没有明确的答案,我在国外的图中见到:用于固定轴的多用凹端紧钉螺钉GBT号码。我是这样认为的:平端的紧钉螺钉(GBT号码)适用于固定接触面为平面的,凹端的紧钉螺钉(GBT号码)适用于固定接触面为圆柱面的,理由:固定时应避免接触面为点接触。这只是个人理解我在英文中查到的:One might often need to use a flat point when the screw must press perfectly flat against a surface. The most common type is the cup point. This type works well because the surface is rounded so that a small surface area is in contact, but it does not have extremely high stress at one point like that of a cone point. Durability studies show that
