components. A total of 45 machines were required to perform 22 processes on the blocks, which could be made in three different sizes. The machines were almost entirely made of metal thus improving their accuracy and durability. The machines would make markings and indentations on the blocks to ensure alignment throughout the process. One of the many advantages of this new method was the increase in labour productivity due to the less labour-intensive requirements of managing the machinery. Richard Beamish, assistant to Brunel's son and engineer, Isambard Kingdom Brunel, wrote: So that ten men, by the aid of this machinery, can accomplish with uniformity, celerity and ease, what formerly required the uncertain labour of one hundred and ten. By 1808, annual production had reached 130,000 blocks and some of the equipment was still in operation as late as the mid-twentieth century. Terry's clocks: success in wood Eli Terry was using interchangeable parts using a milling machine as early as 1800. Ward Francillon, a horologist concluded in a study that Terry had already accomplished interchangeable parts as early as 1800. The study examined several of Terry's clocks produced between 1800–1807. The parts were labeled and interchanged as needed. The study concluded that all clock pieces were interchangeable. The very first mass production using interchangeable parts in America was Eli Terry's 1806 Porter Contract, which called for the production of 4000 clocks in three years. During this contract, Terry crafted four-thousand wooden gear tall case movements, at a time when the annual average was about a dozen. Unlike Eli Whitney, Terry manufactured his products without government funding. Terry saw the potential of clocks becoming a household object. With the use of a milling machine, Terry was able to mass-produce clock wheels and plates a few dozen at the same time. Jigs and templates were used to make uniform pinions, so that all parts could be assembled using an assembly line. North and Hall: success in metal The crucial step toward interchangeability in metal parts was taken by Simeon North, working only a few miles from Eli Terry. North created one of the world's first true milling machines to do metal shaping that had been done by hand with a file. Diana Muir believes that North's milling machine was online around 1816. Muir, Merritt Roe Smith, and Robert B. Gordon all agree that before 1832 both Simeon North and John Hall were able