What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
1. Ordinary outer hexagon - widely used, characterized by relatively large tightening force, the disadvantage is that there must be enough operating space during installation, and adjustable wrench, open-end wrench or glasses wrench can be used during installation, all of the above wrenches require a large amount of space. operating space. 2. Cylindrical head hexagon socket - is the most widely used of all screws, because it has a relatively large tightening force, and can be operated with a hexagon wrench. It is very convenient to install and is used in almost all kinds of structures. The appearance is more beautiful and neat. The disadvantage is that the tightening force is slightly lower than the outer hexagon, and the inner hexagon is easily damaged due to repeated use and cannot be disassembled. 3. Pan head inner hexagon - rarely used mechanically, the mechanical properties are the same as above, mostly used in furniture, the main function is to increase the contact surface with wooden materials and increase the ornamental appearance. 4. Headless inner hexagon - must be used in certain structures, such as the top wire structure that requires a large top-tight force, or where the cylindrical head needs to be hidden. 5. Countersunk head hexagon - mostly used in power machinery, the main function is the same as the inner hexagon. 6. Nylon lock nut - a nylon rubber ring is embedded in the hexagonal surface to prevent the thread from loosening, and it is used on strong power machinery. 7. Flange nuts - mainly play the role of increasing the contact surface with the workpiece, mostly used in pipes, fasteners, some stamping parts and casting parts. 8. Ordinary hex nut - the most widely used and one of the most common fasteners.
The first person to describe the spiral was the Greek scientist Archimedes (c. 287 BC - 212 BC). An Archimedes screw is a huge spiral contained in a wooden cylinder that is used to irrigate fields by raising water from one level to another. The real inventor may not be Archimedes himself. Maybe he was just describing something that already existed. It may have been designed by the skilled craftsmen of ancient Egypt for irrigation on both sides of the Nile. In the Middle Ages, carpenters used wooden or metal nails to attach furniture to wooden structures. In the 16th century, nail makers began producing nails with a helical thread, which were used to connect things more securely. That's a small step from these kinds of nails to screws. Around 1550 AD, the metal nuts and bolts that first appeared in Europe as fasteners were all made by hand on a simple wooden lathe. Screwdrivers (screw chisels) appeared in London around 1780. Carpenters have found that tightening a screw with a screwdriver holds things in place better than hitting with a hammer, especially with fine-grained screws. In 1797, Maudsley invented the all-metal precision screw lathe in London. The following year, Wilkinson built a nut and bolt making machine in the United States. Both machines produce universal nuts and bolts. Screws were quite popular as fixings because an inexpensive method of production had been found at that time. In 1836, Henry M. Philips applied for a patent for a screw with a cross recessed head, which marked a major advance in screw base technology. Unlike traditional slotted head screws, Phillips head screws have the edge of the head of the Phillips head screw. This design makes the screwdriver self-centered and not easy to slip out, so it is very popular. Universal nuts and bolts can connect metal parts together, so by the 19th century, the wood used to make machines to build houses could be replaced by metal bolts and nuts. Now the function of the screw is mainly to connect the two workpieces together and play the role of fastening. The screw is used in general equipment, such as mobile phones, computers, automobiles, bicycles, various machine tools and equipment, and almost all machines. need to use screws. Screws are indispensable industrial necessities in daily life: extremely small screws used in cameras, glasses, clocks, electronics, etc.; general screws for televisions, electrical products, musical instruments, furniture, etc.
The independent pocket spring pad includes a large number of independent pocket springs, and these independent pocket springs are regularly arranged in rows and columns to form a spring pad. Wherein, each row of pocket spring rows is laterally bonded to the adjacent row of pocket spring rows.
The purpose of Guangdong Yueluo Hardware Industry Co., Ltd. is to provide a low-carbon steel rivet nut fastener, which can be easily fixed on a thin wall without welding, easy to operate, firm riveted, and suitable for single-sided riveting.
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