Post-based windmills

Let’s begin with the post-based windmills (or stolbovka, stolbovaya melnitsa, stolbianka in Russian). In Russia, these mills are also called kozlovki or kozlovy mills; in Europe they are called German, as opposed to smocks, which are named Dutch mills. Post-based mills appeared before the smocks. But in Europe they were replaced by smocks and practically did not survive anywhere except for Russia. Frankly speaking, even in Russia we have counted only 23 post-based windmills, three of which are falling into ruin.

So, why is it called a post-based windmill? As mentioned before, the mill needs to rotate, so the sails face the wind direction, and the rotation has to be in the horizontal plane. The whole windmill’s barn rotates, and it turns around a, so-called, dead post dug into the ground. This is where the name of the windmill comes from (central post). The post is one of the main supporting elements of the structure, and also the most common reason for the post-based windmills to fall when it rots.

A windmill rotates around the post, but does not stand on it. The windmill stands “on a special frame surrounding the post” called trestle. This frame narrows towards the top, whereas the mill barn narrows downwards, so the place of their connection is the narrowest place in the mill, which reduces friction, and the mill is easier to rotate. Unfortunately, this also means that as soon as the central post falls down, the entire windmill barn collapses too, because the area of the connection is not enough to hold it.

We have found six survived types of trestle and one more which can be seen only in pictures, because it hasn’t been preserved. However, if the trestle is replaced by, let’s say, a concrete block, the mill will not cease to be a mill, so we do not agree with the classification of mills based on the trestle type, which is given in a variety of sources. Instead, we suggest another classification, which we’ll talk about a little later. The most common type of trestle now is high ryazha (crib) (1). Frame is a little less common type (2). There have been preserved three mills (1, 2, 3) with a frame on poles (kozly in Russian) (3). There are even fewer mills with a low ryazha (crib) (4), two mills (1, 2) have a stone trestle (photo) and the most exotic one is the Finnish version of the trestle, which can be found only in one windmill in Russia (5), though there are many mills like this in Finland. The sad fact is that one of the most rational ideas — to put the mill on a full house barn — has not lived to the present day (5а), The most famous mills with such a trestle are from the villages of Kegoostrov and Maloe Tokarevo.






Now when we’ve learnt about the base, let’s talk about the barn. As the barn needs to rotate, it must be light, and so that it does not fall. It also shouldn’t be big and bulky. For this reason, post-based mill barns never served the role of the grain or flour storage place, but only a room for the windmill mechanism. The barns of all the post-based mills are two-floor. Most barns are made of logs (log constructions) but several of them are quite specific. Firstly, they are mills on a stone base and mills on a Finnish base — their barns are frames, upholstered with boards. Secondly, there is an interesting mill from the village of Srednyaya Medlesha in Malye Korely, which has a barn first made of logs, then a frame, and then logs again. All of this is done to reduce the weight, because the windmill is quite high. Do you think now you know everything about the barns? – Wait a minute, there is something else. Another important point is that the post-based windmills hang over the ground, so, in the snow regions, which actually means everywhere, it is quite dangerous. Therefore, there are holes (6) made in the four lower corners of the barn, where logs are inserted in autumn to support the windmill and help it survive winter. The same technology is used now for the restoration of the post-based windmills to avoid unnecessary movements in the barn.


Well, if there is a barn, you need to enter it somehow. You’ve probably thought of a ladder and you are absolutely right. But remember that the post-based windmill is not a simple building: the barn rotates; and the porch of the barn always «runs away» from the ladder. The solution is clear — to make a suspended ladder and not to dig it into the ground. But the question is: what is the length of the ladder? Or rather the height of the porch of the barn? Here it is necessary to mention direct/regular/non-inverted and inverted post-based windmills. Let’s look at them.

