In many drawings and parts lists, you will see a simple note such as “M10 bolt + spring washer + flat washer”. For a small component, the spring washer carries a lot of responsibility. It is expected to keep the joint tight, even when the assembly is exposed to vibration, movement, or temperature changes. But what does a spring washer really do, and when should you specify it?
For buyers and engineers working with machinery, vehicles, and construction fixings, understanding the basic role of spring washers helps you choose the right locking method. It also keeps expectations realistic: a spring washer is not magic, and it works best when combined with good joint design and proper preload.
This article gives a practical overview of spring washers, how they work in a bolted joint, common types, key standards, and what you should check when sourcing them for projects in Australia, New Zealand, the Pacific region and other markets.
What Is a Spring Washer?
A spring washer is a washer that provides elasticity in a bolted joint. Instead of being a flat ring like a plain washer, it has a shape that allows it to flex and exert a spring force when compressed. That spring force helps maintain tension in the bolt and resists loosening.
Common examples include:
- Helical split spring washer – A ring cut and twisted into a helical shape, often called a split lock washer.
- Wave washer – A thin washer with a wave-like profile around the circumference.
- Belleville (conical) washer – A cone-shaped washer that flattens under load and acts like a very stiff spring.
Technical guides for fasteners describe spring washers as locking washers that are used when there is a need to prevent a fastener from loosening due to vibration and to maintain tension in the joint.bolts.co.uk+1
How Spring Washers Work in a Joint
When you tighten a bolt, the main goal is to create preload – a clamping force that holds the joint members together. As long as the external forces and vibration are lower than that preload, the joint stays tight.
A spring washer contributes in two basic ways:
- Elastic energy storage
- The washer is compressed when the nut or bolt head is tightened.
- Its spring characteristics allow the joint to absorb small changes in thickness (for example, from thermal expansion, creep, or gasket relaxation) without losing all preload.
- Friction and “bite” (especially for split-lock types)
- The sharp edges of a split spring washer can dig slightly into the underside of the nut and the joint surface.
- This can increase friction and make it harder for the nut to rotate under vibration.bolts.co.uk+1
However, modern research also shows that traditional helical spring lock washers do not always prevent loosening in severe vibration conditions if the joint is poorly designed or the preload is too low.Bolt Science+1 That is why they are often used together with other measures such as correct tightening torque, thread-locking compounds, or special locking washers.
Common Types of Spring Washers and Their Roles
Helical Split Spring Washers
This is the most familiar spring washer: a ring with a single cut, twisted into a slight helix. When you tighten the bolt, the ends of the washer close, and its edges bite into the contact surfaces.
Role and features:
- Provides moderate spring action and additional friction
- Widely used in general machinery and equipment
- Typically manufactured to standards such as DIN 7980 for square-section metric spring washersWASCA+1
- Often combined with flat washers to protect soft surfaces
Helical spring washers are popular because they are cheap and easy to install. But they should not be seen as a replacement for correct bolt size and torque.
Belleville (Conical) Washers
Belleville washers are cone-shaped discs that flatten under load. Because of their geometry, they can generate high spring forces in a compact space.
Their basic role:
- Maintain high preload in joints that experience relaxation or thermal expansion
- Offer adjustable spring characteristics by stacking multiple washers in series or parallel
- Often used in flange joints, electrical connections, and heavy machinery
Compared with split washers, Belleville washers can provide more predictable spring characteristics, especially when designed according to relevant standards and calculation methods.globalfastener.com+1
Wave Washers
Wave washers have one or more waves formed around the circumference. They are usually thinner and softer than Belleville washers.
Typical use:
- Provide light-to-moderate preload
- Take up play in bearings, electric motors, and small assemblies
- Reduce noise and vibration in lightly loaded joints
Wave washers are not primarily locking devices; their main role is to maintain contact and remove rattle where space is limited.
Spring Washers vs Flat Washers and Other Locking Methods
It is helpful to compare the basic roles of different washer types:
- Flat washers
- Distribute load over a larger area
- Protect painted or soft surfaces
- Bridge oversized holes
- Provide almost no resistance to loosening by themselvesrb-hardware.com+1
- Spring washers
- Add elasticity to the joint
- Help maintain tension and absorb small movements
- Provide some locking effect, especially split types
- Special locking washers (e.g. toothed, wedge-lock)
- Designed specifically to resist rotation under vibration
- Often offer more reliable locking performance, but at higher cost
In many applications, a combination is used: for example, a flat washer to protect the surface, plus a spring washer or other locking device closer to the nut or bolt head.
