The whole spindle drive tube (Quill) will drop out.
remove all tools
remove the quill manual drive assy by pulling spring load assy and extract shaft out other side.
left side of box, remove set screw jam, under it is actual set screw dog point which sets into groove in Quill
then loosen the quill lock and drop out quill.
there is a lock nut assy on top of spindle to be removed then all the bearings and spindle slide apart.
Stock bearings are conical rollers, good for most usage, and when reassembled are set to zero plus one lock.
A better replacement bearing is a low end angular contact ball set #'s are:
top, (koyo) 7206BGC3 FY S0607
bottom, (koyo) 7207BGC3 FY S0605
These will require a little more preload setting, mine took zero +3 on the lock to take out all slack when warmed up. I started at +1 and after warming spindle I grabbed spindle and wiggle checked it then tightened +1 on lock and repeated. when I reached +3 it remained solid when warm from use.
Also, and I feel this is important ! I took an old boot and cut a round out of the leather that will lay on the bottom threaded spindle nut, and cut a tight hole to slide over spindle, then put this on nut and run the nut home as a seal. This prevents the melting grease from escaping and coolant from washing out bottom bearing. It is amazing how simple yet effective it is at keeping the lube where it belongs for the bottom bearing. Next thing is to use the best grease for the spindle bearings that you can find, If you have a bearing supply house local, go in and ask for some, spindle grease has a much better ability to stay with the bearing than does automotive bearing grease.
After you have done it once you can effectively do all this in an hour or two. It does not take that long so there is no reason to not keep these bearings in proper condition.
I have no idea what the tool is for as all my bearings slipped off and on easily by hand !
The cost of these angular contact bearings is just slightly more than the stock bearings and well worty it if you are planning on increasing spindle speed. There are much more expensive AC bearings available, but not worth the expense !
Again, don't skimp on the grease ! My spindle totally vaporized the stock grease and the bearings were on the verge of exploding in a very short period of time. But then again, my gear box and quill was contaminated with cast iron fine too ! That is one of the issues which Gene put the KYBOSH too right away ! Cleanlyness, and QC !
Almost forgot, I don't have any idea how Aaron did his drive, this may alter the above description of what to expect ! You may find that you will need to remove motor and gear box lid ! It all depends on how he attached the drive to the spindle. The stock drive allows the spindle to drop out of it very easily !