Notes on Gristmills and Milling in Pennsylvania
The subject of "Old Water Power Grist Mills" is one that has never been written up as a separate paper in the archives of this society. Now that these mills are fast falling into ruin and disappearing it is necessary an effort be made to preserve in written form and in pictures some of the details of their construction, operation, and other general information in connection with them. The contents of this paper will be mainly concerned with the construction of the older type mills and their wooden gearing and machinery. In the course of my narration, details will be given for the construction of a complete mill, including the dam, raceway, mill-house, and machinery. Realizing that too much material of a technical nature is poor reading, references to local streams and their mills will be made and some anecdotes related about that venerable old worthy-the miller.
Before I take you into the mysteries of millwrighting and milling, join me for a moment and come with me once more to the old mill, as you were wont to do in your childhood days. Everybody is acquainted with some old mill where as a child you often accompanied your father or older brother with the farm grist. Later in your teens this errand became yours to discharge. Experience once more that feeling of elation with seized you as you approached the rumbling old structure on the drowsy midsummer's afternoon. How your childish curiosity was aroused by the vertical row of doorways, once for each floor and often numbering as high as five. Directly above the row of doors projected the overhang from which hung the miller's faithful servant, -the hoist rope, with its heavy chain and hook. Sometimes it was necessary to urge the quiet and trusted farm horse up to the mill door, especially if he was not regularly used for going to the mill. Since the mill usually lay in a hollow, the approaches in either direction were sloping which made it necessary to use brakes, so that the dragging and scraping of wagon wheels was a common sound at the old mill. Instances of teams having become frightened at the combined nose of the brakes and the mill occasionally happened. The wagon and its contents usually wound up in the mill race or the nearby creek. When you drew up to the mill it was not usually to be fourth or fifth in line, so great was the volume of business done by the local mills in the years gone by. While awaiting your turn you watched the unloading of the teams ahead, particularly the bags of grain as they were hoisted aloft, and skillfully swung in though the open door by the miller, all white and dusty. How the gurgling and rushing of the water along the mill race tempted you to get down from the wagon and try your luck at sailing boats or fishing. But a quick glance at father or brother who was talking to one of the waiting farmers told you that it was advisable to wait for a better opportunity. Another sore temptation, both hazardous and fascinating, was the desire to unlatch the lower half of the first floor mill door and go exploring into the very midst of all that rumbling and grinding machinery. The hand-hewn posts and timbers, the easy stairways, the flapping belts and grinding cog wheels, the miller's bag truck and the piles of filled sacks- a most interesting place to go and a temptation the average child could not resist. How nice it was to throw grains of corn or wheat into the big cog wheels and then listen to the crunching as the cogs crushed them. Some of you actually made one trip to the race, to sail a boats or unaccompanied, started to explore the interior of the mill. You had taken advantage of the situation, while the others were busily engaged in conversation, to slip away unnoticed. Now that you are older and have felt anxiety and responsibility yourself, you can realize the apprehension and fear that must have seized your father or brother when he saw you were gone. Delusions of fishing your limp body out of the race or picking your crushed remains from under the cogs momentarily seized them. These were not idle delusions either, for there was a hardly a mill that did not have its tale of horror relating to some one having been killed, or of arms, legs, fingers, or toes that were torn off. How nimbly those seven-year-old legs of yours carried you back to the wagon, and every time you slowed up the least bit there was the added impress of the flat palm of a strong hand to increase your momentum.
When your turn came you drove up or rather followed the team ahead of you until you were directly beneath the overhang of the hoist. In a moment the miller allowed the hoist rope to descend atop the sacks of grain on your wagon, and, if you were not expecting it, you were likely to be mildly startled when the heavy hook and chain struck the bed of the wagon. There was pulling and tugging as the chain was wrapped around the middle of a bag of wheat or corn hooked. Then- a wave of the hand, and a loud "All right." Up went the bag like a feather wafted on a light breeze to the very peak of the mill, where the miller seized it, and at the same time releasing the slender hoist cord which controlled the hoisting machinery swung it in through the door. Bags of grain were usually hoisted to the top floor and then emptied into a garner or bin and allowed to run down a chute to the burr stones. While a bag or bags were being taken up on the hoist, great care had to be taken that no one was standing beneath, lest something go wrong- either the rope break or some of the machinery fail and the bag come down like a shot and instantly kill any one beneath. In a remarkabley short time the wagon was empty. The miller must decend to the first floor and give you the grist which was ground from the grain that you brought the day or week before. You received your grist from the platform at the first floor door which was constructed to be level with the bed of the wagon. In some mills the hoist was used for loading as well as unloading, but those mills usually had a reversible geared windlass of modern construction, the friction hoist common in the older mills having been torn out.
