M20 Galvanised Hexagon Thin Nut - Grade 4 - Din 439 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 - 32.95 mm (min) m - 9.1 mm (min) s - 30 d - M20 Thread Pitch - 2.50 mm DIN439