Product

Secure Your Bolted Joints
with Confidence

Introducing Wedge Washer from Kee Safety – the innovative bolt locking system that physically locks your connections, preventing self-loosening due to vibration or dynamic loads. Unlike traditional methods, Wedge Washer maintains bolt tension for ultimate safety and reliability in critical applications. Trusted globally, our products are engineered for peace of mind, reducing maintenance costs and ensuring long-term performance.

How Wedge Washer Works

Wedge Washer consists of a pre-glued pair of washers that install like a single unit, easily replacing standard washers.

  • Serrated Outer Faces: Hardened edges bite into the bolt/nut and mating surface for a secure grip.

  • Inner Cam Design: Angled cams steeper than the pitch of the thread create a “wedge effect” – when loosening forces act, the cams lock together, maintaining clamp load.
  • No Re-Tightening Needed: Joints only undo with manual force, eliminating the need for constant checks.

Why Choose Wedge Washer Over Traditional Options?

Traditional methods are perceived to “lock” but in reality they can still come undone under dynamic and vibrations conditions and fail – here’s why Wedge Washer stands out:

  • Single “Lock” Washers: Rely on friction, which varies and can’t provide true locking. They lose a high percentage of clamp load under joint movement and dynamic load conditions.
  • Prevailing Torque Nuts: Grip threads but don’t stop loosening from dynamic loads – even 1/4 turn drops clamping force dramatically.
  • Wedge Washer Advantage: Proven to maintain over 80% clamp load after 2000 cycles in the rigorous Junker Test (DIN 25201), outperforming alternatives.

Proven Performance: Junker Test Certified to DIN 25201

The Junker Test is the industry standard for assessing fastener self-loosening. It simulates movement between a bolt, nut, and clamped joint under real-world dynamic loads, providing engineers with confidence that a product will maintain its clamp load over time.

Wedge Washers are tested to DIN 25201, a stringent standard that ensures joint integrity under repeated motion. During testing, clamp load is measured throughout 2,000 cycles — a pass requires maintaining 80% or more of the original clamping force.

Compared to traditional locking methods, Wedge Washers are the only product consistently to meet this benchmark, delivering proven, reliable locking performance for critical joints.

  • Key Result: Wedge Washer retains more than 80% of the bolts tension; markings stay aligned post-test.
  • Peace of Mind: Rigorous testing for function, materials, corrosion, and dimensions. Compliant with ISO standards and more.

Wedge Washer Versus Traditional Devices –
Post Junker Test

Wedge Washer
PASS

You can see from the image above that the markings made before the Junker testing to DIN 25201 are still aligned showing the joint has been locked in position. The yellow line on the Graph below shows that once material settlement has happened the Wedge Washer maintains the majority of the Clamp Load in the joint and passes DIN 25201 with more than 80% maintained.

Single “Lock” Washer
FAIL

A single washer with serrations, teeth or spring action can only reduce the effects of the nut or bolt loosening by increasing friction under the bolt or nut head but can not provide a physical locking element. This friction element will change dramatically across each bolted connection even on the same application and therefore does not provide peace of mind the joint is locked. You can see the yellow markings have separated and on the graph below the line named split lock washer shows how it losses the majority of the load and fails DIN 25201 like the others do also.

Prevailing Torque Nut
FAIL

A Pre-vailing Torque Nut uses Friction to grip onto the thread which prevents the nut from coming off the thread, but it does not stop it from loosening when subject to severe dynamic loading. It only takes a small amount as you can see from the yellow marks (around 1/4 of a turn) to lose a dramatic amount of clamp load and fail the requirement to DIN 25201.

Clamp Load during 2000 Cycles of the Junker Test to DIN 25201 – Comparisons