Patent ID: 7413496

Claim:
A method of polishing a thin-plate cylindrical metal ring for use in an endless belt of a continuously variable transmission, comprising: a projecting step of projecting the metal ring; a first brush polishing step of polishing one edge of the metal ring projected in the projecting step by a polishing brush; an inverting step of inverting the metal ring whose one edge is polished in the first brush polishing step; a second brush polishing step of polishing the other edge of the metal ring inverted in the inverting step by the polishing brush; and a clearing step of clearing the metal ring whose other edge is polished by the second brush polishing step; wherein the first and second brush polishing steps comprise the steps of: holding the metal ring substantially in a circular shape to rotate the ring in a circumferential direction; further allowing the polishing brush formed in an annular shape having a diameter larger than that of the metal ring to be rotated to abut on the metal ring so as to cross the edge of the rotating metal ring, and the polishing brush enters the metal ring at an incidence angle in a range of 20° to 45° with respect to a track of the rotating metal ring and passes between an inner peripheral surface of the metal ring and a rotation center of the metal ring and leaves the metal ring at an outgoing angle in a range of 20° to 45° with respect to the track of the metal ring, when the polishing brush crosses the edge of the rotating metal ring.