Abstract: In a golf ball having at least a set of large and small diameter dimples, the large and small diameter dimples are of the same cross-sectional shape in their lower portion. The small diameter dimple (2) has the same shape in cross-sectional view from a depth of 0.01 mm below the dimple (2) edge (3) to the bottom as that of the bottom portion of the large diameter dimple (1). A master model is prepared by feeding a cutter into a hemispherical surface of a master block to different depths while rotating the cutter, thereby forming a set of large and small recesses, respectively, wherein the large and small recesses have the same cross-sectional shape. The master model having plural types of dimples can be briefly fabricated and has increased freedom of design. Using the master model, a golf ball featuring uniform and densely distributed dimples can be manufactured.

Abstract: A golf ball having a plurality of dimples formed in its surface and a diameter of 43 to 45 mm, wherein when a phantom great circle is depicted on the ball surface to divide the ball into two hemispheres and one hemisphere is developed by Lambert conformal projection to depict a planar expansion chart, the dimples are arranged to with respect to the planar expansion chart so as to meet the requirement (I) that when the planar expansion chart has a center 0, two large and small regular triangles AABC and Aabc centered at 0 are depicted on the chart with corresponding two apexes aligned with an identical radial line from center 0, and the respective sides of the small regular triangle Aabc are extended to intersect with the sides of the large regular triangle AABC to define one regular triangle coincident with the small regular triangle Aabc, three trapezoids, and three parallelograms, six dimples are contained in the one small regular triangle, nine dimples are contained in each of the trapezoids, and four dimp

Abstract: In a golf ball of the icosahedral dimple arrangement pattern having twenty identical phantom regular triangles projected on its spherical surface, all dimples are arranged within the triangles such that no dimples may intersect the sides of each triangle and a great circle which does not intersect the dimples at all may not be depicted. Some dimples may be arranged at the apexes of each triangle. The golf ball travels a longer distance and provides consistent flight independent of impact points. Also provided is a mold consisting of upper and lower mold cups whose cavity surface is provided with dimple-forming protrusions such that the inventive dimple arrangement may be accomplished. The mold is easy to design and fabricate.