ASME B18.2.1 pdf download Square, Hex, Heavy Hex, and Askew Head Bolts and Hex, Heavy Hex, Hex Flange, Lobed Head, and Lag Screws (Inch Series) 2 GENERAL DATA FOR BOTH BOLTS AND SCREWS 2.1 Heads 2.1.1 Top of Head. Top of head shall be full form and chamfered, withthe diameterofchamfercircle equal to the maximum width across flats, on square or...