Patent ID: 7640665

Claim:
A method of manufacturing a shaft unit for a motor having a rotor supported by a radial fluid dynamic bearing mechanism that will surround the shaft unit, the method comprising: readying machining stock as a workpiece, wherein the machining stock has a hole which extends axially along a center axis of the stock and forms a first mouth in a first end of the stock, and the readying comprises chucking the workpiece in a state in which the workpiece is rotatable relative to a cutting tool about a first axis coincident with the center axis; inserting sealing material into the hole to seal the hole; subsequently machining the workpiece along the periphery thereof radially outwardly of the hole with the cutting tool to form a shaft having a central longitudinal axis that is coincident with the center axis; and transecting the workpiece along a boundary that passes through the center axis on an opposite side of the sealing material from where the first mouth is located to separate from the workpiece a shaft unit which includes the shaft and the sealing material.