5/16"-18 Zinc Finish Grade 5 Finished Hex Nut / THREAD CLASS: 2B THREAD DIRECTION: RIGHT-HAND NUT STYLE: A12 HEXAGON NUT HEIGHT: 0.258 INCHES MINIMUM AND 0.273 INCHES MAXIMUM END ITEM IDENTIFICATION: 4320-01-617-7587 WIDTH ACROSS FLATS: 0.489 INCHES MINIMUM AND 0.500 INCHES MAXIMUM THREAD SERIES: UNC THREAD QUANTITY PER INCH: 18 NOMINAL THREAD SIZE: 0.312 INCHES BEARING SURFACE TYPE: FLAT PART NAME ASSIGNED BY CONTROLLING AGENCY: GRADE 5 FINISHED HEX NUT MATERIAL: STEEL OVERALL SURFACE TREATMENT: ZINC OVERALL