I think it won’t be an eye-opener to say that there is a shaft in the barn that holds sails and millstones. Now, the mill structure completely depends on how they are located towards each other vertically. In an ordinary/non-inverted mill, the windshaft is at the highest point of the barn, with the millstones below it (7), both on the second floor of the mill. What does it mean? It means that the barn does not need to be raised high, because the sails are already high anyway. The sacks do not need to be hoisted high because the millstones are at the bottom anyway, and you do not need to think about balancing the mill because the centre of gravity is at the bottom of the mill too. «Well, sure,» you will say, «why?» The point is, strangely enough, half of the preserved post-based mills are inverted. (8) Really, they are literally put upside down. They have the windshaft and the sails on the first floor, and millstones above them — on the second one. Everything has been turned upside down! As a result, you should build a high construction under the barn now to lift the sails somehow, to lift heavy sacks along the staircases, and to balance the mill so that it does not collapse, because the millstones are under the roof now. «Why? Who has invented this? » you might ask and you will be absolutely right. The exact answer is that it’s not exactly clear who invented the inverted post-based mill. There are some guesses though. It seems that this is the oldest type of windmill, which was copied from the water mills that had appeared earlier. Imagine, we take a water mill and replace its water wheel with the sails and raise its barn above the ground. Actually, this is how water-mills look like: the stones are above, so that the grain does not get wet; the sacks should be carried to the ground level, because the river is lower than that, and there is no center of gravity at all because the mill is standing on the ground. You see! Whether the inverted post-based mills appeared like this or not, nobody knows, but the fact is that they exist and certainly have the right to be.



After such an excursion, the difference between the constructions under the mill barn should be clear: the mills on poles or high ryazha (crib) are inverted, all the others are direct/non-inverted. Then what about this supporting construction here? (9). It’s not ryazha (crib) or poles. That’s exactly the reason why we abandoned this classification and chose another one which influences the design of the mill mechanism much more (non-inverted and inverted mills). Whatever it is under the barn (even a concrete base), the most important thing is that the barn can rotate.


Let’s get back to the stairs. With non-inverted post-based mills everything is clear: it’s easy to put a small ladder down from the porch. But what about the inverted post-based mills? It turned out that there are at least three options. Arkhangelsk version (10): the ladder is under the porch and is hanging on special hooks (kuritsa in Russian – thin spruce trunks with the root). Vologda version (11): in the middle of the trestle there is a platform that goes all around the mill. It is connected with the ground with the usual ladder, and then the barn is connected with this platform with a small mobile ladder, which is perpendicular to the first one. Finally, Kostroma version (photo): the ladder is perpendicular to the porch and far from the barn. It can be tied to the tailpole, or, and it is the least convenient way, we can just pick it up and drag it while rotating the mill.



It seems we have sorted out everything with the ladders. But what about twisting and turning the barn? How can this be done? For this reason there is a tailpole in all post-based mills. It is a log fixed with its one end to the barn, and with the other one descending to the ground level. People and horses would lean on this log and thus turn the mill. But this is not the end of the story. There are different kinds of tailpoles! There could be one log from the middle of the back wall of the barn, which goes to the side of the barn (12): Mezen. There could be two logs from the corners of the rear wall of the barn (photo): Germanov Pochinok (Kostroma Sloboda). There is one log that enters the side wall of the barn (photo): Gorka (Kirillo-Belozersky Monastery), Razlivnoye (Kostroma Sloboda). For straight posts there is just one log (13): several mills in Malye Korely and Kizhi, or two logs forming a triangle (14): Menajlovo, Kalgachikha (Malye Korely). In order for the mill not to turn after adjusting to the wind, small pegs were digged around it, and a simple system of ropes was tied to a tailpole. In addition, the horizontal tailpoles of post-based mills ended with a wheel that was rolling on the ground. «And what about the strength?» — you will ask. Non-operating mills are hard to move: manually there is not enough strength, and with technology you can easily tear off the tailpole. But if the mill is an operating one, if the connection between the barn and the trestle is lubricated enough (14a), if the mill was first rotated by a tractor, then if it is rotated from time to time, without letting it stiffen, two or three people will be enough to turn it.





