Carbon graphite materials are purchase in billet form with various O.D. and I.D. configurations. These materials are impregnated to seal the pores and increase chemical and wear resistance. Machining is performed on dedicated and modified engine lathes. Carbon graphite machining includes turning, boring and grooving operations, utilising carbide and diamond tools. Milling, drilling and tapping operations are performed on conventional manual type milling and drilling machines Carbon seal faces are finished, lapped and polished on standard lapping and polishing machine.