M18 Galvanised Hexagon Nut - Grade 8 - Din 934 Tapped Oversize Since hot-dip galvanizing typically adds 2.2 to 5 mils of thickness to the threaded portion of a fastener, galvanized heavy hex nuts are tapped oversize to compensate for the corrosion resistant coating on the thread of the bolt Where: e = point to point m = thickness s = across flats d = Thread e - 29.56 mm (min) m - 14.3 mm (min) s - 27 d - 18 Thread Pitch - 2.5 mm DIN934