Abstract: Minute and uniform line marks can be formed on the surface of a glass substrate for a magnetic disk by pressing a woven cloth tape comprising plastic fibers preferably by a rubber roller with hardness greater than 60 and causing it to run thereover while supplying a suspension containing abrading particles and a solution which contains hydroxyl groups such as a KOH solution.

Abstract: A glass substrate for a magnetic disk has one or both of its surfaces processed by applying a suspension of a specified kind onto the surface to be processed while the substrate is rotated and a polishing tape is pressed and run against the surface to be processed. The suspension includes abrasive particles with average diameter selected according to the purpose of the processing and an aqueous solution containing a reacting liquid capable of causing a solid phase reaction at contact boundary surfaces between the surface of the glass substrate and these abrasive particles. The polishing tape is removed from the glass substrate when the polishing is over but while the tape is still running and the glass substrate is rotating. The supplying of the suspension is thereafter stopped and a washing liquid such as water is applied to the polished surface or surfaces while the substrate is still rotating. Both surfaces of a glass substrate may be polished at the same time.

Abstract: Minute and uniform line marks can be formed on the surface of a glass substrate for a magnetic disk by pressing a tape planted with hairs against the substrate surface and causing it to run thereover while supplying suspension containing abrading particles and a solution which contains hydroxyl groups such as a KOH solution.

Abstract: A mirror-finishing method embodying this invention, with which the above and other objects can be accomplished, may be characterized as comprising the step of supplying a solution containing hydroxyl groups on a target surface to be polished of a glass substrate while simultaneously pressing onto this target surface an elastic sponge material having abrading particles affixed therein and a plurality of indentations on a polishing surface thereof, and causing the substrate and the sponge material to move with respect to each other.