Threshing Machine

Threshing Machine
 
 
Early attempts to improve on the flail resulted in a thresher with revolving paddles that beat the sheaves with the resulting grain and separated straw exiting the bottom. Although winnowing was still done by hand at first, the thresher was latter coupled with a fanning mill to clean straw and chaff from the grain. This is the essence of the threshing machine and later the modern combine. A thresher beating the grain from the straw coupled with a fanning mill cleaning the grain.
 
The Museum has a rare 1918 Wager Lagemo “Hooverizer” threshing machine. The name was chosen because after the First World War Herbert Hoover was sent to “clean up” Europe. The machine is built with a steel frame, with wood used where strength was not needed, such as the sides. It was touted as economical to operate and efficient at separating grain.
 
In operation, bundles were pitched from the bundle wagon into the feeder (folded up in the display). The feeder was a conveyer with flat chains on each side connected by wooden slats to carry the bundles into the threshing machine or “the separator."  Ideally, the bundles would be laid in the center of the feeder single file head end first, with each touching the previous one (it was frowned on to feed a bundle crosswise or butt end first). With a little practice, a farmhand could effortlessly toss the bundles into the feeder from any point on the bundle wagon.
 
Arriving at the end of the feeder, the bundles encountered a wicked set of knives which were oscillating arms fitted with the same triangular teeth used on the sickle of a binder. (The action is much like a cat scratching). The knives cut the twine on the bundle and dragged it into the machine.
 
Entering the machine, the broken bundle was dragged down by osculating feed rakes and lower feed pans to the cylinder. The rapidly rotating cylinder lined with stubby blunt steel teeth pulling the grain between the cylinder and tooth lined stationary plates (concaves).  The grain and straw were then flung further back in the machine where they encountered the “blower.” This is not the large fan at the back of the threshing machine, but a fluted little  fan about 12 inches in diameter. The purpose of the blower was to help disperse the straw and grain evenly across the width of the machine on the straw racks. The straw racks were a series of four steps of wooded saw-toothed slats slanting upward. They were fairly open to hold up the straw while allowing the grain to fall through. Below this is a similar series of grates sieves that catch any straw while grain and smaller stuff falls through. The straw racks and grates osculate forward and back, moving the straw toward the back of the machine while shaking grain out of the straw. The grain fell on a lower osculating grain pan. This was a shallow flat pan moving the grain back toward the sieves. The combined forward and back movement of straw racks and grain pan caused the whole threshing machine to rock slightly back and forth. The grain pan brings the grain back to an osculating sieve that separates the grain. As the grain slides off a sloping ramp below the sieve, a fan blows air to separate chaff and dust. Adjustable plates on the intake of the fan housing (the wind box) regulate the air flow so it will clean the grain, but not blow it out with the straw. The grain ends up in a spiral screw conveyor, while the oversize material on the sieve falls into a second screw conveyer.
 
The oversize material is moved by the screw conveyer to an inclined return conveyer on the left side of the machine where it is returned for another pass through the cylinder. The second screw conveyor moves the grain to a second vertical conveyor that raises it to the weigher at the top of the machine. Both conveyors contain wooden or metal pedals attached to an endless flat chain that raise the material and return back down empty.
 
The grain falls from the vertical conveyor into an ingenious weigher. The weigher is a suspended square metal bucket attached to a weighing arm with a counterweight. When the weight of grain in the bucket exceeds that of the counterweight, it moves down a couple inches. This drops a flap over the exit of conveyor stopping further grain flow. A gate on the bottom of the bucket opens dropping the grain into the hopper of yet another horizontal screw auger. Meanwhile, this movement advances the dials of the tally counter by one-half bushel. Empty, the bucket rises again as the bottom gate closes and the conveyor flap opens to allow grain to flow into it again. The grain is moved by the screw auger which is positioned over a grain wagon which will move it to the granary for storage.
 
The weigher and tally provided a fairly accurate measure of grain threshed. This was important for estimating yield, and paying the operator of the threshing rig for the number of bushels harvested. Note however, that grain is measured in bushels, which is by volume, but the weigher measures weight. The weight of a bushel varies depending on the type of grain as well as the quality of the grain itself. In practice, a small amount of grain would be threshed and a sample of known volume collected and weighed. The counterweight on the weigher arm would then be adjusted. The arm was graduated in pounds/bushel) to correctly indicate the number of bushels.
 
