| 摘要 |
<p>A grinding operation is performed by rotating a motor hub (1) at high speed around the central axis thereof, and urging an outer peripheral surface of a grinding wheel (8) rotated at high speed around the central axis against the upper surface of the outwardly extending flange (4) for supporting on its upper surface (B) the lower surface of the central portion of a magnetic disk. The upper surface of the flange (4) can be processed in high precision. Thus, a compact, large capacity, and reliable hard disk drive device is to be provided by reducing the rotational runout of the magnetic disk incorporated within the hard disk drive device. <IMAGE></p> |
