1 A ball bearing company uses precision machinary for maintaining limits and tolerences specified as per the standards.
For that they are using precision lathe for turning of the pipes initially,cylindrical grinding m/c for the rough finished surfaces,honing machines, lapping machines for the lapping of balls.
All these machines uses well advances CNC(computer numerical controlled) machinaries.
These operations are carried out at a constant temperature so that the tolerence/limits on machining should not be improper. This is possible if different components are machined at different temperature.
You also may be interested in how the balls are filled in between inner race and outer race.Pl. read:
(A Conrad bearing is assembled by placing the inner and outer races radially offset, so the races touch at one point and have a large gap on the radially opposite side. The bearing is then filled by placing balls in to the large gap, then distributing them around the bearing assembly. The act of distributing the balls causes the inner and outer races to become concentric. If the balls were left free, the balls could resume their offset locations and the bearing could disassemble itself. Thus, a cage is inserted to hold the balls in their distributed positions. The cage supports no bearing load; it serves to keep the balls located. Conrad bearings have the advantage that they take both radial and axial loads, but the disadvantage they cannot be filled to a full complement and thus have reduced load-carrying capacity compared to a full-complement bearing. The Conrad bearing is named for its inventor, Robert Conrad, who got British patent 12,206 in 1903 and U.S. patent 822,723 in 1906.
A slot fill radial bearing is one in which the inner and outer races are notched so that when they are aligned, balls can be slipped in the slot in order to fill the bearing. A slot-fill bearing has the advantage that the entire groove is filled with balls, called a full complement. A slot-fill bearing has the disadvantages that it handles axial loads poorly, and the notches weaken the races. Note that an angular contact bearing can be disassembled axially and so can easily be filled with a full complement.
The outer race may be split axially or radially, or a hole drilled in it for filling. These approaches allow a full complement to be used, but also limit the orientation of loads or the amount of misalignment the bearing can tolerate. Thus, these designs find much less use.
Most ball bearings are single row designs. Some double row designs are available but they need better alignment than single-row bearings. )

2 They put the molten steel into a mold that shapes it. If they want to do another one, they use the same mold.

3 check out National Geographic channel or discovery channel in your area. Got a progran called How it's made. Shows 4 different things each time it’s aired and it airs couple times a day. I know for a fact they had ball bearings on there once. Done with a machine. May be on one of their websites too.

4 Balls are headed so they are roughly round. They are then subjected to several hours of grinding in a batch. The grinding operation continuously makes then rounder, and rounder. It takes many hundred hours of grinding to completely finish a batch. The size of the batch is a function of the size of the balls.