the grade 8 steel hex bolt has a zinc yellow-chromate plated finish & an external hex drive, meets american society of mechanical engineers asme b18.2.1 & society of automotive engineers sae j429 specifications, & is made in usa. Grade 8 steel, composed of quenched & tempered medium carbon alloy steel, is stronger than grade 5 steel & is often used in applications where strength is the primary concern. The material is magnetic. The zinc yellow-chromate plating offers good corrosion resistance. The external hex drive has six flat sides that a wrench can grip to turn the screw from the side, enabling use when there is no space above the head for a driver.
cap screws & hex bolts are threaded fasteners with thick hex-shaped heads that can be used with threaded nuts or in areas with limited clearance above the tapped (threaded) hole. Cap screws have slightly different dimensions than hex bolts & have a washer face underneath their unflanged hex head to act as a large bearing surface against the mating material.