Farm machinery and farm motors

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Preface

Instruction pertaining to Farm Machinery and Farm Motors has b^en quite recently added to the agricultural course in the majority of the agricultural colleges in the United States. Although the need and importance of such a study was self-evident, it was a new field, one in which the knowledge pertaining to the subject had not been prepared and systematized for instructional purposes. The latest book on the subject of Farm Machinery was written by J. J. Thomas in 1869, before the general introduction of labor-saving machinery for farm work. Many books have been written on the various motors used for agricultural purposes, but it is not believed that an attempt has been made to place in one volume a discussion of them all. The authors have felt the need of a text for instructional purposes, and it is this need that has prompted them to prepare this book. It is a revision of the lecture notes used before their classes for several years. These notes were prepared from a careful study of all the available literature on the subject, and from observation made in the field of the machines at work and in the factories where they are made.

A list of the literature consulted is given at the close of the book. Free use has been made of all this as well as all the trade literature available, and for this an efifort has been made to give due credit. Many of the illustrations have been prepared from original drawings by the authors ; however, the larger number are those of machines upon the current market.

A discussion of all the farm machines did not seem possible, and attention may be called to the omission of

VI PREFACE seed grading and cleaning machinery, cotton machinery, potato machinery, garden machinery, and other classes. The amount of information at hand concerning these classes of machinery did not justify their inclusion. Farm Motors has been made more complete, but some of the motors used to a limited extent in agricultural practice, as hot-air engines and water-wheels, have been omitted. Although electrical machinery is not much used in agriculture, its use is increasing and the interest in the subject has been so general that a chapter on the same has been included. As the efificiency and life of farm machinery depends largely upon the way and manner it is repaired, a short chapter on the Farm Workshop has been added.

To make instruction in Farm Machinery and Farm Motors efficient it should in all cases be supplemented with laboratory and field instruction, and it is not the purpose of this book to displace such instruction.

An attempt has been made to make the material practical, useful and helpful, and although written primarily for a text book, it is hoped that it will be useful to many engaged in practical work.

The authors know that their attempt to prepare a text book has not been perfect, and not only will errors be found in the subject matter, but the material will lack pedagogic form in places. Any criticism or suggestions from instructors in these respects will be duly appreciated. They wish also to acknowledge the obligations they owe many friends for suggestions and aid in many ways. Thanks are due the publishers for their work in preparing the illustrations, which at first seemed to be an almost endless task.

J. B. Davidson.

L. W. Chase.

Part I Chapter Page

Introduction i

I. Definitions and Mechanical Principles 8

II. Transmission of Power 28

III. Materials and the Strength of Materials .... 43

IV. Tillage Machinery 51

V. Tillage Machinery (Continued) 78

VI. Seeding Machinery . 102

VII. Harvesting Machinery 136

VIII. Haying ]\Iachinery 162

IX. Manure Spreaders IQI

X. Threshing Machinery 203

XI. Corn Machinery 221

XII. Feed Mills 234

XIII. Wagons. Buggies, and Sleds 241

XIV. Pumping Machinery 258

XV. The Value and Care of Farm Machinery .... 277

P.^RT II

CHAPTER PAGE

Introduction 281

XVI. Animal Motors 284

XVII. Windmills 298

XVIII. Steam Boilers 3i7

XIX. Steam Engines 3oi

XX. Gas. Oil. and Alcohol Engines 40i

XXI. Traction Engines 436

XXII. Electrical Machinery 46i

XXIII. The Farm Shop 499

PART 1

Introduction

I. One of the requirements for a steady, healthy growth of any people or nation is a bountiful supply of food. The earth can be made to produce in abundance only when the soil is tilled and plants suitable for food are cultivated. As long as the people of the earth roamed about obtaining their subsistence by hunting and fishing, conditions were not favorable for a rapid increase in population or an advance in civilization. Tribes or nations constantly encroached upon each other's rights and were continually at war. History shows that when any nation, isolated so as to be protected from the attacks of other nations, devoted itself to agricultural pursuits, its government at once became more stable and life and property more secure. Protected in this way, a great nation, shut off from the rest of the world by natural means, and located in a fertile country, arose along the banks of the Nile long before any other nation reached prominence. The Gauls became mighty because they devoted themselves to agriculture and obtained in this way a more reliable supply of food. Pliny, the elder, in his writings tells of the fields of Gaul and describes some of the tools used. It has been estimated that there never were more than 400,000 Indians in North America, and they were often in want of food. Compare this number with the present population. The tribes that flourished

H, FARM MACHINERY

and increased in numbers were those who had fields of grain and a definite source of food.

