#8-32 x 1/4" ASTM F835 Hex Drive Black Oxide Finish Alloy Steel Button Socket Cap Screw - HoloKrome USA / THREAD CLASS: 3A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 0.188 INCHES MAXIMUM FASTENER LENGTH: 0.250 INCHES NOMINAL HEAD STYLE: C30 BUTTON HEAD DIAMETER: 0.298 INCHES MINIMUM AND 0.312 INCHES MAXIMUM HEAD HEIGHT: 0.077 INCHES MINIMUM AND 0.087 INCHES MAXIMUM INTERNAL DRIVE STYLE: D5 HEXAGON NOMINAL THREAD DIAMETER: 0.164 INCHES WIDTH ACROSS FLATS: 0.094 INCHES NOMINAL THREAD QUANTITY PER INCH: 32 MINIMUM TENSILE STRENGTH: 137000 POUNDS PER SQUARE INCH HARDNESS RATING: 38.0 ROCKWELL C MINIMUM OVERALL AND 44.0 ROCKWELL C MAXIMUM COLOR: BLACK OVERALL MATERIAL: STEEL OVERALL MATERIAL DOCUMENT AND CLASSIFICATION: ASTM F835 ASSN STD SINGLE MATERIAL RESPONSE OVERALL SURFACE TREATMENT: OXIDE OVERALL THREAD SERIES DESIGNATOR: UNC