Fastener Standard Specification Encyclopedia

Standards are norms, and each country and department has its own standards. At present, the most commonly used standards in our usual business are the following:

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 many standards in our country, in addition to industry standards, professional standards and departmental standards. National standards are divided into GB (mandatory standards), GB/T (recommended standards) and GBn (national internal standards). What we usually see like GB30, GB5783, etc. are all mandatory standards.

In addition to the differences in the basic dimensions of the above several standards, such as the opposite side of the head and the thickness of the head, the most important thing is the difference in the thread part. The threads of GB, DIN, JIS, etc. are all based on MM (millimeters), collectively referred to as metric threads.

Other threads such as ANSI and ASME are called American standard threads 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 the Wyeth thread. (Guide: Types and use objects of metal gaskets)

Metric thread is based on MM (millimeter), and its cusp angle is 60 degrees. Both American and British 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 measurement units, the representation methods of various threads are different. For example, M16-2X60 represents a metric thread. His specific meaning is that the nominal diameter of the screw is 16MM, the pitch is 2MM, and the length is 60MM. Another example: 1/420X3/4 means that the inch thread is, and his specific meaning is that the nominal diameter of the screw is 1. /4 inch (one inch u003d 25.4MM), there are 20 teeth on one inch, and the length is 3/4 inch.

In addition, if you want to indicate American screws, UNC and UNF are usually added after the British screws to distinguish between American coarse threads and American fine threads.

In the usual domestic sales business, the most frequently encountered standards are GB (National Standard) and DIN (German Standard).

In terms of non-Fragrant products, the following standards are mainly encountered: 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 established a new standard for standard parts, which is generally called the new standard in business. The most used ones are mainly GB5780, GB5781, GB5782, GB5783, and GB5784. GB5780 is a hexagonal head thick shank half-thread screw, and its accuracy grade is C-level 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 hexagonal head full-thread screw. Thread screws, accuracy grade is C grade product. It can be replaced by GB5783 (GB5783 is a hexagon head full-thread screw, and its accuracy grades are A and B). GB5784 is a hexagonal screw with a thin rod and a half tooth.

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