The Unique Oliver Hart-Parr 18-27 Tractor
Mar 14, 2017
Written By Larry Gay
On April 2, 1929, the Oliver Farm Equipment Company was formed by merging the Hart-Parr Company (tractors), the Oliver Chilled Plow Works (tillage tools), and the Nichols & Shepard Company (harvesting equipment). The American Seeding Machine Company (planting equipment) was added in May. This new full-line farm equipment company introduced three new tractors in 1930, two standard-tread models and one row-crop model. All three models were manufactured at the former Hart-Parr tractor factory in Charles City, Iowa.
However, the initial development work for the row-crop tractor had not been done by the Hart-Parr Company, but had started at the Oliver Chilled Plow Works in South Bend, Indiana. The first prototype was built in 1926 and test work started in Texas that year. There are company photographs of the experimental tractor taken in 1927 which show mid-mounted implements attached to two cross pipes which extended through two holes in the tractor’s frame, a single front wheel with a concave rim, and two large diameter rear wheels attached to a straight bar axle. The ability to change the rear wheel tread by positioning the wheels on the axle in a wide setting for cultivating and a narrow setting to reduce side draft when plowing is what made this tractor unique.
After the merger, development work on this new row-crop tractor was moved to the Charles City tractor factory for one year before the tractor was introduced in February 1930. The production Oliver Hart-Parr Row Crop tractor had a Waukesha-Oliver 4-cylinder vertical engine instead of the Hercules engine in the experimental Oliver Chilled Plow Works tractor. However, the basic configuration was retained with the two cross holes for mounting implements, the single front wheel with the concave rim, and the large diameter rear wheels which could be positioned on the straight axle. The rear wheels were 59.5 inches in diameter and were known as the “Tip-Toe” wheels. The wheel tread was adjustable from 60 to 74 inches by sliding the wheels on the axle.
When the Oliver Row Crop tractor was tested at Nebraska in April 1930, it developed a rating of 18.1 drawbar horsepower and 27.1 belt horsepower, so the 18-27 became its model number. The design of large diameter rear wheels mounted on a straight axle for an adjustable wheel tread appeared on the Farmall F-12 in 1933, the John Deere A in 1934, the John Deere B in 1935, and the Farmall H and M tractors in 1939.
Larry Gay is the author of four tractor books published by the American Society of Agricultural and Biological Engineers, including A Guide to Hart-Parr, Oliver and White Tractors. This book may be obtained from ASABE by calling 800-695-2723.