Well, that’s all about the external elements of the post-based mills. You might think it’s time to go to the sacred place — the machine room, well… no, — to the mill barn, i.e. to its mechanisms. Mill mechanism doesn’t have any main or secondary details, because each and every of them is used for the mechanism to operate. We’ll start with the windshaft. The windshaft is the only shaft in a post-based mill (at least it is so in all the preserved mills and those known from the photographs). It is wooden. In fact, it is a processed log. The rear end of the shaft has a metal rod, which is fixed on the wall of the barn. (15) The front edge of the shaft can be fixed in three positions.


First, the windshaft can lie on the front wall of the barn. It is clear that the sails should be outside, so, the windshaft lies in the hole in the wall that is specifically made to place the windshaft there. However, if you simply place the windshaft on the wall logs, the consequences can be unpredictable. You might be thinking the windshaft will wear off — well, you are right. Maybe you are thinking it can ruin the barn — that’s also true. However, the worst of all is that the friction between the windshaft and the wall of the barn may start the fire. Therefore, it shouldn’t be done this way. Instead, a metal plate or a concave stone (16) is placed on the log of the wall, and the windshaft is put on it. To prolong the life of the wood, special metal pieces are inserted into the windshaft in the place where it touches the log (16a).



Secondly, the windshaft can lie on a small balcony of the mill (17). It is fixed the same way: a stone, metal inserts, but there is a particular detail. All this construction must be lubricated. The more, the better. Therefore, the balcony must be reached somehow. Lucky are those who can enter the balcony from the porch, as in Mezen (18). What if not? For this purpose, a “mysterious” square hole near the windshaft (19) was made in the mills of Razvilnoye (Kostroma Sloboda), Petukhov’s windmill (Shchelkovskiy khutor) and Srednyaya Medlesha (Malye Korely).




Finally, the windshaft can be supported by a separate frame (20) standing outside the mill, as in Kizhi. First, let’s try to figure out why? Kizhi mills (1, 2) have the biggest number of sails — eight. And as you can imagine, the sails of the mill are not a simple plastic fan. The sails couple together almost like in an airplane. Each couple of sails forms one board central part of which goes through the hole in the windshaft and gets fixed this way. If there are four couples of sails, then there should be four through holes in the windshaft. Logically, the windshaft must spread out far from the barn so that all these sails could «fit» on it. Well, and why the outer frame has the ladder (21) — you’ve probably guessed yourself already: to climb and lubricate the joint. Such a mechanism can also be found in the mill with four wings from Gafostrov .Because of the small size of the mill barn, the sails may outweigh the windshaft.



The windshaft can be either in the center of the mill or on its side. In the second case, the balance is compensated by a porch with a ladder on the other side of the mill. Why could the windshaft be displaced? If the mill is inverted, then the central post must pass through all the floors reaching the last one. And since the post is axial, it is located exactly in the center, so you have to move the windshaft. The only non-inverted post-based mill with a displaced windshaft is Bolshaya Shalga (Malye Korely) (22). The designation of such a construction is not exactly clear.


Let’s leave the topic of sails for a while and discuss what the windshaft should turn. It rotates itself and transmits the rotation moment to the operating elements, i.e. the millstones. Let’s have a closer look at the millstones. Firstly, the working mechanism is always made up of a pair of millstones: the upper one and the lower one. Secondly, such a mechanism in Russian is called «postav» or a pair of millstones, and the number of couples of millstones is one of the indicators of the mill’s power. Here everything is simple. In all Russian post-based mills there is only a pair of millstones, or at least no more than that. We’ll talk about it in detail later. The pair of millstones consists of a bottom millstone which is cone-shaped (with a slight curve, of course, don’t imagine a pyramid), and the upper one which is concave so that the millstones fit tightly together. The grain turns into flour between the millstones. Through the central opening in the upper millstone the flour falls between the rotating millstones and through the special grooves in the millstones it is dumped from the lower millstone into the vat by the power of gravity (the lower millstone is cone shaped). The question is: why to rotate both millstones? It’s right — there is no need to. The turning millstone is only the upper one, and it’s called the runner stone. The bottom one simply lies there, that’s why it’s called a bedstone.

