Small scale manufacture of replacement crankshaft

Abstract

Local production of spares has been recognised to have direct economic advantage for the national economy in which the equipment operates. The crankshaft of a single cylinder diesel engine for which the approximate cost of a replacement is a third of the cost of a new engine was considered a prime product for local development of a production process. A single throw crankshaft of a 6kW diesel engine was designed and casted in spheroidal graphite iron. The casting was subsequently heat treated in two stages for homogenization, and for toughness and strength respectively. The strength properties achieved averaged 750 N/mm2 with elongation to failure of 2%. A minimum hardness No. of 33 was measured on the Rockwell C. scale. The performance of the crankshaft based on engine bench tests was considered normal