Atco introduced its first rotary mower in 1957. The design was available in 18" and 21" cut width. These mowers were powered by small Villiers two-stroke engines, the 70cc Mk3G and the 95cc Mk7F respectively. Both machines were painted yellow and this was the first time that Atco had produced a standard production that was not the familiar green and red combination.
Although Atco had produced motor mowers since 1921 the company was relatively slow to see the significance of the rotary machine. The first rotaries were produced in the 1930s by Power Specialities (later renamed Rotoscythe and subsequently part of Shay) and Hayter introduced its first machines soon after the end of the Second World War.
It is possible that UK patent law prevented other companies from producing similar machines for some years. But by the second half of the 1950s a number of the leading companies - including Atco and Ransomes - were beginning to develop their own models.
Like all Atco mowers produced in the 1950s the model designations adhered to the company's simple convention. This was basically a four digit number where the first two digits were the cutting width in inches and the second two were the year of manufacture. The first rotary mowers were therefore designated as the 1857R and 2157R where the "R" showed that this was the rotary mower. This helped avoid any confusion with conventional machines. Atco was able to use this simplified designation system because it produced a small range with few variations - the width and year were usually enough for the service engineer or spare parts supplier to identify the machine and know which components were used.
The first rotaries were replaced in 1960 by the 1860R (with 87cc BSA four-stroke) and the 2160R (with 150cc Villiers four-stroke). These machines had the distinctive colour scheme of green engine with cream body. Both had "automatic" height adjustment, in other words the height of the four wheels (and hence the cutting height) was controlled from a single lever that was linked to all four wheels. These models continued in production until about 1966 when new versions were introduced.
Atco rotaries are now becoming more collectable. Good examples are sought after by collectors although values are still modest compared with earlier machines.