飞雪樱子
螺丝其实是不正规的称呼，标准名词中只有：螺钉、螺栓、螺母、螺杆，比较小的螺栓就称为螺钉，无端帽的螺栓就称为螺杆，螺母就是与螺钉、螺栓，螺杆连接的带内螺纹的零件。
黄小仙128
说法比较多，仅供参考：一、有无螺母（本人及多数人观点）螺钉一般是直接上在某件工件上，螺栓一般和螺母配合，做连接与紧固。二、受力方式（某资料定义）1、工具在圆周旋动的是螺栓，2、工具在圆心旋动的是螺钉，3、不能使用工具旋动的是螺柱。三、look（英文的定义）螺栓(bolt)定义是：headed fasteners having external threads that meet an exacting, uniform bolt thread specification (such as M, MJ, UN, UNR, and UNJ) such that they can accept a nontapered nut（螺母）.螺钉（screw)的定义是:Screws are defined as headed, externally-threaded fasteners that do not meet the above definition of bolts.
