| 摘要 |
<p>PROBLEM TO BE SOLVED: To make it possible to obtain stable directivity simply when a golfer makes a swing in an ordinary manner without adjusting the swing over of the entire shaft number of a golf club set. SOLUTION: The angleθformed by plural pieces of face line grooves 3... parallel with each other formed on a ball hitting face 2 when viewed from the direction perpendicular to the ball hitting face 2 and the horizontal line H of a head 1 is decreased by 1 to 3 deg. each successively or stepwise as the shaft number is higher. The angleθformed by the face line grooves 3 and the horizontal line H of the head 1 is set within±15 deg..</p> |
