The metric thread is in MM (millimeters) and its cusp a […]
The metric thread is in MM (millimeters) and its cusp angle is 60 degrees. Both American thread and inch thread are in inches. The tip angle of the American thread is also 60 degrees, while the tip angle of the English thread is 55 degrees. Due to the different units of measurement, the representation of various threads is also different. For example, M16-2X60 indicates 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, for example: 1 / 4-20X3 / 4 is the inch thread, and his specific meaning is the nominal diameter of the screw It is 1/4 inch (one inch = 25.4MM), there are 20 teeth on an inch, and the length is 3/4 inch. In addition, to indicate American screws, UNC and UNF are usually added to the back of the English screws to distinguish between American coarse teeth or American fine teeth. In the usual domestic sales business, the most commonly encountered standards are GB (national standard) and DIN (German standard).
In terms of non-Fangsheng products, the main standards are: 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 At present, GB30 (old national standard) has been replaced by GB5783 (new national standard) in the standard book. GB52 (old national standard) has been replaced by GB6170 (new national standard) in the standard book.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, the state formulated new standards for standard parts, commonly known as new standards. The most commonly used are GB5780, GB5781, GB5782, GB5783, and GB5784. GB5780 is a hexagon head thick rod half-tooth screw, and its accuracy level is C grade product, which can be replaced by GB5782 (GB5782 is a hexagon head thick rod full-tooth screw, and its accuracy is grade A and B.) GB5781 is a hexagon head full Tooth screws, with accuracy class C. It can be replaced by GB5783 (GB5783 is a hexagon head full tooth screw, and its accuracy grade is A grade and B grade). GB5784 is a hexagonal screw with a thin rod and half teeth. The difference between the new standard and the old standard is that the products of the M8, M10, M12, M14, M22 series differ in the width of the opposite side. In addition to the new products of the M22 series, the head-to-edge of the new standard products M8, M10, M12, and M14 is 1 mm smaller than that of the old standard. Respectively, 13, 16, 18, and 21MM. For the new products of the M22 series, the new standard is 2MM larger than the opposite side of the old standard. 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 the width of the opposite side. M10, M12, M14's head-to-side new standard is 1MM smaller than the German standard. The M22's new product has a head-to-edge width 2mm larger than that of the German standard. Others can be used universally.
For hexagon nuts, commonly used standards are: GB52, GB6170, GB6172 and DIN934, the main differences between them are: GB6170 is thicker than GB52, GB6172 and DIN934, commonly known as thick nuts. The other is the difference on the opposite side. In the M8 nut series, the opposite sides of DIN934, GB6170 and GB6172 are 13MM smaller than the opposite side of GB52 14MM. The nuts of M10, the opposite side of DIN934 and GB52 are 17MM, than The opposite sides of GB6170 and GB6172 are 1MM larger, the M12 nuts, the opposite sides of DIN934 and GB52 are 19MM, and 1MM larger than the opposite sides of GB6170 and GB6172 18MM. For the nuts of M14, the opposite side of DIN934 and GB52 is 22MM, which is 1MM larger than the opposite side 21MM of GB6170 and GB6172. The other is the nut of M22. The opposite side of DIN934 and GB52 is 32MM, which is 2MM smaller than the opposite side of 34MM of GB6170 and GB6172. (Except for the different thickness of GB6170 and GB6172, the width of the opposite side is exactly the same) The rest of the specifications can be used universally without considering the thickness.