US Patent 8678949 Golf club head and manufacturing method for the same

A golf club head manufacturing method, including: welding a first reinforcing piece with first thickness to a central portion between a toe and a heel, so as to extend along an edge of a face side of a sole part, the sole part being part of a lower part formed integrally with a side part; welding a second reinforcing piece of second, larger thickness to a central portion between the toe and heel so as to extend along the edge on the face side of the first piece; welding a face part to the first and second pieces from an inner space of the lower part; welding a hosel part to the lower and face parts; welding a crown part to the lower, face and hosel parts; and welding the lower and face parts together from the outside.