The grade 8 steel hex jam nut has a zinc yellow-chromate plating and meets American Society of Mechanical Engineers ASME B18.2.2 specifications. Also called a thin nut, it is thinner than a standard hex nut for use in tight areas and is often used with another jam nut to help prevent loosening. It has six flat sides that a wrench can grip to turn from the side, enabling use when there is no space above the nut. Grade 8 steel, composed of quenched and tempered medium carbon alloy steel, is stronger than grade 5 steel and is often used in applications where strength is the primary consideration. The zinc yellow-chromate plating offers good corrosion resistance.
Nuts are internally threaded fasteners that are used with bolts and threaded rods and studs to connect components. Several different nut styles fit a variety of application and installation requirements. Some styles, such as hex nuts, acorn nuts, flange nuts, and coupling nuts, must be tightened with a tool. Others, such as eye nuts, thumb nuts, and wing nuts, can be tightened by hand. Some nuts have a self-locking mechanism, such as a nylon patch or distorted threads, that makes them suitable for applications with a high amount of vibration.