2. Change from hand to machine methods. — When people began to turn their attention to farming they began to devise tools to aid them in their work. Various kinds of hoes, crude plows, sickles, and scythes were invented, but were practically all hand tools. Work with these was necessarily very laborious and slow. The hours of labor in consequence were very long, and the social position of the tiller of the soil was low. He was in every sense of the term "the man with the hoe." He became prematurely old and bent ; his lot was anything but enviable.

For more than 3.000 years the farmers of Europe, and in this country until after the Revolutionary War, used the same crude tools and primitive methods as were employed by the Egyptians and the Israelites. In fact, it has been, relatively speaking, only a few years since the change from hand to machine methods took place. In the Twelfth Census Report the following statement is made : ''The year 1850 practically marks the close of the period in which the only farm implements and machinery other than the wagon, cart, and cotton gin were frhose which, for want of a better designation, may be called implements of hand production."

McMaster, in his "History of the People of the United States," says : "The Massachusetts farmer who witnessed the Revolution plowed his land with the wooden bull plow, sowed his grain broadcast, and when it was ripe, cut it with a scythe and threshed it out on his barn floor with a flail." He writes further that the poor whites of Virginia in 1790 lived in log huts "with the chinks stuffed with clay ; the walls had no plaster, the windows had no glass, the furniture was such as they themselves had lN"IR0m'CT10N' 3

made. Their grain was threshed by driving horses over it in the open field. When they ground it they used a rude pestle and mortar, or placed it in a hollow of a stone and beat it with another."

3. Effects of the change. — At any rate, a great change has taken place and all in little over a half century. This great change from the simplest of tools to the modern, almost perfect implements, has produced a marked eft'ect upon the life of the farmer. He is no longer "the man W'ith the hoe." but a man well trained intellectually.

4. Physical and mental changes. — It is not dillficult to realize that a great change for the better has taken place in the physical and mental nature of the farmer. It is vastly easier for a man to sit on a modern harvester, watch the machine, and drive the team, than it is to work all day with bended back, scuffling along, running a cradle. How much easier it is to handle the modern crop, though much larger, with the modern threshing machine, where the bundles are simply thrown into the feeder, than to spend the entire winter beating the grain out with a flail. The farmer can now do his work and still have time to plan his business and to think of improvements.

5. Length of the working day. — One of the marked effects of the change to modern machinery methods has been a shortening of the length of the working day. When the work was done by hand methods, the day during the busy season was from early morn till late at night. Often as much as 16 hours a day were spent in the fields. Now field work seldom exceeds 10 hours a day.

6. Increase in wages. — According to AIcMaster,* in 1794 ''in the States north of Pennsylvania" the wages of

*Mc]\Iaster: "History of the People of the United States," Vol. II., p. 179.

the common laborer Avere not to exceed $3 per month, and "in Vermont good men were employed for £18 per year." Even as late as 1849, the wages, according to several authorities, did not exceed $120 a year. Under present conditions, the farm laborer is able to demand two, three, and even five times as much. In countries where hand methods are still practiced, wages are very low. Men are required to work all day from early morning till late at night for a few cents. In some of the Asiatic countries it is said that men work from four in the morning until nine at night for 14 cents. Women receive only 9 or 10 cents and children 7 or 8 cents.

7. The labor of women. — Woman, so history relates, was the first agriculturist. Upon her depended the planting and tending of the various crops. She was required to help more or less with the farm work as long as the hand methods remained. Machinery has relieved her of nearly all field work. Not only this, but many of the former household duties have been taken away. Spinning and weaving, soap-making and candle-making, although formerly household duties, are now turned over to the factory. Butter and cheese making are gradually becoming the work of the factory rather than that of the home. Sewing machines, washing machines, cream separators, and numerous other inventions have come to aid the housewafe with her work.

8. Percentage of population on farms. — During the change from hand to machine methods there was a great decrease in the percentage of the people of the United States living upon the farms. It has been estimated that in 1800 97 per cent of the people were to be found upon the farms. By 1849 this proportion had decreased to 90 per cent, and according to the Twelfth Census Report it was only 35.7 per cent.

INTRODUCTION 5

9. Increase in production. — Notwithstanding this decrease in the per cent of the people upon the farms, there has been, since the introduction of machinery, a great increase in production per capita. In 1800 it is estimated that 5.50 bushels of wheat were produced per capita; in 1850, according to the Division of Statistics of the Department of Agriculture, production had decreased to 4.43 bushels. This was before the effect of harvesting machinery had begun to be felt. People were leaving the farms and the production of wheat per capita was falling off. The limit with hand methods had been reached. Economists were alarmed lest a time should come when the production would not supply the needs of the people. Through the aid of machinery the production increased to 9.16 bushels per capita in 1880, 7.48 bushels in 1890, and 8.66 bushels in 1900. Perhaps this also shows that the maximum production of wheat per capita with present machinery has been reached. The production of corn has also increased, but the increase is not so marked. The production of corn per capita in 1850 was 25.53 bushels ; in 1900 it was 34.94 bushels.

