Abstract: A synthetic aqueous machining fluid admixture, that is free of sulfur containing and chlorine containing lubricants, and usable in heavy duty machining (e.g. stamping, punching and drawing) operations comprises a) water, b) a water soluble or dispersible fatty acid or water soluble or dispersible fatty acid salt, c) a water soluble or dispersible ethylene oxide propylene oxide copolymer having at least one terminal hydroxyl group or water soluble or dispersible derivative of an ethylene oxide propylene oxide copolymer and d) a water soluble or dispersible organic phosphate ester. Methods for heavy duty machining comprise the steps of applying a force to a workpiece by a tool contacting the workpiece and applying the synthetic aqueous fluid admixture to the interface between the tool and workpiece. The fluid exhibits safety and environmental advantages in use compared to prior art fluids comprising vanishing oils while providing equal or superior lubricity.