Here is a rather large (for me) bull nose ball bearing center. It is 3" in diameter with a Morse Taper 2 shank.
The MT2 is machined out of one piece of steel along with the bearing hub. I should have taken some pics of that part prior to assembly to show how the bearing is retained.
I will try to explain it:
First off the inner race of the bearing is an interference fit to the shaft. I froze the shaft and warmed the bearing (no grease yet). It is a good tight fit. I then greased the bearing and added the large turned washer to retain it. (not really needed but just in case). After re-freezing the greased bearing and MT 2 arbor with the washer installed, I heated the cone to about 600 degrees and slipped the two pieces together.
There is a 1/2-13 set screw in the nose. It's purpose is simply to keep chips out of the inside where they
could get to the bearing. If it ever needs to come apart I will remove the set screw and then press it apart.
Doubt that I will ever have to take it apart but maybe someday someone will!