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Senior thesis

Making time for old-fashioned engineering

By Steven Schultz

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Rebecca Gillespie restored the Prospect House grandfather clock for her senior thesis project.

Princeton NJ -- Rebecca Gillespie’s senior research project has taught her a lot about keeping track of time — not due to the rapidly approaching deadline, but because of the months she spent restoring the intricate workings of an old grandfather clock.

Gillespie has dismantled and is rebuilding the 19th-century timepiece that has stood, not working, in the lobby of Prospect House for several decades. As a mechanical and aerospace engineering major, Gillespie could have chosen among cutting-edge research projects from rocket science to biotechnology, but yearned for old-fashioned gears and moving parts.

“I had done work in fluid dynamics and computer simulations, but I was interested in doing something that involved a mechanism, a simple mechanism,” she said. When her adviser, professor of mechanical and aerospace engineering Michael Littman, suggested the Prospect House clock, she jumped at the idea.

“The clock is really interesting mechanically,” she said. “It’s absolutely amazing what people came up with.”

The clock, which was missing its pendulum and weights and had a number of worn out and badly restored parts, proved to be a real challenge. Littman and Gillespie enlisted the help of professional clock restorer Dean Morrison of the Pennington Clock Shop, who advised them about proper restoration techniques. By spring break, the clock appeared to be working and Gillespie returned the mechanism to the wooden case in Prospect House for a trial run. After a few days, however, the clock stopped and Gillespie brought the mechanism back to the lab.

Puzzling out problems is part of the project’s allure, she said. “There is no textbook answer. You can’t ask the professor; he doesn’t know either.”

As Gillespie and Littman poked at the device and speculated about the cause of the problem on a recent afternoon, they also marveled at the complex, yet elegant design. The clock translates the pull of the weights into movements of the hour, minute and second hands, plus the correct number and tempo of hourly chimes, the turning of the date wheel and the 28-day cycle of a wheel that shows the phases of the moon.

“It’s incredibly economical,” said Gillespie. “I’ve learned a lot about clocks, but it also gives me a lot of insight into the early days of engineering. I have a huge amount of respect for the people who designed these clocks.”

That historical perspective is one of Littman’s goals for his students. In recent years, he has developed an interest in antique technologies and incorporated them into his teaching.

“I think there is a great deal that one can learn from deconstructing existing devices,” said Littman, whose expertise is in lasers and optical systems. “That is how I taught myself electronics. Also in some cases it’s a way to regain a lost art and gain an appreciation of devices. You get to the pith, what’s really important, quickly.”

While Princeton students learn sophisticated mathematical techniques and master computer-aided design, they also can benefit from seeing how engineers solved problems with fewer resources, he said.

Part of Gillespie’s project is to analyze the works with modern techniques to figure out why the design is good, or where it could have been improved. She also is researching the history of the clock, which dates from between 1820 and 1840, and was donated by Hugh Adams of the class of 1935. The historical research also has been challenging because the clock does not appear to have come from a major clock-making shop and may have been pieced together from more than one mechanism.

As she continues to research and tinker, Gillespie is motivated by the idea that the fruits of her work will be on view at Prospect House and the chime of the clock will be a constant presence. “I didn’t want to do a project that would just be put in a corner and never seen again,” she said. “I hope in 20 years I can come back and see my clock, which would just be really cool.”