Socket Flat Head Screw Head Type Flat System of Measurement Inch Drive Type Socket Drive Size 3/16 in Material Alloy Steel Finish Black Oxide Thread Size 5/16 In.-18 Minimum Thread Length 1 1/8 in Fastener Length 1 3/4 in Head Height 0.198 in Head Diameter 0.656 in Pack Size Small Pack Thread Style Partially Threaded Special Features Not Applicable Countersink Angle 82 Degrees Dimensional Standards ASME B18.3 Flange Diameter Not Applicable Flange Thickness Not Applicable