GOLDEN STAR EDM POLISHING STONE EDM Polishing Stone · Premium Aluminum Oxide · Medium Structure with Fast Breakdown Made with premium aluminum oxide grain and a proprietary treatment process, the Golden Star finishing stone delivers exceptional performance on EDM (electrical discharge machining) surfaces, milling and machining marks. The Golden Star is of medium hardness and has a fast breakdown offering quick material removal. It contours quickly and leaves a silky smooth finish. The Golden Star works on all tool steels and is terrific when used during hand stoning with one of our Hand Holders as well as with reciprocating profilers like our U-Lap and Turbo-Lap Air Profilers. Lengthy pre-lubrication is not required before use, but the Golden Star should be used with a lubricant. Try our Premium Stoning Oil or BORI-LUBE 10! Available in 150-1000 grit and a wide variety of sizes. Also available in regular and fine grit kits. x