5/16"-18 x 3/4" Grade 5 Zinc Finish Hex Cap Screw / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.720 INCHES MINIMUM FASTENER LENGTH: 0.720 INCHES MINIMUM AND 0.750 INCHES MAXIMUM HEAD STYLE: C1 HEXAGON HEAD HEIGHT: 0.195 INCHES MINIMUM AND 0.211 INCHES MAXIMUM WIDTH BETWEEN FLATS: 0.489 INCHES MINIMUM AND 0.500 INCHES MAXIMUM END ITEM IDENTIFICATION: 4320-01-617-7587 NOMINAL THREAD DIAMETER: 0.312 INCHES THREAD QUANTITY PER INCH: 18 PART NAME ASSIGNED BY CONTROLLING AGENCY: HEX CAP SCREW MATERIAL: STEEL OVERALL SURFACE TREATMENT: ZINC OVERALL THREAD SERIES DESIGNATOR: UNC