PRODUCT SPECIFICATIONSPart #: 0000-117947Fastener Type: Finished Hex Nut - USASize Description: 5/8"-18Diameter/Nominal Size: 5/8"Thickness: 35/64" (0.535-0.559")Wrench Size/Across Flats: 15/16" (0.922-0.938")Width Across Corners: 1.051-1.083"Thread Pitch: 18Thread Pitch Type: FineThread Direction: RightSystem of Measurement: InchGrade: 5Material: Medium Carbon SteelFinish: Zinc PlatedDrive Type: External HexUsed with: Bolts/Screws up to Grade 5Average Piece Weight: 0.0710000 lbs.Country of Manufacture: United StatesNuts are almost always used in conjunction with a mating bolt to fasten multiple parts together; kept together by a combination of their threads' friction, a slight stretching of the bolt, and compression of the parts to be held together.