To provide a manufacturing method of a glass substrate for a magnetic disk with which flatness of a main side is excellent to an outer circumferential terminal portion and a polish step that requires large machining allowance can be omitted.
A manufacturing method includes: a molding step of molding a glass blank by press-molding a lump of molten glass; a shape machining step of performing shape machining on the molded glass blank into a disk-shaped glass substrate; a chamfer face forming step of forming a chamfer face at least in an outer circumferential terminal portion of the disk-shaped glass substrate; and a polishing step of polishing a main side of the glass substrate having the chamfer face formed. In the molding step, central portions of a pair of main sides are recessed and the glass blank is molded to increase the thickness from the central portion to the outer circumferential terminal portion. In the chamfer face forming step, the glass substrate is formed in which a projection is interposed between the main side and the chamfer face. In the polishing step, the glass substrate is polished in such a manner that the projection becomes as high as the main side.
YANO HIDEKAZU
MURAKAMI AKIRA
SATO TAKASHI
SATO MASAMUNE
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