Shaughnessy in his workshop. Photograph: Gary Wayne Gilbert

Under a ceiling of pink insulation in a tidy basement workshop in Plymouth, Massachusetts, Thomas Shaughnessy leans over a rough-hewn slab of spruce until his nose nearly touches it and counts the parallel lines radiating from the core. “There should be 35 tree rings for 35 years,” he says of the timber, harvested from an old-growth forest in Alaska and air-dried for 50 years. “The wood I’m after will have six of those cycles, evenly spaced; if it gets there any faster, I don’t want it.”

Shaughnessy is the sole craftsman at Violins of Plimoth, an enterprise he started in 2004, three years into his retirement. For almost 55 years, he has been an avid amateur violinist, and he plays now with local chamber groups and symphonies. For 35 years, he was also a physicist, designing and overseeing facilities for the fabrication of silicon microprocessors. A self-described “born tinkerer,” he varnished his first violin—a prefabricated unfinished-wood model—in 2001. Now he carves and shapes the wooden components of his instruments from scratch, arching and planing the hourglass-shaped plates, bending the maple ribs, then fastening them all together with rabbit-hide glue and coating the finished product with 15 layers of hand-mixed varnish. He is self-taught, and his specialty is the reproduction of early instruments: not just the violins and violas designed by Baroque masters such as Antonio Stradivari (c. 1644–1737) and Andreas Guarneri (1626–1698), but also lesser-known precursors like the five-stringed viola pomposa, dark-sounding and briefly popular in the 1700s.

Shaughnessy finds the plans for his instruments in museums or, occasionally, on the Internet. Today, most new stringed instruments are mass-produced in China, he says. In the interest of efficiency, a factory may choose to produce a single model by Stradivari, for instance, and neglect the other 650 by the master that also survive. The variety of instruments—and of subtly different sounds, Shaughnessy maintains—is dwindling, save for in the antiques market and shops of scattered artisans.

Shaughnessy makes three or four rare-model instruments a year and sells mostly to musician acquaintances. Surrounded by his seven workbenches topped with unfinished maple scrolls, ebony fingerboards, and half-carved spruce faceplates, he says his goal is to help preserve the field of “interesting sounds.”

Read more by Cara Feinberg