The Science of Friction Shims
The Science of Friction Shim Surface Locks: Achieving Maximum Sustainable Friction
Category: Engineering Authority | Friction Technology
In most areas of engineering, friction is the enemy.
Engineers spend countless hours reducing it with lubricants, precision bearings, polished surfaces, and advanced coatings. The goal is simple: minimize resistance and keep systems moving efficiently.
But when it comes to the joints that hold together aircraft, spacecraft, and other mission-critical structures, friction becomes something entirely different.
It becomes the last line of defense.
Every bolted joint, every structural connection, and every critical assembly relies on friction to prevent movement. If that friction is lost—even momentarily—the consequences can range from reduced performance to catastrophic failure.
To understand what separates an ordinary joint from an exceptionally secure one, you need to understand the most important number in mechanical locking:
The Friction Coefficient
The friction coefficient (represented by the Greek letter μ) measures how much grip exists between two surfaces.
In simple terms, it tells us how difficult it is for one surface to slide across another.
Mathematically:
μ = F / N
Where:
- F = Friction force (the force resisting motion)
- N = Normal force (the force pressing the surfaces together)
The higher the coefficient, the greater the resistance to movement.
A low coefficient—around 0.05—is comparable to walking on ice. There’s very little grip, and movement occurs easily.
A typical steel-on-steel connection achieves a friction coefficient of approximately 0.15. While adequate for many applications, that level of friction can be overcome when exposed to high-G forces, vibration, thermal cycling, or dynamic loading.
At that point, traditional surface contact reaches its limits.
Achieving a Maximum Sustainable Friction Coefficient requires a fundamentally different approach.
It requires transforming surface contact into surface interlock.
The Bite: How Surface Locks Work
Traditional bolted joints depend on friction generated by two surfaces being pressed together.
The challenge is that smooth surfaces can only generate so much resistance before microscopic movement begins.
Diamond Claw® technology changes the equation.
Instead of relying solely on surface-to-surface friction, Diamond Claw® friction shim surface locks create a true mechanical interlock.
Engineered with industrial diamond particles embedded in a precisely designed micro-texture, these surface locks physically bite into the mating materials. Rather than depending on the smoothness of the metal, they create thousands of microscopic locking points across the entire contact area.
The result is a connection that actively resists movement in every direction.
This isn’t simply friction.
It’s friction reinforced by mechanical engagement.
Why a Friction Coefficient of 1.0+ Matters
In high-performance applications, reliability is measured by what happens before failure becomes visible.
Most joint failures do not begin with dramatic movement.
They begin with micro-slippage.
These microscopic shifts are often invisible to the naked eye, yet they initiate the chain of events that can lead to preload loss, fastener loosening, wear, fatigue, and eventual structural failure.
Diamond Claw® friction shims are designed to stop that process before it starts.
By mechanically interlocking the mating surfaces, they prevent the initiation of micro-slip while maintaining the serviceability of a bolted joint. Unlike a welded connection, the assembly remains fully removable and maintainable.
The result is a joint that behaves as a unified structure while retaining the flexibility of mechanical fastening.
Predictability: When Failure Is Not an Option
In aerospace and other critical industries, uncertainty is the enemy.
Every unexpected variable introduces risk.
Diamond Claw® friction shims are engineered with a higher diamond density than many competing products. By increasing the number of engagement points, the load carried by each individual diamond is reduced.
This means the diamonds are better able to maintain their grip under extreme conditions without fracturing or disengaging.
The result is a more durable, more predictable locking interface designed to perform when systems are pushed beyond normal operating limits.
Because reliability isn’t measured when everything goes according to plan.
It’s measured when conditions become extreme and failure is not an option.
Diamond Claw® surface lock technology is engineered for those moments—helping ensure that when everything is on the line, your joint remains exactly where it belongs.