The earliest power hammers were powered by steam and were predominantly used in industrial settings. Steam hammers were made and used into the middle of the 20th century in the USA. At the end of the 19th century the mechanical power hammer became popular in smaller blacksmith and repair shops. The majority of these machines were powered by line shaft flat belt systems or later electric motors that rotated a crank on the machine that drove the ram. These machines were typically rated between 25 and 500 pounds of falling weight. Many may still be seen in use in artist-blacksmith shops today. In the middle of the 20th century power hammers driven by compressed air began to gain popularity and several manufacturers are currently producing these hammers today.
Freund, Douglas, Pounding Out The Profits, Mingus Mountain Machine Works, Jerome AZ, 1997 isbn 0-9657652-0-2