It was the custom to go to the mill once or twice a week, depending on the distance. Grain to be ground was brought to the mill and the finished grist which had been ground from the grain brought on the trip before was taken home. Corn, wheat, buckwheat, oats, rye, and sometimes barley were the different grains which the burr mills could grind. Today, the few of them that still exist do little besides the chopping or cracking of corn and the grinding of corn meal and buckwheat flour. We must not forget the mill office which usually occupied a small boarded space in one corner of the first floor and boasted of the only heat t be had in the building in the cold winter time. Here, the miller sat at odd moments when no customers were outside or when the parcel he was grinding was large, requiring considerable time. Such accounts of the business as were kept consisted mainly of tolls, charged for grinding. The taking of toll was the method used for having your grist ground. While speaking of the practice of tolling, I am reminded of two anecdotes which used to be told. They both allude to the practice of over tolling, which did occasionally occur. The first anecdote concerns a miller who bought a small mill which was in a run down condition. He was doing his best to make the mill pay but had not succeeded. One day a feed salesman stopped. In the course of their conversation, the miller complained that, although he was busy grinding most of the time, his toll bin failed to pay him for his efforts and allow any profit. "Let me see your toll measure," said the salesman. After looking at it, he remarked, casually: "Try one that is twice as large as this one." Some time later the salesman on his yearly rounds was astonished to see the mill nearly white-washed and with a new roof. When he entered, he noticed new machinery and things in general appeared to have been overhauled. Seeing the miller comfortably seated in his little office he exclaimed, in surprise, that he had not expected to see this. "Why?" asked the miller. "Well," replied the salesman "last year when I was here things were in bad condition and you complained that you would probably have to shut down." "No in the sort time that has passed since I was here I find everything has been repaired and your business looks prosperous. What is your secret?" "Well," replied the miller, "I took your advice and made my toll measure twice as large." The other is told of a small boy who was sent by his father to the mill with a sack of grain. "Be sure and bring the empty sack home," his father said. The boy, upon arrival at the mill, gave the sack to the miller and watched him empty it through a hold in the floor. For some reason the miller lost hold of it and sack and all went down the chute. The boy, much dismayed, returned home to his father without the empty sack and mournfully said, "He took everything, he didn't even leave me the empty sack." Tolling, as a method of payment for grinding has passed away. Now all mills have fixed charges for grinding and you pay according to weight or measurement in cash. So, week after week, you made the same trip. Probably never leaving the seat of the wagon or entering the mill. The miller enjoyed the full trust of his customers in the matter of taking his toll and rarely was there occasion to doubt the integrity of those worth artisans. I say worthy, because, to a large extent the health of a community depended on their skill as millers to grind good quality flour and meal for the bread, cakes and pastry that our forbears ate. You must remember that the era of easy transportation, good roads, and patent flour was then still in the future. Most people in a certain locality were forced to patronize the nearest mill because the expense, time and the difficulty of hauling grain to another mill and then going for the finished grist was too great. All that I have just narrated has become a memory in most communities. Here and there, where one of the old mills continues to operate, you will find that both the machinery and the methods have been modernized. Housewives demand snow white flour. Snow white flour, such as we are accustomed to, cannot be ground with burr stones because flour made on burr stones always contains a certain amount of bran and middlings. It has been the foolish demand for the less nutritive white flour that has helped to drive "The Old Mill" out of business. In Bucks County, out of a total of nearly one hundred burr stone mills, there are at the most two or three that still operate. However, in the western part of the state and in the mountain regions there are quite a number of the old burr mills which still do their chopping, grinding, and the making of buckwheat flour with the stones. There are few millers left who can pick, sharpen, set up, and properly grind with burr stones. Mills now carry a varied assortment of ready prepared patent flours and feeds bought from the western mills. Little grinding of local grain is done by them, with the exception of some chopping and attrition mill work in the preparation of stock feed. There can be little doubt but that the community has lost another bulwark of its self sufficiency and independence in the passing of its mills. With them has gone the ability to supply its own flour and meal for human consumption as well as the feed for the livestock. Today, our supply comes from afar, which is all very good until some hitch occurs in the system of supply. Then how prices rise; but there can be no escape, for our means of local supply is gone and there is nothing to do but bear the burden. Deforestation must be changed with its share of the guilt in driving the old mill on the rocks. Small streams, which were formerly considered of great value for their power to turn mills, are now nearly dried up or filled in, and their channels diverted. In general, they are worthless and considered as a menace to highways, for, though during most of the season they can be bridged with a culvert, there are times when after heavy rains they rise over their banks and flood low areas. Hence it is necessary to build high and expensive bridges. Many strong and never failing streams have dwindled to mere trickles and rills, -a fine commentary on the foresting methods of our sometimes short sighted ancestors. Large areas of once fertile hills and valleys now lie barren, a hopeless maze of gullies and ditches. So complete has this deforestation been in some