Sir:
Regarding Carl’s question of cleaning and harvesting grain. First get some horses and a binder, it’s much easier than by hand.
Regarding proper use of a scythe: It is largely a matter of gaining a rhythm. Proper rhythm will allow you to cut all day without much effort., merely swinging your body. To exaggerate, swing the scythe to catch between 1?2 and one inch of grain/grass. At the last second jerk it toward you. In practice, if you have a good swing, it more or less does the jerk by itself. I have found that doing it properly will lay down the crop in rows, and it is almost as easy to pick it up by hand, rather than raking it. If you are using an 18th century basket to transport (No ends but a long handle) Pick up a handful of grain/grass, lay it on the basket with the heads in one direction, and you get about a bundles worth before you have to transport it. If the grain is ripe, and you lay the heads over the end of a flat surface, all you have to do is whack the heads only, and the kernels will fall out. (Or you can do it on a tarp or something on the ground. But still, whacking the heads only on ripe grain makes it easy to remove the straw by hand.) After cutting, the grain should be let dry to loosen the seeds from their hulls.
As to the cleaning of grain, I have seen several versions of a hand operated fanning mill. All were about three feet to 40 inches square. (And about 5 feet tall.) At the top, a hopper the width of the machine and between two and three feet wide with a sloped bottom so the grain would gravity feed. Depth of hopper about 18 inches to a max of two feet) (The whole machine shakes somewhat so feeding isn’t that difficult.) At the bottom of the hopper a variable crack feeds the whole screening area. (A metal or wooden bar that you can tie down with clamps when you have the right amount of flow.) (Facing the machine from the front, the hopper feeds the back of the first screen, and the crank handle is on the right.) The first screen slopes downward to the front. The crud pile is right at your feet.
I think at this point it would be wise to interject that the majority of the machine (except for the fan, the hopper, and the frame,) is a series of sloping screens. All of these screens are zig zagged downwards in a “Screen frame” that all move or vibrate more or less in unison. (Separate from the frame of the machine total.) (And which will be described later)
The screens are the difficult part in an 18th century setting. The top screen has holes large enough for the seeds to fall through. (Of course different grains have different sized and shaped holes.)(Wheat, oats, barley for example so you need different screens.) This first screen is to remove stones, straw, rabbit poop, or any larger items. It simply dumps all of the garbage that makes it to the end of the screen onto the floor in front of the mill.
The second stage (screen) is sloped in the opposite direction. And depending on how the fan is situated, is designed and sized so that the wheat must travel the whole distance because the holes are too small for it to fall through, but weed seeds and dirt get through the small holes and are directed on a solid metal sheet to discard. Either before hitting this second screen, or after, the stream of air coming from the fan is directed at the stream of falling grain. This, if adjusted properly, blows all the light stuff onto the refuse pile. The grain, being heavier than the air can readily move, falls down to the next screen.
Depending on how fancy you want to get, you can get other screens as well, but the two major things are to remove the big, heavy stuff, and the small light stuff which leaves you with the grains you wanted. (And sometimes some very small rocks)(Heavy enough to not be moved by air, and the right size to make it through the screens.)
Regarding the fan. Most of the units I have seen were a sort of straight sided barrel on its side. (Mounted on the rear of the mill.) (15-18 inches in diameter, some smaller. 18 is too big IMHO.) A metal rod with a gear at the end, driven by a chain off the crank, went in one end through a larger than necessary hole (Acts as air intake) You have seen these river boat stern paddlers? That is exactly what the interior fan looks like. A series of flat boards which move the air by centrifugal force, out through a variable slot on the side of the barrel. In what I think were the more efficient (Albeit more prone to breakage and more difficult to repair) models, the air was piped by a stationary oblong box type pipe to the area where the grain was falling off the first screen on its way to being caught by the second screen. This blows the light crud out into the same pile as the heavy stuff falling from the first screen. Not a lot of air is required. Usually the problem is that you are blowing light seeds out into the refuse, and if nothing else they can be fed to the animals. But then, if you are fanning for seed, you can re-fan the crud pile using less air and get the small grain.
In this simplified model, with two screens and one air output, the grain comes out the back. (Which most of them were.)
The “Screen frame”. I saw one (never saw it in operation.) that had a rigid box frame. I would think with so much vibration going on that it would not have lasted long Usually the tray type holders for the screens were part of the screen frame. Under the screen frame was usually two, but occasionally four eccentrics which had a gear on the end, driven by the chain from the crank handle. (Often the gear itself, with a protrusion on the side acted as the eccentric.) The crank chain had three contact points. The crank handle gear, the fan gear and the eccentric gear.
The “screen frame” was simply four hardwood slats ”hinged” at the four corner contact points with the screen trays and the eccentric frame. (Hinged meaning it had a bolt type rod with a sleeve to act as a bearing so the whole thing could flex.) Note that they do require regular greasing, just as wooden wagon wheels.) The whole object of this exercise is to make the grain and materials bounce and roll down a bit so they can hit holes in the screens, and either fall through, or not, to separate them. Not a lot of vibration is needed, but enough bounce is needed get a kernel with its small end stuck in a hole on the screen out and on its way. In fact, I would think the old mills erred on the side of too much bounce if anything. It has been a lot of years since I saw and used these things, but from memory the bounce was about half an inch, and the slope of the screens was three to five inches in 36 [inches], with a favor toward the three inch end of that dimension. (I would use [a] four [inch in 36 inch slope] if I were building one)
To summarize, the whole machine is built of wood with the exception of: the screens, the crank handle and its attachment to the machine, the gear and rod for the fan, the gear and rod (and probably the eccentric itself) for the vibrator, and the flat chain to drive the latter two. (And of course the nails or bolts to hold it all together.) The crank handle could be mounted on the fan, but design problems would likely make it the wrong height, and therefore uncomfortable to operate for long periods. As well, you can vary the speed of the fan, and the vibrator too for that matter, by changing the number of teeth on the gears. – JustaMereFarmBoy
