Origin of the Row-Crop Tractor: The Farmall Regular

International Harvester's McCormick-Deering Farmall led the row crop tractor revolution

| June 2007

In the early teens of the 20th century, most tractors were still designed as prime movers for pulling tools like trailing plows, field cultivators, reapers and mowing machines.

It was generally accepted that, although tractors could ease those burdensome tasks, the farmer still needed to maintain a team of horses to handle the precision work of cultivating and planting since even the smaller and more affordable tractors of the day were plainly not suited to row crop work.

In 1915, the year International Harvester tested its first known experimental motorized cultivator, the concept of a general purpose row crop tractor had not yet gone mainstream, but it was soon put to the test.

Developing the concept

Early iterations of Harvester’s Motor Cultivator featured a tricycle design with two wheels in front and a single wheel in back for steering and power (the engine sat atop the wheel’s spindle and turned with it). Some company engineers felt sure their concept warranted further development, but difficulties related to the cultivator’s high center of gravity and minimal drawbar functionality doomed it to a short life. In 1919, even though demand for Motor Cultivators remained strong, Harvester brass decided to scrap their limited production Motor Cultivator program ... but not the concept.

By 1920, Harvester engineers were thinking about a general purpose tractor/motor cultivator that led them away from the single rear drive wheel to a live front-axle design (with chain drive from axle end to the wheels) with a transverse frame-mounted engine powering the two front wheels through a conventional differential. As before, steering was accomplished with a single wheel, still located in back, but similarly designed machines were soon built with the two drive wheels in the rear and the single steered wheel in front.

Eventually, the experimental tractor’s transversely mounted engine was replaced with a longitudinally mounted unit, which helped balance the machine and inadvertently led to development of the conventional PTO for powering driven implements. Still uncertain about which way to go, engineers continued this tractor’s development as a bidirectional machine.

Operators of bidirectional prototypes were particularly fond of the now-conventional configuration that placed a pair of drive wheels in the rear because they discovered front-mounted cultivator adjustments were then easily made with the steering wheel. By late 1921, Harvester took that nimble maneuverability one step further and linked specially designed pivoting cultivator gangs directly to the steering system, which made position adjustments while traveling down the row even more responsive. Cable-operated left- and right-steering brakes were added to facilitate sharp end-of-row turns using only the steering wheel to create what came to be known internally as the “heavy Farmall tractor.”