Standards are norms, and each country and department has its own standards. GB-Chinese National Standard (GB) 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
The GB-National Standard is one of many standards in China, and there are also industry standards, professional standards, and departmental standards. National standards are divided into: GB (mandatory standards) and GB/T (recommended standards) and GBn (national internal standards). The things we usually see like GB30, GB5783, etc. are all mandatory standards.
In addition to some basic dimensions such as head-to-edge, head thickness, etc., the above-mentioned criteria are the difference of the thread portion. GB, DIN, JIS and other threads are all in MM (mm) units, collectively referred to as metric thread. Another thread like ANSI, ASME, etc. is called American Standard thread in inches. In addition to the metric thread and the American thread, there is also a BSW-inch standard, the thread is also in inches, commonly known as Wyeth's thread.
Screws
In the domestic sales business, the most commonly encountered standards are GB (GB) and DIN (Germany).
In terms of raw products, the following standards are mainly touched: GB30; GB5783; GB5782; GB52; GB6170; GB818; GB819; GB845; GB846; GB70; DIN912; DIN933; GB30 (old national standard) has been replaced by GB5783 (new national standard) in the standard book. GB52 (old national standard) has been replaced by GB6170 (new national standard) in the standard book.
new standard
In 1986, the state set a new standard for standard parts, commonly known as the new standard, the most used are mainly GB5780, GB5781, GB5782, GB5783, GB5784. GB5780 is a hexagonal head coarse half-screw screw, its accuracy grade is C grade product, can be replaced by GB5782 (GB5782 is a hexagonal head coarse rod half-tooth screw, its accuracy waits for grade A and B grade.) GB5781 is hexagonal head full Screws, accuracy class C grade. GB5783 can be used instead (GB5783 is a hexagonal head full-screw screw with accuracy class A and B). GB5784 is a semi-hexagonal screw with a thin rod.
The difference between the new standard and the old one is that the products of the M8, M10, M12, M14, and M22 series are different in the width of the opposite side. In addition to the new products of the M22 series, the head-to-edge of the new standard products M8, M10, M12, and M14 is 1 mm smaller than the opposite side of the old standard. 13, 16, 18, 21MM, respectively, and the M22 series of new products, the new standard than the old standard on the opposite side to 2MM, should pay special attention. For head thickness, there is a slight difference between the new standard and the old standard, which can be used if the requirements are not very strict.
The difference between the new standard and the German standard is: The product specifications of M10, M12, M14, and M22 are different in the width of the opposite side. The head-to-edge mark of M10, M12, and M14 is 1 mm smaller than the German mark. For the M22's new products, the head-to-edge width is 2mm larger than that of the German standard, and the others can be used universally.
Screws
For hex nuts, the commonly used standards are: GB52, GB6170, GB6172 and DIN934. The main differences between them are: GB6170 thickness is thicker than GB52, GB6172 and DIN934, commonly known as thick nuts. The other is the edge of the difference, M8's nut series DIN934, GB6170, GB6172 on the opposite side is 13MM than the GB52 on the opposite side 14MM to be smaller 1MM, M10 nut, DIN934 and GB52 on the opposite side of 17MM, than GB6170 and GB6172 on the opposite side of the larger 1MM, M12 nut, DIN934, GB52 on the opposite side of the 19MM than the GB6170 and GB6172 on the opposite side 18MM to 1MM. For the M14 nuts, the opposite side of DIN934 and GB52 is 22MM larger than that of GB6170 and GB6172. The other is the M22 nut, DIN934, GB52 on the opposite side of the 32MM, than the GB6170, GB6172 on the opposite side of the 34MM to 2MM. (Besides the thickness of GB6170 and GB6172 is different, the width of the opposite side is exactly the same.) The remaining specifications can be used without considering the thickness.
In the internal hexagon, there are two versions of the national standard, one for the GB70-76, 76 years version, one for the GB70-85, 85 years version, most of the implementation of DIN912 standards, so in the actual business operations should pay attention to the difference: where GB70 -85 completely coincides with DIN 912, so there is no difference in the use of the new standard, mainly between GB70-76 and DIN912: M8 series of hexagonal products, GB70-76 round head diameter of 12.5MM, It is smaller than DIN912 13.27MM, M10 series of hexagonal products, GB70-76 round head diameter of 15MM, smaller than DIN912 16.27, M12 series of hexagonal, GB70-76 round head diameter of 18MM, Compared with DIN912 on the opposite side of 18.27 to be smaller, and the other like M16, M20 series of hexagonal GB70-76 round head diameter than DIN912 smaller than the 0.33MM, respectively 24MM, 30MM. DIN912 is 24.33MM and 30.33MM respectively. In addition, the inner-to-edge width between the old mark and the German standard hexagon is different due to different standards, and the inner edge of GB70-76 should be smaller, and should also be noted in the business operation.
In addition, the carriage screws that may be used at ordinary times also have some differences. Here is an explanation. In the national standard, there are two standards for carriage screws, that is, GB12 (small semi-circular head square neck screws) and GB14 (large semi-circular head side (Neck screws), usually in the market more commonly used in Germany standard DIN603. These three are now distinguished: For the round neck, in the same specification comparison: GB12 <GB14 <DIN603 <SPAN>. Usually when the carriage screw is used, the head and neck are often required to be large and thick, so the standard of the DIN603 carriage screw fully meets the requirements.
The above is the introduction of the specification standard. Jiuzheng Hardware Net Xiaobian thinks that in addition to the specifications, it is necessary to understand the following types.