Standards and Guidance for Spring Washers
Several standards and guides are relevant when you select or specify spring washers:
- DIN 7980 – Square section spring lock washers for metric bolts. Often used as a reference in catalogs for metric spring washers.WASCA+1
- ISO washer standards – ISO 7089, 7090, 7092, 7093, 7094 and others define dimensions for plain washers used together with spring and locking washers.国际标准化组织+1
- AS 1237 series – Australian standards for plain washers for metric bolts, screws and nuts, widely referenced by local suppliers and distributors.intertekinform.com+1
While these standards focus more on plain washers and dimensions, they are often used together with catalog specifications for spring washers, especially in the AU/NZ market.
When you issue a purchase order, it is helpful to refer to the relevant standard (for example “Spring washer DIN 7980, steel, plain” or “Spring lock washer for M12, hardness 35–45 HRC”) to avoid confusion.
Practical Selection Tips for Buyers and Engineers
When you choose spring washers for a project, consider the following factors:
- Joint function and load
- Is the main goal to prevent loosening under vibration, to compensate for relaxation, or both?
- For high-vibration joints (pumps, crushers, transport equipment), consider whether a spring washer alone is enough, or if you also need locking nuts, adhesive, or wedge-lock washers.
- Environment and corrosion
- Indoor dry areas may only need zinc-plated carbon steel.
- Outdoor or coastal locations often require hot-dip galvanized or stainless spring washers to match the corrosion class of the bolt.
- Material hardness and compatibility
- The washer should be harder than the clamped material, but not so hard that it damages the surface excessively.
- For structural steel joints, hardened washers compatible with the bolt property class are usually preferred.
- Space and assembly method
- Belleville washers and wave washers are useful where space is limited but a specific spring force is needed.
- Split spring washers are simple and fast to assemble, suitable for mass production where tightening torque is controlled.
- Standards and documentation
- Clearly state size, standard, material, coating, and hardness on your BOM and enquiry.
- Ask your supplier for technical data sheets if the joint is safety-critical.
Quality and Inspection Points
Even for small parts like spring washers, consistent quality makes a difference. Some simple checks include:
- Dimensions – Outer diameter, inner diameter, and thickness should follow the specified standard or drawing.
- Surface finish – Coating should be even and free from heavy burrs or sharp edges that may damage the mating surface.
- Hardness – For structural applications, hardness should fall within the specified range to avoid permanent flattening or brittle fracture.
- Elastic behaviour – A basic functional check is to assemble the washer in a test joint, tighten to the planned torque, and confirm that it still provides spring force and remains intact.
For larger orders, buyers often request batch traceability and test reports from the supplier, especially when spring washers are used together with high-strength structural bolts.
How Linkworld Can Support Your Spring Washer Requirements
At Linkworld, we supply a wide range of bolts, nuts and washers for general engineering and construction, including different types of spring washers and matching flat washers. You can see an overview of our fastener lines here:
https://linkworldfast.com/
For more details on bolts, nuts and washers that work together with spring washers in your assemblies, you are welcome to browse our products page and washer-related categories:
https://linkworldfast.com/products/
https://linkworldfast.com/product-category/bolts-nuts-washers/
If your project also needs matching screws, concrete anchors or rigging hardware, you can combine multiple items in one enquiry:
https://linkworldfast.com/product-category/screws/
https://linkworldfast.com/product-category/concrete-fasteners/
We work with our own cold-forming production and selected partner factories to support different materials, coatings and packing options. Our team is happy to review your drawings, packing list and project conditions so we can suggest suitable combinations of bolts, spring washers and flat washers for your market. You can learn more about our background here:
https://linkworldfast.com/about-us/
Summary: A Small Part with an Important Job
Spring washers are small components, but they play an important role in many bolted joints. Their basic function is to add elasticity, maintain tension and, in some designs, provide extra friction to resist loosening. By understanding the differences between split, wave and Belleville washers, and by choosing standards, materials and coatings carefully, you can improve the reliability of your assemblies without adding much cost.
When you prepare your next enquiry or project BOM, consider how each joint will be loaded and what level of locking performance you really need. If you would like to discuss options for spring washers, matching bolts, or small packing for your warehouse and distribution, you are welcome to contact us at info@linkworldfast.com or through our contact page:
https://linkworldfast.com/contact/
We will work with you to select practical, project-ready fastener solutions for your target market.