A magnetic-disk glass substrate containing an alkali metal component as a glass composition includes a pair of main surfaces and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface with a roughness percentage that is 40% or more when a bearing ratio of a roughness cross-sectional area is 50%, in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained by etching the outer circumferential side edge surface by 2.5 μm is measured.

A magnetic-disk glass substrate containing an alkali metal component as a glass composition includes a pair of main surfaces and an outer circumferential side edge surface that is a mirror surface. The outer circumferential side edge surface includes a surface with a roughness percentage that is 40% or more when a bearing ratio of a roughness cross-sectional area is 50%, in a bearing ratio curve of roughness cross-sectional areas obtained when a surface roughness of the outer circumferential side edge surface obtained by etching the outer circumferential side edge surface by 2.5 μm is measured.

Various examples are provided for polishing techniques for flexible tubular workpieces. In one example, a method includes supporting a tubular workpiece on a rod that extends axially through it; positioning a turning wheel against an external surface of the tubular workpiece, where it is held by magnetic attraction; and rotating the tubular workpiece by rotating the turning wheel. The external surface of the tubular workpiece is polished by the abrasive particles during rotation of the tubular workpiece. In another example, a polishing system includes a workpiece holder including a rod configured to axially support a tubular workpiece; a turning wheel with abrasive particles distributed about an outer surface; a wheel support assembly configured to position the outer surface of the turning wheel against the an external surface of the tubular workpiece, where it is held by magnetic attraction. The external surface is polished during rotation of the tubular workpiece.

Various examples are provided for polishing techniques for flexible tubular workpieces. In one example, a method includes supporting a tubular workpiece on a rod that extends axially through it; positioning a turning wheel against an external surface of the tubular workpiece, where it is held by magnetic attraction; and rotating the tubular workpiece by rotating the turning wheel. The external surface of the tubular workpiece is polished by the abrasive particles during rotation of the tubular workpiece. In another example, a polishing system includes a workpiece holder including a rod configured to axially support a tubular workpiece; a turning wheel with abrasive particles distributed about an outer surface; a wheel support assembly configured to position the outer surface of the turning wheel against the an external surface of the tubular workpiece, where it is held by magnetic attraction. The external surface is polished during rotation of the tubular workpiece.

A magnetic field manipulated localized polishing system includes a container holding a volume of a magnetic abrasive fluid. The magnetic abrasive fluid contains abrasive particles. A motor is positioned under the container. A magnet is coupled to the motor such that the motor induces rotation of the magnet. A workpiece is suspended in the container.

A magnetic field manipulated localized polishing system includes a container holding a volume of a magnetic abrasive fluid. The magnetic abrasive fluid contains abrasive particles. A motor is positioned under the container. A magnet is coupled to the motor such that the motor induces rotation of the magnet. A workpiece is suspended in the container.

Various examples are provided for hybrid tools including fixed-abrasive and loose-abrasive phases. In one example, a hybrid tool for finishing an internal surface of a workpiece includes a metallic rod and magnetic abrasive bonded to one or more defined portions of the metallic rod by an adhesive that dissolves when n contact with a lubricant used to finish the internal surface of the workpiece. In another example, a method for finishing an internal surface of a workpiece includes mounting the workpiece in a chuck of a lathe; positioning a hybrid tool inside an internal cavity of the workpiece using one or more pole-tips; providing an amount of the lubricant to the internal cavity; and rotating the workpiece with the lathe while controlling positioning of the hybrid tool inside the internal cavity using the one or more pole-types.

Various examples are provided for hybrid tools including fixed-abrasive and loose-abrasive phases. In one example, a hybrid tool for finishing an internal surface of a workpiece includes a metallic rod and magnetic abrasive bonded to one or more defined portions of the metallic rod by an adhesive that dissolves when n contact with a lubricant used to finish the internal surface of the workpiece. In another example, a method for finishing an internal surface of a workpiece includes mounting the workpiece in a chuck of a lathe; positioning a hybrid tool inside an internal cavity of the workpiece using one or more pole-tips; providing an amount of the lubricant to the internal cavity; and rotating the workpiece with the lathe while controlling positioning of the hybrid tool inside the internal cavity using the one or more pole-types.

A method for subjecting garment accessories to a surface electrolytic treatment provides various metallic colors to metallic garment accessories in a cost effective manner. The method can provide a first metallic color on one side of outer surface of the garment accessory and provide a second metallic color on the other side of the outer surface, by placing one or more metallic garment accessories in an electrolytic solution in a non-contact state with an anode and a cathode for passing electric current through the electrolytic solution, passing electric current through the electrolytic solution and generating a bipolar phenomenon on the garment accessory.

A method for subjecting garment accessories to a surface electrolytic treatment provides various metallic colors to metallic garment accessories in a cost effective manner. The method can provide a first metallic color on one side of outer surface of the garment accessory and provide a second metallic color on the other side of the outer surface, by placing one or more metallic garment accessories in an electrolytic solution in a non-contact state with an anode and a cathode for passing electric current through the electrolytic solution, passing electric current through the electrolytic solution and generating a bipolar phenomenon on the garment accessory.