August 1, 2005

1 min read

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Ease the Grind—Working Knowledge on Ball Bearings

By Mark Fischetti

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Hidden from sight, ball bearings are key to almost all devices that spin or roll: power plant turbines, steering columns, wheels, skateboards, yo-yos, dentist drills, and the electric motors in everything from refrigerators and can openers to computer hard drives and CD players. In each case, the balls allow efficient, low-friction movement of rotating parts. Each sphere must be perfect, or the motion it facilitates will come to a grinding halt. Yet manufacturers produce them by the millions for pennies apiece. How do they make the balls so incredibly round and smooth?

Metal, ceramic and plastic balls ranging from an ounce to hundreds of pounds share a similar genesis. An initial plug is cut from wire or extruded and is then stamped by a press into an approximate sphere. That globe is massaged into greater roundness between heavy plates and honed to exact sphericity and smoothness by rolling through grindstones hundreds, if not thousands, of times. The same process creates pellets for air guns and balls for ballpoint pens and roll-on deodorant.

Rights & Permissions

Mark Fischetti was a senior editor at Scientific American for nearly 20 years and covered sustainability issues, including climate, environment, energy, and more. He assigned and edited feature articles and news by journalists and scientists and also wrote in those formats. He was founding managing editor of two spin-off magazines: Scientific American Mind and Scientific American Earth 3.0. His 2001 article “Drowning New Orleans” predicted the widespread disaster that a storm like Hurricane Katrina would impose on the city. Fischetti has written as a freelancer for the New York Times, Sports Illustrated, Smithsonian and many other outlets. He co-authored the book Weaving the Web with Tim Berners-Lee, inventor of the World Wide Web, which tells the real story of how the Web was created. He also co-authored The New Killer Diseases with microbiologist Elinor Levy. Fischetti has a physics degree and has twice served as Attaway Fellow in Civic Culture at Centenary College of Louisiana, which awarded him an honorary doctorate. In 2021 he received the American Geophysical Union’s Robert C. Cowen Award for Sustained Achievement in Science Journalism. He has appeared on NBC’s Meet the Press, CNN, the History Channel, NPR News and many radio stations.

More by Mark Fischetti
Scientific American Magazine Vol 293 Issue 2This article was published with the title “Ease the Grind” in Scientific American Magazine Vol. 293 No. 2 ()
doi:10.1038/scientificamerican082005-7y3m5h0mx4Ocgrpv81Dsqt
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