People + Process = Precision

Precision Gearing from Skilled Craftsmen

Overton Chicago Gear is a full-service manufacturer of open gearing and gearboxes. For more than 130 years we have delivered high performance, mission critical gearing and gearboxes.

We design and build custom gearboxes to meet each customer’s specific application and requirements. We build to print, reverse engineer a single gear or deliver a complete gearbox. We rebuild and upgrade gearboxes from any manufacturer, and create upgraded designs that drop into existing spaces. When you choose Overton Chicago Gear, you get a reliable supplier that delivers quality product, on-time and at a competitive price.


Long-Term Manufacturer and Standards Advocate

Founded in 1888, Overton Chicago Gear combines rich history and specializations from Overton Gear, Chicago Gear, D.O. James, Illinois Gear, Balfre Gear, Franke Gear, and Ignition Engineering. These well-known brands help make OCG a premier, diversified gearing supplier.

Overton Chicago Gear is a founding and active member of the American Gear Manufacturers Association (AGMA). The association defines standards for design, manufacture, acceptance criteria and usage of gearing—many now adopted by ISO and used by their member companies. AGMA represents member gear companies worldwide, facilitating technology transfers, offering education, and lobbying governments. Our employees continue to drive gearing forward by participating on committees with AGMA. OCG was admitted to the AGMA Hall of Fame in 2016.


Custom Gearing Backed by Personal Service

Long-term manufacturing success depends on both products and people. Overton Chicago Gear continues to lead in quality, innovation and service with a focus on attention to detail. We keep pace with the latest technology advances and strive for perfection in production scheduling to expedite your orders. We believe in personal service and we are committed to resolving any issue quickly and completely.


Dedicated Team of Gearing Experts

At OCG, cutting edge machinery, leading edge technologies and knowledgeable professionals work together like the precision gearing we manufacture. Our integrated team of engineers, metallurgists, technicians, and support staff are focused on delivering the high performance gearing products when you need them.

Leadership Team

Manufacturing and Quality Processes

ISO9001 Registered, Computer Controlled Manufacturing
Overton Chicago Gear uses leading-edge computer-controlled equipment and tight process control to design and manufacture gearing and gearboxes. Large or small gearing, we turn, mill, drill, broach, hob, shape, grind, finish and inspect with great efficiency. We have longstanding exclusive partnerships with offshore manufacturers. This gives our customers greater flexibility on delivery and price, along with our full range of engineering, quality and after-sale support.

Our facilities have been ISO 9001 registered since 1996.


Our quality policy

Overton/Chicago Gear is committed to process driven, world class manufacturing and continually improved quality systems that deliver reliable solutions at the best possible value to all stakeholders.


Gear Geometry Verification and Inspection

Our dedicated gear geometry inspection machines ensure that our customers receive the geometry they expect each and every time. This verification step is independent of the manufacturing equipment, eliminating problems associated with improper machine setup that can result in gears that pass inspection but perform poorly in service.

Our inspection equipment verifies spurs, helicals, double helicals and bevel gears, plus checks double helical timing to ensure proper installed-tooth alignment. OCG also uses coordinate measuring machines (CMM) to verify otherwise difficult to check attributes. Our largest CMM checks a one meter cube. Larger gears are checked by inspecting them one portion at a time. Measuring instruments are regularly checked against calibrated and certified masters to maintain accuracy and reliability.


Nondestructive Testing and Metrology

Our modern, state-of-the-art, climate-controlled gear metrology laboratory is capable of measuring to AGMA 2000, AGMA 2015, ISO 1328, and DIN 3960 gear accuracy tolerances.

We have Level 2 magnetic particle inspectors (MPI) to prevent gearing with surface discontinuities from leaving our shop. Non-destructive testing includes magnaflux & nital etch capability. Other Nondestructive testing is outsourced to qualified firms when needed.


Surface Temper Etch

We surface temper etch every carburized gear setup in tooth grinding. Surface temper etch testing is important enough to performance and reliability that it has its own AGMA standard, yet most shops performing tooth grinding cannot perform this test, which can lead to premature failure of the end product. Our surface temper etch tanks fully accept 60-inch diameter gears, making them some of the largest tanks in North America.

Manufacturing and Testing Facilities

Overton Chicago Gear manufacturing facilities are located in the Chicagoland area. Our main headquarters in Addison is about 20 minutes southwest of O’Hare International Airport.

(105,615 sq. ft.)

530 Westgate Drive
Addison, IL 60101

Phone: (630) 543-9570

(48,000 sq. ft.)

50 W. North Avenue
Lombard, IL 60148

Phone: (630) 543-9570

(55,850 sq. ft.)

2823 W. Fulton Street
Chicago, IL 60612

Phone: (773) 638-0508