A Complete Guide to Compression Springs

The purpose of this guide is to provide an overview of various key types of compression springs, and some of the more common roles they are used in.

We will cover several of the most popular styles and sizes available online in the UK, as well as where to buy compression springs for a range of everyday uses. We will also look more closely at how they work and explain how to properly measure them. The aim is to make it easier to choose the best coil springs for a specific job.

Compression springs work by resisting and pushing back against any downward or inward force that tries to squash and hold them in a compressed state. They push back against these forces, always seeking to return to their natural open or slightly extended state when not held under pressure.

Another effective way to answer the question ‘how do compression springs work?’ is to contrast them with different types of springs. Nearly all springs in widespread use are described and defined by the way they should be loaded.

Common examples of products that rely on different types of loads, torques and forces to coil springs include (ex)tension and (ex)torsion models.

• A tension spring is designed to create a pulling force. It is installed and held under tension while fully extended and will immediately try to return to a fully contracted state when released. In this sense, it effectively performs as the opposite of a coil spring
• A torsion spring is held in twisted rotation around its central axis, such that it wants to snap back when pressure is released (or applied, in the case of an extorsion spring). Clothes pegs, chair adjustment controls, workshop clamps, and many types of hinges are all everyday examples of a torsion/extorsion spring in action

The amount of force that a compression spring can resist - in other words, the overall strength, stiffness, or spring rate of a given product - depends on various metrics and specifications. These include its physical design, material strength, and manufacturing methods.

However, generally, the best way to manufacture a compression spring to be stronger or weaker is to adjust the ratio of wire diameter to overall spring diameter. Thicker wire or a narrower coil will make the spring rate higher, while thinner wire or a larger diameter coil will result in a weaker spring force.

There are many types, styles and sizes sold in the UK and elsewhere. Compression spring manufacturers provide high-quality products in a range of diameters, lengths, and materials, to suit every industry and application. The majority are made from open-coil steel wire (often stainless steel or high carbon steels), but aluminium compression springs are also widely available. However, stainless steel compression springs are the most popular.

Regardless of size and stiffness, the standard design will almost always be a helical wire coil. This can be compacted and held under varying amounts of pressure, but in its natural state, any true coil spring will immediately return to its fully extended form. Conical compression springs are also available but these are less widely used than the standard design.

Many products sold by spring manufacturers as coil springs will primarily be intended for use on cars. Their ability to effectively absorb impact or shock makes them an integral component in many vehicle suspension systems. However, this trait also makes compression springs of all sizes and stiffness an ideal component in many other settings.

Different types and formats include:

Small Compression Springs

Very small coil springs - often called micro springs - are commonly found in a diverse array of pocket-sized devices and tools. Wire diameters for everyday use at this scale typically start from as little as 0.25mm, with an overall outer diameter of a micro spring measuring somewhere in the region of 2-3mm. However, for more specialised uses and devices, small springs can be made considerably thinner even than this.

Large Compression Springs

Large compression springs tend to be designed with thicker diameters and higher spring rates. They are used widely across many different products, industries and applications. Some of the most common uses for these types of large coil springs include:

• Cars, trucks and other vehicles
• Suspension systems, pneumatic and hydraulic components
• Valves, engines and turbines
• Door hardware, gates and locking mechanisms
• Printing and stamping presses

Heavy-Duty Compression Springs

Heavy-duty versions are often branded as high load compression springs. These are much larger and thicker springs, capable of supporting and resisting significant pressure forces or storing large amounts of energy long-term. They are often found in applications as diverse as architecture (buildings and bridges), aerospace engineering, mining and drilling rigs, and industrial lifting platforms.