Standards are norms, and each country and sector has its own standards. At present, the standards we most commonly use in peacetime are as follows:

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 is one of the many standards in our country, in addition to 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). What we usually see like GB30, GB5783 and so on are mandatory standards.

In addition to some basic dimensions such as head to side, head thickness, etc., the most important thing is the difference in the thread part. GB, DIN, JIS and other threads are in MM (mm) as a unit, collectively known as metric threads. Another thread like ANSI, ASME and so on is called the American standard thread in inches. In addition to metric threads and American threads, there is also a BSW-inch standard, whose threads are also in inches, commonly known as Wyeth threads.

The metric thread is measured in MM (mm), and its cusp Angle is 60 degrees. Both American and British threads are measured in inches. The tip Angle of the American thread is also 60 degrees, while the tip Angle of the British thread is 55 degrees. Due to the different units of measurement, the representation of various threads is not the same. For example, the M16-2X60 represents the metric thread. His specific meaning is that the nominal diameter of the screw is 16MM, the tooth spacing is 2MM, and the length is 60MM, and for example: 1/4-20X3/4 indicates the imperial thread, his specific meaning is that the nominal diameter of the screw is 1/4 inch (an inch =25.4MM), and there are 20 teeth in an inch, the length is 3/4 inch. In addition, if you want to indicate American screws, you will generally add UNC and UNF to the end of the British screws to distinguish between American coarse teeth and American fine teeth.

In the usual domestic sales business, the standards we most often encounter are GB (national standard) and DIN (German standard).

In terms of products, the following standards are mainly exposed: GB30; GB5783; GB5782; GB52; GB6170; GB818; GB819; GB845; GB846; GB70; DIN912; DIN933; DIN931, etc. At present, 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.

In 1986, our country developed a new standard for standard parts, commonly known as the new standard in the business, the most used mainly GB5780, GB5781, GB5782, GB5783, GB5784. GB5780 is A hexagonal head thick rod half-tooth screw, its accuracy level is C-class products, can be replaced by GB5782 (GB5782 is a hexagonal head thick rod full-tooth screw, its accuracy is A and B levels.) GB5781 is a hexagon head full tooth screw with a C-class accuracy. It can be replaced by GB5783 (GB5783 is A hexagon head full tooth screw, its accuracy grade is A and B). GB5784 is a hexagonal screw with half teeth.

The difference between the new standard and the old standard is that the products of M8, M10, M12, M14 and M22 series are different in the width of the opposite side. In addition to the new products of M22 series, the opposite side of the head of the new standard products M8, M10, M12 and M14 is 1MM smaller than the opposite side of the old standard. They are 13, 16, 18, 21MM, and the new products of the M22 series, the new standard is 2MM larger than the old target, and special attention should be paid to it. For the thickness of the head, there is a slight difference between the new standard and the old standard, and it can be used in the case of not very strict requirements.

The difference between the new standard and the German standard is that the product specifications of M10, M12, M14 and M22 are different in the width of the opposite side. M10, M12, M14 head side of the new standard is 1MM smaller than the German standard. The new product of M22, the opposite side of the head is 2MM larger than the opposite side width of the German standard, and the other can be universal.

For hexagonal nuts, the commonly used standards are: GB52, GB6170, GB6172 and DIN934, the main difference between them is: the thickness of GB6170 is thicker than GB52, GB6172 and DIN934, commonly known as thick nuts. In addition, the opposite side of DIN934, GB6170 and GB6172 in the M8 nut series is 13MM smaller than the opposite side of GB52 14MM, and the opposite side of DIN934 and GB52 is 17MM, which is 1MM larger than the opposite side of GB6170 and GB6172. The opposite side of the M12 nut, DIN934, GB52 is 19MM than the opposite side of GB6170 and GB6172 is 18MM larger than 1MM. For the nuts of M14, the opposite side of DIN934 and GB52 is 22MM, which is 1MM larger than the opposite side of GB6170 and GB6172, 21MM. In addition, the nut of M22, the opposite side of DIN934 and GB52 is 32MM, which is 2MM smaller than the opposite side of GB6170 and GB6172. (GB6170 and GB6172 in addition to their thickness is not the same, the opposite side width is exactly the same) The rest of the specifications can be universal without considering the thickness.

In terms of inner hexagon, there are two versions of the national standard, one is GB70-76, 76 year version, one is GB70-8585 year version, our company is now implementing the DIN912 standard, so in the actual business operation should pay attention to the difference: Among them, GB70-85 and DIN912 fully coincide, so there is no difference in the use of the new target, mainly between GB70-76 and DIN912: M8 series hex socket products, The head diameter of GB70-76 is 12.5MM, which is smaller than the 13.27MM of DIN912, the head diameter of GB70-76 is 15MM, which is smaller than the 16.27 of DIN912, and the head diameter of GB70-76 of M12 series is 18MM, which is smaller than DIN912 The opposite side 18.27 is smaller, and the round head diameter of the hexagonal GB70-76 of the M16 and M20 series is 0.33MM smaller than that of DIN912, respectively 24MM and 30MM. DIN912 is 24.33MM and 30.33MM respectively. In addition, the width of the inner opposite side between the old standard and the German standard hex is different due to different standards, and the inner opposite side of GB70-76 is smaller, which should also be paid attention to in business operations.

In addition, there are also some differences in the carriage screws that may be used in peacetime, here is also a description, in the national standard, there are two kinds of carriage screws, namely GB12 (small half round head square neck screws) and GB14 (large half round head square neck screws), usually more commonly used in the market and German standard DIN603. Now to distinguish these three: for round neck, in the same specification comparison is: GB12<GB14<DIN603< SPAN>. Usually in the use of carriage screws, it is often required that the head and neck are large and thick, so the standard of DIN603 carriage screws fully meet the requirements.

Name:

1. Machine screws 2. Self-tapping screws 3. Drilling screws 4. Wall board nails 5. Fiberboard screws 6. Wood screws 7. Hexagonal wood screws 8. Captive screws 9. Combination screws 10. Micro screws 11. Furniture screws 12. Electronic screws

Head type:

1. hexagon head 2. hexagon head with flange 3. square head (4) T head (hammer head) 5. mushroom head(truss head) 6. cheese head (round head) 7. Round head (round head) 8. countersunk head (flat head) 10. Countersunk head (flat head) 10. raised countersunk head (oval.) Raised countersunk head (oval

Groove type:

1. Philip 2. Ten/word 3. Word 4. Inner triangle 5. Inner corner square 6. Cross 7. Rice word 8. Flower shape 9. Plum shape 10. Flower-shaped line 11. Special shape 12. Hex socket