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What Is Crush Washer? The Different Types Of Washers


What Is Crush Washer

We use various machines, objects, and instruments to accomplish several tasks now and then . All of these instruments comprise several interconnected components.

Fasteners, such as screws, nuts, and bolts, hold these pieces together. But these fasteners can sometimes put too much pressure on the object they are fastening.

Solving the problem requires the work of another type of fastener called washers. Washers relieve this pressure by dispersing the fasteners’ load on the object. And there are different types of washers.

 In this article, we’ll look at a type of washers called crush washers.

What Is Crush Washer?

Crush washers are soft metal fasteners composed of aluminum or copper. They seal fluid or gas connections in internal combustion engines and hydraulic systems.

Crush washers deform when installed. When a bolt tightens against it, the washer fills in the shape around the bolt, providing a liquid-tight barrier that prevents leakage. The crush washer beneath the oil drain plug on most cars is typical.

To appreciate what crush washers are, we’ll need to understand the concept of washers in general. So, what are washers?

What Are Washers?

A washer is a component that works with a fastener, such as a bolt, screws, or nuts, to prevent it from loosening. It also spreads the load from the fastener head over an expanded area. Washers can be plastic or metal. 

If the joint’s surface isn’t smooth, the screw is more likely to compress higher places over time and become loose.

Rubber or fiber gaskets are washers used to prevent water leaks in taps. They’re not the traditional machine fasteners, and while they may look similar, washers and gaskets have different designs and functions.

Bolted joints need tough steel washers to avoid pre-load loss after torque application. Washers also protect steel screws from galvanic corrosion by isolating them from aluminum surfaces. In rotational applications, they are also useful as bearings.

Functions Of Washers

We’ve highlighted some functions of washers, but we’ll now discuss them in full detail.

Washers distribute load:

Most washers equally disperse the load of the threaded fastener on their subject material. However, threaded fasteners put a lot of strain on their subject material. For example, driving a screw into the wood may cause the wood to crack around the surface.

Washers lessen the danger of such damage by uniformly dispersing the load of the fastener across the material’s surface. On the other hand, washers protect the wood and other relatively soft materials from damage when the threaded fastener drives into the material.

Washers function as spacers:

Washers function as spacers as well. So what does a spacer do? You won’t be able to drive the threaded fastener into the object if it’s longer than the object’s depth. In cases like this, the fastener will protrude out of the back. Washers solve this problem. 

Threading washers create padding through the fastener before it drives into the object. This technique prevents the fastener from going too deep.

Washers absorb vibrations:

Some washers are specifically designed to absorb vibrations. These washers are usually not made of metal. Instead, they are a softer fastener made from plastic, rubber, or urethane. 

Softer materials absorb vibrations better than hard metallic materials. For example, if a threaded fastener connects two objects and one of them vibrates profusely, vibration-damping washers can protect the other object from being damaged.

Washers offer water and liquid protection:

Other types of washers keep liquids and water out. They’re commonly used to create a waterproof seal in water pipes and connections. Liquid-sealing washers are made of a soft substance that may press entirely against the object’s surface.

Washers come in different types. So let’s consider some of the most common ones.

Types Of Washers

There are different types of washers. Each type has a distinct shape, design, and function.

Flat Washers: Flat washers disperse the load of the fastener while reducing heat and friction during tightening. They can also function as spacers. Flat washers, also known as plain washers, can also provide electrical insulation.

Fender washers: Fender washers are flat with a small hole and a large outside diameter. This type of plain washer can distribute loads across a larger surface area than flat washers.

Fender washers are common in signboards, panels, drywall, cars, plumbing, sheet metal, and electrical applications. They’re usually a thin metal that derived its name from the widespread usage of offenders on automobiles.

Spring washers offer axial load to fasteners to reduce movement when there’s vibration or thermal expansion. Spring washers are made of metal.

They are preferred over similar, more expensive, heavier, and larger springs that take up more space. As a result, they’re ideal for applications requiring some level of adaptability. As a result, spring washers are common in actuators on airplanes, including flight controls and landing gear.

