Labor Saver: Threshing Machine

Out in the woods on Owl Acres, along with several other pieces of once-valuable farm equipment, lies part of a threshing machine. The inhabitants of Owl Acres most likely used it to thresh oats which were then fed to the cattle and horses.

The first step in harvesting the grain—oats or wheat or barley—was to cut the stalks and tie them into bundles, then stand them up in “shocks” to dry.

The next step was to thresh the grain, meaning to separate the grain from the plants. Before the threshing machine, there was the flail. The flail was basically a stick with another stick connected to it at the end by a cord. The first stick served as a handle, and the second stick or rod swung freely from the handle and was used to beat the shocks of grain to knock out the seeds. You can imagine that this was backbreaking work. You can also imagine where the verb to flail comes from. It is said to have required as much as 25% of the farm labor when it was in use.

Efforts at inventing a workable threshing machine are documented from the 1600s. They mostly didn’t work or broke down early on. The idea persisted that you had to beat the grain like with the flail. So they built beating machines that broke. It took a totally new concept to be successful. In 1786, a Scottish engineer named Andrew Michael invented a threshing machine that relied on a drum spinning against a concave surface. This concave surface is cleverly called a concave.

The threshing machine became so successful in England that it put farm laborers out of work. In 1830, a riot, called the Swing Riot, broke out to protest low wages, high taxes, and the threshing machine. The rioters attacked and destroyed as many threshing machines as they could. The response was harsh. Nine rioters were sentenced to be hanged and about 450 were deported. 

In the middle of the 19^th century, Iowa farmers were still preparing their crops by hand for threshing. The first thing they had to do was cut the stalks with a sickle. Then they gathered stalks into a bundle and tied it with another stalk or with twine to hold them together. Once that was done, they collected bundles of oats from the field and stood them on end leaning against each other to form a shock. The shocks would be left to dry for a few days. Then they would be picked up on a wagon ready to feed to the threshing machine. 

Here’s a concise description from Wikipedia of how the threshing part of a modern combine works. Combines are so named because they combine the reaping or cutting of the crop and the threshing into one machine.  

“Today, as in the 19th century, threshing begins with a cylinder and concave. The cylinder has sharp serrated bars, and rotates at high speed (about 500 RPM) so that the bars beat against the entire plant as it is mechanically fed from the reaping equipment at the front of the combine to the gap between the concave and the rotating beater/cylinder. The concave is curved to match the curve of the cylinder, and the grain, now separated from the plant stalks falls immediately through grated openings in the concave as it is beaten. The motion of the rotating cylinder thrusts the remaining straw and chaff toward the rear of the machine.

“Whilst the majority of the grain falls through the concave, the straw is carried by a set of “walkers” to the rear of the machine, allowing any grain and chaff still in the straw to fall below. Below the straw walkers, a fan blows a stream of air across the grain, removing dust and small bits of crushed plant material out of the back of the combine. The residues fall to the ground and occasionally are collected for other purposes, such as fodder.

“The grain, either coming through the concave or the walkers, meets a set of sieves mounted on an assembly called a shoe, which is shaken mechanically. The top sieve has larger openings and serves to remove large pieces of chaff from the grain. The lower sieve separates clean grain, which falls through, from incompletely threshed pieces. The incompletely threshed grain is returned to the cylinder by means of a system of conveyors, where the process repeats.”

The straw is blown out the back of the threshing machine where, in earlier times, it was stacked with pitchforks for later use as animal bedding.

In 1903, Charles Dammeier, farming on Owl Acres, filed a patent for a straw stacker. It was basically a metal tube through which the straw was blown out the back of the threshing machine. This tube could be manipulated to sweep side to side but also to be raised and lowered so that the straw could be piled up. It is unclear whether he ever actually built a model of his idea, but some of the junk deep in the woods could have once been a prototype.

Meanwhile threshing machines got better and better. They were initially powered by horses walking around and around on a tread mill, but by the middle of the 19^th century, steam engines were being employed to run the machines.

By 1900, when the Dammeiers were farming owl Acres, threshing was done using steam power. Itinerant threshers would bring a steam-powered threshing machine to the farm and, with the help of the neighbors, all the threshing would be completed in short order.

Threshing dinners, prepared by the women of the neighborhood, are legendary in Iowa lore for their opulence and as iconic symbols of a time gone by. In 1934, Grant Wood painted “Dinner for Threshers” illustrating a threshing dinner. The original resides at the Fine Arts Museum of San Francisco.

One of the Dammeiers’ neighbors, Jack Healy, owned a steam traction engine. Very likely, the Dammeiers borrowed that steam engine to run the threshing machine in the 1920s and 1930s. Today, 100 years later, the same steam engine is used to demonstrate threshing oats at regional power shows.

Photo by Author. Alt text: More archaeology behind the house. The winnowing body of a threshing machine lies on its side, discarded but not forgotten, in the woods on Owl Acres.  At its most basic, the threshing machine is a wind box. It blows air upward though an agitated mass of plant materials: straw, chaff, and grain. The grain falls to the bottom and the lighter materials are carried up and away, to be blown into a straw stack on the ground. Moving arms called straw walkers, visible in the photo, work the stems toward the back where they’re blown out. The “shoe,” a shaking frame which carries the sieves, is also visible below the straw walkers. Barely visible through the tangle of brush is the drum-shaped blower housing, source of the wind that makes it all happen. The grain is collected at the bottom of the machine and fed into an elevator for loading to a wagon.