ID. Cost of production. — Although the cost of farm labor has doubled or trebled, the cost of production has decreased. According to the Thirteenth Annual Report of the Department of Labor, the amount of labor required to produce a bushel of wheat by hand was 3 hours and 3 minutes, and now it is only 9 minutes and 58 seconds. The cost of production, as compiled by Quaintance,* was 20 cents by hand (1829-30) and 10 cents by machinery (1895-96). It is also stated in the Year Book of the Department of Agriculture for 1899 that it formerly required II hours of man labor to cut and cure i ton of hay. Now

*Tlie Influence of Farm Machinery on Production and Labor. Publications of the American Economic Association. Vol. V., No. 4.

the same work is accomplished in i hour and 39 min utes. The cost of the required labor has decreased from 83 1/3 cents to 16 1/4 cents a ton. Not only is it true that machinery has revolutionized the work of making hay, but nearly every phase of farm work has been essentially changed.

11. Quality of products. — Machinery has also improved the quality of farm products. Corn and other grains are planted at very nearly the proper time, owing to the fact that machinery methods are so much quicker. By hand methods the crop did not have time to mature. It was necessary to begin the harvest before the grain was ripe, and hence it was shrunken. The grain is obtained now cleaner and purer. It would be difficult at the present time to sell, for bread purposes, grain which had been threshed by the treading of animals over it.

12. Summary. — Great changes can be accounted for by the introduction of machine methods for band methods. For all people this has been beneficial. It has caused the rise of our great nation on the Western Hemisphere. To no class, however, has this change been more beneficial than to the farm worker himself. J. R. Dodge summarized the benefits derived by the farm worker when he wrote : "As to the influence of machinery on farm labor, all intelligent expert observation declares it beneficial. It has relieved the laborer of much drudgery; made his work and his hours of service shorter; stimulated his mental faculties; given an equilibrium of effort to mind and body ; made the laborer a more efficient Avorker, a broader man, and a better citizen."*

Conditions in America have been very favorable for the development of machinery. We have never had an

*American Farm Labor in Rept. of Ind. Com. (1901), Vol, XL, p. III.

INTRODUCTION 7

abundance of farm labor. The American inventor has surpassed all others in his ability to devise machines. By this machinery the farmer receives good compensation for his services and is able to compete on foreign markets with cheap labor of other countries.

Lastly, it seems conclusive that an agricultural college course is not complete in which the student does not study much about that which has made his occupatio'n exceptionally desirable. It should be an intensely practical study, for under present conditions success or failure in farming operations depends largely upon the judicious use of farm machinery.

Chapter I Definitions And Mechanical Principles

13. Agricultural engineering is the name given to the agricultural achievements which require for their execution scientific knowledge, mechanical training, and engineering skill.

It has been but quite recently that departments have been organized in agricultural colleges to give instruction in agricultural engineering. The name is not as yet universally adopted, the term farm mechanics or rural engineering being preferred by some. It is hoped that in time "agricultural engineering" will be generally accepted, as it seems to be the broadest and most appropriate term to be given instruction defined as above. Implement manufacturers in Europe have been pleased to call themselves agricultural engineers, and the term is not altogether a new one.

Agricultural engineering embraces such subjects as: (i) farm machinery, (2) farm motors, (3) drainage, (4) irrigation, (5) road construction, (6) rural architecture, (7) blacksmithing, and (8) carpentry.

14. Farm machinery. — Part I. of this treatise, after the present chapter of definitions and mechanical principles and chapters on the transmission of power and the strength of materials, will be a discussion of the construction, adjustment, and operation of farm machinery, and will include the major portion of the implements and machines used in the -growing, harvesting, and preparing of farm crops, exclusive of those used in obtaining power. These will be considered in Part II. under the title of

P'arm Motors. The following definitions and explanations will prove helpful :

15. A force produces or tends to produce or destroy motion. Forces vary in magnitude, and some means must be provided to compare them. Unit force corresponds to unit weight and is the force of gravitation on a definite mass. This unit is arbitrarily chosen and is called the pound. The magnitude of all forces, as the draft of an implement, is measured in pounds. Forces also have direction and hence may be represented graphically by a line. For this reason a force is sometimes called a vector quantity. Two or more forces acting on a rigid body act as one force called a resultant.

