The difference between coarse and fine U-shaped threads

Updated:2021-04-09
Summary: The U-bolt manufacturer takes you to understand ...
The U-bolt manufacturer takes you to understand the difference between coarse thread and fine thread
Threads are generally divided into coarse teeth and fine teeth. There are also metric teeth, American teeth, inch teeth, German standard teeth and Japanese standard teeth. But in China, we usually use metric teeth. The so-called coarse thread is the standard thread, which can be found in the thread national standard. Generally, the screws and bolts that we can buy outside are coarse threads. Compared with fine threads, coarse threads have the characteristics of high strength and good interchangeability. They are widely used and should be the best choice.
Compared with coarse threads, fine threads have an inspection standard. See the mechanical design manual for details. Try to choose standard specifications when designing. The fine thread space is small in size and self-locking. It is mostly used in places where the force is small and can be precisely adjusted, such as fixing the lens of various optical instruments, micrometers and other measuring instruments, and some threaded joints that do not want to use tools, such as oil cups Cover, battery cover of metal shell LED flashlight, etc. Due to the small pitch of the fine thread and the small height of the tooth profile, it is easy to get in and out of the tooth during installation. The burrs have a great influence on the assembly and must be cleaned.
At the same time, the number of disassembly and assembly of fine threads should not be too many. The thick one has high strength and the thin one has good sealing. The guaranteed load of the same level is not much different (the fine teeth are slightly higher), and the pre-tightening load of the two is similar when tightening. Without anti-loosening measures, the anti-loosening effect of fine threads is better than that of coarse threads. Generally used for thin-walled parts and parts with high requirements for anti-vibration. When adjusting, thin lines are more advantageous. Disadvantages of thin wire: Not suitable for materials with too thick structure and poor strength, and too much tightening force is easy to slip.
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