Eli Terry Sr. (April 13, 1772 – February 24, 1852) was an inventor and clockmaker in Connecticut. He received a United States patent for a shelf clock mechanism. He introduced mass production to the art of clockmaking, which made clocks affordable for the average American citizen. Terry occupies an important place in the beginnings of the development of interchangeable parts manufacturing. Terry is considered the first person in American history to actually accomplish interchangeable parts with no government funding. Terry became one of the most accomplished mechanics in New England during the early part of the nineteenth century. The village of Terryville, Connecticut is named for his son, Eli Terry Jr.
Background
Terry was the son of Samuel and Huldah Terry, born in what is now South Windsor, Connecticut (at the time of Terry's birth, South Windsor was part of East Windsor, Connecticut).
He began his career as an apprentice under Daniel Burnap ("the forerunner of manufacturing"). It's also likely that he received limited instruction from Timothy Cheney, a clockmaker in East Hartford. Cheney specialized in the making of wooden clocks, which was fairly unusual at the time. The use of wooden components would show great influence in Terry's later career.
Terry's apprenticeship to Burnap ended in 1792, and he quickly established himself as both a clockmaker and a repairer of watches in East Windsor. Terry relocated to Northbury Connecticut in 1793, and helped incorporate Plymouth, Connecticut in 1795. Terry was appointed the town Sealer of Weights and Measures. His first clock shop was attached to his dwelling. Terry boarded girls like Candace Roberts to work in his shop painting clock dials. His second shop was considered the first water powered clock shop in the United States, and was built twenty feet square over Niagara Brook, which flowed through his property. Some of his earliest clocks were fitted with silvered brass dials, which were engraved for him by Burnap. The movements of the clock were made primarily of wood, or brass, depending on the requests of his customers. Brass was more commonly used for movements at the time, but it was also considerably more expensive and difficult to work with. In 1801, Terry was granted a patent on an equation clock. This was the first patent for a clock mechanism that was ever granted by the United States Patent Office.
Career
In 1795, Terry invented his first Milling machine to produce interchangeable parts. Terry crafted these milled movements until the Porter Contract. Soon after 1802, Terry's production of wooden clocks grew considerably. Like other Connecticut clockmakers, Terry knew that apprentices could cheaply rough-cut wooden wheels for more skilled journeymen to shape precisely into clockworks, making clocks slightly more cheaply. And Terry was one of a number of Connecticut clockmakers who began to substitute water-powered machines for apprentices in the production of these rough-cut wheels. In 1802 or 1803, Terry purchased a mill to produce wooden clock wheels, which still had to be finished by hand by skilled journeymen clockmakers. He purchased a grain mill and used the water wheel and main shaft to run saws and lathes, which helped speed the production of parts. He later created jigs and fixtures to produce a large number of interchangeable clock parts. This allowed for the rapid adjustment and assembly of clocks, freeing Terry from the task of fitting and modifying each individual piece of each clock. Using his own ingenuity and inventiveness, Terry was thus able to speedily cut wheels, pinions, and other important clock parts accurately and repetitively.
In the year 1806, Terry signed the Porter contract to produce 4,000 wooden clock movements (other shops would make the cases). According to historian Diana Muir writing in Reflections in Bullough's Pond, at that time a skilled craftsman could produce six to ten clocks per year. In the third year he produced 3,000 wooden clocks. He sold his manufactory to two of his assistants Seth Thomas and Silas Hoadley and retreated to his workshop to create the first machine in the world to be mass-produced using interchangeable parts.
