How to Choose the Right Compression Spring – An Engineer's Guide
Share
Compression springs are the most common spring type in industrial use - but choosing the right one from thousands of variants can be a challenge. This guide walks through the key parameters step by step, so you can quickly find the right spring for your application.
Start with the application
Before looking at dimensions, ask yourself: what does the spring need to do? Compression springs resist compressive force and return to their original length when the load is removed. Common applications include valves and pressure regulators, tooling and fixtures, vehicles and machinery, and electronics and consumer products.
If your application requires pulling force, choose an extension spring instead. Rotational movement? A torsion spring is the right choice.
The key dimensions
A compression spring is defined by three main dimensions:
Outer diameter (D) - the spring's outer diameter. Make sure it fits its housing with some clearance - typically 0.5–1 mm on each side.
Wire diameter (d) - the thickness of the wire. Thicker wire gives a higher spring rate and load capacity.
Free length (L0) - the spring's length in the unloaded state. Note that the spring will be compressed in your application - free length is always longer than the installed length.
Spring rate - R (N/mm)
Spring rate tells you how much force is needed to compress the spring by one millimetre. A spring with R = 10 N/mm requires 100 N to compress it 10 mm.
Calculate the force you need at your target compression and choose a spring whose rate matches. As a rule of thumb, avoid loading a spring beyond 80% of its maximum compression in normal operation - this preserves fatigue life.
Material
AxiSpring compression springs are available in two main materials:
Carbon steel (1.1200/1.0500) - the standard choice for most industrial applications. High strength and long service life in normal environments. Lower cost.
Stainless steel (1.4310) - choose this where corrosion resistance is required, for example in humid environments, the food industry, or outdoors. Slightly lower spring rate for the same dimensions compared to carbon steel.
End type
Compression springs are available with different end types that affect how the spring seats against its contact surface:
Closed and ground - flat seating surface, best stability and precision. Most common in demanding applications.
Closed, not ground - suitable for lighter applications with lower precision requirements.
Open ends - simpler design, rarely used in precision-critical applications.
For most industrial applications, closed and ground ends are recommended.
Find the right spring
AxiSpring stocks over 8,000 compression springs for immediate delivery. Use the filter table in our collection to search by outer diameter, wire diameter, free length and spring rate - and find the exact spring in seconds.
Need something outside the standard range? Contact us for a custom spring quote.