Lock washers: Lock washers prevent fasteners from rotating or losing friction from vibration or torque. There are numerous varieties, but they all work by securing the nut and bolt. Unfortunately, some use their ends to bite into the bolt and nut. 

Lock washers are popular in the automotive and aerospace industries, although useful in household appliances like washing machines.

Lock washers come in three types, split, internal tooth, and external tooth lock washers.

Split lock washers are rings with opposing angled ends. The rings are non-continuous, and each end of the dividing lock washers digs into the mating surfaces once they are secure. 

An internal lock washer has teeth which pierces the nut or bolt on the inside diameter. This washer prevents a fastener head from loosening using the teeth’ strut action. This washer can also absorb shocks and vibration. It’s used to secure shallow-headed fasteners.

An external lock washer has teeth outside that pierce a surface to maintain compression. This washer prevents a fastener head from loosening using the teeth’ strut action.

They operate well with screws that have a large head. The external tooth on a lock washer bears the most torsional resistance. It is also used to secure fasteners with deep heads

Tab washers: Tab washers have a single tab or several tabs and notches that contour to fit around bolts and nuts. Sometimes, they lie flat. Tab washers are perfect for difficult areas, as they can withstand high temperatures and vibrations.

Shoulder washers: Shoulder washers work in electrical equipment to insulate fasteners or shafts. As a result, non-conductive materials form the make-up of shoulder washers. As a tip, if you’re in a humid climate, don’t use it.

Countersunk washers: Countersunk washers make installing flat or oval head countersunk screws flush with the part surface. They’re commonly found in consumer products like cabinets and furniture.

We’ve said that washers work with fasteners to spread the load and prevent leakage. So let’s consider some of the types of fasteners that require the work of washers.

Types Of Fasteners That Use Washers

Fasteners include bolts, screws, and nuts. But they’re many others. Here, we discuss the different types of fasteners. 

Bolt: A bolt is a threaded fastener that always accompanies a nut. A bolt comprises a head, cylindrical body, and threads along its length. 

Bolts have an external male thread, and nuts have an internal male thread. Bolts generally have a flathead which means they lack a head grove. It generally has the design on its periphery to get driven by the wrench tool, and the same goes for the nut.

Screws: Screws are the fasteners that create their threads while fastening into the material. They normally have a head and a shank with helical threads. They come in a variety of head styles and recess or drive styles.

Nails: Nails are widely used in homes. It’s easy to distinguish between a screw and a nail because a nail doesn’t have threading. While a nail lacks the gripping power of a screw, it does have greater shear strength, making it a better choice in some circumstances.

Many different types of nails are named after the jobs they’re used for, making it simple to find the right one. In addition, they usually have characteristics specific to the materials or applications in question.

Rivets: Rivets are permanent fasteners having a head, shank, and tail. You can’t disassemble them without damaging the joints. Riveting is the process of applying force to two materials to join them together, manually or using a machine. 

Anchor fasteners: Anchor fasteners connect structural and non-structural elements to concrete or other materials in the building industry. These fasteners take a position by drilling a hole larger than the fastener diameter in the base material.

They then insert the anchor to a depth known as embedment depth. Mechanical anchor fasteners and chemical anchor fasteners are the two most common types.


Crush washers are aluminum or copper-based soft metal fasteners. They’re used in internal combustion engines and hydraulic systems to seal fluid or gas connections. Crush washers deform when installed as they fill in the shape around a tightening bolt to create a water-tight seal against leakage.

Fasteners such as screws and bolts hold components of instruments together. However, they can sometimes put too much pressure on the fastening object.

Solving the problem requires the work of another type of fastener called washers. Washers relieve this pressure by dispersing the fasteners’ load on the object.

Jacob Lindsey

Jacob is a home remodeling guru having worked over 15 years in construction in Reno, NV, mainly focused on home renovations. He likes taking ideas from his clients and making them a reality.

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