A forge hammer is almost any kind of hammer used in shaping metal during the forging process. A forge hammer can be human-powered or steam-powered and works with both cold and hot forging. Often, a forge hammer is paired with an anvil, but double hammers are sometimes used.
Originally, the hammer used in a forge was wielded by a blacksmith. Using this tool and the muscular strength of his arm, he would shape metal into household implements, tools and ornaments. A forge hammer could range in weight and be lighter for detailed work.
Though this type of forge hammer is not obsolete, the scale of the items made was limited to what could be done by one man or a group of men. As the Industrial Revolution progressed and machines became larger in scale, so did the scale of different types of hammers used to create ship's anchors and parts for steam engines.
In 1837, drop hammers, which weighed hundreds of pounds and were driven by their own weight, were used to shape parts for ships. Problems arose when an English forge was working to create the paddle shaft for the S.S. Great Britain, then the largest ship ever built. The part was so large that few forges were equipped to handle it. The force of a stroke made by a drop hammer, which was driven by gravity, never varied and was not equal to the task.
In response to this challenge, English engineer James Naysmith developed the steam hammer. This type of forge hammer consisted of a piston enclosed inside a cylinder. Depending on the pressure of the steam, the operator could cause the hammer to fall with a heavy blow or one light enough to crush an egg inside a wineglass without harming the wineglass.
Whether driven by muscle, gravity or steam, all these types of forge hammers required an anvil on which to place the metal. An anvil absorbs the excess shock of a hammer blow. Drop hammers, steam hammers and other types of hammers are therefore required to be built in a vertical position.
A counterblow hammer is a type of forge hammer where both the hammer and the anvil are driven towards each other. It consists of two hammers working in tandem. Instead of losing excess energy as heat, sound or as vibrations in the anvil, the excess power is used in the hammer's recoil. This type of design allows for quicker forging time in a smaller area, as well as applying very large amounts of force to the metal. Like other forging hammers, a counterblow hammer can be powered by air or steam.