Gillespie Brothers & Co. / Gillespie Tool Co.
Pittsburgh, PA (The Railroad, Telegraph, Electric and Steamship Builders' Buyers' Guide, 1897)
This company first appears in September of 1877, posting various service and product advertisements in local newspapers. Some years later, the company is referred to as the Gillespie Tool Company. R. G. and T. A. Gillespie are noted in the 1885 Pittsburgh Directory. During the 1890's, the company (could be a different entity) is being referred to as W. A. & R. G. Gillespie. The vast majority of their work is pipelines, oil wells, and construction.
John Cain Patent #298,285 - Die for Making Vise Jaws - Assigned to Gillespie Tool Co.