This firm's name was variously rendered as Ætna Iron Works, AEtna Iron Works, and Aetna Iron Works. The name Etna Iron Works generally refers to a Works in New York City, or another one in Polk County, Pennsylvania, but we have seen it used to refer to the San Francisco works also.

From 1867 to 1883, and likely for much longer, this foundry and machine shop's product lineup included sawmills and steam engine. Their product lines, as perhaps was to be expected for a company serving the Western frontier, was diverse: flour mills, water wheels, ornamental castings, and a full line of mining and ore processing machinery.

The Ætna Iron Works were operated by Hanscom & Co., whose partners were J. O. Hanscom, W. W. Hanscom, H. S. Smith, and T. Pendergast. They were located at the "Southeast corner Fremont and Tehama Streets, San Francisco." By 1875 the Ætna Iron Works were being operated by Pendergast & Smith, a partnership of Thomas Pendergast and Henry S. Smith.

In 1863, there was a foundry and machine shop called Palmer, Hanscom & Co., with John O. Hanscom as a principal partner and T. Pendergast as a partner. Their product line was similar to Hanscom & Co.'s, but their works were called the Golden State Iron Works and they were located on First Street. We do not know if this firm was a direct predecessor of Hanscom & Co.

Information Sources

• Ad in 1863 San Francisco Directory for Palmer, Hanscom & Co., operators of the Golden State Iron Works, which were located "on the site formerly occupied by the Sutter Iron Works on First Street." The partners of Palmer, Hanscom & Co. were Wales L. Palmer, John O. Hanscom, Thomas Pendergast, and William A. Palmer.
• Ad in 1867 through 1875 San Francisco Directory. The 1867 directory provides the following biography:

  Ætna Foundry—Is situated in the rear of the Gas Company's Works on Fremont, near Howard Streets. These works turn out a large quantity of mining machinery, force and lifting pumps, and turbine wheels, both of which latter they have made specialties in their business. Hanscom & Co., proprtrs.

• A 1926 issue of Pacific Marine Review had this snippet: "Their port engineer, James W. Prendergast, has been with the firm for over twenty-two years. A native of San Francisco, he knows the marine engine and steamer work, having learned the trade of marine machinist at the Aetna Iron Works."
• A genealogy webpage about Meldon LeRoy Hanscom says, "In 1872 he gained an interest in AEtna iron works from his brother John."
• From the Bodie, 1859-1900, by Frank S. Wedertz, 1969: "THE SPAULDING MILL The Spaulding was a ten-stamp mill made at the Aetna Iron Works in San Francisco. The machinery of the mill was fired up for the first time on February 27, 1880. Its 800 pound stamps could crush 30 tons per day. ..."
• A lawsuit involving this company provides another data point on their years of operation. "On July 28, 1883, the AEtna Iron-Works of San Francisco entered into a contract with the Gregory Consolidated Mining Company to build and equip for it at Gregory, mont., a complete concentrating mill of specified capacity." The mine superintendent, one Professor Hesse, averred that the machinery provided was "of first-class workmanship". In two court proceedings and an appeal, Ætna was found to be completely without fault, and Gregory Consolidated was ordered to pay what they owed plus an additional 10 percent in damages.