1/2"-13 x 3-1/2" ASTM A574 Hex Drive Black Oxide Finish Alloy Steel Socket Cap Screw - HoloKrome USA / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND FASTENER LENGTH: 3.500 INCHES NOMINAL NOMINAL THREAD DIAMETER: 0.500 INCHES THREAD QUANTITY PER INCH: 13 PART NAME ASSIGNED BY CONTROLLING AGENCY: BLACK OXIDE ALLOY STEEL SOCKET CAP SCREW COLOR: BLACK OVERALL MATERIAL: STEEL OVERALL OR STEEL UNS K03104 SURFACE TREATMENT: OXIDE OVERALL THREAD SERIES DESIGNATOR: UNC