As Ferguson had noted, mechanical engineers of the United States cultivated a peculiar concept of “democracy” during the 19th century. They equated democracy with material abundance enjoyed by people, as Eugene S. Ferguson had noted. They believed in spreading new machines and mechanical know-how which would enable more diverse and affordable goods, as their own civic virtue. Any power and wealth acquired by this missionary zeal were never problematic. After the Independence, some North Eastern elites, such as Stevens’, Browns and Livingstons assimilated immigrated mechanical talents into their social startum offering partnerships and marriage ties. These elites regarded materializing this machinery passion as the contribution to the society and civilization. The power of government and state were, alongside their inventive minds. one of the means to achieve this goal. These precedents kept the quasi-kinship and patronage as the main conduits of exercising influence in American engineer community even well after the 19th century. The apprentice system of engineer education and the American Industrial Revolution ware main factor of this persistence. Master engineer often included an apprentice or journeyman into his quasi-kinship networks. The more loyally an apprentice followed his master’s leadership, the more frequently he was able to be a partner, the successor to his master’s business or to establish himself in another town or industrial sector. Industrial revolution under continuos population growth and economic expansion enabled master mechanical engineers to regard a talented apprentice not as an future competitor but an candidate to enlarge his sphere of influence. Under this circumstance, machine tool engineers, especially, those of Philadelphia emerged as the most powerful and influential engineer group in the middle of 19th century. For machine tool engineers engaged almost every mechanized industry and Philadelphia had the largest mechanical industry. Philadelphian machine tool engineers occupied the most ideal socio-technical niche for their proteges. The Sellers system of screw standard announced in 1864, its spread and the arguments against the metrication of that system reveals bits of American engineer mores: They mobilize governmental influences to achieve their own goals without hesitation, but are firmly against direct governmental intervention. They try to follow exactly the foot steps of succeeded engineers now with epoch making innovations. Even many decades after the demise of Philadelphian machine tool industry, these bits are manifest among American engineers as well as their peculiar concept of “democracy”.