Washers

Washers are a thin, flat ring of material with a hole in the centre, designed to be used with a fastener such as a screw, nut, or bolt. They are an essential part of any secure fastening assembly, serving to distribute the load of the threaded fastener, prevent loosening due to vibration, and protect the surface of the material being joined. Washers are typically manufactured from durable materials like stainless steel, steel, brass, or nylon, with various finishes to suit different applications and environments. Using the correct metal washer can enhance the security, stability, and longevity of your fastening solution.

Types of Washer Fastener

Washers are categorised by their function, shape, and material. Choosing the right type of washer is crucial for the safety and longevity of your application. Here are some of the most common types available:

Plain Washers

Also known as flat washers, plain washers are the most common type. Their primary function is to distribute the load from a fastener over a larger surface area, minimising damage to the material being fastened. Their flat, thin shape also helps to reduce the risk of loosening when used with nuts and bolts.

Torque Washers

Torque washers are designed to produce a consistent and controlled torque output, which prevents over-tightening of bolts and screws, which can cause damage to the components or affect assembly integrity. They are often used in precision applications where torque accuracy is mandatory.

Flat Washers

A simple, flat, circular disc with a hole in the middle, this washer increases the bearing surface of a nut or bolt. This helps to distribute the pressure of the fastener over a wider area, preventing damage to the surface and providing a more secure hold.

Fender Washers

This type of washer has a much larger outside diameter compared to its inner hole. Fender washers are used to distribute the load over a large area, making them ideal for securing soft or thin materials like sheet metal.

Shoulder Washers

Featuring a cylindrical sleeve that extends from the centre, shoulder washers are designed to insulate screws, rivets, and other fastening components. They are often used in electrical applications to prevent metal-to-metal contact and short circuits.

C-Washers

Shaped like the letter 'C' with an open side, these washers are designed for quick and easy installation or removal in tight spaces. They can be inserted from the side of a shaft without needing to remove the fastener.

Spring Washers

Spring washers, also known as disc or wave washers, are versatile washer fasteners that act as springs to maintain tension under fastening components. This continuous force helps prevent loosening caused by vibration or thermal expansion/contraction, maintaining reliable fastener tightness.

Lock Washers

Lock washers, also known as anti-vibration washers, are designed to create a friction-based or form-fitting lock that prevents a fastener from loosening. They are commonly used in machinery and automotive applications where vibration is a concern. They come in various forms such as split (helical) washers, toothed washers, and wedge lock washers.

Washer Materials and Their Properties

Choosing the right washer material is essential for performance, compatibility with the application environment, and longevity. Some common materials used for washers include:

Stainless Steel: Stainless steel lock and flat washers offer excellent corrosion resistance, strength, and durability, suitable for harsh environments including marine and chemical exposure.
Brass: Offers good corrosion resistance and strong electrical conductivity. Brass construction lock washers are widely used in plumbing systems and electrical assemblies where both strength and conductivity are required.
Aluminium: Lightweight yet corrosion resistant, aluminium washers are not as strong as steel but are highly valued in aerospace, automotive, and similar applications where reducing weight without sacrificing durability is critical.
Copper: Exceptional thermal and electrical conductivity make copper metal washers suitable for heat exchangers, electrical connections, and specialised industrial uses.
Nylon and Plastic: Non-metallic washers that provide electrical insulation, corrosion resistance, vibration dampening, and chemical resistance. Ideal for electronics, plumbing, and applications requiring lightweight or non-conductive washers.
Rubber: Flexible and compressible, rubber washers excel at sealing. Commonly used in plumbing, hydraulics, and construction, they help prevent leaks while reducing vibration.

How to Choose a Washer

Selecting the right washer fastener ensures secure assembly, durability, and reliable performance. Whether you’re working with flat washers, locking washers, or other metal washers, consider the following factors before making your choice:

Size Compatibility: The washer's inner diameter should closely match the fastener size (e.g., M8). Outer diameter and thickness must suit the load distribution and space constraints.Properly sized construction washers help prevent loosening and damage to surfaces.
Material Properties: The washer material should be compatible with the environment (corrosion resistance, electrical insulation, chemical exposure) and the mechanical demands (strength, flexibility).
Shape and Function: Flat washers distribute load evenly across surfaces, while locking washers prevent loosening from vibration. Fender and shoulder washers are ideal when insulation or precise spacing is required.
Mechanical Load and Environment: Consider vibration levels, thermal expansion, mechanical stresses, moisture, or chemical exposure to determine washer selection.
Standards Compliance: Selecting washers that comply with ISO, DIN, ANSI, or other relevant standards ensures dimensional accuracy and reliable performance.

Applications of Locking Washer

Lock washers play a critical role in preventing fastener failure in applications where vibration and movement are common. Their unique design creates tension or a mechanical lock, ensuring a secure and reliable connection.

Construction: In construction, lock washers are used in structural steelwork, bridges, and other large-scale assemblies to maintain the integrity of joints despite heavy loads and vibrations from environmental factors like wind and traffic.
Automotive: Automotive engines and chassis are subject to constant vibration. Lock washers are used on critical components such as engine mounts, wheel assemblies, and suspension systems to prevent bolts from loosening over time, ensuring safety and performance.
Machinery and Manufacturing: Industrial machinery, from CNC machines to conveyor belts, operates with high-frequency vibrations. Lock washers are employed to secure machine parts, preventing operational downtime and potential safety hazards caused by loose fasteners.
Plumbing: Lock washers are used in plumbing installations to create tight seals and prevent leaks in pipes and fixtures. They help to maintain the integrity of connections under water pressure and temperature fluctuations.
Electrical: In electrical systems, lock washers are used to secure terminals and connections. They ensure a stable electrical contact by preventing connections from loosening due to vibration, which could lead to power loss or a short circuit.

Maintenance and Inspection of Washers

For critical applications, regular inspection and maintenance of washers and fasteners is recommended to:

Check for signs of wear, corrosion, or deformation in metal washers and construction washers.
Ensure washers maintain proper tension and position.
Replace any washers that show significant degradation to prevent assembly failure.

Applying the correct torque and selecting the right locking washers can extend maintenance intervals and improve overall fastening reliability.

By incorporating regular checks and replacing faulty components, you can maximise the service life of your fasteners and ensure that washers continue to perform as intended.

RS Singapore Is Your Trusted Partner for Construction Washers

As a leading supplier and distributor, RS Singapore is your trusted partner for a vast range of high-quality washers. We stock thousands of products from global brands like Heico, ABB, and our very own RS PRO, ensuring you find the right component for any job.

In addition to washers and fasteners, our user-friendly website makes it easy to search, compare, and order other essential products you need like wire ties, pvc insulated cables, and crimping tools. RS Singapore offers fast delivery of our full range of products. For more details on delivery services and fees, please refer to our Delivery page.