The Allen Scythe, sometimes called the Allen Power Scythe, is a petrol-powered finger-bar mower. It was made from 1935 until 1973 by John Allen and Sons in Cowley, Oxfordshire. The company was formerly the Eddison and Nodding Company, was bought by John Allen in 1897 who renamed it the Oxford Steam Plough Company, and then renamed it again to John Allen and Sons.
The Allen Scythe does not resemble a hand scythe but serves the same purpose. The engine drives a 2-foot-wide (0.6 m) or 3-foot-wide (0.9 m) or 4ft wide toothed blade sliding back and forth horizontally across stationary teeth to produce a scissor action, and also drives two large wheels for forward travel. There are handles to allow the machine to be controlled by an operator walking behind it, controls comprise throttle and clutch. Separate ratchets allow either one or both wheels to be driven. In normal use only one is engaged so that turning is easier. The machines are extremely robust and many from the 1950s are still in regular use. They can be dangerous, as the clutch system only disengages the wheel drive from the engine: the blades cut all the time the engine runs.
Later models were available with different attachments, including rotating brushes that replaced the cutting head, air or water pumps and saws or hedge trimmers that drove from the starting pulley side of the engine.
John Allen and Sons used a number of engine types, the most common being a Villiers two-stroke with magneto ignition and rope start. The engines may fail to start because of ignition problems. The spark should occur when the piston is 3/16 of an inch before top dead centre (TDC) on all Villiers engines except for the Villiers Mk. 11C & 25C which should spark 5/32 of an inch before TDC.
- Edbury, Christine (January 2012). "Aerial Photographs: Major Allen's Life and Work (1891–1940)". British Archaeology at the Ashmolean Museum: Rationalisation and Enhancement of the Historic Collections. Ashmolean Museum. Retrieved 19 October 2014.
- Allen Scythe User Manual and Villiers 25C Operating Instructions[clarification needed]
- Mower of the Month Number Fourteen: The Allen Scythe from The Old Lawnmower Club
- Engine Settings from The Old Lawnmower Club