THE photographs reproduced on this and the following page show some of the main stages in the production of precision castings by the lost wax process, as carried out at the new Droitwich works of Deritend Precision Castings Ltd. The investment casting process is now widely used for the production of parts of intricate shape in materials difficult to machine, such as Stellite; stainless, tool and die steels, Nimonic alloys, and beryllium copper. Its application to gas turbine blades is well known.