Hay Creek Trip Hammer 

Cornwall Iron Furnace


Historic Hay Creek Trip HammerThe Hay Creek facility was a trip hammer forge erected in 1740 by iron master William Bird (1706-1761) in Birdsboro, Berks County, Pennsylvania. This region was ideally suited for the production of iron because of the numerous streams providing water power, large tracts of hardwood forests needed to produce charcoal, and abundant deposits of iron ore. The Hay Creek Forge consisted of a stone building with an arched brick forge at one end. At the opposite end of the structure there was a trip hammer, anvil, water wheel shaft and gearing. The trip hammer, one of the few remaining in the country, was raised by a large cast iron gear. This was attached to the water driven wooden shaft; as the gear rotated, the hammer was “tripped” or dropped upon heated iron stock or “pigs” that had been placed upon the anvil to produce malleable iron. Over time, iron production ceased, and in the late 19th century the forge building was used as a blacksmith shop and eventually fell into disrepair. In 1929, the building and its contents were purchased by the Commonwealth of Pennsylvania for the purpose of reassembly and display in Valley Forge Park. By 1934 the trip hammer forge had not been moved and became the subject of much political wrangling. After several months, State Museum Director C. F. Hoban had the internal workings of the forge delivered to the old State Museum in Harrisburg where they installed it in the basement. In the 1950's the trip hammer and its components were once again disassembled and transferred to the PHMC Landis Valley Museum, and then moved to the PHMC Cornwall Iron Furnace collection in the 1970's



Rotting Wood and Concrete FillThe trip hammer and related supports and gearing were in poor and unstable condition due to years of neglect in substandard storage areas. Numerous wooden components, including the trip hammer shaft, had been structurally compromised by fungal decay. The wooden water wheel shaft had been sawn in half during the first reassembly in 1934, retaining only the interior half of the two foot diameter chestnut timber. The proper left vertical trip hammer support timber, which had deteriorated prior to disassembly, had been filled with over 400 pounds of concrete during the earlier “installation / restoration”. Large sections of wood, weakened by cubical brown rot, had become dislodged and lost during storage and subsequent transport. All iron components had areas of active corrosion and accumulated scale; they had become deeply pitted over time. Numerous iron teeth, fit into the large cast iron ring and used to lift and trip the hammer, had been lost. Many original mechanisms, including the water powered blast box, visible in historic photographs of the forge building, were missing.



Hay Creek Trip Hammer on ExhibitConservation of the Hay Creek trip hammer began as a collaborative effort between B.R. Howard & Associates, Inc. and PHMC curators. Components from other mills had been stored with the Hay Creek trip hammer in the Cornwall storage area, and involvement from the PHMC was crucial in order to properly identify the original Hay Creek machinery. Initially, a thorough vacuuming and cleaning of the components was performed using both aqueous and solvent based cleaning systems. Nearly all of the wooden elements required consolidation of those areas that had been in direct contact with the dirt floor. The trip hammer shaft, proper right vertical support, and water wheel shaft bearing block required structural repair; these three components support the nearly two ton cast iron ring used to trip the hammer. When possible, all of the original elements of the trip hammer were used in its reassembly. When that was not possible, the missing elements were recreated by matching all of the original specifications including dimensions, grain, and species. The iron was chemically and mechanically stabilized and hot waxed prior to reassembly. Where iron components were missing, reproductions were cast and fit. Upon completion, the trip hammer was installed in the Orientation Exhibit of Cornwall Iron Furnace, located in Cornwall, Pennsylvania for display purposes. This vital piece of Pennsylvania history is similar to the trip hammer that would have been used at Cornwall, and directly relates to the site's goal of chronicling the Commonwealth's iron industry.