METHOD FOR MANUFACTURING METAL FITTING, METHOD FOR MANUFACTURING SPARK PLUG, AND METHOD FOR MANUFACTURING SENSOR

摘要

PROBLEM TO BE SOLVED: To reduce cost of manufacture in a method for manufacturing a metal fitting.SOLUTION: The method for manufacturing a metal fitting including a tool engaging part with which a tool engages includes a cold-forging step. The cold-forging step includes the steps of: (a) forming a trunk part having a first maximum length and a root part having a second maximum length longer than the first maximum length and continued to the trunk part; and (b)forming the tool engaging part by drawing at least part of the root part in an axial direction.