Patent ID: 7424817

Claim:
A method of working a recessed portion in a headrest stay which is provided in a stay portion of said headrest stay formed of a pipe, comprising the steps of: preforming a recess by rotatingly pressing against said stay portion an outer peripheral portion of a first punch roller for preforming having a rounded portion on the outer peripheral portion in a side view; and directing toward and rotatingly pressing against said recess an outer peripheral portion of a second punch roller on the outer periphery portion of which a punch portion for final forming has been formed, so as to form a recessed portion, wherein the outer peripheral portion of said first punch roller is asymmetrical, further including an inclined surface which slopes downward toward the rounded portion, and wherein the outer peripheral portion of said second punch roller is asymmetrical, further including an inclined surface which slopes downward toward the punch portion, and wherein the punch portion includes a vertical portion and a flat portion which intersect at a right angled portion.