Screw classification introduction

Screw classification introduction

Standard Specification for Screws Standards are norms, and each country and department has its own standards. At present, the most commonly used standards in our daily business are as follows: GB-China 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 many standards in my country, and there are also industry standards, professional standards and departmental standards. National standards are divided into: GB (mandatory standard), GB/T (recommended standard) and GBn (national internal standard). We usually see GB30, GB5783, etc. are mandatory standards.

In addition to the differences in some basic dimensions such as the opposite side of the head and the thickness of the head, the most important thing for the above standards is the difference in the threaded part. The threads of GB, DIN, JIS, etc. are all in MM (millimeters), collectively referred to as metric threads. Threads like ANSI, ASME, etc. are in inches and are called American standard threads. In addition to metric threads and American threads, there is also a BSW-British standard, and the threads are also in inches, commonly known as Whitworth threads.

The metric thread is in MM (mm), and its cusp angle is 60 degrees. Both American and Imperial threads are measured in inches. The cusp angle of the American thread is also 60 degrees, while the cusp angle of the British thread is 55 degrees. Due to the different units of measurement, the representation methods of various threads are also different. For example, M16-2X60 represents a metric thread. His specific meaning means that the nominal diameter of the screw is 16MM, the tooth pitch is 2MM, and the length is 60MM. Another example: 1/4-20X3/4 means the inch thread. His specific meaning is that the nominal diameter of the screw is 1/4 inch (one inch=25.4MM), there are 20 teeth on one inch, and the length is 3/4 inch. In addition, if you want to indicate American-made screws, UNC and UNF are usually added after the British-made screws to distinguish between American-made coarse threads and American-made fine threads.
In the usual domestic sales business, the standards we most often encounter are GB (National Standard) and DIN (German Standard). In terms of non-fragrant products, you will mainly come into contact with the following standards: GB30; GB5783; GB5782; GB52; GB6170; GB818; GB819; GB845; GB846; GB70; 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 formulated new standards for standard parts, which are generally called new standards in business, and the most used ones are mainly GB5780, GB5781, GB5782, GB5783, and GB5784. GB5780 is a hexagonal head thick shank half-thread screw, and its precision grade is a C-grade product, which can be replaced by GB5782 (GB5782 is a hexagonal head thick shank full-thread screw, and its accuracy is grade A and B.) GB5781 is a hexagon head full-thread screw with a precision grade of C-grade product. It can be replaced by GB5783 (GB5783 is a hexagonal head full-thread screw, and its precision grades are grade A and grade B). GB5784 is a hexagonal screw with a thin rod and half thread.
The difference between the new standard and the old standard is: M8, M10, M12, M14, M22 series products are different in width across sides. In addition to the new products of the M22 series, the opposite sides of the heads of the new standard products M8, M10, M12, and M14 are 1MM smaller than the opposite sides of the old standard. They are 13, 16, 18, and 21MM respectively, and for the new products of the M22 series, the opposite side of the new standard is 2MM larger than the old standard, so special attention should be paid. For the thickness of the head, there is a slight difference between the new standard and the old standard, and it can be used universally if the requirements are not very strict.
The difference between the new standard and the German standard is that the product specifications of M10, M12, M14, and M22 differ in width across sides. For M10, M12 and M14, the head-to-side new standard is 1MM smaller than the German standard. As for the new product of M22, its width across sides of the head is 2mm larger than that of the German standard, and other products can be used universally.
For hexagonal nuts, the commonly used standards are: GB52, GB6170, GB6172 and DIN934. The main differences between them are: the thickness of GB6170 is thicker than that of GB52, GB6172 and DIN934, commonly known as thick nuts. In addition, there is the difference on the opposite sides. In the M8 nut series, the opposite sides of DIN934, GB6170, and GB6172 are all 13MM, which is 1MM smaller than the 14MM opposite sides of GB52. For M10 nuts, the opposite sides of DIN934 and GB52 are 17MM. The opposite sides of GB6170 and GB6172 are 1MM larger, and the opposite sides of M12 nuts, DIN934 and GB52 are 19MM larger than the opposite sides of GB6170 and GB6172, which are 18MM. For M14 nuts, the opposite side of DIN934 and GB52 is 22MM, which is 1MM larger than the 21MM opposite side of GB6170 and GB6172. The other is the M22 nut. The opposite side of DIN934 and GB52 is 32MM, which is 2MM smaller than the 34MM opposite side of GB6170 and GB6172. (Except for the thickness difference, GB6170 and GB6172 have exactly the same width across sides) The rest of the specifications can be used in common without considering the thickness. .

• Year Established
  --
• Business Type
  --
• Country / Region
  --
• Main Industry
  --
• Main Products
  --
• Enterprise Legal Person
  --
• Total Employees
  --
• Annual Output Value
  --
• Export Market
  --
• Cooperated Customers
  --