目前我国机器制造业中使用的螺纹制度还没有统一的标准。螺纹是机器制造业中最基本和最常应用到的一种零件要素。例如机器用螺钉,虽然由於缺乏统计数字,不能说明在数量上所达到的庞大的程度,但举机器制造中的一个专业──纺织机械来说明,每月产二百万枚以上的螺钉制品,也许还不 At present, there is no uniform standard for the threading system used in China’s machine-building industry. Threads are the most basic and commonly used component element in machine manufacturing. For example, the use of screws for machinery, although due to the lack of statistics, can not explain the magnitude of the amount achieved, but a professional in the machinery manufacturing - textile machinery to illustrate the monthly production of more than 2 million screw products, Maybe not yet