标准摘要
[中文适用范围]： 指定 ISO 公制螺纹的这些钻头的尺寸（表 1 和表 2）。 ISO 英制螺纹（表 3 和表 4）和管螺纹（表 5 和表 6）。 适用于正常啮合长度的螺纹，钻头直径约等于螺纹标称直径减去螺距。 尺寸（带星号指示的尺寸除外）是从 ISO 235 中选择的，并将在将来使用。 [外文原描述]： Specifies the sizes of these drills for ISO metric threads (tables 1 and 2). ISO inch threads (tables 3 and 4) and pipe threads (tables 5 and 6). Applies to screw threads of normal length of engagement, the drill diamter being approximately equal to the nominal diameter of the thread minus the pitch. The sizes (except for those sizes indicated by an asterisk) have been selected from ISO 235 and are to be used in the future.
英文名称Drills for use prior to tapping screw threads