①,Bolts and screws shall have a thin rod with a diameter of d. The diameter of the washer shall conform to GB/T 97.4 for free rotation. ②,The distance from the bearing surface to the beginning of the complete thread of the first buckle should be increased to the maximum thickness at which the gasket can be accommodated. For this type of product, the thread is ground to a position close to the gasket. ③,The size of the flat washer should be in accordance with GB/T 97.4 ④,After the agreement between the supplier and the buyer, a U-shaped undercut can be used under the hex head bolt head. |