The runner stone is strung on a spindle — a metal rod (you will understand why it’s metal later), which drives it and goes through the bedstone (23). Thus, it is necessary to transfer the rotation from the windshaft to the spindle, while they rotate in different directions. Both the windshaft and the sails rotate vertically, whereas both the spindle and the millstones — horizontally. What a task! To connect the windshaft with the spindle in all the post-based mills, the brake wheel connects to the stone nut. The brake wheel is fixed on the windshaft, and the stone nut is on the spindle (24).



The brake wheel is always a crown wheel which consists of different pieces (25). On one side it has inserted cams, which are fixed to the other side by perpendicular sleeves (25a). The stone nut is usually a cage gear. It is two circles cut from the boards, with holes cut along the edges. (26) Canes are hammered into the notches and are covered with a metal rim. To prevent stitching, the canes can be reinforced with metal rivets (27). In some post based windmills, the windshaft is slightly inclined to catch the wind better. In this case, the stone nut may be conical (28).






And this is it, you you might think. To fix one gear on one shaft, and the second on the other one. Well, yes and no. The brake wheel should be fixed in a certain way. Surprisingly, in the completely wooden mechanism of the mill, the connection of the gears must be calibrated to a millimeter. If it’s more than that, the windshaft with the sails will fall out. Why ? Because the cams of the brake wheel are shredded in size to reduce friction (29), and because of this they will start to push the windshaft forward. If it’s less than that, the gears will jam and break. So what? — you may say. Why not to measure everything at the construction stage, and that’s it. Well, it’s not like that. The barn is not rigid, the distance between the wheels changes. In winter, the mill does not work at all because the shafts bend. In addition, the sails are spinning under the clamping force of the wind, and it influences the windshaft, so it must also be taken into account and compensated for.


For this purpose, a brake wheel calibrating system was invented. It is not rigidly fixed on the windshaft, and can be moved both closer to the stone nut or away from it by means of wedges and blocks (30). Normally, the brake wheel has two diameters that cross at a right angle (31). These diameters enter the grooves on the windshaft. But the grooves are longer than the fastening of the wheel. This is how it can move along them! And as soon as the miller notices the displacement of the wheels, he calibrates the gears with the help of the wooden wedges. But even here there are differences in the mills: there is one mill where the brake wheel is fastened with four diameters (32) Srednyaya Medlesha (Malye Korely) and one more where the brake wheel is a whole wheel (33) Yuksozero (Malye Korely).





Ok, we’ve calibrated the brake wheel, put it next to the stone nut — can we start the mill now? No, we can’t. Now we need to adjust the distance between the millstones. After all, the quality of milling can be different. When it is necessary that the millstones are close to each other, then the runner is lowered, once the coarse grinding is needed — then they are lifted. But how? It’s a good question! The runner stone is attached to the spindle. That is why it is always metal, i.e. it needs to withstand a big weight. The spindle rests on a beam, which in English has a special name — branchtree. This beam is fixed in the grooves of the vertical boards. As you have guessed, the slots in the boards are longer than necessary, so with the help of the wedges the height of the beam, the spindle and the millstone can be adjusted. But wait, what about the gears? They are adjusted only a bit. The height of the stone nut is enough to ensure that in both extreme positions it provides good grip with the brake wheel. All in all it is slightly elongated. (34). So, do we use wedges only? No, not only. There is one mill, in Kalgachikha (Malye Korely), where the beam is regulated by a threaded jack (35). But it’s the only one.



At this point, let’s just come back and try to remember that we said there exist inverted and non-inverted post-based mills. Now, when the connection of the gears is clear, let’s talk about their difference. In the inverted post-based mill, the stone nut is connected to the brake wheel at the top of the latter and the spindle goes up to the second floor of the mill, ending in the millstone. The beam which supports the spindle with stone nut is positioned exactly above the windshaft (more precisely between it and the upper edge of the brake wheel — the diameter of the brake wheel is sufficient.) In direct post-based mills, the stone nut is at the bottom of the brake wheel and the millstones are in the center of the spindle, which is fixed to the beam a floor below (it can not just reach the millstone, for the reasons mentioned above: the millstones can not stick together, there must be a distance between them). In addition, the direct post-based mills have one more beam, in English called sprattlebeam, that meets the spindle from the top (37).