areas that whole water course for miles have ceased to exist, except during times of heavy rains. Bucks County's largest streams, the Big and Little Neshaminies, become so low during dry seasons that there is not enough water flowing over the ripples to wet one's feet. Yet, as I mentioned before, it is bridged at many points with large and expensive stone and steel bridges. Of the numerous mills that formerly stood along the banks of the Neshaminy and were busily engaged in supplying the needs of the surrounding communities only one is operating. "Mechanics Run," to the east of Doylestown, has five mill buildings still standing along its banks still standing along its banks, all of them were grist mills at one time or another. Today all are silent except one which is operated by Oliver Rice when there is any grinding to be done, and if there is any water in the dam. Inability to adequately serve their customers in time of drouth led to the loss of business or the installation of expensive engines and motors, which eventually increased running expenses so that the business did not pay. One by one, the old millers locked their doors and opened the waste gates of their races. Some, for lack of other occupation and because of advanced age, clung to their dwindling business until death released them. Then the "Old Mill Wheel," for lack of a master, ceased forevermore its splashing and dripping rotations. Time, the elements, decay, rust, and fire have contributed their share toward obliterating the old mill structures. Many of the old buildings have been transformed into tea houses and, in rare cases, into dwellings. "Tis with a feeling of emptiness and sadness that you return to the region of your childhood days and gaze upon the ruins of the "Old Mill," once the scene of bustling activity. And, so the march of time goes on, casting aside the old and replacing it with the new, which, in turn, shall suffer the fate of its predecessor. Now, for the brighter aspect of my subject. Although the old mills and their builders are fast disappearing, it gives me great pleasure to be able to present, in these humble efforts of mine, numerous interesting and correct details of "The Art of Millwrighting." We can safely say that there will never exist again such painstaking and hardy artisans as the old millwrights, who, for all their eccentricities, builded well. They are among the obscure and forgotten builders of this mighty nation of ours.
The first thing to be considered in the building of a mill is the selection of a stream with a strong, never failing flow of water. After choosing a suitable stream you must next determine the best point of location for your mill seat. In selection the site for the mill seat two things must be considered. First, the point chosen must give you the greatest possible fall, and secondly, it must be high enough so tat a tail race may be dug of not too great length, which will carry off the water as soon as it leaves the wheel. If your tail race flows slowly there will be great loss of power from backwater slowing the motion of the wheel. After carefully leveling your mill seat and knowing the fall as well as the quantity of water available, you must next select the proper type of water wheel. There are six types of water wheels that may be used, each depending on the volume of water or the fall that you may have.
The size types of water wheels that the millwright can choose from are" 1. Undershot, 2. Overshot, 3. Pitch-back, 4. Breast Wheel, 5. Tub Wheel, 6 Reaction Wheel which much resembles the modern turbine.
Undershot wheels were used on streams where the volume of water was large and the fall not very great. The undershot wheel gets its name, owing to the fact that the water strikes the blades or buckets on the under part of the wheel instead of on top as with the overshot wheel. The efficiency of undershot wheels was usually low because it was the impact of the water alone which turned the wheel. The three other types of wheels, excepting the tub wheel, make use of the weight of the water after the force of the head is spent. An undershot wheel will be only half as powerful as an overshot wheel of the same size, the same volume of water being allowed to act on both. The undershot wheel will stop as soon as the force of the water is spent, unless the flow be constant. Knowing these facts, the undershot wheel ought no to be adopted, except where there is little fall, but a great plenty of water. All of the mills on both branches of the Neshaminy were turned by undershot wheels, because of the little fall but the great volume, of the two streams. Such was the case when the mills were built, but in later years both branches failed frequently to supply enough water to their mills in the dry seasons. Darrah's Mill, at Hartsville, the last to operate on the Little Neshaminy, lost much of its custom when the parapet was carried from the dam, thus reducing the volume of water that could be stored during dry weather. Overshot wheels, a type where the water is laid on the top, acting first by percussion against the blades or buckets of the wheel and afterwards by gravity or weight, are highly efficient and operate on a minimum of water. They were the type of wheel used if the fall in the stream was greater than twelve feet and the flow of water was not very great. The larger an overshot wheel is, or any type water wheel for that matter, the less water it will require, and the more power you will get. The reasons: First, a larger wheel will cast off the water better. Secondly, we have a simple problem in physics dealing with levers, the arms or spokes of the wheel acting as levers to turn the shaft. The force exerted by a lever is equal to the force applied at the end multiplied by the distance from the end of the lever to the fulcrum. Hence the longer the arms of the water wheel the more force you will get from the weight of the water in the buckets of the wheel, which act on the arms through the medium of the shrouds. An eighteen-foot overshot water wheel turning a run of stones should be six inches wide for every foot the stone are in diameter. So an eighteen-foot overshot wheel to turn a run of five-foot stone one hundred and six revolutions per minute should be thirty inches wide from shroud to shroud. This wheel will require six cubic feet of water per second. A large dam well built, situate on a very small stream, if once filed can operate an overshot