ISO 2306-1972 使用前先攻螺纹用钻头

标准号：ISO 2306-1972
中文标准名称：使用前先攻螺纹用钻头
英文标准名称：Drills for use prior to tapping screw threads
标准类型：J41
发布日期：1999/12/31 12:00:00
实施日期：1999/12/31 12:00:00
中国标准分类号：J41
国际标准分类号：25.100.50
适用范围：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.