What Does a “Combine” Combine?

June 30, 2023 Archive Insight

The combine — a piece of agricultural machinery — gets its name because it combines the three major tasks of harvesting grain:

• Harvesting: cutting and gathering the crop in the field.
• Threshing: removing the kernels or seeds of the crop from the rest of the plant.
• Separating: separating the kernels from other plant material such as stalks, chaff or straw.

Combines save large amounts of time and labor because they combine many activities into a single task. Self-propelled combines culminated 150 years of monumental changes in farming technology.


Efforts to perfect combine technology date to the early 1800s, but horse-drawn — and later tractor-drawn — machines were large and unwieldy. This combined harvester operated in California grain fields around 1900. / THF702847 

The modern, self-propelled combine is versatile. By changing the front cutter section, or head, a combine can harvest a variety of crops, from small grains such as wheat, rye and oats to rice, corn and soybeans. For example, the 1975 Sperry New Holland machine in Henry Ford Museum of American Innovation is fitted with a corn harvesting head (see above). In a single pass, combines like this could cut down cornstalks, separate and husk the ears, chop the stalks for fodder, and shell the kernels from the ears.

Commercially successful combines are relatively new, but the idea of a combine is something farmers have been trying to perfect for many years. The first successful combine was demonstrated by Hiram Moore and John Hascall in Climax, Michigan, in 1834. Horse-drawn and tractor-drawn combines were developed in the early 1900s but could only be used on very large farms with big fields because they were unwieldy. The first modern combine was the 1938 Massey-Harris Number 20 (also on exhibit at The Henry Ford). This commercially successful, self-propelled combine could operate in a variety of conditions. 


The self-propelled 1938 Massey-Harris Number 20 was the first modern combine. / THF110562 

Sperry New Holland TR70 Combine

The Sperry New Holland TR70 represented a major step forward in the speed and efficiency of combines. Earlier combines, such as the Massey-Harris Model 20, threshed grain by bouncing it along conveyor belts on the cutting head. These "straw walker" combines used the force of gravity to remove and separate the kernel from the stalk.


This illustration from a 1952 Massey-Harris trade catalog depicts the “straw walker” design that predated rotor-based combines. / THF702894 

The TR70 replaced straw walkers with twin axial flow rotors, patented in 1975. These rotors had two major advantages over straw walkers:  

• The rotors replaced gravitational force with centrifugal (spinning) force and ran the grain over multiple threshing plates, which did a more complete job.  
• The rotors were positioned along the length of the combine so the capacity of the combine could be increased without making it wider. 
  

The TR70 was initially most effective for crops with heavier kernels, such as corn and soybeans, but as the design was perfected, it soon replaced straw walker-based combines for all grains.

The serial number of The Henry Ford’s TR70 combine is 1975-1, indicating it was the first one built. It is likely a hand-built, preproduction unit, used to promote the new model at demonstrations and agricultural shows. The many promotional decals on the sides of the combine suggest this as well. It was probably never used in an actual harvest.


This cutaway image from a 1977 Sperry New Holland trade catalog illustrates the TR70 combine’s twin rotor design in action. / THF298866 

The Combine's Effect on Farming  

In the 1830s, it took 250-300 man-hours to plant and harvest 100 bushels of wheat. By 1975, when the The Henry Ford’s TR70 was built, it took three hours to produce the same quantity of wheat. Much of this time savings came from the invention of machines to do the hard work of harvesting in place of people.

The combine replaced many traditional agricultural tools and implements: the sickle, scythe, grain cradle, reaper, binder, flail, thresher, winnowing basket, fanning mill, separator, corn knife, husking palm, corn picker, corn husker, corn sheller — and of course, horses, mules and oxen.

With less labor needed to produce the nation's food, people left the farm for newly developing industrial cities. The United States was transformed from a rural to an urban nation. Many of us have parents or grandparents who lived on a farm, but now farmers represent only a tiny fraction of the workforce. Combines and other agricultural artifacts at The Henry Ford help tell their story.

This post by Jim McCabe, former collections manager and curator at The Henry Ford, originally ran in August 2009 as part of our Pic of the Month series. It was updated for the blog by Saige Jedele, associate curator.