Diamond Sharpening Disc GB 3/4" Harvester ChainGB Forestry Diamond Coated Disc for 3 4" Harvester Chain GB diamond coated discs are suitable for sharpening both steel and tungsten carbide tipped 3 4" harvester chains. These discs keep their shape perfectly throughout their service life, with no dressing required. During production, discs are machined to a fine tolerance to eliminate vibration, resulting in a sharper, long lasting cutter. Specification Details Size 145 x 22. 2 x 8mm Pitch 3 4"