Born on the Fourth of July

On July 4,1938, while families were viewing fireworks and celebrating the birth of the United States, Caterpillar quietly announced a secret that had been under development for some time. It was the “birth” of a completely new model of motor grader: The Cat® Diesel No.12.

The First Modern Motor Grader 

Recognized as one of Caterpillar's most significant motor grader designs of all time, the Diesel No.12 was originally called an Auto Patrol. And, while motor graders were initially designed for highway maintenance, the No.12 was also developed to do construction work. 

With its wide range of blade adjustments, and the combination of tandem drive and low-pressure tires, the No.12 had both the traction and the speed necessary for construction and highway maintenance work. 

A Leader in Yellow Iron

Caterpillar was, and remains today, the leader in development of what we call “yellow iron.” In fact, you can see the DNA of the Diesel No.12 in the Cat 12M series. It is the longest-running production model in the grader product line.

The No. 12 is an example of Caterpillar using cutting edge technology to provide our customers with the solutions they need. Today, we continue to focus on the changing needs of our customers by expanding our product and service offerings. 

To learn more about Caterpillar’s long history of innovation, go to


Diesel No.12 Auto Patrol