MACHINERY 



MACHINERY 



1943 



don, 1908: "The first plow was simply a form of hoe made from a 

 crude stick of the proper shape to penetrate and loosen the soil as it 

 was drawn along, .... The records of the ancient Egyptians 

 illustrate such a plow. 



"At an early time the point of the plow was shod with iron. 

 Virgil describes a Roman plow as being made of two pieces of wood 



2248. Moldboard view of a steel moldboard walking-plow 

 showing beam wheel. 



meeting at an acute angle and plated with iron. During the middle 

 ages there was but little improvement over the crude Roman plow 

 as described by Virgil. The first people to improve the Roman plow- 

 were the Dutch, who found that a more perfect plow was needed to 

 do satisfactory work in their soil. The early Dutch plow seems to 

 have most of the fundamental ideas of the modern plow in that it 

 was made with a curved moldboard and was provided with a beam 

 and two handles. The Dutch plow was imported into Yorkshire, 

 England, as early as 1730 and served as a model for the early Eng- 

 lish plows. 



"Howard was one whose name may be mentioned among those 

 instrumental in the development of the early English plow. . . . 

 .lames Small, of Scotland, was another who did much toward the 

 improvement of the plow. Small's plow was designed to turn the 

 furrow smoothly and to operate with little draft. Robert Ransome, 

 of Ipswich, England, in 1785 constructed a plow with the share of 

 cast-iron. In 1803, Ransome succeeded in chilling his plows, mak- 

 ing them very hard and durable. The plows of Howard and Ran- 

 some were provided with a bridle or clevis for regulating the width 

 and depth of the furrow. 



"Before the Revolutionary War, the plows used in America 

 were much like the English and Scottish plows of that period. The 

 plow used during the later Colonial period was made by the village 

 carpenter and ironed by the village smith with strips of iron. The 

 beam, standard, handles, and moldboard were made of wood and 

 only the cutting edge and strips for the moldboard were made of 

 iron. Among those in America who first gave thought to the 

 improvement of the plow was Thomas Jefferson. Daniel Webster 

 is another prominent American who, history relates, was interested 

 in the development of the plow. He designed a very large and cum- 

 bersome plow for use upon his farm. It was over 12 feet long, 

 turned a furrow 18 inches wide and 12 inches or more deep, and 

 required several men and yokes of oxen to operate it. Charles 

 Newbold, of Burlington, New Jersey, secured the first letters patent 



2249. Bottom view of steel moldboard plow. 



on a plow in 1797. Newbold's plow differed from others in that it 

 was made almost entirely of iron. Jethro Wood gave the American 

 plow its proper shape. The moldboard was given such a curvature 

 as to turn the furrow evenly and to distribute the wear well. 



"As farming moved farther west the early settlers found a new 

 problem in the tough sods of the prairie states. A special plow with 

 a very long sloping moldboard was found to be necessary in 

 order to reduce friction and to turn the sod over smoothly. Owing 

 to the firmness of the sod it was found that curved rods might be 

 substituted for the moldboard. Later, when the sod became 

 reduced, it was found that the wooden and cast-iron plows used in 

 the eastern portion of the country did not scour well. This diffi- 

 culty led to the use of steel in the making of plows. Steel, haying 

 the property of taking an excellent polish, permitted the sticky 

 soils to pass over a moldboard made of it where the other materials 

 failed. 



"In about 1833 John Lane made a plow from steel cut from an 

 old saw. Three strips of steel were used for the moldboard and one 

 for the share, all of which were fastened to a shin or frame of iron. 

 John Lane secured in 1863 a patent on soft-center steel, which is 

 used almost universally at the present time in the making of tillage 

 tools. It was found that plates made of steel were brittle and warped 

 badly during tempering. Welding a plate of soft iron to a plate of 

 steel was tried and although the iron supported the steel well when 

 hardened it warped very badly. The soft-center steel, which 

 was formed, by welding a heavy bar of iron between two bars of 

 steel and rolling all down into plates, permitted the steel to be 

 hardened without warping. It is very strong on account of the 

 iron center which will not become brittle. 



"In 1837 John Deere built a steel plow from an old saw which 

 was much similar to Lane's first plow. 



The modem steel moldboard plow is a three-sided 

 wedge which is pulled through the soil by means of a 

 beam and held steady by two handles behind. (Figs. 

 2248-2250.) The main parts of the plow may be 

 enumerated as follows: (1) The share, or cutting edge, 

 of which the point is the part first penetrating the soil, 

 and the heel is the outside corner; (2) the moldboard, 

 forming a twisted face which turns the furrow; (3) the 

 landside, which receives the side pressure produced 

 when the furrow is turned and aids in preventing the 

 furrow from becoming crooked, particularly when 

 irregularities in the texture of the soil are encountered; 

 and (4) the frog, or metal shape to which the mold- 

 board, landside and share are attached. 



The functions of the plow with reference to the soil 

 are a cutting function, an inverting function, and a 

 pulverizing function. The cutting of the soil is effected 



2250. Landside and back view of steel moldboard plow, 

 showing subsoiling attachment. 



in two planes, one vertical and the other horizontal. 

 The inversion of the furrow-slice requires first a lifting 

 and then a rolling of the slice to one side, bottom up. 

 The pulverizing of the slice of soil is effected by bend- 

 ing the slice upon itself more or less abruptly and then 

 dropping it suddenly upon the ground, the intensity of 

 which effect is governed largely by the shape of the 

 moldboard. 



In general, there are two extreme types of moldboard 

 plow, namely, the breaker and stirring plow. Between 

 these extremes occur several intermediate forms to 

 meet all soil conditions. The average, or medium, of 

 these is the so-called general-purpose plow. 



The breaker (Fig. 2251) has a long low moldboard 

 with no abrupt curvature which turns the slice of tough 

 virgin sod gradually with minimum friction and effects 

 little or no pulverization. This type of plow has been 

 adopted for breaking tough prairie land owing to the 

 advantage as regards draft over the other types. In 

 some of the breaker plows the moldboard is replaced 

 by rods bent to the shape of the moldboard, thus 

 further reducing friction and consequently the draft. 



The stirring or stubble plow has a short, high, and 

 rather wide moldboard with an abrupt curvature, 

 which turns the furrow-slice of old soil over suddenly 

 and produces the maximum pulverization for a plow in 

 that particular soil. 



456 

 2251. Types of moldboard plows adapted to different kinds of 

 plowing: 1, prairie breaker bottom; 2, rod breaker bottom; 3, 

 stubble bottom; 4, general- purpose bottom; 5, black land bottom; 

 9, tame sod breaker bottom. 



