Method for manufacturing spark plug and apparatus for carrying out the same

摘要

A method for manufacturing a spark plug that can calculate, in measurement of a gap, an accurate gap regardless of inclination of a workpiece (a spark plug) with respect to a measurement device and can manufacture the spark plug at high accuracy as well. Also disclosed is an apparatus for carrying out the same. A plurality of measurement points are determined on the outline (tip edge E 2 ) of a ground electrode spark gap definition portion of a ground electrode W 2 facing a spark gap and on the outline (tip edge E 1 ) of a center electrode spark gap definition portion of a center electrode W 1 . The measurement points represent the outlines of the respective spark gap definition portions. A single measurement point on the outline of one spark gap definition portion is selected as a reference point. A measurement point on the outline of the other spark gap definition portion is found such that the distance between the measurement point and the reference point is the shortest. The gap is determined based on the shortest distance.