5/16"-18 x 5-1/2" Grade 8 Plain Finish Hex Cap Screw / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.875 INCHES NOMINAL FASTENER LENGTH: 5.400 INCHES MINIMUM AND 5.500 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 NOMINAL THREAD DIAMETER: 0.312 INCHES THREAD QUANTITY PER INCH: 18 SPECIAL FEATURES: 5/16-18X5-1/2 GRADE 8 PLAIN FINISH HEX CAP SCREW MATERIAL: STEEL OVERALL THREAD SERIES DESIGNATOR: UNC