Permanent mold and sand castings can be produced with a variety of surface finishes, dimensional precision, finish allowances and drafts. The flexibility of these forms of castings give the engineer and manufacturer wide latitude in design to meet specific requirements. The Engineering Series is established for the individual requirements involved in producing a usable, unmachined casting consistent with normal production practices, reproducibility, reasonable mold or pattern life and maintenance costs, normal inspection, packing and shipping procedures. Special requirements for finish, tolerances, etc., beyond the standard may be specified where required although additional costs may be involved. Consultation with the foundry will usually result in such requirements being properly considered in the quotation and mutually understood. Conversely, more liberal values should be indicated where acceptable since they tend to keep costs to a minimum.
These Engineering Standards are not designed to reduce quality level, lessen competition, restrict customer requirements or increase costs. On the contrary, for the types of castings to which they may be applied, the program will improve understanding of quality levels, widen the area of available sources of supply, increase the customer's ability to distinguish special requirements, and reduce costs by eliminating the specification of unnecessary rigid limits where they are not required.