High Speed Steel Jewelers' Slim Reamer Burs These hand-cut, high speed steel burs last longer than standard jeweler's burs. They offer exceptional cutting efficiency and are available in a wide variety of shapes and sizes for cutting most metals. All have 3/32" (2.4mm) shanks and will fit most flexible shaft handpieces. Sizes 13 and 19; diameters 3.30mm and 4.70mm. Supplied individually.