I know there has been a little bit of discussion in the past about worn bearings and how to get them out, but I wanted to add my experience for future bearing replacers. I have been restoring a super jolly and the burrs were a little rough (too loud for my little kitchen) so I decided to replace them since they aren't expensive. I spent several hours researching types of bearings (lots of different grades and specs) and devising removal and installation plans/homemade tools. I started to try and pull the old bearings myself but I gave up when I got to the bottom bearing. It does have a threaded hole but I was just stripping this out; bearings weren't budging!

Here is what I did (and what you should do too if you don't have experience with bearings and access to a puller and press.)
I removed the four screws from the bottom bearing carrier and obviously the burrs and top bearing cover. Then with the lower burr carrier bolt reinstalled in the motor shaft, I used a regular old hammer to tap the armature (rotor) out the bottom. I placed a towel under the grinder to cushion the fall. Now that the bearings were accessible, I emailed a few bearing suppliers in the area and asked if they would be able to pull the old bearings and press the new bearings. One place said they might be able to if I brought the piece for them to look at. I did this but they were unsure about it and didn't want to damage anything, so they referred me to an electrical shop down the street that apparently specializes in electric motors. I was in and out of there in about 10 minutes. They had the bearings on hand (they "upgraded" me to sealed bearings after they denied my concern that sealed bearings might be louder) and were able to effortlessly pull and press the two bearings. This all ran me $20. The bearings were $10 a piece and they didn't charge me for labor. I think the same bearings online are about $7 so the added price at the shop provided me with removal and installation service. A pretty good deal in my book! So if anyone is considering bearing replacement, I'd suggest just take it to an electrical shop in your area (after giving them a call and confirming they do work on electric motors) and save yourself a lot of time and hassle. One thing to note, I could not remember which way the bottom bearing carrier went on (I had a photo at home) so they pressed the bearing into the carrier but then left it up to me to install the carrier and in turn press the carrier and bearing assembly onto the shaft. Not a huge deal, but an extra 10 minutes of my time I wouldn't have had to spend working on this thing (using the mounting screws to press the carrier on) if i just knew the orientation of the carrier. I hope this is useful information to whoever it concerns!

Hey John, my serial number is 9708146. I guess it would be a '97? Not sure if that is correct logic or not. The stock bearings were metal shielded, but the new ones are rubber sealed.