What Are The Different Types Of Washers?

There are many different types of washers, some only applicable to specific situations, but all follow the same principle of holding the nut and bolts in place.

Common Washers

Flat Washers

Flat washers spread the force caused by tightening a nut across a wider surface area on the material being tightened. Looseness most often occurs when the screw bearing surface sinks under the surface pressure and can be negated by using a washer to resist this pressure. 

Flat Washers are used in domestic and industrial applications and can also be used to provide electrical insulation.

Commonly associated with: General manufacturing, maintenance, and repair.

Repair Washers 

Repair washers, although the name suggests otherwise, are not used to repair materials or fixings.  

They are, however, far superior for fixing to weak or damaged materials as their outside diameter is much greater than standard washers. Their increased surface area spreads the force from tightening the fixing over a much greater area, reducing the pressure in one single spot. 

They are available in metric and imperial sizes; imperial repair washers are thicker than metric repair washers and so better suited for heavy-duty applications.  

Spring Washers

Spring Washers, or Lock Washers, are designed to provide an axial load to fasteners to withstand vibration or thermal expansion or to limit movement.

Spring Washers are appropriate for applications that require a degree of flexibility and is why they are commonly used in the aerospace industry for actuators, including flight controls and landing gear.

Commonly associated with Automotive, aerospace, and domestic applications.

Serrated Shakeproof Washers

Serrated Shakeproof Washers, or Tab Washers, are ideal for harsh environments as they can withstand extreme heat conditions or heavy vibrations. Tab Washers are designed with single or multiple tabs and notches that form to shape around the fasteners, or it is designed to lie flush.

There are two types of shake-proof washers – internal and external.

Commonly associated with Aerospace and medical applications.

Branded Washers

Nord-lock Washers

Nord-lock Washers are innovative locking washers that use tension, rather than friction, to achieve the lock. They are typically sold in pairs.

They utilise a cam face on one side and radial teeth on the other side. Upon tightening, the radial teeth grip and lock the coupling surfaces producing a wedge effect preventing the fastener from rotating loose.

Commonly associated with Engineering, construction, manufacturing, and rail.

Schnorr Safety Washers

Schnorr Safety Washers are a variation of a spring safety washer that features a conical serrated disc and are used with environments that are prone to vibration.

The locking serrations can prevent friction whilst also safeguarding components from damage.

Commonly associated with Automotive, Machinery, Agricultural and constructive engineering, Textile Machines, and others with anti-vibration requirement, such as mowing machines.

Specialist Washers

Crinkle Washers

Crinkle Washers, also known as Wavy Washers or Wave Washers, are a variation of locking washer that can be used in replacement to other locking washers.

They are appropriate for applications that require light pressure to avoid damage to the surface that is being clamped.

They are designed for pre-loading and spacing to improve the number of contact points for added stability.

Commonly associated with Engineering, construction, and manufacturing.

Square Plate Washers

Square Plate Washers are typically used where a larger clamping surface is needed, and a normal round washer is inappropriate.

Commonly associated with Timber construction.

Red Fibre Washers

Red Fibre Washers are used to create an effective seal to prevent leaks.

Commonly associated with Plumbing and automotive.

Taper Washers

Taper Washers, or D Washers, are used under the head of bolts on the tapered faced of steel joists to provide a level seating.

They are also commonly used beneath nuts that have tapered flanges to ensure that the bolt sits squarely when tightened.

Commonly associated with Automotive, marine, medical, and more.

Starlock Washers

Star-lock Washers are a variation of push-on fasteners that feature teeth and are designed to grip on to round shafts.

Once they are secured onto the shaft, they immediately grip and are almost impossible to remove without damaging and likely destroying them.

Star-lock washers are available in a capped and uncapped variant.

Capped versions feature a push-on cap that hides the internal serrated section.

Commonly associated with Automotive, Electrical, Medical, Industrial, Manufacturing, Marine, and more.

Washer Finishes

Plain Finish/Self Colour

 These washers boast no additional coating, exposing their bare metal surface.

• Pros: Cost-effective. Typically used in applications where appearance and extra corrosion resistance are not critical.
• Cons: Prone to rust and corrosion.

Zinc-Plated

These washers are coated with a thin layer of zinc.

• Pros: Corrosion-resistant, economical.
• Cons: Limited lifespan in harsh environments.

Galvanised

These washers are coated with a layer of zinc to protect against corrosion.

• Pros: Excellent corrosion resistance.
• Cons: More expensive than zinc-plated.

Stainless Steel

Made from stainless steel, these washers are inherently resistant to rust and corrosion.

• Pros: High strength, excellent corrosion resistance.
• Cons: More expensive than other finishes.

Purpose and Applications

• Load Distribution - washers assist in spreading the load of a fastener over a wider area, preventing damage to the material. This is a particularly prevalent purpose in wood/metalworking and construction.
• Vibration Reduction - washers help in minimizing the loosening chances of a fastener connection due to vibrations. This is helpful in automotive and machinery-based industries where fast-paced movement and vibrations can occur.
• Sealing - washers can prevent leakages by creating a tighter seal in environments and applications such as plumbing, fluid systems and gas lines.
• Spacing - washers can help ensure the correct spacing between components in precision engineering and machinery assembly applications.
• Insulation - washers can electrically insulate fasteners from the material they are fastening.

Washer Sizes

Washer sizes are typically measured by their inner diameter (the hole size), outer diameter, and thickness. Accurate measurements ensure a proper fit for fasteners and applications. Standard sizes are available, but custom sizes can be manufactured to meet specific requirements. Always refer to size charts and specifications when selecting washers, like our metric flat washers dimension guide.

Washers may be small, but their importance in ensuring the integrity and functionality of assemblies cannot be overstated. Understanding the different types, finishes, and purposes of washers can help you choose the right one for your specific needs, ensuring the longevity and safety of your projects. Keep this guide handy for reference, and you'll always be prepared to make the best choice when it comes to washers.

Interested in more information about Washers?

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