摘要:
A method of forming a fracture start portion of a con rod for forming fracture start portions of a con rod at opposing positions in an inner peripheral surface of a large end of the con rod made of metal, includes a first step of forming a groove portion at a position corresponding to the fracture start portion by using a first insert tip with a large tip end and a second step of forming the fracture start portion, which has become a V-shaped groove, by machining a bottom portion of the groove portion smaller by using a second insert tip having a tip end smaller than the first insert tip.
摘要:
A method of forming a fracture start portion of a con rod for forming fracture start portions of a con rod at opposing positions in an inner peripheral surface of a large end of the con rod made of metal, includes a first step of forming a groove portion at a position corresponding to the fracture start portion by using a first insert tip with a large tip end and a second step of forming the fracture start portion, which has become a V-shaped groove, by machining a bottom portion of the groove portion smaller by using a second insert tip having a tip end smaller than the first insert tip.