In The Clutch - How It's Made

Power Transfer Mastered by Quarter Master®


The history of racing and the development of innovative products is the story of ingenious design and technology breakthroughs. Within the pages of this chronicle are countless product improvements to meet the ever increasing demands of higher horsepower and much more aggressive racing conditions. From chassis to driveline and everything in between the landscape of race product development is clear evidence of the outstanding ingenuity of aftermarket companies.

Some innovations have been more critical than others in meeting the challenges of racing’s hostile environment. But when it comes to power transfer, there are few as important as the racing clutch. Without the high performance race clutch that successfully transfers power to the ground, all of the horsepower in the world would be useless.

There are many clutch brands in the marketplace but most informed racers acknowledge Quarter Master® as the category leader. Quarter Master® has a solid range of technologically advanced clutches and it is no accident.

Quarter Master® has mastered the process of clutch design and manufacturing through their sophisticated and highly scientific process. It is a process that involves several steps ending with the manufacture of high-tech, high-quality clutch units.

As the saying goes, "A chain is only as strong as its weakest link." But in the case of creating a clutch the saying is changed to; "There can be no weak link in the chain." That’s because every step in the process must be flawless and requires the absolute best possible engineering, computerization, and manufacturing procedures possible. That’s how Quarter Master® approaches its design philosophy. And regardless of the application, the process must follow the same procedure for every design.

To understand more about how a clutch is made, Quarter Master® engineers shared the “non-proprietary” basics of what it takes to bring a clutch out of the ground. This overview is taken from the concept stage all the way through completion providing highlights of each step.

The process of clutch design and manufacture is fundamentally comprised of six steps; 3D concept, Finite Element Analysis (FEA), Computer-Aided Manufacture (CAM), Computer Numeric Controlled (CNC) machining, inspection and testing.


Model of Perfection

Making a clutch begins with a concept, a concept that meets the objective of solving a power transfer for a specific application. The concept phase is where the best design engineering minds combined with the most sophisticated computerization come together to get the process moving.

Moving a concept forward requires a lot of things, but most importantly, it requires the creation of a model for every component in a clutch system. Not only is a model required, but it must be 3D so engineers can begin the analysis of each component in a 360 degree view to assure design accuracy and integrity.

To create a 3D model, Quarter Master® design engineers use the most sophisticated software in the industry, a program called Solid Works 3D Modeling. This highly technical program, along with engineering expertise, makes possible the translation of a fundamental concept into a sophisticated 3D model.

Going from concept to a 3D model might sound simple, but it’s not. In fact, developing a 3D model is a highly intensive and time consuming engineering process that can take a year or longer to accomplish. But it is at this most critical stage that Quarter Master® invests everything it takes to get a solid concept created before it ever goes forward to the next step.

3D modeling facilitates a 360-degree scrutiny of every component and permits virtual component assembly.
This ability is irreplaceable in the design, development and manufacture of a clutch. It takes countless man
hours to proceed from concept to 3D modeling but it is the most sophisticated and exacting design process possible.

Handling Stress

When a concept has achieved 3D model status, engineers put the design through analysis that assures each component will perform up to its design criteria. To do that, each model is scrutinized through a process called Finite Element Analysis (FEA).

FEA reveals to engineers the strength and weakness of each component in a “virtual” sense before it is ever made. It also provides a method for engineers to efficiently make design improvements ensuring the performance of every component is maximized for strength, durability and mass.

To do an FEA, Quarter Master® uses the most advanced software available, called ANSYS FEA. This cutting-edge software enables engineers to actually see in graphic form how a design functions when the expected forces are applied.

FEA has two functions; first, it takes the 3D model and translates it into a structure of points called beams and nodes. Each point is assigned a value from which the program calculates deflection and stress concentrations throughout the part. The calculations range in the millions and it is from this data that the second function of FEA takes place, that of producing a graphic delineation of the forces.

From the millions of calculations, a wire-like mesh is produced that is the geometry of the beams and nodes. The mesh is applied to the design, which results in the creation of a color-coded virtual simulation rendering. It’s from this rendering that engineers validate designs and ensure every component will deliver the performance required. As each FEA is studied, a design may be revised to address any deficiencies detected to assure each component will perform to its required application.

This is an example of FEA analysis. Note the wire-like mesh that covers the entire part. Each line in the grid is
a beam and the point of intersection is a node. From this finite grid the computer calculates load on each beam
and stress of each node. From this, engineers observe the virtual result of stress and load on any component.

