Each country and department has its own standards in the production of Dongming fasteners. At present, the standards commonly used in our daily production of Dongming fasteners are as follows:
Dongming Fastener GB is one of many standards in China. In addition, there are industry standards, professional standards and sector standards. National standards are divided into GB (mandatory standard), GB/T (recommended standard) and GBN (national internal standard). What we usually see is the mandatory Dongming fastener standards, such as GB30, gb5783, etc.
Apart from some basic dimensional differences, such as the opposite sides of the head and the thickness of the head, what is important in the above standards is the difference in the threaded portion of the fastener. GB, DIN, JIS and other fastener threads are all measured in millimeters (mm) and are collectively referred to as metric fastener threads. Another ANSI and ASME-like fastener thread unit is inches and is called American Standard Fastener Thread. In addition to metric fastener threads and US fastener threads, there are also BSW British Standards. Its fastener threads are also measured in inches and are often referred to as Wyeth fastener threads.
The unit of Dongming fastener is mm (mm), and its tooth tip angle is 60 degrees. Both US and UK lines are in inches. The acute angle of American fastener threads is also 60 degrees, while the acute angle of British fastener threads is 55 degrees. Due to the different units of measurement, different fastener threads are represented differently. For example, m16-2x60 represents a metric fastener thread. Its specific meaning is that the nominal diameter of the fastener is 16mm, the pitch is 2mm, and the length is 60mm. For example, 1/4-20x3/4 means imperial fastener threads. His specific meaning is that the nominal diameter of the fastener is 1/4 inch (1 inch = 25.4mm), there are 20 teeth on 1 inch, and the length is 3/4 inch. Also, for American fasteners, UNC and UNF are usually added after British fasteners to distinguish American coarse from American fine.
In the usual domestic Dongming fastener sales business, the standards we often encounter are GB (national standard) and DIN (German standard).
For non-aromatic products, we will mainly comply with the following standards: GB30; GB5783; GB5782; GB52; GB6170; GB818; GB819; GB845; GB846; GB70; DIN912; DIN933; DIN931, etc. At present, GB30 (old national standard) in the standard book has been replaced by GB5783 (new national standard).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 1986, my country formulated a new standard for Dongming fasteners, commonly known as the new enterprise standard. Mainly use Gb5780, gb5781, gb5782, gb5783 and gb5784. Gb5780 is a hexagonal head thick rod half-tooth fastener, and the accuracy grade is C-grade product, which can be replaced by gb5782 (gb5782 is a hexagonal head thick rod full-tooth fastener, and the accuracy grade is A, B grade). Gb5781 is a hexagonal head full-tooth fastener with a precision grade of C grade.