Are Lock Washers Single-use?

Whether a lock washer can be used in a single use depends on the type of lock washer, material, application and the situation after use, and needs to be decided on a case-by-case basis. Here are some details:
I. Disposable Lock Washers
1.Elastic Deformation Washers
Typical products: Spring gasket and elastic lock gasket.
How it works: Provides slack resistance through elastic deformation. After tightening, the gasket is compressed, producing elasticity.
Reasons for disposal:
Material Fatigue: After repeated assembly and disassembly of washing machines, the elasticity gradually decreases, resulting in a decrease in anti-loosening effectiveness. For example, after repeated use, Spring gaskets may become permanently deformed and lose their original elasticity.
Preload Loss: Flexibility of the elastic gasket depends on the initial preload. If the same preload cannot be restored after assembly and disassembly, the anti-loosening performance will be greatly reduced.
Usage: For low voltage piping, electrical equipment, etc., where anti-loosening requirements are not high, disposable use is generally recommended to ensure safety.
2.Mechanical Damage Washers
Typical product: inner and outer lock tooth washer. Principle: The tooth tips joins the nut surface and connecting components to form a mechanical grip.
Reasons for disposal:
Apical wear: During assembly and disassembly, the tip of the tooth may become dull or worn due to friction, resulting in a decrease in grip strength.
Meshing surface damage: After meshing, the tip of the tooth will leave indentations on the meshing surface. Repeated use can cause these indentations to expand, affecting anti-loosening properties.
Uses: If tooth tips or surfaces of the teeth, such as construction machinery and agricultural equipment, are not significantly damaged, they can be reused carefully in a slightly vibrating environment, but must be carefully inspected.
ii. Reusable Lock Washers
1. Mechanical Interlocking Washers
Typical products: Double-Stack Self-Locking Washers and Wedge-Shaped Self-Locking Washers (such as the NORD-LOCK series).
How it works: Loose resistance is achieved by mechanical structures,such as wedge-shaped bevels and serrated teeth, rather than elastic deformation.
Reusability reasons:
Elastic-free aging: Mechanical interlocking structure is not affected by material fatigue, and the original anti-loosening properties are maintained after assembly and disassembly. Wear-resistant design: For example, the serrations of NORD-LOCK washers are made of a high hardness material and are highly abrasive, allowing for repeated assembly and disassembly.
Application: Reuse is generally supported in high-reliability applications such as aerospace, wind turbine towers and rail transit, but the condition of gaskets and bolts needs to be checked regularly.
2. High-Performance Material Washers
Typical product: Lock gasket made of stainless steel or special alloy.
Principle: Adopt high strength corrosion resistant material to reduce deformation and wear during assembly and disassembly.
Reusability reasons:
Material Stability: Repeated assembly and disassembly of Stainless steel or alloy material to maintain their elasticity and mechanical properties.
Corrosion resistance: Corrosion resistant materials can prevent performance degradation caused by corrosion and prolong service life.
Uses: In corrosive environments such as marine engineering and chemical equipment, washing machines can be reused if there are no cracks or distortions.
III. Pre-Reuse Testing Criteria
Regardless of the washing machine, the following items must be subjected to rigorous safety and reliability checks before being reused:
Appearance Integrity: Check washing machine for cracks, deformation, tooth tip wear or plating peeling.
For example, check that the spring gasket incision is uniform and that the tooth tips of the inner and outer lock gaskets are intact.
Flexibility (if applicable)
Test the springback ability of the spring gasket to ensure it returns to its original shape.
METHODS: The thickness of gasket was measured by caliper and whether the compression the gasket was restored to its original value was observed.
Mechanical interlocking function (if applicable)
Verify that the serrations of the double-layered self-locking gasket are clear and the bevel of the wedge self-locking gasket is smooth.
Example: The upper and bottom half of a NORD-LOCK washer should be unbound.
Mating surface condition
Check nuts and joints for excessive indentations or damage.
Risk: Damage to mating surface may prevent the gasket from fastening and reduce cushioning.
IV. INTRODUCTION INTRODUCTION INTRODUCTION Industry Practice Recommendations
Key connections such as threaded connections for aerospace and nuclear power are recommended. Even if the washing machine appears to be in good condition, stick to the "safety first" principle. For non-critical joints, such as building supports and general machinery, gaskets and mating surfaces can be reused carefully if they are in good condition. However, the number of demolitions and disassembly and assembly times times should be recorded and replaced periodically.
Manufacturer's Guide: Please refer to the the gasket manufacturer's technical manual. Some products, such as NORD-LOCK, will be explicitly labeled "reusable" or "recommended for one-time use."