SKL Tooth Face Self-Locking Washers (French Lock Washers): Features, Standards and Industrial Applications

SKL Tooth Face Self-Locking Washers: French Standard Anti-Loosening Washers for Industrial Fastening Systems

In modern mechanical assemblies, maintaining secure bolted connections under vibration and dynamic loads is essential. SKL tooth face self-locking washers, also known as French lock washers or serrated conical washers, are designed to provide reliable anti-loosening and anti-slip performance in demanding industrial environments.

Manufactured to the French NFE-S standard and meeting DIN 6796 performance requirements, these washers are widely used in electrical equipment, elevators, rail transportation, and industrial machinery.

Due to their elastic structure and serrated locking surface, SKL self-locking washers significantly improve the stability and reliability of bolted connections.

What Are SKL Tooth Face Self-Locking Washers?

SKL tooth-face self-locking washers are disc-shaped, conical washers with serrated teeth on one side. The tooth structure creates friction between the washer and the mating surface, preventing bolts or nuts from loosening under vibration.

These washers are also commonly known as:

• French lock washers

• CS washers

• SK washers

• Serrated conical lock washers

• Tooth surface self-locking washers

Typical size specifications range from M3 to M20, making them suitable for a wide range of industrial fastening applications.

Standards and Design Characteristics

SKL self-locking washers are produced according to international engineering standards, including:

• NFE-S.L.M.Z French standard

• Performance characteristics similar to DIN 6796

• Industrial fastening specifications used in mechanical      assemblies

The design incorporates striped serrations or tooth patterns that increase friction and locking force when compressed.

Different product styles are available, including:

• M pattern

• S pattern

• L pattern

• I pattern

Each design provides specific locking characteristics depending on the fastening requirements.

Key Features of SKL Tooth Face Self-Locking Washers

Excellent Anti-Loosening Performance

The serrated tooth structure provides high friction against the mating surface, preventing bolts or nuts from loosening under vibration or dynamic loads.

Uniform Load Distribution

When compressed to the correct torque level, the washer distributes the clamping force evenly across the fastening surface, improving joint reliability.

Elastic Compensation for Material Settling

The conical structure provides an elastic rebound force, which compensates for material settling or surface deformation, minimizing pressure loss.

Enhanced Vibration Resistance

These washers absorb part of the dynamic load generated by vibration, helping maintain a consistent clamping force in mechanical assemblies.

Materials and Surface Treatments

SKL French lock washers are manufactured from high-quality materials to ensure durability and performance.

Common Materials

• 65Mn spring steel

• SK5 / SK7 high-carbon spring steel

• 304 stainless steel (A2)

• 316 stainless steel (A4)

Heat Treatment

All products undergo strict elastic hardening and hardness control to ensure optimal spring performance and durability.

Surface Treatment Options

Carbon steel washers may include:

• Black oxide treatment

• Zinc plating with dehydrogenation

• Zinc-magnesium coating

• Dacromet corrosion-resistant coating

Stainless steel washers typically undergo:

• Surface hardening

• Polishing treatment

• Surface color finishing when required

These treatments improve corrosion resistance, wear resistance, and mechanical performance.

Installation Guidelines for SKL Self-Locking Washers

Proper installation ensures optimal locking performance.

Correct Orientation

When installing the washer, the concave side of the conical washer should face the clamped components.

Compression Requirement

The washer should be compressed to the correct tightening level to achieve maximum elastic reaction force.

Compatibility with Fastener Grades

The washer thickness is designed to work effectively with Grade 8.8 bolts and similar fastener strength levels.

Use of Matching Conical Washers

In some assemblies, using a smooth conical washer together with the SKL serrated washer can further improve load distribution and locking performance.

Industrial Applications of SKL Tooth Face Self-Locking Washers

Due to their excellent anti-loosening capability, SKL washers are widely used in industries where vibration resistance is critical.

Electrical and Electronic Equipment

Used to secure components in electrical assemblies where stable fastening and vibration resistance are required.

Elevator and Lifting Systems

Applied in elevator equipment and lifting systems to ensure safe and stable mechanical connections.

Rail Transportation and Locomotive Manufacturing

Used in rail vehicles and locomotive assemblies where vibration loads are common.

Communication Equipment

Installed in communication infrastructure and equipment that require reliable fastening under long-term operation.

Medical Machinery

Used in medical equipment where reliable fastening and vibration control are essential for operational safety.

Advantages of SKL French Lock Washers in Industrial Fastening

Compared with conventional washers, SKL self-locking washers provide:

• stronger anti-loosening performance

• better vibration resistance

• improved clamping force stability

• longer service life of bolted joints

• enhanced reliability in mechanical systems

These advantages make them an ideal solution for high-vibration industrial environments.

Conclusion

SKL tooth-face self-locking washers are an advanced fastening solution designed to prevent bolt loosening and maintain a stable clamping force in mechanical assemblies.

With their serrated locking surface, elastic rebound force, and high-strength materials, these washers are widely used in electrical equipment, transportation systems, and industrial machinery.

Selecting the correct washer type, material, and installation method ensures optimal fastening performance and long-term reliability.

Contact Juxin Fasteners

If you are looking for high-quality self-locking washers, spring washers, or customized industrial fastener solutions, our engineering team is ready to support your project.

JUXIN FASTENERS – 23 Years of Industrial Fastener Manufacturing

Website
https://www.juxinfasteners.com

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