Thus in Fig. i, O A and O B represent in direction and magnitude two forces acting through the point O. O C is the diagonal of a parallelogram of which O A and O B are sides, and represents the combined ^^^" action of the forces represented by

O A and O B, or is the resultant of these forces. This principle is known as the parallelogram of forces.

16. Mechanics is the science which treats of the action of forces upon bodies and the effect which they produce. It treats of the laws which govern the movement and equilibrium of bodies and shows how they may be utilized.

17. Work. — When a force acts through a certain distance or when motion is produced by the action of a force, work is done. Work can therefore be defined as the product of force into distance. Work can be defined in another way as being proportional to the distance through which the force acts, and also to the magnitude of the force.

DEFINITIONS AND MECHANICAL PRINCIPLES II

i8. Unit of work. — It has been stated that the unit of force is the pound. The unit of distance is the foot. The unit of work is unit force acting through unit distance and is named the foot-pound. A foot-pound is then the amount of work performed in raising a mass weighing I pound I foot. It is to be noted that the amount of work done in raising i pound through lo feet is the same as raising lo pounds through i foot. It is to be noted further that, in considering the amount of work, time is not taken into account. It is the same regardless of whether i minute or many times i minute was used in performing the operation. The horse-power hour is another unit of work commonly used and will be understood after power has been defined.

19. Power is the rate of work. To obtain the power received from any source the number of foot-pounds of work done in a given time must be determined. The unit of power commonly used is the horse power.

20. A horse power is work at the rate of 33,000 foot-pounds a minute, or 550 pounds a second. That is, if a w^eight of 33.000 pounds be raised through i foot in i minute, one horse power of work is being done. This unit was arbitrarily chosen by early steam engine manufacturers to compare their engines with the power of a horse.

If a horse is walking 2.5 miles an hour and exerting a steady pull on his traces of 150 pounds, the effective energy which he develops is :

21. A machine is a device for applying work. By it motion and forces arg modified so as to be used to greater advantage. A machine is not a source of work. In fact, the amount of work imparted to a machine always exceeds the amount received from it. Some work is used in overcoming- the friction of the machine. The ratio between the amount of work received from a machine and the amount put into it is called the efficiency of the machine.

22. Simple machines are the elements to which all machinery may be reduced. A machine like a harvester, with systems of sprockets, gears, and cranks, consists only of modifications of the elements of machines. These elements are six in number and are called (i) the lever, (2) the wheel and axle, (3) the inclined plane, (4) the screw', (5^ the wedge, and (6) the pulley. These six may be conceived to be reduced to only two — the lever and the inclined plane.

23. The law of mechanics holds that the power multiplied by the distance through which it moves is equal to the weight multiplied by the distance through which it moves. Thus, a power of i pound moving 10 feet equals 10 pounds moving i foot. This is true in theory, but in practice a certain amount must be added to overcome friction.

24. The lever, the simplest of all machines, is a bar or rigid arm turning about a pivot called the fulcrum. The object to be moved is commonly designated as the weight, and the arm on which it is placed is called the weight arm. The force used is designated as the power, and the arm on which it acts is called the power arm. Levers are divided into three classes ; for an explanation of the classes refer to any text on physics.* The law of mechanics may be applied to all levers in this manner. The power multiplied by the power arm equals the weight multiplied by the weight arm.

*"General Physics." Bj' C. S. Hastings and F. E. Beach and others.

DEFINITIONS AND MECHANICAL PRINCIPLES

If P = Power, Pa = Power arm, W = Weight, and Wa = VVeiglit arm, P X Pa — W X Wa.

If three of these quantities are known, the other is easily calculated. The arm or leverage is always the perpendicular distance between the direction of the force and the fulcrum.

25. The two-horse evener or doubletree. — The two-horse evener is a lever of the second class where the clevis pin for the whififletree at one end acts as the fulcrum for

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FIG. 2 — WAGON EVENER IN OUTLINE. SHOWING THE ADVANTAGE THE

LEADING HORSE HAS WHEN THE CLEVIS HOLES

ARE NOT A STRAIGHT LINE the power applied by the horse at the other end. The weight is the load at the middle. If the three holes for the attachment of each horse and the load be in a straight line and the arms be of equal length, each horse pulls an equal share of the load even if the evener is not at right angles with the line of draft. But more often the end holes in the evener are placed in a line behind the hole for the center clevis pin. Then if one horse permits his end of the evener to recede, he will have the larger portion of the load to pull because his lever arm has been shortened more than the lever arm of the other horse. The author's attention has been called to a wagon doubletree in which the center and end holes for clevis pins are made by iron clips riveted to the front and back sides of the wood. The center hole was thus placed 4^ inches out of the line of the end holes. This evener is shown in outline in Big. 2.

