M20 Galvanised Heavy Hexagon Nut - A194 Grade 2H tapped oversize Quenched & tempered carbon steel heavy hex nuts 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 - 33.53 mm (min) m - 19.48 mm (min) s - 29.67 mm (min) d - M20 Thread Pitch - 2.5 mm