National Tube Company
"National Tube" had its origins with the Flagler brothers of Boston, John and Harvey. They had operated a small plant welding iron tubing in East Boston, but decided to move their operations to the Pittsburgh district to be closer to iron makers. They purchased the Fulton, Bolman Company of McKeesport, and built there in 1872 a new mill for welding tubes. Within a year the mill was turning out tubes as large as fifteen inches in diameter and twenty feet long.
All welded tubes started out as sheets cut to size known as "skelp." For smaller tubes, "butt" welding in a single step formed the tube and welded its edges together inside a cone-shaped "welding bell," while for larger tubes the sheet-like "skelp" was first rolled into a tube and then closed up by "lap" welding in separate welding rolls.
In the 1880s the company installed rolling mills to form the "skelp" for tube making, built its own blast furnaces to make raw iron, and increased its lap and butt welding furnaces to ten and seven, respectively. Tubes in great variety thus came from a highly automated factory.
Between 1891 and 1901, three waves of corporate mergers washed over McKeesport.
In 1891, the Flagler brothers consolidated their various iron and steelmaking interests together with the South Side works of Republic Iron into an $11.5 million concern. Soon after, McKeesport built a new Bessemer steel plant and literally retired its numerous skilled iron puddlers.
In 1899 a Morgan-financed merger brought sixteen of the country's largest pipe and tube manufacturers into one dominant tube concern, still known as National Tube. Among the prominent firms was the Riverside Iron Works, which sold steel tubes to John D. Rockefeller's Standard Oil, the world's largest tube consumer. In the third and final wave, the U.S. Steel Corporation in 1901 merged together the remaining tube competitors, including the independent Shelby Steel Tube.