Of all the moving parts, we haven’t talked yet only about the sails. In all known post-based mills (perhaps except for the south ones), the sails are covered with wooden boards. There are either four, six or eight sails (in Kizhi). The sails of the working mill should be at a certain angle. If you see flat sails — it is a dummy. The sails of the working mill should be covered with boards. If you see lattice sails during the milling season — it is a dummy. Why do we say «during the season»? Because some mills have removable sails. Well, actually, not the sails themselves, but the wooden lining/panels, which actually catch the wind. Moreover, they are not only removable for the winter, they are also adjustable. It means that the “working” surface of the sail can be changed depending on the wind speed. In most museums the sails of the mills are latticed, but it’s hard to say whether it’s a dummy in front of you or the panels were simply removed. What is certain is that these mills do not work. By the way, the panels on the sails are a necessary, but not a sufficient condition. For example, the mill in the village of Menjaylovo has all the sails covered with wooden panels, but it has not been working for many, many years. In museums, sails are made in such a way that they do not react to the wind. Thus, the lattice sails that do not catch the wind help to protect the windmills from hurricanes and strong gusts.

Now we know the whole chain of motion transfer from the wind to the millstone. But we are only in the middle of the road. After all, the mill is a perfect mechanism. Let’s consider an important part of the mill, called a brake. Yes! There are brakes in the mill. Otherwise, how will you fix a “naughty” mill before the storm? You wouldn’t want to catch it by its sails, as in cartoons. According to the laws of physics, the easiest way is to stop the brake wheel. So, this is what is done in all the post-based mills without exception. However, as it turned out, there are plenty of options of how to stop it. You can follow the method used in Pogorelts (38) and put a board, wedged under its size above the brake wheel. You can do the same, but from below: Srednyaya Medlesha (Malye Korely). You can do both, from above and below, as in Kesloma. It is also possible to make a large real brake: the system of bars enveloping the upper half of the brake wheel: Kalgachicha (Malye Korely) (39), or it is possible to encircle the wheel with a curved tree and tie it to the stopper: Kimzha (40). In all these variants there is one detail – the wheel is stopped by friction. And this means that the brake must never touch the wheel during the ordinary movement of the mill. The fires caused by the friction of the brake were the main cause of ignition of windmills. But that was before. Not anymore.




Let’s discuss how the grain gets intto the millstones and where the flour comes from. It is clear that the grain should be put into the central hole of the runner stone, and the flour should be collected along the bedstone, but if we talk about big industrial manufacturing doing it manually is definitely not a good idea. In this case some tricks have been invented.

Above the runner they hang a hopper (41), where the grain from the sacks is put manually. The trouble is that the grain has to be dosed somehow and doing this manually as well is just too much trouble. So, the solution is brilliant. Under the hopper, which is rigidly fixed, there is a movable tray — a shoe, which is almost flat, so the grain accumulates in it and does not fall further. As the lower end of the shoe is exactly above the hole in the runner stone (for the grain to fall exactly into the hole), there is a wooden or metal stick — shaker -that connects the shoe and the millstone. The millstone is not flat, therefore, when it rotates it moves the shaker, which in turn shakes the freely suspended shoe. When the grain from the shoe falls onto the millstone, new grain is immediately added from the hopper. That is amazing, right? But that is not all. The stronger the wind, the faster the millstone turns and the more grain it can simultaneously grind. So, the faster the millstone rotates, the more the shaker shakes, and the more grain gets onto the millstone. That’s pure automation!


