The picture of a blacksmith most people have in their minds is that of a big well muscled man standing in a shop with a raging furnace in a corner and using a huge hammer to shape a piece of red hot metal. The principles of blacksmithing have not changed with the passing of time and the basic concepts of the trade remain the same. Except now the blacksmith does not have to be a huge overly muscled man with the ability to apply massive force to the hammer blow. By the end of the 19th century power hammer became available that allowed metal to be worked into shape without the application of human muscle.
The first hammers that did not use direct muscles power to strike the metal were trip hammers. These were lifted to the top of their frame water power (and later by steam) and once they were at the top of the frame, were released and fell with their own weight to make the strike. Basically, it used gravity to create the force of the blow. Power hammers are a development of the trip hammer. In the case of the blacksmith's power hammer, energy is stored in the form of compressed air or steam and using a system of mechanical linkages this energy is added to the force of gravity and increases the force of the hammer blow. Power hammers are categorized according to the force applied at the time of the hammer hitting the metal and large industrial hammers exceed 100 tones in force.
The first power hammers were steam powered and continued to be in use till the middle of the 20th century. However, by the beginning of that century, smaller mechanical power hammers became popular with blacksmiths. These hammers were powered by electric motors that powered the ram that drove the hammer. These were easier to use and since no boilers were required to create the steam pressure they occupied much less space and were also safer. The motor driven hammers were also easier to control and set for the desired force behind the hammer blow.
Modern blacksmiths power hammers are extremely precise machines, often with micro chip based controls and moveable beds that allow for the easy placement and adjustment of the metal to be worked on. Since the force of the hammer blows are variable, they can be used not just for the gross shaping of the metal in the initial stages, but also for the finer shaping and finishing required to complete the piece being manufactured.
The modern blacksmith metal artist uses power hammers that range between 25 to 500 pounds of strike force, although larger one are used for very large projects.
The blacksmith of yore used his muscles combined with his skill to produce metal objects of high quality that were often works of art. The power hammer removes the need for physical strength and allows those of slight build to shape metal and become blacksmiths and, in increasing numbers, metal artists.