Written by Larry Gay
International Harvester started producing in 1924 the Farmall tractor with a new configuration which was capable of cultivating row crops. The rear wheels were spaced to straddle two rows and the dual front wheels ran between the two rows. The Farmall with its 4-cylinder, vertical engine and 3-speed transmission was rated as a 2-plow tractor. The 30 inches of clearance under the rear axle provided clearance for cultivating. However, the non-adjustable rear wheel tread of 74 inches needed for cultivating resulted in side draft when pulling a 2-bottom plow.
During 1931-1933, International Harvester expanded its line of row-crop tractors to three models. The F-30 model was a larger 3-plow tractor. The original Farmall became known as the Farmall Regular and was replaced by the F-20 with an increase in power and a 4-speeed transmission. The F-12 was a smaller 1-plow, row-crop tractor. However, it differed from the F-20 and F-30 with its large diameter rear wheels mounted on a straight bar axle which provided an adjustable rear wheel tread. In mid-1938, the F-12 was upgraded and became the F-14.
International Harvester introduced the H and M tractors in mid-1939 as the replacements for the F-20 and F-30 with the H rated as a 2-plow tractor and the M as a 3-plow tractor. Industrial designer Raymond Loewy had given these two models an attractive appearance by adding a grill over the radiator and blending the hood and fuel tank together. The H and M were similar in design with 4-cylinder, vertical engines for distillate or gasoline. Later a diesel engine was made available for the M and it was identified as the MD model. The 5-speed transmissions provided four working speeds plus a fifth speed of 16 miles per hour if the tractor was equipped with rubber tires.
The large diameter rear wheels were mounted on a straight bar axle which permitted adjusting the rear wheel tread to a narrow setting for plowing and a wide setting for cultivating. The operator’s station was mounted above the transmission for good visibility while cultivating. The flat platform and tilt-back seat provided space for standing while operating the tractor. For operator convenience, the clutch pedal was located on the left side and the left and right brake pedals were located beside each other on the right side. The Farmall H was the more popular of the two models until 1949 when the trend to larger farms caused sales to shift toward the M. Production of the H and M ended in 1953 and 1952, respectively. Due to a combination of features, performance, and reliability, the Farmall H and M tractors were classic tractors for the 1940s.
Larry Gay is the author of four tractor books published by the American Society of Agricultural and Biological Engineers, including Guide to Oliver Tractors and Guide to Ford Tractors. These books may be obtained from ASABE at 800-695-2723 or asabe.org, click publications and then click book catalog.