Heavy Nuts are often called heavy hex nuts or large hex nuts. These are oversized nuts for structural bolting applications. They are oversized, both in thickness and hexagon across flat dimensions. There are many grades, but large diameter, high strength bolts are most frequently made using the heavy design. A heavy Hexagonal body requires more wrenching torque while supplying enough strength to the bolting joint. Heavy Nuts are used with heavy hex bolts or screws, fine pitch (UNF), national coarse pitch (UNC), fixed pitch (UN), and iso metric thread profile.