This is a treadle-operated grindstone used by blacksmiths, farmers, or any other profession who worked with iron tools. It is operated by sharpening iron on the sandstone grindstone which can be rotated at varying speeds by the foot pedals. The types of tools that required frequent sharpening included plows, scythes, knives, and axes. The original design for a treadle-operated grindstone dates back to the late 1400s. Prior to this, rotary grindstones were hand-crank operated, and before that a simple whetstone was used.