To provide a polishing stone, etc., which improves its straightness during mirror-finishing, and also prevents a burn mark produced on a cut surface.
The polishing stone is provided with a stone part 52 arranged at least on an outer peripheral part of at least one side face, and a plurality of grooves 58 formed by cutting off a part of the stone part. A contact area of the polishing stone with a workpiece during polishing is sufficiently minimized by providing the stone part on the outer peripheral part of the side face of the polishing stone and further by providing a plurality of grooves on the stone part according to this configuration. Therefore, the sufficient straightness during polishing is achieved even if the polishing stone is thin, and as a result, the accuracy of the mirror finishing is improved. Further, because a sufficient coolant is supplied to the polishing point through a plurality of the grooves formed on the stone part, the polishing point is satisfactorily cooled.
Tetsuo Kanamoto
Koji Hagiwara