Above: An exact replica of the first McCormick Reaper made in 1831
Following is a short overview of how crops were harvested before Cyrus brought us his reaper. The next page on IH Combines brings us the changes through the last 100 years. Hope this brings back memories for some of you, and reminds the rest of you how much times have changed in the last 150 years!
“Reaping Hook" or Sickle With the sickle or reaping hook one man could cut from one-half to one acre in a hard day's work. The cut grain was later bound by hand.
Cradle The cradle was the most efficient means of cutting grain before McCormick's invention of the reaper. The cradle consisted of a broad scythe with a light frame of four wood fingers attached to it. The advantage of the cradle was that by a turn to the left the operator could throw the grain into a swath, ready to be raked and bound into sheaves. This improvement was introduced in America about 1776, according to Professor Brewer of Yale, and was the common instrument of grain harvesting as late as 1840. For cradling grain, two acres was considered a day's work.
ScytheThe scythe was the companion tool to the reaping hook or sickle. It was always used for mowing grass but sometimes oats and barley were cut with it. It was not generally used for cutting wheat. With the scythe a man could cut up to three acres a day.
The first reaper included these essential elements:Reciprocal knife, Fingers or guards, Revolving reel, Platform, Master wheel, Forward draft, Divider. The McCormick reaper of 1831 has a wide master wheel which carried most of the weight of the machine and, through ground transaction, supplied power to operate the reel and the reciprocal knife. The world's first reaper incorporated seven basic principles (listed above) which have ever since been found essential in virtually all grain-cutting machines.
While this first machine required only 2 people for operation (a person to ride the horse and a man to rake the cut grain from the platform), it cut as much grain in one day as 4-5 men with cradles or 12-16 men with reaping hooks.
The McCormick Patent Reaping Machine of 1857 combined machinery for reaping and mowing, and was built from 1852-1865. Its chief improvements over the 1831 reaper were seats for driver and raker, a cutting knife fabricated in sections rather than one piece, and an all-metal main wheel. This machine also cut a wider swath than the first reaper and was pulled by two horses. 
McCormick Harvester and Binder of 1876 at work in the field. This was the first practical self-binder ever built. People traveled miles to see the first machine controlled by one man, which cut and bound grain in a single operation. McCormick built and sold 50,000 of these binders between 1877 and 1885. 
McCormick Harvester and Twine Binder manufactured in 1881. This was McCormick’s first binder which tied the bundles with twine. After the development of this machine, only minor improvements, tending to give greater durability and lighter draft were added.
The McCormick Light Steel Binder built in 1888. This was an improvement over the first steel binder of 1885. The knotter was improved for the first time since the binder came into existence. Improvements in the reel construction were made and an adjustable canvas grain shield was added on the rear of the platform. 
The McCormick-Deering Tractor Binder is operated from the Farmall tractor through the shaft running out of the rear, thus making the binder independent of ground conditions. This power take-off, as it is called, is regularly supplied with all Farmall tractors. The binder, being independent of ground conditions, can operate when a horse-drawn binder would find it difficult, if not impossible, to cut grain.
McCormick-Deering Harvester-Thresher is the most modern type of grain-harvesting machine. It cuts 40-50 acres per day and threshes the grain, delivering it after a thorough cleaning, into a grain tank. From the tank, the grain can be drawn off into a motor truck or wagon and hauled to the grainery.
This Windrow-Harvester cuts grain and leaves it in a windrow on top of the stubble. After the grain cures on the stubble it is picked up by an attachment on the platform and threshed. The windrow-harvester makes it possible to cut grain earlier (avoiding natural hazards such as winds and hails) and to better harvest woody grain (because the weeds dry out with the crops before threshing)
Article from; Shenandoah Valley AREC, Steeles Tavern, VA; Grain Harvesting History information obtained from McCormick Reaper Centennial Source Material (International Harvester Company: Chicago) 1931
