Ordinary threads are the most widely used. The threads on threaded fasteners (bolts, studs, screws, nuts, etc.) are generally ordinary threads.
Ordinary threads are divided into coarse ordinary threads and fine ordinary threads. Fine-tooth ordinary threads are mostly used for precision parts and thin-walled parts.
In the marking of threads, the pitch of fine-pitch ordinary threads must be noted, while the pitch of coarse-pitch ordinary threads is generally not marked.
Pipe threads are generally used in the connection of pipelines (water pipes, oil pipes, gas pipes, etc.). The markings of pipe threads are marked with a guide method, and the guide line points to the major diameter of the thread.
Marking of pipe thread:
It is composed of thread feature code, size code and direction of rotation. The size code is not the size of the major diameter of the thread, but the size of the pipe diameter (English). The rotation direction is not marked in the mark is right-handed.
3、 Trapezoidal thread and sawtooth thread
Trapezoidal threads and sawtooth threads are often used on lead screws that transmit motion and power. When the trapezoidal thread is working, both sides of the tooth are stressed, while the serrated thread is stressed on one side when working.
The markings of trapezoidal thread and sawtooth thread are similar to ordinary thread.