In Eli Terry entered into a contract with 2 other men to manufacture 4000 clock movements with dials, hands, weights, and pendulums in a 4 year period. This in clock circles is known as the Porter Contract. In 1806 Terry bought a sawmill that used water power in Plymouth CT. He then hired laborers with specific abilities to produce the various pieces of the clocks, to an accuracy that made the parts interchangeable. One of the first in America to accomplish interchangeable mass produced parts for a product. The fact that the parts were made and assembled by skilled craftsmen, kept the cost down and allowed a much greater production volume, way more than 1 clockmaker could accomplish by himself. Thus was started, in this country, a new business of mass producing clocks, which brought the cost of a clock down to where the masses could afford them. Clocks were no longer for just the aristocrats. Apprenticing with Eli Terry at this time was Seth Thomas and Silas. Hoadley, who both went on to be noted American clockmakers. In my career of over 40 years, I have had the pleasure of restoring several of the now 210 year old all wood movements.