Method of forming a hub for use in a disk drive motor

A method of forming a hub for use in a disk drive motor, comprising:

• providing a hub structure having opposite first and second surfaces, the hub structure having formed therein a first conical void and a second conical void, the first conical void and the second conical void each having a wide opening and a narrow opening and formed in the hub structure so that the narrow openings meet at a center opening, the wide opening of the first conical void is formed at the first surface, and the wide opening of the second conical void is formed at the second surface;
• providing, from the wide opening of the first conical void, a cutting tool having an outer radial surface for machining the inner surfaces of the first conical void and the second conical void, wherein relative dimensions of the cutting tool and the center opening allow the cutting tool, when the outer radial surface of the cutting tool is positioned against the inner surface of the first conical void, to traverse the center opening on a path parallel to an axis of rotation of the cutting tool;
• and
• machining the inner surfaces of both the first conical void and the second conical void while maintaining the providing of the cutting tool from the wide opening of the first conical void.