Socket Set Screw, Cup, 1/2 in Overall Length, 5/16-18, Alloy Steel, Black Oxide, PK 100/ THREAD CLASS: 3A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.500 INCHES NOMINAL FASTENER LENGTH: 0.500 INCHES NOMINAL HEAD STYLE: C101 HEADLESS (SETSCREW) POINT DIAMETER: 0.156 INCHES MINIMUM AND 0.172 INCHES MAXIMUM POINT STYLE: F19 FLAT INTERNAL DRIVE STYLE: D5 HEXAGON END ITEM IDENTIFICATION: TOOLS NOMINAL THREAD DIAMETER: 0.312 INCHES WIDTH ACROSS FLATS: 0.156 INCHES NOMINAL THREAD QUANTITY PER INCH: 18 MATERIAL: STEEL OVERALL THREAD SERIES DESIGNATOR: UNC