It’s all clear about the grain, but what about the flour? The flour falls out from all sides of the bedstone. Therefore, the millstones are placed in a so-called flour tray-vat, which is often an octagonal box that fits the whole millstone (42). The flour in it twists in the same direction as the millstone and sooner or later it finds a hole down, called a mealspout. Both in inverted, and non-inverted post-based mills the mealspout goes from the second floor (where the millstone is located) to the first one. In the inverted mills it goes out just next to the camwheel. This means that you can put sacks for flour just on the floor below and get the ready-made flour. Is this all? We are almost done. To change the flour sacks the flow of flour must be stopped, and many mills still have flaps on the mealspot, apparently just for these purposes.


Wait, wait, this is not the end of the story. Are you going to carry the sacks using a narrow, shaky ladder? Or will you make the peasants do it? Well, isn’t it cruel? In the tall inverted post-based mills there is a flour sack hoist on the porch, a simple roller, as in a well. The mill from Gorki (Kirillo-Belozersky Monastery) has preserved the internal roller to move sacks from the first floor to the second one.

Wait a second, but the millstones are not eternal, right? Yes. The millstones wear out. Both the roughness of their surface and internal grooves get smoother and flatter with time. In addition, they get clogged with dirty grain. Periodically it is necessary to raise the runner stone, clean and renew the working sides of the millstones. But they weigh almost a ton! Yes, true. Therefore, in all the smocks and some post-based mills there were special devices — cranes. Three standing logs, meeting in one point, with iron pincers or a rope at the end. This design helped to lift the upper millstone for maintenance and then put it back to its place. The spots where the cranes were installed are noticeable by the peculiar round holes in the floor near the posts (43). In other post-based mills there were special grooves and decks to roll the upper millstones to the side (instead of lifting), but, since these are removable devices, they haven’t preserved.


Actually, this is not all. Is it only the millstones that can be the operating mechanisms? No. Another mechanism in the post-based mills is a crushing system (perhaps, earlier they were also sawmills, butter churns or honey extractors, but there are no known mills like that). A crushing system, or «stupa» in Russian is meant to crush the grain. What does that require? There should be a crushing bank where the grain is crushed (44). Crushing is the result of the movements of the boards called rams, which enter the holes in the upper part of the crushing bank (45). But how to move rams with the wind power? In the post-based mills there is only one shaft, and it is a windshaft. Usually the brake wheel is on its end opposite the sails, but no one says that its full length can not be used. “Bars-cams” (similar to cams on a brake wheel) can be inserted through the entire length of the windshaft, and “bars-fingers” can be added to the rams (46). Now the windshaft has also become cam-shaped, and during its rotation, the rams crush the grain in the crushing system.




A few remarks. Firstly, the barn of the two-function mill must be large enough, so only non-inverted post-based mills of this type have been preserved. Secondly, only six or eight-sail crushing mills have survived, although it may be a coincidence. Thirdly, to be more effective, the rams must be heavy, and therefore long. Logically, the highest mills in Srednyaya Medlesha (Malye Korely) and Petukhovo (Shchelkovsky khutor) are crushing mills. In addition, in a mill with two mechanisms, there certainly should be a possiblity to turn off one of them. Turning off the crushing system is relatively easy: they make fixed cams, where the rams from the windshaft are transferred. Turning off the mill is trickier — for this it is necessary to move the stone nut away from the brake wheel, and as this should be done frequently, the wedges will not help here. To do this, they move one of the boards into which the spindle is inserted — Bolshaya Shalga (Malye Korely) (47). One of the mills is also equipped with a detachable stone nut — Kalgachikha (Malye Korely) (48). The purpose of this mechanism is unclear.



Altogether there are five post-based mills that combine the functions of the flour mill and the crushing mill: Srednyaya Medesha and Bolshaya Shalga from Malye Korely, Volkostrov and Voroniy Ostrov from Kizhi and the only one that still remains on the historical site, although in ruins — Grishkino. Well, and the last question for today. Is there a crushing mill with no millstones, but only a crushing system? — Yes, there is. The only known preserved mill without millstones has been brought from the village of Petukhovo to Shchelkovsky khutor (homestead) museum in Nizhny Novgorod.

We hope you were not bored to read this text. Actually, that’s all about these small but very old post-based mills, even without going deep into special technical details. Well, shall we now turn to the Smocks?