PFERD vitrified bond Ceramic mounted points in hardness grade J is manufactured from a mix of white aluminum oxide and blue ceramic sintered aluminum oxide in a vitrified bond. The soft bond in combination with the easy to break down, sharp-edged white aluminum oxide and the self-sharpening effect of the microcrystalline sintered aluminum oxide allows extremely high stock removal rates with excellent service life. The hardness grade J is perfectly suited for surface work on titanium materials, nickel and cobalt-based alloys, steel components and buildup weld deposits. Application: Re-finishing of airplane turbine blades. Follow-up repair welding in tool and mold construction. Grinding of repair welds and turbine blades. Pferdefficiency - recommends mounted points in hardness grade J for long, fatigue free and resource saving work, with perfect results in the shortest possible time. Specification: Shape/Form: W189; Diameter (inches): 1/2; Length (inches): 2; Shank Diameter (inches): 1/4; Shank length (inches): 1-1/2; Grit: 80; Maximum Rotational Speed (RPM): 24000; Material: Ceramic Oxide.