Dickson Bearings & Transmissions Ltd - KM6 SKF Lock nut for use with a lockwasher (MBSeries)
KM6 Metric Lock Nuts M30 x 1.5 | The Bearing Company
J.W. Winco KM-6 KM Bearing Lock Nut, M30 x 1.5 Thread, 45 mm OD, 7 mm Thickness, 5 mm Slot Width-2 mm Slot Depth (4): Amazon.com: Industrial & Scientific