Pittsburg Shear Knife & Machine Co. was manufacturing steam hammers in 1901, when the city's name was spelled without an h. The firm was founded in 1889 as Tretheway Manufacturing Co. to manufacture rolling mill equipment, including shear knives and steam hammers, and changed its name in 1898. The steam hammer line was sold to Erie Foundry Co. in 1902.
The company changed names again in early 1904 to Heppenstall Forge & Knife Co., which operated for several more decades. For more about Sam Heppenstall, see the Google Books link below.
Information Sources
- Forging and Heat Treating, Vol. 8, No. 9, Sep. 1922, Pg. 385. Google Books
- United States Congressional Serial Set, Vol. 4579, Report No. 922, 1904, Pg. 3.