Birch, Stewart, Kolasch & Birch, LLP
Manufacturing method of golf club head
A manufacturing method of the present invention includes the steps of: preparing a pre-line forming member having no face line; and cutting the pre-line forming member using a cutter 12 to form the face line on the pre-line forming member. The cutter 8 has a tip part having a cutting surface. The cutting surface has a recessed curved surface c4. An edge of the face line 8 is cut by the recessed curved surface c4. Preferably, the step of cutting is carried out by axial rotation of the cutter 8. Preferably, the cutting surface has a plane part c5 formed on an upper side of the recessed curved surface c4. Preferably, the upper side plane part c5 is perpendicular to a rotation axis rz of the cutter 12. Preferably, the cutting surface has a conical surface Fc formed on a lower side of the recessed curved surface c4. 
SRI Sports Limited
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Takashi
Nakano