From fired teenager to Vice President: The story of Don Cummins

When Cummins Engine Company was little more than an ambitious startup, Donovan Joel “Don” Cummins entered the family business before he was even old enough to officially work there. Like many early Cummins employees, he learned by doing, helping wherever he was needed in a company that was still finding its footing. Although company records show Don officially joined the payroll in 1922, he had already been contributing to the operation as a teenager, working alongside his brothers, Clessie and Deloss, during the company's formative years. By the end of 1921, Cummins had become a true family enterprise, employing its founder's father, brothers, and brothers-in-law.

The young Don quickly discovered that family ties did not earn him special treatment. Clessie Cummins expected precision from everyone around him, including his younger brother. In fact, Don was fired twice as a teenager for machining mistakes. Rather than driving him away, those experiences helped shape his career. The lessons learned under Clessie's exacting standards would prove invaluable as Don matured into one of the company's most trusted engineers and managers.

During the 1920s and early 1930s, Don became heavily involved in the engineering and testing efforts that helped establish Cummins diesel engines nationwide. He assisted with engine installations and preparations for the famous diesel-powered demonstration vehicles that were used in various stunts to bring national attention to the company during the Great Depression. 

One of Don's most notable contributions came during the celebrated Indianapolis Motor Speedway endurance test of 1931. The event was designed to prove the reliability of the new Cummins diesel-powered truck through thousands of miles of continuous operation. During the run, mechanical issues inevitably emerged with the truck. Working alongside Jay Chambers, Don performed repairs while the truck was in motion, addressing steering and crankshaft seal problems without stopping the vehicle. The feat demonstrated not only the engine's durability but also the creativity and resolve of the small engineering team supporting it.

As Cummins expanded through the 1930s and into the wartime era, Don's responsibilities grew with the company. He rose into research leadership and eventually became Director of Research, helping guide technical development and solve increasingly challenging engineering problems. He also played an important role in the creation of Cummins' modern engineering laboratory around 1940, helping improve the company's capabilities in testing, materials research, and engine development.

Don's impact reached beyond the laboratory. In 1945, he was appointed Quality Manager, where he helped establish more rigorous engine-testing procedures. Eventually, he moved into broader engineering leadership roles and earned the respect of Cummins Chairman of the Board, J. Irwin Miller, who praised Don's organizational ability and talent for building effective teams.

One of the more exciting chapters in Don's career took place in the early 1950s when Cummins returned to racing. The company's 1952 Indianapolis 500 effort featured a diesel-powered race car intended to showcase the performance and durability of Cummins technology. Don played an important role in the engineering and development activities surrounding the program, drawing upon decades of expertise and experience with the company. More than two decades after helping keep diesel race cars and endurance vehicles running on the track and on the road, he was still working on projects that put Cummins engineering before a national audience. The Cummins Diesel Special race car won the pole position at the Indianapolis 500 that year and served as a test for the Cummins PT Fuel system. 

Don's impact stretched beyond the United States. In 1956, he led the effort to establish Cummins' first overseas manufacturing operation in Shotts, Scotland. Serving as managing director, he guided the facility through its challenging startup period and successfully brought Cummins into the international realm. 

By the mid-twentieth century, Donovan Joel Cummins had become far more than the founder's younger brother. He was a researcher, development engineer, racing-team contributor, and international pioneer whose work touched nearly every aspect of the company's growth. His career culminated in his appointment as Vice President of Engineering, completing a remarkable rise from unofficial teenage helper and twice-fired machinist to one of the most influential engineering leaders in Cummins history.