WHY A "STEEL" PLOW
In view of the facts and the probabilities based on them, how is the legend of the John Deere steel plow to be explained? There are several likely reasons. It is possible that the first plow, in 1837, was made from a broken steel mill saw. It is also possible that within a few years puddled iron came to be used for the moldboards because of the scarcity of suitable steel, either in the form of broken mill saws or as plates ordered from foundries in America (the high price of steel imported from England made this an impractical source). However, it seems more likely that it became known as a steel plow owing to the importance Deere attached to his plows having steel shares, as shown in his advertisement in 1843. A steel share, tougher than cast iron, would hold an edge much better than wrought iron, and John Muir's description of prairie plowing, quoted earlier, substantiates the importance of a tough, sharp share.
Deere's plows, probably distinctive by reason of their steel shares, may have been called "steel" plows, in the regions where they were used, to distinguish them from the standard wooden plows and from the newer cast-iron implements. The term "wooden plow" has a similar history. For well over 2000 years in Europe some plows have been made with iron shares and the rest of the structure wood. Plows in 18th-century America were made principally of wood with iron shares, colters, and clevises, and with strips of iron frequently covering the wooden moldboard. These implements were called, simply, plows of various regional types. Not until the development and spread of the factory-made plows with cast-iron moldboards, landsides, and standards did the term "wooden plow" come into use to differentiate all these plows from the newer ones. Subsequently writers have been led to assume that "wooden plow" meant a plow with no iron parts and consequently to make unwarranted statements about the primitiveness of the 18th-century implements.
A second reason for use of the term "steel plow" may have developed from the supposition that the moldboards of the first John Deere plows were made of diamond-shaped sections cut from old mill saws, which later writers seem to have assumed were made of steel. (It is probable that from the late 1850's on Deere plows had steel moldboards.) However, mill saws of the early 19th century were not necessarily made of steel, which was then relatively expensive. I have been told of an old mill saw made of wrought iron on which was welded a steel edge that carried the teeth.[21] Rees' Cyclopaedia[22] describes saws as being made of either wrought iron or steel, the latter being preferable. Therefore, it seems most likely that Deere's plows, from his first until the middle 1850's were made with highly polished wrought-iron moldboards and steel shares.