| 摘要 |
<p>Three cylindrical concaves (reduced thickness portions) are formed in the intermediate portion between the centering so as to be spaced apart each other in the direction of the axis of the shaft inserting hole. The cylindrical concaves are formed to have an inner diameter of 11.3 mm that is larger than the inner diameter at the centering portions by removing the thickness of the hosel portion from its inner diameter of the centering portions towards outer side. The summed lengths of the bottom surfaces (peripheral surfaces) of the cylindrical concaves in the direction of the axis of the shaft inserting hole is 12 mm, thus reducing weight of the hosel portion by 3.03 g compared with conventional hosel portions. The reduced weight can be reallocated, to the sole portion. The gold thus produced in less expensive and has a reduced weight of the hosel.</p> |
