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Spring washers are rarely first on the design list. Most fastener designs start with the bolt, then the nut, then specify whatever washer stack fills the gap. But in any application where vibration, thermal cycling, or load fluctuation can loosen a fastener; the spring washer is often the one component determining whether that joint holds over years of service. The spring washer stores mechanical energy and pushes back against the joint, maintaining preload even as conditions change.
Size and scale vary far more than people expect. A spring washer for an M2 electronics fastener might be barely 2-3 mm across; while a Belleville washer for a structural flange bolt on heavy machinery can span several inches and carry tons of preload.
Quantity varies by assembly. A single bracket might use one spring washer on one bolt, while a gearbox or aircraft subassembly can involve thousands of fasteners, with spring washers specified wherever vibration resistance matters. The right question to ask is which joints in your design need that stored energy to keep working, and how can we achieve that goal?
Not all spring washers perform in the same way. The right choice depends on function, shape, and material. The wrong selection can mean premature loosening, fatigue failure, or wasted axial space. Here’s how to break it down.
Categorizing by Function
Spring washers generally serve one (or more) of these purposes:
- Preload maintenance: keeping constant pressure on a joint so it doesn’t loosen under vibration
- Load distribution: spreading force evenly across a soft or uneven surface
- Gap take-up: compensating for stack tolerances in an assembly
- Locking/anti-rotation: resisting fastener back-off through friction or mechanical bite
Categorizing by Shape
Belleville (disc spring) washers are cone-shaped discs that flatten as bolt tension compresses them. In doing so, they convert that small axial deflection into a reaction force pushing back against the joint, or a high force in a compact package. They’re a go-to in high-load, space-constrained joints, such as bolted flanges, valve assemblies, and heavy machinery.
Wave washers have a rippled, sinusoidal profile. They provide a lighter spring force that deflects under load to provide a compensating spring force and sustain a load or absorb shock. Wave washers are common in electric motors, bearing preload applications, and consumer electronics.
Curved washers use a single curve rather than multiple waves, which makes them well suited to designs where weight and space are at a premium. They exert relatively light thrust loads, absorb axial end play, and help reduce vibration, for a common choice as products get smaller and lighter without giving up joint stability. They’re typically stamped from finely tempered spring steel, with stainless steel options where corrosion resistance matters, in material thicknesses that can run from a few thousandths of an inch up to around 0.100″ or more depending on the application.
Split lock (helical spring) washers are the familiar split-ring washer, with the two ends offset to bite into both the fastener and the mating surface. A split lock washer resists loosening primarily through friction and edge engagement, making them a low-cost, general-purpose option for lighter vibration environments.
Categorizing by Material
Material choice affects spring rate, corrosion resistance, and operating temperature range:
- Carbon steel — economical, strong, common in general industrial use; usually needs a plating or coating for corrosion resistance
- Stainless steel (301, 302, 17-7PH) — corrosion resistance plus good spring properties; standard for food, medical, and outdoor equipment
- Phosphor bronze / beryllium copper — used where electrical conductivity matters, such as grounding washers
- High-temperature alloys (Inconel, Elgiloy) — for aerospace, exhaust systems, and other high-heat environments where standard steels would lose their spring temper
Application Examples
- Automotive: Belleville washers in clutch assemblies and suspension components; wave washers preloading wheel bearings
- Electronics: finger washers for grounding, wave washers taking up tolerance stacks in connector housings
- Aerospace: high-temp alloy Belleville washers in engine mounts and control linkages
- Industrial machinery: split lock washers on general fastener joints exposed to moderate vibration
Key Specs to Nail Down
Whichever type you land on, a supplier will need the same core dimensions to quote and manufacture it correctly:
- Inside & outside diameter — the most fundamental sizing dimensions
- Thickness or working height — either the raw material thickness, or the installed (working) height once compressed
- Rated or working load — the maximum or optimal load the washer is designed to carry in service
| Washer Type | Load Capacity |
Space Needed |
Deflection | Typical Use Case |
|---|---|---|---|---|
| Belleville | High | Very low(axial) | Low-moderate | Heavy bolted joints, valves, high-load stacks |
| Wave | Low-moderate | Low | Moderate | Bearing preload, motors, tolerance take-up |
| Curved | Low | Very Low | Low | Light cushioning, appliances |
| Split lock | Low-moderate | Low | Low | General-purpose anti-loosening |
| Finfer (grounding) | Low | Low | Low | Electrical bonding, grounding paths |
As a rule of thumb: reach for a Belleville washer when axial space is tight and load is high, a wave washer when you need smoother preload over a wider deflection range, and a split lock or finger washer when the job is mostly about resisting rotation or maintaining an electrical path rather than carrying significant load.
Sourcing the Right Washer
Getting the shape and material right on paper is only half the job. Consistency in forming, heat treatment, and flatness tolerance is what determines whether a spring washer performs the same way on unit one and unit ten thousand.
Elyria Spring & Stamping manufactures precision spring washers, including a strong lineup of curved and wave designs. The components are stamped from finely tempered spring steel and stainless steel, along with copper, brass, and high carbon steel for other stamped components.
Production runs on punch press, progressive die, and fourslide equipment up to 176 tons, supporting parts for consumer electronics, automotive electronics, computer hardware, communications equipment, fasteners, and automotive interior trim. With an in-house tool and die shop and value-added services like grinding, assembly, and vendor-managed inventory, Elyria Spring can take a washer from small quantities to high-volume production without changing suppliers along the way.