What is CNC machined parts thread?
The thread is a shape that has a uniform helix raised on the cross-section of the solid outer surface or inner surface.
Cross section shape
The thread is divided into triangular threads, rectangular threads, trapezoidal threads, and zigzag threads according to its cross-sectional shape (dental shape).
Among them, the triangular thread is mainly used for the connection (see thread connection), and the rectangular, trapezoidal and zigzag thread is mainly used for the transmission. Pipe threads are used for tight coupling of pipes. The rectangular thread has high efficiency, but it is often replaced by a trapezoidal thread because it is not easy to grind and the internal and external threads are difficult to rotate and center. The working edge of the sawtooth thread teeth is close to the straight edge of the rectangle, and is mostly used to withstand one-way axial force.
The cone thread has a triangular shape, mainly relying on the deformation of the teeth to ensure the tightness of the thread pair, and is mostly used for pipe fittings.
Note: The triangular thread self-locking performance is good. It is divided into two kinds of coarse teeth and fine teeth, generally coupled with coarse thread. (Used to fasten wood materials.) Small teeth have a small pitch, a small angle of rise, and better self-locking properties. They are often used in thin-walled thin parts, in connection with vibration or variable loads, and in fine-tuning devices.
Inside and outside distribution
The thread is called the external thread on the external surface of the mother's body, and is called the internal thread on the surface of the mother's body.
The thread on the surface of the bolt is the external thread and the thread of the nut is the internal thread. The internal thread with the same nominal diameter is larger than the external thread. Because the external thread is screwed into the internal thread.