Hi Tesser. Welcome to our little corner of the 'net.
As others have indicated, getting parts for older power tools from Sears is akin to searching for the Holy Grail... both impossible to find.
As Charles stated, the bearing should be a generic item. If you have an industrial supply house, or even a shop that repairs small electric motors, you should be able to source the bearing thru them.
Sometimes I wonder whether the world is being run by smart people who are putting us on
or by imbeciles who really mean it.