Meanwhile the straw is shaken off the straw racks at the rear of the machine, where it falls into the blower fan. The fan entrains the straw and blows it out through a large (about 1 foot diameter) tube or blower away from the machine. The blower can be traversed in direction and elevation to produce a large straw pile for bedding.
 
The Wager Lagemo threshing machine has a unique design for the blower fan. Other threshing machines have the blower fan on the same side of the machine as the pulley powering it. This resulted in a shorter shaft that had to be supported on bearings on the outside of the machine. The Wager Lagemo machine has the blower fan on the opposite side from the power pully, with a shaft running through where the straw is passing out. There are angled arms on the shaft that act as a sort of rudimentary screw conveyor to move straw to the fan, but it would seem like the rotating shaft and arms would perfect for getting wrapped with weeds and cut twine strings.
 
Threshing machine pulleys
 
 
 
 
 
 
 
 
 
 
 
 
 
 
 
Looking at the threshing machine, there is a bewildering variety of pulleys of various diameters and widths. The different diameters assured that each pulley rotated at correct speed relative to the cylinder speed. The pulleys were powered by flat leather or fabric belts. Some belt paths were rather convoluted, with idler pulleys used to allow one belt to power several pulleys. The width of the pulley and belt is an indication of how much power was required (most power was needed for the cylinder and straw blower). Two belts were mounted twisted in a figure 8 on the Wager Lagemo machine. The drive belt was twisted when powering it with a tractor because a tractor drive pulley turns clockwise and the cylinder pulley attached to it had to turn counterclockwise. A steam engine  could turn its pulley in either direction, but twisting the long drive belt helped it to track better than without a twist. The second twisted belt was between the cylinder pully and the straw blower pully. Because of the design, the cylinder pully was turning counterclockwise but the blower fan had to turn clockwise. For some reason, the design also had the belt to the blower fan running between the side of the machine and the vertical conveyor to the bagger. Notice that there are no safety guards for the belts or any other moving parts. Wary caution was needed working around a threshing machine when it was operating.
 
Threshing began with “setting up” the machine. If at all possible, the machine was positioned facing into the wind. This blew the chaff and dust away behind the machine rather than toward the steam engine or tractor. More importantly, the long drive belt would whip side to side in a crosswind and possibly tear the belt or rip out a splice if the belt moved too far to one side on the cylinder pully. Next, two shallow holes about 6 inches deep were dug for the back wheels and the threshing machine backed into them. This sloped the grain pan slightly, so the grain would flow toward the back more easily. Finally, the machine was leveled side-to-side by pulling the machine back out of the holes and adding or removing a little dirt. If not level, the grain would pile up on the low side of the grain pan and flood over with the straw. Modern combines still suffer from this happening on steep side hills.
 
Now came getting the threshing machine ready. The feeder was released from its folded travel position and locked in the extended position. The straw blower was raised by cranking a worm gear and rotated to the rear. The blower is telescoping, so when in position it was extended to project the straw further. The grain auger was lifted from its cradle and secured in position over where a grain wagon would be. Then came “belting the machine.” The leather or composite belts would shrink when wet from dew or rain and possibly get tight enough to break or tear out a splice. Every night the belts were removed and placed under shelter to keep them dry.
 
Meanwhile, the tractor was unhitched from the threshing machine, positioned facing the machine, and the heavy drive belt run out to the tractor. The tractor had to be positioned with the drive pulley and cylinder pulley in line with and parallel to each other. This usually required several iterations of backing and filing. The drive belt was then put on the tractor drive pulley with a twist in the belt and the tractor backed up a little to place proper tension on the belt - not taut, but not contacting the ground. Usually, there was an idler pulley just ahead of the cylinder pulley that could be rotated horizontally so the shaft was not parallel to the cylinder shaft  to adjust for small mismatches in the tractor and threshing machine alignment.
 
 
SOURCES:
Wagner-Lagemo Threshing Machine
Wagner Langemo Thresher Restoring
Saving the grain saver: Minnesota man restores rare 1922 thresher. - Free Online Library (thefreelibrary.com)
 
By Don McCollor. October 2022
Photos by Linda Westrom