Distortion during machining can result in high scrap rates and increased manufacturing costs. Distortion results from either the introduction or elimination of residual stresses during manufacture. Residual stresses which are induced in the surface by machining and grinding, or throughout the body by welding or heat treatment, can generally be measured and controlled. Distortion caused by re-equilibration after removal of stressed material during machining is more difficult to avoid and is the primary cause of scrap in precision components. Examples of the residual stress distributions typically seen in heat treated components and the development of finite element models to minimize distortion are presented.