John Lane Sr., not John Deere, invented the self-scouring plow

(Update: a more extensive history,  an expanded history)

John Lane arrived in the Joliet area from New England in 1833.

Like other early settlers in the region, Lane experienced great difficulty plowing the thick prairie land with an eastern-style plow. Not only was the matted prairie grass hard to turn, but the soil kept sticking to the surface of the cast iron plow. Frequent stops were necessary to scrape the moldboard with a sturdy stick or wooden paddle. 

John Lane began experimenting in his blacksmith shop and soon developed a plow with steel surfaces that would "scour" or clear itself of prairie soil. Since plate steel was not yet available, Lane had to improvise. He obtained a worn-out saw blade from a nearby mill and welded strips of the steel blade to an iron plow. Lane hammered and fashioned the plow into the desired shape, ground and polished the steel surface, attached a wooden handle and beam, and gradually created a plow that worked well in prairie soil.

Although Lane did not patent his invention, he did supply local farmers who came and asked for one. "By 1850, Lane's operation included three employees who annually produced some fifty plows with total sales of $600. Other blacksmiths, including John Deere, borrowed the idea. John Deere manufactured and sold so many steel plows that it is mistakenly believed that he was the plow's originator."

[JOLIET Transportation & Industry A PICTORIAL HISTORY by Robert E. Sterling, pp116,117]

KBC Tools & Machinery posted

The stories I have read about John Deere also mention that he used an old saw blade for his source of steel for his first plow. This raises the question of how was the steel made to make the blades? Was it a blade for a band saw or a circular saw? I wonder where John Deere got steel to support his increased production. Bessemer (economic) steel was not made in America until 1864.

60" Blade

Sloan Implement Co posted
The 9620 RX with a 2720 Ripper handling the mud great!
[The idea of replacing wheels to rubber tracks to improve traction and decrease compaction while still being able to travel at high speeds down paved roads was "borrowed" from CaseIH.]

Sloan Implement Co posted
New John Deere X9 class 10 combine
Chris Lynne New Holland with Twin Rotors that started before 1978. Now John Deere paint cool.
[I saw a diagram of the interior that showed the twin rotors, but I forgot to save it.]