1.1 EVOLUTION OF A DESIGN

Most likely you have, right at this moment, at least one machine design project in progress. Maybe you were the originator of the design, but I suspect you inherited this design from others. I further suspect that you have already identified elements of the design you feel could be improved. You might be under pressure from customer service or marketing to respond to some need for change. In responding successfully, either to your own observations for change or to those of others, the design will evolve. Recognizing that the evolutionary design process is decidedly complex, with a seemingly random sequence of steps, the primary purpose of Standard Handbook of Machine Design is to make the information you need as readily accessible and usable as possible.

As an example of how a design can evolve, and to provide perspective on how the information in this Handbook has traditionally been used, let me review for you a project I was given in my first job as a mechanical engineer. It involved the positioning of a microwave feed horn for a 30-ft-diameter antenna dish. The original design (not mine, by the way) called for a technician to climb up onto a platform, some 20 ft off the ground, near the backside of the feed horn. The technician had to loosen a half dozen bolts, rotate the...