wheel for a day's grinding of at least ten hours, and easily refill itself at night in preparation for the next day's grinding. I will present some figures to probe this statement. Suppose our pond or dam contains three acres and is on the average of three feet deep. An acre of mill pond contains 43,560 cubic feet of water for every foot of its depth. Assume our dam covers three acres and is on the average of three feet deep. It will contain three acres time three feet time 43,560 cubic feet (of water in an acre), which will be 392,040 cubic feet of water. By previous statement I said that an eighteen-foot overshot wheel, thirty inches wide, turning a run of stones will require six cubic feet of water per second. However, we will allow ten cubic feet of water per second to take care of leaks and seepage. Divide 392,040 cubic feet (the contents of our dam) by ten cubic feet (used per second), and we find that our mill pond will contain enough water to run the mill 39,204 seconds or ten hours and fifty-three minutes. Allowing the stream that feeds the mill pond flow of two cubic feet per second, our dam would also be replenished to the extent of nearly 80,00 cubic feet in eleven hours, which would give us a total of 472,000 cubic feet of water available. In this instance we are assuming that no part of the dam is any lower than the entrance to the race. It was because of the adaptability of "Mechanics Run" for the use of overshot wheels that we find five mills in the short distance of two and one-half miles. Pitch-back and breast shot wheels work on the same principle as overshot wheels, in that they are both acted on by the percussion and the weight of the water. This type of wheel is used where the the fall of and the volume of water is not very great. Breast wheels are always more than eighteen feet in height or diameter, although the fall of the water may be less than twelve feet. It is called a breast wheel if the penstock is lower than the shaft of the wheel. The water is not carried over the wheel as in the case of overshot wheels, but instead the penstock carries the water directly toward the wheel. Then it is diverted by a chute down against the buckets on the same side of the wheel as the water is flowing toward. A close fitting sheeting covers the wheel on the side which receives the water. This sheeting or covering prevents the loss of much water, which would occur when it strikes the buckets or floats at right angles. When the penstock is nearly as high as the wheel, the water may be carried partly over the wheel and shot on backwards. The part of the penstock next to the wheel is in the form of a chute to guide the water into the wheel. The entire side of the wheel will need to be closely sheeted to prevent the loss of water. This type of wheel is called a pitch-back wheel. The head of the water may be reduced to the same as it is for an overshot wheel, and the motions of the two wheel will be the same, likewise their power will be the same. Breast and pitch-back wheels have been built with their diameters as great as forty feet, giving tremendous power and using a minimum of water. Two large wheels of this type were used on the Union Canal to pump water up to the summit lever near Lebanon. Perhaps the simplest and cheapest type of mill to suit your mill seat would be a "Tub Mill." It is a curious piece of machinery and very similar to the "Norse Mill," except that the norse mill wheel does not have the hoop (tub) around it as does the tub wheel. A tub mill has a vertical water wheel that is acted on by the percussion of the water alone. The shaft is vertical, carrying the stone on top of it, and serves in place of a spindle. The lower end of this shaft is set in a step fixed in a bridge tree, by which the stone is raised and lowered. The water is shot on the upper side of the wheel in the direction of a tangent with its circumference. The wheel runs in a hoop, like a mill stone hoop, projecting so far above the wheel as to prevent the water from shooting over the wheel and whirls it about until it strikes the buckets. The water is shot on in a deep narrow column, nine inches wide and eighteen inches deep, to drive a five-foot stone. The whole of this column cannot enter the buckets until a part has passed half way around the wheel, so that there are always nearly half the buckets struck at once. The buckets are set obliquely that the water may strike them at right angles. As soon as the water strikes, it escapes under the wheel in every direction. For the complete description of a tub mill I am indebted to U. J. Jones, author of "Early Settlements in the Juniata Valley," who has ably described the early mills of the Juniata Valley. He secured his information from Edward Bell of Blair County. Mr. Bell, a millwright, died in 1850, but before his death he visited the last of the Continental Tub Mills in the valley and minutely examined it. This mill was built before the Revolution and stood near Dorsey's Forge, on the Little Juniata, in Huntingdon County. The mill house was about twelve feet high and fourteen feet square, made of small poles and covered with clapboards. There was neither floor nor loft to it. The husk was made of round logs built into the wall; the water or tub wheel was some three feet in diameter, and split boards driven into the sides of the shaft made the buckets. The shaft had a gudgeon in the lower end and a thing they called a spindle, in the upper end, and was not dressed in any way between the claws. The stones were about two feet four or six inches in diameter, and not thick, and in place of a hoop they had cut a buttonwood tree that was hollow and large enough to admit the stones, and sawed or cut it off to make a the hoop. The hopper was made of clapboards, and a hole was driven near the eye of the stone, from which a pin projected, serving the purpose of a dampsil (damsel), which struck the shoe every time the stone revolved. The meal trough, made out of part of a gum tree, completed the grinding fixtures. The bolting chest was about six feet long, two and one-half feet wide, and four feet high, made of live wood puncheons, split, hewed, and jointed to hold flour, with a pair of deer skins sewed together to shut the door. There was not one piece of iron about the chest or bolting reel. It had a crank or handle on one end, made of wood - the shaft, ribs, and arms, of the same material; and the cloth was leona muslin, or lining