PURPOSE: To enable the formation of an inside bevel ring without any fracture or peeling of a plated layer and in a shorter process than grinding by forming a peripheral groove on the upper surface of a ring and grinding the inner surface thereof up to the end of the external surface groove after surface treatment and finish machining.

CONSTITUTION: A V-groove of about 1mm width and depth is formed on the periphery of the upper surface of a piston ring having a rectangular cross section, about 8mm inward from the external surface of the ring 1, and masking is applied to the bottom surface and the inner surface of the ring 1. Then, a chrome plating layer 2 of about 100μm thickness is formed according to the conventional method. And the during 1 with the abutment thereof closed is mounted on a lathe and the upper inner surface thereof is turned, thereby forming an inside bevel ring.