Abstract: A dummy substrate is formed with a disk-shaped glass substrate having a center hole, and a magnetic recording film on an outer circumferential surface along a thickness direction of the glass substrate and an inner circumferential surface of the center hole, and a surface roughness (Ra) of one surface and the other surface of the glass substrate is in a range of 0.2 nm or more and 100 nm or less.

Abstract: A gun drill machine capable of shortening a margin dimension required in a gun drill as much as possible. In a free zone between a chip box and a moving spindle unit, a plurality of swing stopping devices for loosely holding a gun drill and suppressing the swing of the gun drill are arranged, and each swing stopping device is configured to freely retract from a steady action position where a swing stopping action is performed to avoid interference with the spindle unit that moves in the free zone.

Abstract: A dummy substrate is formed with a disk-shaped glass substrate having a center hole, and a magnetic recording film on an outer circumferential surface along a thickness direction of the glass substrate and an inner circumferential surface of the center hole, and a surface roughness (Ra) of one surface and the other surface of the glass substrate is in a range of 0.2 nm or more and 100 nm or less.

Abstract: A gun drill machine capable of shortening a margin dimension required in a gun drill as much as possible. In a free zone between a chip box and a moving spindle unit, a plurality of swing stopping devices for loosely holding a gun drill and suppressing the swing of the gun drill are arranged, and each swing stopping device is configured to freely retract from a steady action position where a swing stopping action is performed to avoid interference with the spindle unit that moves in the free zone.

Abstract: There is provided a method of producing a substrate for magnetic recording media which is capable of efficiently removing alumina abrasive grains in the latter polishing step that have been stuck in the former polishing step during polishing of the substrate for magnetic recording media in which a NiP plating film has been formed on the surface of an Al alloy substrate, the method including: a rough polishing step for polishing the surface of a substrate for magnetic recording media, which is prepared by forming a NiP plating film on the surface of an Al alloy substrate, using a first grinder while supplying a polishing liquid containing alumina abrasive grains; and a finish polishing step for polishing the substrate for magnetic recording media following washing, using a second grinder while supplying a polishing liquid containing colloidal silica abrasive grains, wherein supply of the polishing liquid containing alumina abrasive grains is stopped and alumina abrasive grains are removed from the grinder b

Abstract: There is provided a method of producing a substrate for magnetic recording media which is capable of efficiently removing alumina abrasive grains in the latter polishing step that have been stuck in the former polishing step during polishing of the substrate for magnetic recording media in which a NiP plating film has been formed on the surface of an Al alloy substrate, the method including: a rough polishing step for polishing the surface of a substrate for magnetic recording media, which is prepared by forming a NiP plating film on the surface of an Al alloy substrate, using a first grinder while supplying a polishing liquid containing alumina abrasive grains; and a finish polishing step for polishing the substrate for magnetic recording media following washing, using a second grinder while supplying a polishing liquid containing colloidal silica abrasive grains, wherein supply of the polishing liquid containing alumina abrasive grains is stopped and alumina abrasive grains are removed from the grinder b