PRODUCTION OF WOOD GOLF CLUB HEAD

PURPOSE:To reduce thermal strain and improve thermal strength by rotating one of both cylinder and sole plate to press the contacting surfaces of both members against each other and bond the melted materials of both members to each other while one end of the cylinder is brought into contact with a predetermined position of the rear surface side of the sole plate. CONSTITUTION:A method of coupling a metal sole plate 3 with a metal cylinder 4 formed with a recess comprises the steps of mounting one of the sole plate 3 and cylinder 4 on a shaft of a rotary drive device, fixing the other and causing the confronting contact surfaces of both members to abut against each other. When the rotary drive device is rotated under such a condition with a predetermined rotational frequency, for example, of about 3,000rpm, frictional heat is generated on said contact surfaces of both metal members and both members begin to melt with the the further continuation of rotation. When the rotation of said device is stopped under such condition and both members are pressed against each other with predetermined pressure, the melted metals themselves are united with each other. When said metals are cooled naturally, the sole plate 3 and cylinder 4 provide an integral structure.