that looked like it. Mr. Jones whose book was published in 1856, went on to say that it was a rather one-horse concern for his day and generation. What would he say today if he were taken to some of the huge mills of Minneapolis or other parts of the United States? I should like to see how some of the people of today would relish bread baked from flour bolted through leona muslin. It might do for dyspepsia. Let it be remembered that tub mills should never be built along streams that fail during dry season. They are suited to those places only where water runs to waste during the whole year. There were hundred of such mills in the United States, which were useless at the season when they were most needed, whilst a well constructed overshot, breast, or pitch-back wheel might be kept constantly running. The reaction wheel, which operates in somewhat the same fashion as the modern turbine is especially adapted for mill seats where there is much back water. Reaction wheels may be set on vertical or horizontal shafts, working equally well either way. Any number of wheels may be put on the shaft, according to the power desired or the water available. They were usually arranged in pairs, one on either side of the cistern, which was a closed downward continuation of the penstock. The water flows through an opening along the shaft on either side of the cistern, into each of the wheels. There is apertures around the rim of the wheel, arranged as curved blades, which are struck by the escaping water, the water spurting out with equal pressure from all the openings. As the water spurts out and strikes the insides of the curved blades the entire wheel is whirled around. By opening or closing the apertures the power and the quantity of water used may be increased or diminished. Thus, with the reaction wheel we have the water acting from the inside of the wheel instead of acting on the outside as it does with other types. Escaping water pushes the reaction wheel around, while confined water pushes the overshot wheel around. Having described the six common types of water wheels and enumerated their good and bad points, we are now ready to choose the proper water wheel for our particular mill seat. We will assume our mill seat is on a stream that has an average flow of ten cubic feet of water per second. There is a fall of twenty feet. Our selection will be an eighteen-foot overshot wheel.
In locating a dam, you much be careful to let the dam and the mill be a sufficient distance apart, so that the dam will not raise the water on the mill, in time of high floods. This has happened in many instances, on large streams, where a mill was set so close to the dam that the pier head, or fore bay, was in the breast. In event of a leak about the fore bay, or mill, there was no chance of shutting off the water or conveying it to another way, as can be done where there is a raceway, but all must be left to its fate. Such mills are frequently broken down and carried away, even the millstones are carried a considerable distance down the stream, buried under the sand and never found. The great danger from this error will appear more plainly, if we suppose six mills on one stream, one above the other, each at the breast of its dam, and a great flood to break one of the dams. At once this increased flood will carry away all the dams below as well as the mills. A case of this type actually happened in Virginia, in 1794. All the mills and the dams of Falling Creek, in Chesterfield County, were carried away at once except the lowest mill. The dam of this mill having broken the year before it was rebuilt a quarter of a mile higher up the creek from the mill, by which means this mill was saved. The site for the dam should have a foundation of solid rocks or stones, so heavy that water will never move them. If the site has a bottom of sand or clay, make a foundation of the trunks of long trees, laid close together on the bottom of the creek, with their butt ends downstream, as low and close together as possible. They should extend across the whole tumbling space, so that the falling water cannot undermine the wall of the dam. On these logs the dam may be built, either of stone or wood. The weight of a stone dam will keep the foundation longs will anchored whereas a wooden dam on a wooden foundation might float away or be moved by a heavy flood. The dam which supplied water for the saw mill on the farm of John M. Darrah, about two miles northwest of Hartsville, was built on a foundation of logs, which extended out about thirty feet from the stone breast of the dam. Many dams are built of timber and small stones, such as the old dam at the Bridge Valley Mill, formerly "Ryan's Sawmill." All of the modern dams of the Lehigh Coal and Navigation Company are built of timber and filled in with stone, gravel and mud. The breast of logs is made perpendicular, with straight logs, laid close to one another, then another wall of logs fifteen or twenty feet upstream is laid, not so high as the breast wall by at least three feet, but fitted very close together to prevent lamprey eels from working through them. These two walls are tied together at every six feet or so, with cross logs, butts downstream, dovetailed and bolted strongly to the logs of the lower wall, especially the upper logs. The ends of the upper logs or timbers must be well fixed and the upstream ends sunken, since floating logs, ice jams and other objects coming down stream will strike them and be glanced over the dam by them. These dams should be bow shaped, with the bow or arch standing upstream. Another common type of dam was the bow, or arch shaped masonry dam, of stone, with the bow or arch standing upstream, so that the pressure of the water pressed the stones more closely together. On the upstream side of the masonry wall was a sloping embankment of earth and stones with helped to glance logs and other debris over the wall as well as strengthening the breast. The third type of dam used on small streams, was the common earth embankment having a layer of planks sunk and fastened, with the upstream end lowest, to prevent the water from washing the newly placed earth away. Many of these earth dams were fifteen to twenty feet thick and served as roadways, sluices or waste gates taking care of flood water and preventing the water from running over the earthen breast. Today, the predominating type of dam is built of earth and graved with a core of concrete.
