For internal races weld a bead around the interior and when it cools the shrink will make them loose - they just about fall out.
I cut the cage, pull the balls or rollers out of the way, and then split the race with a Dremel tool or grinder razor blade to free them from the shaft.
To install just warm the bearings up in an old toaster oven. I laid them on a kerosene heater I was using and dropped them in place. A press is useful too, just use the old races that were welded or split to push on the new races.
See John Smith's site for tips on installing bearings too. I think that is where I got the toaster over idea.
Check the running torque per the manual by wrapping the shaft with a cord and pulling on a fish scale. One has to do a little math to calculate the radius for the torque measurement.