Flange Bolts Dimensional Standards ASME B18.2.1 Drive Hex Drive Size 1/4 in Fastener Length 1 1/4 in Finish Black Oxide Flange Diameter 9/16 in Flange Type Standard Head Height 9/32 in Head Width 3/8 in Manufacturer Location Globally Sourced Material Steel Material Grade/Class Grade 8 Material Quality Standards SAE J429 Minimum Thread Length 3/4 in Pack Size Small Pack System of Measurement Inch Tensile Strength 150 000 psi Thread Size 1/4 In.-20