SOLID GRIND 985 S: Highest precision for sharpening planing cutterheads. The SOLID GRIND 985 S offers you ideal prerequisites for perfect sharpening of planing cutterheads up to 720 mm wide, regardless of whether it be a conventional cutterhead, hydro cutterhead or a shaft cutterhead. Because the knives are sharpened in the cutterhead it is possible to subsequently joint hydro clamped tools.