In the application of stainless steel screws, coarse and fine threads each have their own functional characteristics. Pure Fasteners reminds you that when selecting, you should choose between coarse and fine threads based on the application of your product. Below, the editor will explain the differences between coarse and fine threads and how to distinguish between them.
coarse thread: The so-called coarse thread refers to standard threads. Unless otherwise specified, the stainless steel screws and other fasteners we generally purchase are coarse-threaded. The characteristics of coarse threads include high strength, good interchangeability, and a standardized nature. Overall, coarse threads are generally a good choice. The drawback is that their self-locking performance is lower than that of fine threads, and anti-loosening washers and self-locking devices need to be installed in a vibration environment.
Fine Pitch: Fine pitch screws feature a smaller pitch for better self-locking and anti-loosening capabilities, more teeth to reduce leakage and achieve a sealing effect. In precise applications, stainless steel screws with fine pitch are more conducive to precise control and adjustment. The drawback is that their tensile strength and hardness are lower than those of coarse pitch, and threads are prone to damage, making it not advisable for frequent disassembly. Nuts and other mating fasteners may also be equally precise, but slight dimensional discrepancies can easily damage both the screw and nut simultaneously.
The difference between coarse and fine threads can be observed visually. They differ in pitch and number of teeth. Coarse threads have a larger pitch and fewer teeth compared to fine threads. Fine threads have a smaller pitch and more teeth. Additionally, they can also be distinguished by their markings. Generally, coarse threads do not require pitch marking, whereas fine threads need to be clearly marked. For instance, M12 * 1.25 fine thread diameter indicates a diameter of M12 with a pitch of 1.25, while coarse threads typically do not indicate the pitch.
