ECONOMICS OF TOOLING FOR INTERCHANGEABLE PRODUCTION
When the volume and the variety of the parts produced by a plant increase beyond the point at which the shop mechanic is capable of devising the methods and building the tools for accomplishing the desired results, it becomes necessary to make a division of labor, and a special department on tool division is needed to determine the proper sequence of operations and the suitable equipment to produce the required quantity with the required degree of accuracy. It is necessary that the men be informed regarding the daily and the ultimate numbers of parts to be produced and the tolerances that will be allowed.
The foremost consideration of the production engineer should be economy of production. In this phase of tool engineering, the ultimate number of parts to be produced plays an important role and equipment should be selected that will give the maximum production. All known methods of production should be compared and the most economical one chosen. Rules are given for governing economic tooling and an illustrative problem is worked out for the production of bearing-caps. By means of charts, calculations are made to determine the comparative economy of drilling holes in 100,000 bearing-caps by the use of single-spindle vertical drillingmachines, of single-spindle vertical drilling-machines equipped with four-spindle multiple drill-heads and of multiple-spindle vertical drilling-machines.
Having determined the economical method of selecting equipment, the tools must be produced economically. This involves accurate knowledge of the result to be accomplished, care in the preparation of the preliminary drawings, and the avoiding of unnecessarily difficult pattern-work and unnecessary machining operations. As the principal value of a tool estimate is the paying of bonuses in the toolroom, the group-bonus wage-payment plan employed by the Paige-Detroit Motor Car Co. is described.