Do the Math

When the FEA is complete and engineers are satisfied that all design criteria has been achieved, the next step is to do the math. Doing the math is a simple way to say, a design must be translated into mathematic language that the Computer Numeric Controlled (CNC) production equipment will understand.

To do that requires the use of Computer-Aided Manufacture (CAM) programming. Quarter Master® uses a state-of-the-art program called Master-CAM which is the most sophisticated software available.

This is a highly technical and complex part of the progression that takes an enormous amount of detailed processing to generate machining instructions that insure each component is made to exact design specifications. The instructions produced are called G-Code, which is mathematic language that “talks” to CNC equipment telling it exactly how to cut each component from the raw material. The instructions carry commands on every detail of cutting and drilling, such as bit selection, dimensions, depth, cut path and many more intricate instructions.

Stated another way, the G-Code instructs CNC machines how to do every cut and drill operation for every component. It is an incredibly detailed and multifaceted process that is the essence of ending up with high-tech, high-quality components.

This is an example of Master-CAM. The rendering shows the spindle path the CNC machine will take to make the
component. Each component is planned in this virtual world before it’s manufactured. Some engineers call this
the “Da Vinci Affect,” because like a Da Vinci sculpture that is locked in marble waiting to be released, so too a
component is locked in the raw billet material awaiting to be revealed.

Cut to the Chase

When instructions for CNC processing have been completed, it’s time make a component that you can hold in your hand. This is where the enormous amount of instructions transforms raw material into finished products.

All of the finest designs in the world are useless if the final product is not manufactured to meticulous specifications and tolerances. And every great design is also useless if the material is inferior. Both the manufacturing method and the material used are infinitely critical to the success of clutch units, so it follows that each part of this equation has to be right.

For the manufacture phase, Quarter Master® uses Okuma CNC machining equipment, which is recognized as the most sophisticated of its type in the world. This equipment is known for its accuracy and precision, and what it can produce is second-to-none. With the use of this equipment, engineers know that every component will be crafted to exact specifications and tolerances to assure absolute accuracy and precision.

From a material perspective, clutch units from Quarter Master® are crafted from certified materials. Clutch covers are manufactured from 6061 billet T-6511 stress relieved aluminum and internal components are made from pre-hardened 4140 plate steel. Both have been proven to be the finest and most durable material available for the high impact demands of a clutch unit.

From a friction material perspective, clutch units from Quarter Master® are crafted from certified materials the composition of which is a closely guarded trade secret. However, rest assured that all materials used in production have been lab and field proven to be the finest and most durable available for the high impact demands of a clutch unit.

Passing the Test

When a design has been manufactured, it must then go through rigorous testing that is done in two phases. First is in-lab analysis, and second is field testing.

Lab analysis begins with the use of a Coordinate Measuring Machine (CMM). In this process, the machine uses a probe to measure points on each component. The points are then computer analyzed to verify the accuracy of design dimensions and tolerances.

Lab analysis also includes destructive scrutiny. Simply stated, a design is put through lab-controlled testing until it fails. This destructive testing provides engineers with the final proof that a design meets or exceeds the specifications for which it is designed and the application for which it is intended.

The second part of analysis is field testing. This is where the design is put in a car and the user is encouraged to wail on it. This step provides physical validation that the design will perform in the real world as it is intended.




















This two-pronged approach to testing provides absolute substantiation that each unit will deliver the requirements for performance, quality and safety for each application. In addition, it provides the final assurance that each design meets and exceeds the requirements for its application.

You Choose

It is clear that development of a top grade clutch unit is no accident. From beginning to end, the enormous amount of resources placed in each Quarter Master® design is evident. Each design has been engineered to meet the highest standards and perform with flawless reliability.

Quarter Master® has a wide range of clutch applications for road race, oval track (dirt & asphalt), time and tac, drifting, sport compact endurance racing and many others. And next year, Quarter Master® will debut their new and superior clutch units to the street performance market.

For complete details on the entire Quarter Master® line of products and services, Go to: www.quartermasterusa.com or call 1-847-540-8999

Quarter Master®
510 Telser Rd
Lake Zurich, IL 60047
Phone: 847-540-8999
Fax: 847-540-0526
Toll Free: 888-CLUTCH-1

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