This Standard covers the complete general and dimensional data for nine product types of inch series square and hex bolts and screws. Hex flange head and lobed head designs are new in this revision, as are screw sizes 1 5/8, 1 7/8, and 3 1/8 through 6 inches. Appendices covering gages and gaging information plus formulas on which dimensional data are based are included. Heavy hex structural bolts, formerly covered in ANSI B18.2.1, are now covered in ASME B18.2.6.