Patent ID: 7112112

Claim:
A method for making a spark plug having a center electrode disposed inside an insulator, a metallic shell disposed outside the insulator, and a ground electrode having a base end side connected to a leading end surface of the metallic shell and a leading end side bent so as to have a side surface that is opposed to a leading end surface of the center electrode to form therebetween a spark gap, the method comprising the steps of: for adjustment of a spark gap of a spark plug work having the center electrode and the ground electrode, provisionally pressing the ground electrode of the spark plug work toward the leading end surface of the center electrode and thereby decreasing the spark gap to a predetermined value larger than a final target gap gt; after the step of provisionally pressing the ground electrode, performing an adjustment bending process for bending the ground electrode in the widthwise direction thereof so as to eliminate an eccentricity δ of the ground electrode with respect to a target position; after the step of performing the adjustment bending process, measuring a spark gap g 1 of the spark plug work and measuring a difference (g 1 −gt) between the measured spark gap g 1 and the final target gap gt; and pressing the ground electrode toward the center electrode when the difference (g 1 −gt) is positive; wherein the widthwise direction is different than the direction of pressing the ground electrode toward the center electrode.