I am glad to see Frank has rose up from the dead. He hasnt posted in years.
Yes their are 2 different size holes. The bearing 5/16 and they are steel. The first hole is the size of the bearing and is drilled partway down into the hollow shaft. The 2nd hole is all the way thru so that the bearing doesnt fall down thru. This hole also allows the bearing to protrude thru the hole so we can push it up thru. I do not know the depth of the first hole or the diameter of the second hole. sorry