Hex bolts Hexagonal bolts - ordinary coarse thread Use:    Cooperate with the nut and use threaded connection to connect the two parts into a whole. It is a detachable connection. There are three types of hexagonal bolt accuracy: A, B, and C. Mark: The complete mark of the hexagonal head bolt with thread specification d=M12×1.5, nominal length L=80mm, performance grade 8.8, surface oxidation, and grade A is: GB578M12×1.5×80 Hexagonal bolt-ordinary fine thread Use:  Like ordinary coarse teeth, threaded connection is used to connect the two parts into a whole. It is a detachable connection. Fine-thread bolts have good self-locking performance and are used in areas subject to large impacts, vibrations or alternating loads. They can also be used to adjust fine-tuning mechanisms. Mark: The complete mark of the hexagonal head bolt with thread specification d=M12×1.25, nominal length L=80mm, performance grade 8.8, surface oxidation, and grade A is: GB5785M12×1.25×80 Countersunk head bolts Use:  The head of the bolt can be embedded in the component, and the connection strength is high. Generally used when the connected parts need to ensure a flat surface. For example, the connecting bolts of wear-resistant plates in our line are all connected with countersunk head bolts. Mark:  The complete mark of the hexagonal head bolt with thread specification d=M12×1.5, nominal length L=80mm, performance grade 8.8, surface oxidation, and grade A is: GB70.1M12×80 Use: Eye bolts are used for lifting and hoisting equipment to lift heavy objects. It is generally used on equipment that requires lifting such as motors. U-shaped bolts are generally used for installation and fixation. Generally used in pipe fixing, wire rope fixing and other occasions. Mark: The thread size is 20mm, the material is 20# steel, and the A-type lifting eye bolts are marked: GB825M20 Website : Stay turned Cheers