July 14, 2022
I missed an important point in a product specification this week. Fortunately, my client caught it and I was able to submit another design in time to meet the deadline. It is difficult to admit mistakes and that does not get easier as you age. We are all encouraged to get “perfect score” on school exams. Once we begin our working lives, perfection is an expectation but seldom a reality. Before you start expounding on “six sigma” and other statistical quality measuring systems, let me remind that there are no perfect manufactured parts. Every single part is within a tolerance band, not “dead on” the mean measurement. Highly automated processes are better at making “perfect” things than manual ones. One of the first things analysts look for in reviewing process charts is “operator interference.” They can tell quickly if the operator is adjusting the process too much and preventing it from being in control. Designing machinery has been my life’s work. Over the past 40 years, I have been responsible for over a 1,000 projects. During one particularly busy 12-year-stretch I averaged a gearbox a week! None of those projects was “perfect” but thanks to good co-workers and sound procedures, we delivered great products to customers and had an exemplary warranty record. A favorite baseball manager was once asked what he was going to do about the team’s power hitter’s tendency to strike out. The press room went silent when the sage replied “Nothing. A strike out is much better than hitting into a double play.” We admire sports stars and pay them millions to miss more pitches than they hit; the key for them is to keep their failures from being permanent. In gearbox design terms, this means checking your own work and not getting defensive when a colleague finds room for improvement. A typical gear drawing has several hundred “features” or numbers on it. Even a 99% accuracy will leave a few “mistakes” for others to find.