By calculation it was found that if one horse was 8 inches in the advance of the other, the rear horse would pull 8.4 per cent more than the first, or 4.06 per cent more of the total load. If this difiference was 16 inches, the rear horse would pull 19 per cent more than the first, or 8 per cent more of the total load.

26. Eveners. — When several horses are hitched to a machine as one team, a system of levers is used to divide the load proportionately. The law of mechanics applies in all cases, noting that the lever arm is the perpendicular distance between the direction of the force and the fulcrum or pivot. In general, it may be said that there is nothing" to be gained by a complicated evener. If there is a flexible connection and an equal division of the draft, the simple evener is as good as the complicated or so-called "patent" evener. The line of draft cannot he offset without a force acting across it. This is accomplished with a tongue truck, which seems to be the logical method.

Fig. 3 illustrates some good types of eveners.

27. Giving one horse the advantage. — It often occurs in working young animals or horses of different weights that it is desired to give one the advantage in the share of work done. This is accomplished by making one evener arm longer than the other, giving the horse which is to have the advantage the longer arm. This may be done by setting out his clevis, setting in the clevis

DEFINITIONS AND MECHANICAL PRINCIPLES of the other horse, or placing- the center clevis out toward the other horse. The correct division of the load between horses of different sizes is not definitely known, but it is

Five Horse Tandem.

FIG. 3 — GOOD TVPES OF EVENERS WHICH WILL DIVIDE EQUALLY THE DRAFT

thought that the division should be made in about the same proportion as each horse's weight is of their combined weight.

28. Inclined plane. — The tread power is an example of the utilization of the inclined plane, in which the plane is an endless apron whose motion is transferred to a shaft. The tread power is illustrated in Part II., Farm Motors.

29. The screw is a combination of the inclined plane i i6 and the lever, where the inclined plane is wrapped around a cylinder and engages a nut. The pitch of a screw is the distance between a point on one thread to a like point on the next, or, in other words, it is i inch divided by the number of threads to the inch. Thus, 8 threads to i inch is i/8 pitch, 24 threads 1/24 pitch. There is a great gain of power in the screw because the load is moved a short distance compared with the power. A single-pitch thread advances along the length of the screw once the pitch at each turn ; a double pitch advances twice the pitch. The part of a bolt containing a screw thread on the inside is spoken of as a nut.

The name burr is often given to the nut, but burr applies more particu- Yj^ larly to washers for rivets. The tool

used in making the thread in a nut is called a tap, and the one for making outside threads a die.

30. A pulley consists primarily of a grooved wheel and axle over which runs a cord.

A simple pulley changes only the direction of the force. By a combination of pulleys the power may be increased indefinitely. The wheel which carries the rope is called a sheave, the covering and axle for the sheave the block, and the whole a pulley. A combination of blocks and ropes is called a tackle. With the common tackle block, the power is multiplied by the number of strands of rope less one. The mechanical advantage may be obtained in another

FIG. 4 — SIMPLE PUL- LEY, WHICH ONLY CHANGES THE DI- RECTION OF A FORCE

DEFINITIONS AND MECHANICAL l^RINCIPLES way, as it is equal to the number of strands supporting the weight. This will agree with the former method when the power is acting downward. If the power is acting upward instead of downward, the power strand would be supporting the weight, and so should not be deducted from the total number to obtain the mechanical advantage. Fig. 5 illustrates a tackle which has six strands, but

FORCE MAY BE MULTIPLIED MANY TIMES BY A TACKLE OF THIS KIND

FIG. 6 — DIFFEREN- TIAL TACKLE BY WHICH HEAVY WEIGHTS MAY BE RAISED only five are supporting the weight, so the mechanical advantage in this case is five. If the weight be 1,000 pounds, as marked, a force of 200 pounds besides a force sufficient to overcome friction \yill be needed to raise the weight. This tackle has a special designed sheave which, when the free rope end is carried to one side and let out i8 slightly, the rope is wedged in a special groove and the weight held firmly in place.

The differential pulley shown in Fig. 6 is a very powerful device for raising heavy weights and is very simple. The principle involved is that the upper sheaves are of different diameters, fastened rigidly together and engaging the chain in such a manner as to prevent it from slipping over them. Thus, as the sheaves are rotated, one of the strands of chains carrying the load is taken up slightly faster than the other is let out, shortening their combined length and raising the load.