AS engineering standards have risen, the need for production ingenuity has become greater than ever before. The engineer looks to the shop for major assistance in realizing his ideals of improved products. He expects the shop voluntarily to reduce the variations from dimensional specifications and to improve its facility to meet changes in design.Refinement in design is useless unless the shop can accurately hold the dimensions. Powerplant characteristics are largely controlled by the accuracy of centers and roundness and straightness of bores in cylinders and bearings. Crankshaft balance, quiet valve tappets and uniformity of weight and fit of reciprocating parts are all dependent upon accuracy of machine operations.To be able to make design changes in the product without great expense is vitally important. Tools must be designed with facility for change. Fixed-center boring machines are to blame for considerable engine trouble and may make design changes prohibitively expensive. The machine-tool specialist should be called into consultation while new designs are still in the liquid state. The mental attitude of the men in the shop toward changes in machining methods should be altered, and intimate contact of the shop man with the engineer is needed.