Weight-critical design involves closer than usual tolerances. Precision machine shop tolerances are usually impractical in a production shop. However, combinations of present techniques, along with some new innovations, result in further reduction of redundant weight.
Tolerance optimization, probability of structural integrity and higher than usual rejection rates of detail parts are involved in design tradeoff. Manufacturing philosophy is critical, making “machine-it-to-nominal-and-above” passé. Weight incentive programs, coupled with close supervision, can be made to be successful.
The engineer must consider all aspects of rejection rate/weight/strength/time/cost, if his design is to be successful.