Threshing, before the advent of powered threshing machines, involved striking the straw by hand with a flail. The flail consisted of a long wooden pole (the staff), to which was attached, by means of a short piece of leather on one end, another shorter wooden pole (the supple). The flail was described by the author Edwin Tunis as "simply a club, swiveled with leather at the end of a handle about six feet long." The flail was used by taking hold of the staff, and giving it a swing over the head, to bring the supple down onto the straw with a slap. This process of threshing, by continually striking the straw with the flail, was intended to cause the grain kernels to be knocked out of the heads of the straw.
Threshing was best done on a packed-earth floor. With a wood floor, there was the chance of some of the grain being lost between the flooring boards. The threshing floor was often on the second floor or top level of the barn, and required as tight of a floor as possible in order to reduce the amount of grain lost by falling through floor cracks. The type of floor most often used, therefore, was the type in which the boards were splined together. It might also be noted that by connecting the boards together by splining, they did not need to be nailed to the floor joists. The entire floor (or at least the portion used for threshing) would be tightly connected but simply resting on the joists without being permanently attached.
A variation of the threshing process was that of treading. Treading was less laborious for the farmer, but was not as efficient. The straw was spread either on the threshing floor or on the ground outside, and in a circle. The farmer would then lead one of his oxen or a horse to walk over the straw, thereby pushing the grains out of the heads by their hooves.
Threshing was repeated a number of times, between which the straw would be turned using a hayfork. Hayforks were most often entirely wooden. They were sometimes crafted from a naturally multi-pronged branch or could be constructed by cutting slits in the one end of a pole and inserting wedges in the cracks to force the pieces to spread apart. When the threshing was considered finished, the spent straw was gathered up with the hayfork and placed in a crib to be used as bedding for the animals.
Remaining on the threshing floor was a mixture of grain and the chaff (i.e. the hulls and 'beards'). The grain, of course, now had to be separated from the chaff. The process by which this was accomplished was referred to as winnowing. A winnowing scoop was a large wooden, two-handled scoop constructed with a flat bottom shaped as a semi-circle, with raised sides on all but the straight one. The grain and chaff mixture could be scooped up in this tool and then carried away. It was sometimes carried or lifted up onto a loft under which a sheet was spread. With the doors on opposite sides of the barn opened, and a breeze flowing through, the winnower, holding the winnowing scoop in front of him, would pour the mixture down onto the sheet. The wind would catch the lighter chaff and blow it off to the side, while the heavier grain would land on the sheet. There was no way that anyone in the barn could avoid getting some of the chaff in their eyes, in their hair, or anywhere else on their bodies. A board would be placed upright on the floor in front of the down-wind barn door, fitted into slots in order to hold it tight. Some of the chaff would be carried out the door above the board, which would serve to block the escape of grain. The board, by holding the threshed grain inside, was called a thresh-hold. It gave its name, threshold to the small board wedged between the jambs of the house's entrance door, which helped to prevent dirt blowing into the house by blocking off the crack below the door.
