IEEE PULSE presents

There’s Nothing Like Real Experience: II

State of the Art November/December 2020
Author: Art Johnson

As the saying goes, the point on a pencil is the inspiration and the other end with the eraser is the experience. A pencil without an eraser is next to useless, as I have found out. Yes, I know that, instead of using pencils, we all type on computers these days, but the principle still holds: Experience tempers our creative endeavors with realistic expectations. Whether we are considering engineering solutions to outstanding problems or are considering more broadly how to live our lives, real-life experiences guide our every move.

I have certainly had my share of experiences to remember. There was the time when I and my family of four were returning from a professional meeting out west. We had been traveling by car in our 1965 Plymouth Valiant. We stopped overnight in Wisconsin, and hoped to drive the next day the remainder of the miles to our home in Maryland. When we came out from our overnight accommodations the next morning, we found that there was a flat tire on the driver’s side of the car. We had a good spare, and I was going to replace the flat with the spare so that we could get underway as quickly as possible. I rummaged through our luggage and other stuff in the trunk to find the jack, placed it in the proper place, and raised the car just enough so that I could use the lug wrench, but not so high that the wheel would rotate as I loosened the bolts.

The lug nuts were on very tightly, but that was not unusual. Tire jockeys like to tighten the nuts with their pneumatic impact wrenches, and that keeps the nuts from loosening while driving and having a wheel fall off at high speed as a result. I had to apply a little extra force to the wrench to loosen them. With some effort, the first nut came off, but with it came a part of the bolt, as well. That was not good. I really didn’t want to drive the 800 or so miles to home without all the bolts in place.

I tried another. The same thing happened this time: Nut and sheared-off lug bolt came off together. It was only then that I noticed the “L” stamped in the ends of each of the lug bolts; they were all left-handed threads on that side of the car. Apparently, the engineers who designed the car thought that lug bolts on the left-hand side of the car were less likely to loosen if they had left-handed threads. So, that is the way the car was manufactured.

I learned the hard way that day to inspect things carefully before acting. If I had a question about the meaning of the “L” stamped into the ends of the lug bolts, then I should have called the local Chrysler dealer and asked. As it was, I had to call the dealer anyway to have the tire changed and the bolts replaced before we could get underway with our trip.

I also learned that convention is a powerful motivator for practice. Until that day, all the other bolts that I had ever encountered had right-handed threads. And, as the dealer later explained to me, I was not the only person who found out the hard way about the left-hand threaded bolts. As an engineer, I should carefully consider designs that go counter to accepted convention. They can often result in mistakes or, worse, tragedies. Users often go with habit, especially in panic situations, as happened with the melt-down at the Three Mile Island nuclear power plant.

We have many habits that are so ingrained in us that we hardly ever think about them before acting. Red means danger, or stop, whereas green is the sign of everything being OK to continue. “Up” on an electrical switch means that the power is on, whereas “down” means it is off. For those of us who still use analog timepieces, the hands always go in what we call the “clockwise” direction, not the other way around. Most of us read and spell words from left to right, and do not perform nearly as well when required to go from right to left. We have certain habits for each day of the week, and can seriously wonder which day of the week it is if we fall off schedule, as on vacation, travel, or retirement (or forced isolation during a pandemic). Even personal habits, like how we brush our teeth or which side of our mouths to chew food are done without thinking. All these save time and attention, but pose unfamiliarity, discomfort, or even danger, if not permitted for some reason.

So, the lesson here is to design according to convention or standard practice unless forced to do otherwise by compelling reasons. “Lefty-loosey, righty-tighty” has a special meaning for me as a result of my experience.

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