The thread of a fastener is a crucial element in the world of engineering and construction. Fasteners, such as screws, bolts, and nuts, rely on their threaded design to create secure connections between various components. The thread of a fastener refers to the helical ridge that wraps around the cylindrical body of the fastener, allowing it to engage with a corresponding threaded hole or nut.
This design not only provides mechanical strength but also facilitates ease of assembly and disassembly.
Threads can be classified into different types based on their profile, pitch, and diameter. The most common thread types include Unified National Thread (UN), Metric Thread, and Acme Thread. Each type serves specific applications, with variations in their dimensions and shapes to accommodate different materials and load requirements.
Thread type:
A thread is a shape with a uniform helix protruding on a cross-section of a solid surface or an internal surface. According to its institutional characteristics and uses can be divided into three categories:
1. Ordinary thread: the tooth Angle is triangular, used to connect or tighten parts. Ordinary threads are divided into coarse thread and fine thread according to the pitch, and the connection strength of fine thread is higher.
2. Transmission thread: tooth type has trapezoid, rectangle, saw shape and triangle, etc.
3. Sealing thread: used to seal connection, mainly pipe thread, taper thread and taper pipe thread.
Fit grade of thread:
Thread fit is the size of the slack or tightness between the screw threads, and the grade of the fit is the specified combination of deviations and tolerances acting on the internal and external threads.
For uniform inch threads, there are three grades for external threads: 1A, 2A, and 3A, and three grades for internal threads: 1B, 2B, and 3B. The higher the level, the tighter the fit. In inch threads, the deviation is specified only for class 1A and 2A, the deviation for class 3A is zero, and the grade deviation for class 1A and class 2A is equal. The greater the number of grades, the smaller the tolerance.
Post time: Nov-21-2024
