing outer and it will usually just fall out.