In digging the race, we must remember that water will come to a level on its surface, whatever may be the form of the bottom or the sides. When you have determined on the area of the section or prism of the race, necessary to convey a sufficient quantity of water to the mill, you need only to keep that area in mind, while digging the entire length, without paying much attention to the depth or width, if there be any rocks in the way. Much expense may be oftentimes saved, by making the race deep where it cannot easily be made wide enough, and wide where it cannot easily be made deep enough. One disadvantage in having races very shallow in some places is that, the water in dry seasons may be too low to rise over the shallow places. The current will keep the deep places open, light sand and mud will not settle in them. The amount of fall that the race should have, must be sufficient to give the water a velocity of at least one to two feet per second,- but, the slower, the better, as there will be less fall lost between the dam and the fore bay. A fall of one inch to one hundred feet is enough in most races. Considerable care is necessary when putting in the fore bay. A number of solid frames, each consisting of a sill, two posts and a cap should be set up two and one-half to three feet apart; to these the planks are spiked. The frame at the head next to the water in the race and another six or eight feet in the race, should extend four or five feet on each side of the fore bay into the bank, and be planked in front, to prevent the water, and vermin from working under or around. Next, lay the bottom and sides of the fore bay with good sound plank, well jointed and spiked into the sills. Plank the head to its proper height, leaving a suitable sluice to guide the water to the wheel. A rack should be made across the race at the head of the fore bay, to keep off the floating sticks and matter, that might injure the gates and break the buckets or floats of the wheel. The bottom of the race must be planked between the fore bay and the rack to prevent the water from making a hole by tumbling through the rack when choked, and the sides must be planked outside the posts to keep the banks up. The rack must be twice as long as the fore bay is wide, or else the water will not come through it fast enough to keep the head up. Perhaps this will make clear to you the reason for the wide racks in mill races supplying undershot wheels. To carry the water away from under the wheel after it has been used, makes it necessary that a tail race be dug. This tail race or exodus for the fallen water must be deep enough and wide enough to carry off all the water as it falls from the wheel. If it cannot get rid of the water, the wheel will begin to wallow in it and we have what is know as backwater, which will cut down the efficiency of all types of wheels excepting the reaction and turbine wheels.
There are several very important things to be considered in building the mill house walls. First, the foundation should be laid with large, good stones so deep as to be out of danger of being undermined, in case water might break through at the mill and soften the earth or cause quick sands to form beneath the walls. The center of the weight of the wall should pass through the center of its foundation. It was often the common practice to build the walls plumb outside, and to batter them from the inside, which would throw their center of gravity to one side of their base. If, therefore, the wall settles any it will incline to fall outwards. Good mortar and hard clean cut stone should be used. Good mortar made of pure, well burnt limestone, properly mixed with sharp, clean sand, free from any sort of earth, loam, or mud will, in time, actually turn to the hardness of stone. It is better to put too much sand in your more than too little. Workmen like their mortar rich, because it works easily, but rich mortar will not stand the weather well, nor grow so hard as poor mortar. Mortar that is all lime would have little more strength that clay.
The timbering and woodwork of the mill house should be of the best quality live wood, cut and properly seasoned. Oak from the standpoint of strength and durability is to be preferred for all timbering, joists, and rafters. White pine, yellow pine, chestnut, or hemlock make very good material for floors, partitions, bins, garners, and stair work. To give you an idea of the timber required for a three-story mill I am inserting the following: Bill of scantling for a mill, thirty-two by fifty-five feet, three stories high; the walls of mason work.
2 sills, 29 feet long, 8 by 12 inches, to lay on the walls for the joists to lie on. 48 joists, 10 feet long, 4 by 9 inches, all of timber that will last well in dampness.
2 posts, 9 feet long, 12 by 12 inches. 2 girders, 30 feet long, 14 by 16 inches. 48 joists, 10 feet long, 4 by 9 inches.
