Pearl's Premium Carbide Burs feature precision ground tungsten carbide for aggressive cutting and long working life. Available in a wide range of shapes and sizes and also in double cut or single cut varieties. Pearl Premium Burs are perfect for weld dressing, smoothing castings, shaping holes and more. SD - BALL: Ideal for rounded edge processing, end deburring and end pre-machining before welding The Aluminum Cut is designed to be used on Non-Ferrous metals and has an open cut for aggressive stock removal and avoids loading of material on softer metals.