Finding the Right Combination

One of the hallmarks of a good designer is an unwillingness to settle for the first solution that meets the mission requirements. It is an obsession with finding a “better” way that drives all science and technology forward, even if it frustrates many other people on the team. I completely understand management’s demands to “keep things moving, that is certainly good enough,” but I encourage all of you fledgling designers to resist the pressure to “settle.”

Plenty of gear shops that made “good” products are no longer in business because they had no motivation to improve their “old family recipe” until it was far too late. Even legendary innovators like Henry Ford get complacent; he would have never stopped production of the Model T without his son Edsel’s persistent nagging that the automobile world was roaring past them. [How sad that Edsel is only remembered for a lousy “good enough” product made long after his untimely death.]

Every new project is an opportunity to try out new ideas; even if they never make it off your computer screen you will have learned something from the effort. I have written before about the first big design project of my career. We had a “new” product that was bombing in the marketplace because a competitor had introduced units that fit in the same physical space with higher ratings. The pressure was on to fix it — and fix it fast.

The trouble was, our design “standards” had been followed to the letter in rating the initial series. How do you change the results if you cannot change the inputs? While our technical leaders debated “the rules,” we loyal minions massaged the math models to squeeze in a bit more face width.

I happened upon the “strength balancing” concept described in previous blogs quite by accident. The other “innovation” was a bit more deliberate. It involved juggling the “ratio combinations” within the geartrain to shift more of the reduction to the early stages. This ran counter to years and years of experience, but the “numbers” worked out very well.

Many times, the reasons for doing something a certain way are forgotten. The previous AGMA rating formulas encouraged putting more reduction ratio in the later stages by having a different de-rate factor for each reduction stage. The then “new” method [circa 1976] treated all stages equally and, by using the pinion pitch diameter to the second power, really punished high-ratio pinions.

By simply swapping the stage ratios around we were able to greatly improve our ratings chart. That only happened because of truly understanding what was happening with the math models and being ready to let go of the good old method in favor of a newer approach.

In creative writing circles that is known as “killing your darlings.” It is tough sometimes to discard something you labored long and hard over, but once you see a “better” way you do yourself a disservice to ignore it.

About Charles D. Schultz 678 Articles
Charles D. Schultz is President of Beyta Gear Service and one of Gear Technology's technical editors.


  1. Sir Henry Royce (co-founder Rolls-Royce): “Strive for perfection in everything. Take the best that exists and make it better. If it doesn’t exist, create it. Accept nothing nearly right or good enough.”

  2. Well, being worlds apart, working here in India, it is just amazing that, feelings could be same across the globe. My boss who would always prod for trying various combinations, prior to settling down with the best possible one, was delighted to read your post. Being a well known designer(in gear industries in India) and perhaps in the same age bracket as you, felt so moved that one could read through expressions.

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