New developments in the production of silicon nitride have resulted in very tough and resilient materials. Turning speeds of 1,000 m/min with feed rates up to 0.7 mm/rev has improved the production of components like brake discs, cylinder liners and flywheels beyond anything previously seen. This allied with improved tool life over carbide make it the ideal choice. The milling of cylinders bocks, gearbox casings and turbo housings is equally transformed. Cutting speeds up to 1,000 m/min are common.