1 cross girder, 30 feet long, 12 by 14 inches, for one end of the joists to lie on. 2 posts to support the girder, 12 feet long, 12 by 12 inches. 10 joists, 13 feet long, 4 by 9 inches; all of good white oak, or other timber, that will last in damp places.
4 posts, 9 feet long, 12 by 12 inches to support the girders. 2 girder posts, 7 feet long, 12 by 12 inches to stand on the water house. 2 girders, 53 feet long, 14 by 16 inches. 90 joints, 10 feet long, 4 by 9 inches.
6 posts, 8 feet long, 10 by 10 inches, to support the girders. 2 girders, 53 feet long,13 by 15 inches. 30 joists, 12 feet long, 4 by 8 inches, for the middle tier of the floor. 60 joists, 12 feet long, 4 by 8 inches, for the outside tiers or cornice which extends 12 inches over the walls, for the rafters to stand on. 2 plates, 54 feet long, 3 by 10 inches: these lie on the top of the walls and the joist on them.
54 rafters, 22 feet long, 3 inches thick, 6 1/2 wide at the bottom, and 4 1/2 at the top end. 25 collar beams, 17 feet long, 3 by 7 inches. 2760 feet of lath, running measure. 7000 shingles.
12 pieces, 12 feet long, 6 by 6 inches, for door frames. 36 pieces, 8 feet long, 5 by 5 inches, for window frames.
2 sills, 27 feet long, 12 by 12 inches. 1 sill, 14 feet long, 12 by 12 inches. 2 spur blocks, 4 feet 6 inches long, 7 inches by 7 inches. 2 head blocks, 5 feet long, 12 by 14 inches. 4 posts, 10 feet long, 8 by 8 inches, to bear up the penstock. 2 cap sails, 9 feet long, 8 by 10 inches, for the penstock to stand on. 4 corner posts, 5 feet long, 4 by 6 inches, for the corners of the penstock.
2 sills, 24 feet long, 12 by 12 inches. 4 corner posts, 7 feet long, 12 by 14 inches. 2 front posts, 8 feet long, 8 by 12 inches. 2 back posts, 8 feet long, 10 by 12 inches, to support the back ends of the bridge trees. 2 other back posts, 8 feet long, 8 by 8 inches. 3 tomkin posts, 12 feet long, 12 by 14 inches. 2 inner ties, 9 feet long, 12 by 12 inches, for the outer ends of the little cog wheel shafts to rest on. 2 top pieces, 10 feet 6 inches long, 10 by 10 inches. 2 beams, 24 feet long, 16 by 14 inches. 2 bray trees, 8 1/2 feet long, 6 by 14 inches. 2 bridge trees, 9 feet long, 10 by 10 inches. 4 planks, 8 feet long, 6 by 14 inches, for the stone bears. 20 planks, 9 feet long, 4 by 15 inches, for the top of the husk. 2 head blocks, 7 feet long, 12 by 15 inches, for the wallower shafts to run on. They serve as spurs also for the head block for the water wheel shaft. Quite a pile of timber and saw lumber. One does not have any idea of the material there is in a mill until he goes inside and actually makes a note of the beams, posts, rafters, girders, cross ties, and other woodwork. The woodwork of a mill has to be very solid in order that there will be as little vibration as possible, because the vibrating of different parts will cause the machinery to wear out and in some cases to get so much out of line that it will not work at all. The mill floors must be strong enough to withstand many tons of weight without sagging in order that the head blocks will not be pressed against the tops of upright moving shafts, and prevent them from running or cause them to catch fire.
All of the necessary outside work, in the form of the dam, race, fore bay, and mill house having been completed, we not begin the work of outfitting our mill with the necessary machinery. All of the gearing, shafting, and machinery must be made to fit the mill building, and so arranged that it will not occupy too much space. The mill wright always took the timber in its rough, unfinished condition and worked it up into gearing, cog wheels, shafts, spindles, hoppers, chutes and conveyors. He did all of his work in the mill house, which became his workshop for that particular job. Some mill wrights who employed a number of workmen and did business similar to modern contractors ran a mill wrighting shop where a stock of different parts was kept constantly on hand.
How the mill wright fashioned the water wheel and the master cog wheel and set them up, although complicated, is worth noting. As previously stated, out wheel is to be an eighteen-foot overshot. The following materials will be needed to construct the wheel and also the master cog wheel:
1 shaft, 18 feet long, 2 feet in diameter. 8 arms for the water wheel, 18 feet long, 3 by 9 inches. 16 shrouds, 8 1/2 feet long, 2 inches thick and 8 inches deep. 16 face boards, 8 feet long, 1 inch thick and 9 inches deep. 56 bucket boards, 2 feet 4 inches long and 17 inches wide. 140 feet of boards, for soaling the wheel.
