Common sense of fasteners: threaded element inventory of triangular screws

For the thread of the triangular screw used in the fastener, the three types of teeth, the diameter and the pitch are loaded with the standard thread, which is called the standard thread. The tolerance band and the thread mark of the standard thread are standardized, and the number of threads is standardized. And the direction of rotation, if not specified, it is a single-line right-handed. If the internal and external threads are to be properly screwed together to form a thread pair, the profile, diameter, direction of rotation, number of threads and pitch of the internal and external threads must be uniform.