At its peak in the late nineteenth century, the Poole & Hunt Foundry and Machine Works employed over 700 people, making it one of the largest employers in the Jones Falls Valley after the textile mills. The company manufactured an impressive array of machinery: turbines, boilers and looms for the mills, screwpile lighthouses, railroad machinery, and transmission equipment for cable cars. Perhaps their greatest contribution was to the construction of the United States Capitol Building, to which the company manufactured the structural elements of the dome and cast the columns of its peristyle, made structural elements for the House and Senate wings, and built the derricks, steam engines, and lifting equipment that made the construction of the Capitol possible.
Robert Poole emigrated as a child from what is now Northern Ireland to Baltimore in the 1820s. When he was old enough to work, he found employment at the machine shop of Lanvale Cotton Mill (located near where Penn Station is today) and later worked at Savage Mill. In the 1830s, Poole worked for Ross Winans, the millionaire engineer for the Baltimore & Ohio Railroad. Through these early jobs, Poole gained experience working on machinery for mills and the railroad—two key markets for the company he would later form.
By the late 1840s, Poole was running his own shop in downtown Baltimore with partner William Ferguson. After Ferguson retired in 1851, German Hunt, an executive at the firm, became a partner. The shop burned in 1853 and the company relocated to Woodberry along the Northern Central Railway and near the prospering textile mills. Poole oversaw the shop while Hunt handled the business side downtown. Additions and new buildings were constructed as the company grew and their commissions became more complex. The blacksmith shop, the oldest extant building on the site, was built in 1856 and the foundry was built in 1870. By 1890, the complex included a massive 80 foot high erecting shop, signaling the impressive scale of machinery being manufactured by the company.
In 1854, Captain Montgomery Meigs, a US Army Corps of Engineers official in charge of the US Capitol extension project, commissioned Poole & Hunt to build steam engines and derricks for the construction of the Capitol Building, along with structural ironwork for the roof. Within a year, Meigs offered Poole & Hunt the opportunity to bid on work for the columns of the Capitol dome. The firm won with an extremely low bid, 2/10s of a cent per pound. Poole & Hunt continued to work on the columns until 1859 when Meigs was replaced and the contract for the remainder of the columns went to New York foundry Janes, Fowler, Kirtland & Co.
By this point, Poole & Hunt had made a name for themselves. Robert Poole would build his Second Empire mansion "Maple Hill" across the Jones Falls in Hampden overlooking his factory, while German Hunt resided in fashionable Bolton Hill. Poole involved himself in the lives of his workers by funding the construction of housing, churches for multiple denominations, a general store, and a circulating library. The library closed after Poole donated funds to the construction of an Enoch Pratt Free Library branch in Hampden. The company also cast the iron columns for the library, which originally shared the building with the Provident Savings Bank, also controlled by the Poole family. Robert Poole and German Hunt were also involved in establishing the Woman's College of Baltimore, which became Goucher College. German Hunt served on the college's first board of trustees and Poole donated a significant amount of cash to the endeavor.
In addition to overseeing the lives of local residents, Robert Poole and German Hunt maintained close relationships with the textile mill owners. Robert Poole's daughter, Sarah, married James E. Hooper, who would become president of the Mt. Vernon-Woodberry Cotton Company before splitting off and forming Hooperwood Cotton Mills adjacent to Poole's industrial campus.
German Hunt retired from the company in 1889. Poole made his son George partner and renamed the company Robert Poole & Son. The company was now the largest machine shop and foundry in Maryland, employing over 700 workers at its peak. It garnered national acclaim in trade journals for its impressive manufacturing feats. The Leffel Double Turbine, used to power mills, was praised for its efficiency and durability, and became popular with manufacturers across the country. By the 1880s, the company made a name for itself building machinery for cable car powerhouses along the East Coast and in the Midwest. In 1901, the Calumet and Hecla 65' sand wheel manufactured by Poole, the largest of its kind in the world, made the cover of Scientific American, bringing more national attention to the firm.
Robert Poole died in 1903 and the company continued under the name Poole Engineering & Machine Company. In 1905, the company added an administrative building to the campus. In 1916, to meet manufacturing demand, a new erecting shop was added. World War I brought a new wave of commissions to the company. The company manufactured naval artillery mountings and operated an ammunition works in Texas, Maryland.
In 1934, hard hit by the depression, the company sold much of its original campus to the Franklin Balmar Company, which during World War II was commissioned to provide components to the Manhattan Project's atomic bomb. Some of the buildings were sold to Hooperwood Cotton Mills. The campus was later used by the Aero-Chatillon Company to manufacture components for aircraft carriers.
A kitchen cabinet manufacturer was using the site in 1972, and by the 1990s, a rock climbing gym had taken over the massive erecting shop and artists had set up studios on the campus. In 1995, a large fire that began at the rock climbing gym claimed the life of a firefighter and destroyed the erecting shop and machine shops.
After years of vacancy, the development firm Struever Bros. Eccles & Rouse tackled the large site with a preservation and rehabilitation focus. Designed by architects Cho Benn Holback + Associates, the site is now a thriving complex of residences, offices, shops, restaurants, and even a new crop of hard-at-work artisans. The burned out erecting shop was transformed into apartments, and condos were built on the site of the original machine shop. Not least of its notable attributes, the restoration of Clipper Mill has won, not one, but two historic preservation awards from Baltimore Heritage.