1/4"-28 x 2-1/4" ASTM A574 Hex Drive Black Oxide Finish Alloy Steel Socket Cap Screw / THREAD CLASS: 2A THREAD DIRECTION: RIGHT-HAND THREAD LENGTH: 1.25 INCHES NOMINAL FASTENER LENGTH: 1.21 INCHES MINIMUM AND 1.25 INCHES MAXIMUM HEAD STYLE: C48 FLAT FILLISTER HEAD DIAMETER: 0.365 INCHES MINIMUM AND 0.375 INCHES MAXIMUM HEAD HEIGHT: 0.244 INCHES MINIMUM AND 0.250 INCHES MAXIMUM INTERNAL DRIVE STYLE: D5 HEXAGON NOMINAL THREAD DIAMETER: 0.25 INCHES WIDTH ACROSS FLATS: 0.1875 INCHES MINIMUM AND 0.1900 INCHES MAXIMUM THREAD QUANTITY PER INCH: 28 PART NAME ASSIGNED BY CONTROLLING AGENCY: 1/4"-28X2-1/4" BLACK OXIDE ALLOY STEEL SOCKET CAP SCREW COLOR: BLACK OVERALL MATERIAL: STEEL OVERALL MATERIAL DOCUMENT AND CLASSIFICATION: ATSM A574 ASSN STD SINGLE MATERIAL RESPONSE OVERALL SURFACE TREATMENT: OXIDE OVERALL THREAD SERIES DESIGNATOR: UNF