| 摘要 |
<p>PROBLEM TO BE SOLVED: To hit a ball with appropriate backspin quantity according to each club number by cascadedly reducing a cross-sectional angle of a corner part formed between the hit ball face and a groove inclination face in the cross sectional shape of a plurality of face line grooves provided in the ball face, as the number increases. SOLUTION: In an iron club set composed of a plurality of iron clubs, the numbers of respective iron club numbers are different in order and as the number becomes larger, the loft angle is increased and the length of the club is shortened. In this case, the cross sectional angle of a corner part 5 formed between the hit ball face 2 and a groove inclination face 4 in the cascadedly, as the number increases. The pitch (P) of the face line grooves 3... is set to not less than 1.2mm and not more than 6.0mm. This constitution can provide an appropriate backspin quantity of a hit ball suited to respective number of club without adjusting the hitting way.</p> |
