ITW Heartland Helps Celebrate the Contributions of a Gear Industry Icon

Spiroid gears: “A family of gears in which the tooth design is in an intermediate zone between bevel-, worm-, and face-gear design. The Spiroid design is patented by the Spiroid Division of Illinios Tool Works (ITW), Chicago, Illinios.” -Darle W. Dudley’s “Handbook of Practical Gear Design”

To those in search of a concise, technical definition of Spiroid gearing, the one above might suffice. However, to Rob and Heidi Leeson and their extended families, such definitions are inadequate. To them, Spiroid gearing is more than a unique and useful family of gears – it is the brain-child of Heidi’s bright, multifaceted father, Oliver Saari. On December 17th, 2010, Heidi and her family visited ITW Heartland to experience first-hand the decades-long product of her father’s labor and intelligence.


While visiting ITW Heartland, the Leeson and extended Saari clan were treated to a tour of the Spiroid facilities, a presentation on the history and application-related achievements of Spiroid gearing, and an introduction to many of the ITW employees currently charged with furthering Spiroid’s success. Also, in honor of Oliver’s contribution to ITW and the gear industry, family members were presented with a Spiroid gear and pinion replica, each engraved with Oliver’s name and a special inscription.

Oliver Saari was born in Helsinki, Finland on March 22, 1918. In 1927, his family emigrated to the United States where, over a period of 8 years, they moved from Brooklyn, New York, to Rochester, Minnesota, and finally to Minneapolis. Between graduating from high school in 1936 and entering ITW’s workforce in 1945, Oliver Saari served in the Civilian Conservation Corps (CCC), wrote and published several science fiction novels, learned tool and die making, studied mechanical engineering at the University of Minnesota, and served as a valued employee at both Honeywell and General Motors, where he developed a keen interest in gears.i

In 1945 Oliver joined ITW and by the early 1950’s, Oliver and ITW were well on their way to synergizing his interests in gears with ITW’s inventive culture, deep resources, and rich manufacturing history. In 1954-55, the Spiroid family of gears were born – and initial patents granted.

Today, Oliver’s Spiroid family of gears are engineered and manufactured within the Spiroid Division at ITW Heartland. Spiroid gears and right angle actuators can currently be found in applications around the world ranging from naval weapons handling systems to nuclear power plants to commercial jet wing flap actuators to missile guidance systems to medical devices to commercial and military Unmanned Ground Vehicles (UGV) and beyond. Furthermore, with the help of the ITW Technology Center, ITW’s proprietary Spiroid products have recently experienced yet another influx of innovation, patents, and IP that will continue to make these gears relevant and advantageous to engineers for years to come.

Although Oliver passed away in 2000, this gathering of his children, family and ITW employees makes clear that his presence is still very much alive. At the very least, it can be said that more than a few of his labors of love were united under a single roof this past December.


i Litvin, Faydor L., Development of Gear Technology and Theory of Gearing. (Chicago: University of Illinois at Chicago, 1997) 93.

About ITW Heartland
ITW Heartland is a certified leader in precision engineered machines, parts, gears, and electro-mechanical products. Located in Alexandria, Minnesota, ITW Heartland has four distinct divisions: Spiroid Gearing (design and manufacturing of custom right angle drives, gear boxes and loose gearing); Manufactured Products (low to mid quantity precision machining with a specific expertise in horizontal CNC technology); Strategic Assembly Solutions (complete machine design and assembly services); and ITW Gear Machines (designer and manufacturer of full line of high speed gear inspection and gear burnishing die equipment). As an Illinios Tool Works Company, ITW Heartland operates from a position of financial stability, engineering excellence, and refined manufacturing process.

For more information, visit