3 arms for the cog wheel, 9 feet long, 4 by 14 inches. 16 cants, 6 feet long, 4 by 17 inches. Having assembled the materials for the wheel, our next task is to shape them and then assemble the wheel on its shaft. The shaft for a water wheel with eight arms should be sixteen square, or sixteen sided, about two feet in diameter, the tree to make it being two feet three inches at the top end. Saw this piece square at each end, then set a large compass to half its diameter, and sweep a circle at each end. Next, plumb a line across the center, plumb two more lines on each end of the shaft,. These lines are exactly one foot to either side of the center plumb line and are parallel to the center plumb line. With a chalked line strike lines form the ends of these lines, along the shaft on each side from end to end. Dress or hew the two sides down to the plumb lines. Turn the piece over and setting it level, plumb, line, and dress off the other two sides. The shaft is no four square; to get it eight square, set it exactly on one corner, plumb, line and dress off the four corners. Repeat this on the eight corners to make the shaft sixteen square. After the shaft has been properly shaped and reduced the next task is to lay out and mark the mortises, which must be cut to fit the arms of the wheels. There will be sixteen mortises, one for each of the sixteen sides of the shaft. The mortises are to be one-half inch longer than the actual width of the arms, which is to leave room to drive the keys for holding the arms tight. The gudgeons and end bands are driven on each end of the shaft after the ends of the shaft have been shaped down to fit the bands. A gudgeon is a wrought iron or cast iron piece with a tang usually from two to four feet long, which is rectangular in shape and comes to a tapering end. The entire tang of the gudgeon is driven into the mortise in the center of the shaft. The neck of the gudgeon is five inches long, from two to four inches in diameter and perfectly round, so that it will run evenly in its pillow block, or, in the modern terminology, its bearing. The bands are driven on and keyed, then the gudgeons are driven in and wedged by driving tapering prices of iron into the ends of the shaft on each side of the gudgeons. It is necessary that the bands be very tight, so that the gudgeons will not work loose or the shaft begin to split where the gudgeon is driven in. All of the gudgeons on the different shafts throughout the mill are put on in the same manner, whether for counter cog shafts or bolting reel shafts.
After the bands and the gudgeons have been driven and fastened and the mortises for the water wheel and the master cog wheel have been cut, the shaft is taken and placed on the head and spur blocks, in the water house. The great or master cog wheel usually has six arms which are mortises in the same shaft as the water wheel. In this particular mill the master cog wheel will be nine feet in diameter and will contain 69 cogs, the cogs having a pitch of 4 1/2 inches. All the material used in the cog wheels should be of the best live oak and well seasoned. For the proper preparation of cogs and also the wood for shafts, arms, and other parts of the machinery, the follow procedure is recommended. The cogs should be cut fourteen inches long, and three and one-quarter inches square; this should be done when the sap runs at its fullest and at least a year before they are used, that they may dry without cracking. If either hickory or white oak be cut when the bark is set, they will worm eat, and, if dried hastily, will crack. To prevent cracking or worm eating, boil the wood and dry it slowly or soak them in water for a year. Twenty years in mud and fresh water will not hurt oak providing the air is excluded. When the cogs are taken out of the boiling water, they should be put in a hay mow, under the hay, where, while foddered away, they will dry without cracking. If you do not have time enough to wait for them, a shorter method of drying may be used. Put the wood to be used for cogs and parts of the cog wheels in a malt kiln with a floor of lath two inches apart. Shank the cogs and hang them shank downwards, between the laths, cover them with a hair cloth (wool or horse blanket), and make a fire of wood, the smoke of which will prevent them from cracking. In the same manner boards, planks or scantling are best dried in the kiln, covered so as to keep the smoke amongst them. The fire should be renewed once a day, for twelve or fifteen days; thus they will dry without cracking. The rest of the cog wheels, wallowers and trundles are made with the same explicit care, and their shafts fitted with iron gudgeons and hoops. Other phases of millwrighting that were necessary to complete the outfitting of the mill were: Fixing the head blocks and hanging the wheels, putting in the balance rynds for the millstones, bridging the spindle, constructing a millstone crane and lighter staffs, bottle weights, making the hoops to cover each pair of millstones, facing the millstones with sand and furrowing them with picks, adjusting the hoppers, shoes, and feeders, fashioning bolting chests, reels, fans, shaking sieves and conveyors and elevators.
Through sample Illustration and the picture which shows the cross-section of a mill you will be able to recognize and understand the use of the parts just mentioned.
There are many other things relating to mills as well as countless stories which if time and space would permit I might include in this paper. But the printer demands the manuscript, and so I must give it to him. With this symbolic picture as a fitting ending, we say farewell to the old mill.
Note: Does anyone know if Henry S. Engart of Lebanon, Pennsylvania, ever wrote a second part to this article? It seems just when it was getting interesting it ended. I have only a photo copy of a photo copy of the original article. I there fore will try and use some illustrations similar to what was originally used. Thank you.
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