Yes 1986 the state formulated a new standard for bolt standard parts, which is called the new standard in the industry. Is GB5784 a hexagon-head bolt-thin rod-class B? Products. Which is GB5784? GB30-76/GB2 1-76？ .

The difference between the new standard and the old standard lies in the different relative widths of M8, M 10, M 12, M 14 and M22 series products. Except the M22 series of new products, the head edges of the new standard products M8, M 10, M 12 and M 14 are smaller 1MM than those of the old standard products. They are 13, 16, 18, 2 1MM respectively, but the new standard of M22 series is 2MM larger than the reverse of the old standard, so special attention should be paid. For the thickness of the head, the new standard is slightly different from the old standard, which can be used in cases where the requirements are not very strict.