What is the tolerance range of precision screws?
What is the tolerance range of precision screws?
Traditional rivet nuts are usually cylindrical, and special tools are required to complete the riveting operation between the workpiece and the sheet, and tools are completely required for locking. And in the actual production process, it is often encountered that there are square holes on the workpiece, and bolts need to be installed in the square holes, especially in the power cabinet and the control cabinet when the workpiece with prefabricated square holes is used as the main frame, due to Due to the special structure of the workpiece, the installation nut can only be inserted from the side, and the installation cannot be completed when the side installation space is limited, which brings inconvenience to the installation.
Standards are norms, and each country and sector has its own standards. GB—Chinese National Standard (National Standard) ANSI—American National Standard (American Standard) DIN—German National Standard (German Standard) ASME—American Society of Mechanical Engineers Standard JIS—Japanese National Standard (Japanese Standard) BSW—British National Standard GB—National Standard The standard is one of the many standards in my country, and there are also industry standards, professional standards and department standards. National standards are divided into: GB (mandatory standards) and GB/T (recommended standards) and GBn (national internal standards) and so on. We usually see GB30, GB5783, etc. are mandatory standards. In addition to some basic dimensions such as head-to-side, head thickness, etc., the above standards are mainly different in the threaded part. The threads of GB, DIN, JIS, etc. are all in MM (millimeters), which are collectively referred to as metric threads. Another thread like ANSI, ASME, etc. is called American standard thread in inches. In addition to metric threads and American threads, there is also a BSW-imperial standard, whose threads are also in inches, commonly known as Wyeth threads. In the usual domestic sales business, the most common standards we encounter are GB (National Standard) and DIN (German Standard). In terms of production products, the following standards are mainly encountered: GB30; GB5783; GB5782; GB52; GB6170; GB818; GB819; GB845; GB846; GB70; DIN912; DIN933; DIN931 and so on. GB30 (old national standard) has been replaced by GB5783 (new national standard) in the standard book. GB52 (old national standard) has been replaced by GB6170 (new national standard) in the standard book.
The conventional auger bit structure 1 includes a rod body 11, a screw head 12 provided on one end of the rod body 11, a drill tail 13 provided on the other end of the rod body 11, and a plurality of threads 14 arranged around the rod body 11; Wherein, the periphery of the drill tail 13 defines a parting line 15, and the parting line 15 makes the drill tail 13 symmetrically divided into a side 131 and a side 132, and a cutting end 133 is formed at the junction of the end of the side 131 and the end of the side 132, respectively. The cutting end 133 is concavely provided with a quarter-turn chip flute 134 in the same direction of the helix, and the edge 132 continues the chip flute 134 and has a quarter-turn chip flute 135 with different helical curvatures. , by connecting the chip groove 134 and the chip groove 135 through different helical curvatures, the drill tail 13 can form a symmetrical and complete chip groove of 189 degrees.
Combination bolts refer to a bolt with a spring washer and a flat washer, which are combined by rubbing teeth. Before the combination bolt is used, the bolt, the spring washer and the flat washer are generally combined by a specific machine. The combined production line mainly includes the processes of feeding, discharging, feeding, charging, screwing and tightening. The existing combined bolt production equipment mainly transmits the bolts to each process through the conveyor belt, and finally completes the combined assembly. The machines in each process are scattered and the space is occupied. The vibrating plate feeding generally puts the bolt head up, and its bolts, spring washers, etc. After the flat pad is assembled, the fixation is poor, and it is easy to fall off during the assembly process.
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