Screw is a common fastener, the general material is metal or plastic, widely used in machinery, electrical appliances and buildings, cylindrical shape, the surface is engraved with concave and convex groove called thread. This kind of hardware has a certain amount of standards, then what is the screw specification standard? What are the screw specifications? The following nine is hardware network to explain for you, let’s have a look.

What is the screw specification standard?
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 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.
New standard

In 1986, the state developed a new standard for standard parts, commonly known as the new standard, 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 half-tooth screw, its accuracy is A and B.) 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.