Abstract: A track slider grinder grinds a track slider of ferrite having a tracing surface and an integral C-shaped core positioned on one side of the tracing surface and including a coil support portion in the form of a quadrangular prism having a central axis.

Abstract: A thin electric wire is wound as a coil around a core through a small-diameter hole defined therein. The wire is threaded through the hole on an air stream flowing through the hole which is vacuum generated. Since the wire is drawn into the hole by the air flow, the wire is not required to be positioned correctly with respect to the core hole. After the wire has been inserted through the core hole, the wire enters a suction pipe and is wound around the core by turning movement of the suction pipe. When the wire is to be threaded through the core hole again, the distal end of the wire is positioned and cut off. A cut end of the wire is positioned substantially centrally of the core hole. Thereafter, a vacuum is developed again in the suction pipe to draw the wire through the core hole. The wire is thus wound around the core in as many coil turns as desired.