††††By the end of the 18th century, horse power was used to drive the threshing machine.
Four horses walked round a central gear wheel from which the drive was transmitted to the thresher. Later still, steam power from a traction engine was used to drive the threshing machine.
Today threshing is carried out as part of the work of a combine harvester. However this still uses the drum and concave principle but with various refinements.
