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Finding a reliable small compression spring that fits your exact application can be a frustrating experience — too stiff, too soft, or simply the wrong diameter. Whether you are a hobbyist repairing a pen mechanism, an engineer prototyping a sensor assembly, or a maker building a custom fixture, these small compression springs give you the dimensional precision you need without ordering in bulk.
Each pack contains 10 pieces of helical compression springs wound from carbon steel wire. Wire diameter ranges from 0.7 mm to 0.9 mm (0.028"–0.035"), outer diameter from 4 mm to 14 mm (0.16"–0.55"), and free length from 5 mm to 50 mm (0.20"–1.97"). The springs feature a closed and ground end style typical of this size class, providing stable seating on flat surfaces.
Typical use cases include small compression springs for electronics enclosures, pen and stylus mechanisms, miniature valve assemblies, toy and model components, and light-load return springs in jigs and fixtures. Long-tail applications such as "small steel coil spring OD 5mm" and "compression spring wire 0.8mm replacement" are well served by the wide variant matrix available.
Wire diameters 0.7, 0.8, and 0.9 mm combined with outer diameters from 4 mm to 14 mm and lengths from 5 mm to 50 mm — select the exact combination for your application.
Wound from carbon steel wire for consistent spring rate and reliable elastic return across repeated compression cycles in light-duty applications.
Each order ships as a pack of 10 identical springs, giving you spares for prototyping, testing, or replacement without over-ordering.
Closed end coils provide a flat bearing surface, reducing lateral movement and ensuring the spring seats squarely in bores or on flat platforms.
Uniform wire diameter and coil pitch across the production run deliver repeatable force characteristics, important for precision mechanisms and sensor assemblies.
Suitable for pen mechanisms, miniature valves, toy components, electronic enclosure latches, jig return springs, and other light-load compression applications.
| Spring Type | Helical Compression Spring |
|---|---|
| Material | Carbon Steel |
| Wire Diameter | 0.7 mm / 0.8 mm / 0.9 mm (0.028" / 0.031" / 0.035") |
| Outer Diameter (OD) | 4 mm – 14 mm (0.16" – 0.55") — See variant options |
| Free Length | 5 mm – 50 mm (0.20" – 1.97") — See variant options |
| End Style | Closed (typically closed and ground for this size class) |
| Coil Direction | Right-hand wound |
| Quantity per Pack | 10 pieces |
| Surface Finish | See variant options |
| Operating Temperature | Contact us to confirm for elevated-temperature use |
Wire diameter directly affects spring stiffness (spring rate). A thicker wire (0.9 mm) produces a stiffer spring for the same outer diameter and length, while a thinner wire (0.7 mm) gives a softer, more compliant spring. For light-touch mechanisms such as pen clips or sensor contacts, start with 0.7 mm. For slightly higher-load return springs or latches, 0.8–0.9 mm is more appropriate. If you are unsure, order a small quantity of each wire diameter and test in your assembly.
The outer diameter (OD) of the spring should be slightly smaller than the bore it sits in — typically 0.2–0.5 mm clearance is sufficient for free movement without excessive lateral play. For example, if your housing bore is 6 mm, select the 5 mm or 5.5 mm OD variant. If the spring sits over a pin, the inner diameter (ID ≈ OD minus 2× wire diameter) must be larger than the pin diameter.
Free length is the uncompressed length of the spring. You need a free length longer than your working travel plus the solid height (number of coils × wire diameter). As a conservative rule, select a free length at least 20–30% longer than your maximum compressed working length to avoid coil bind. The available lengths in this range are 5 mm to 50 mm — choose the variant that gives you adequate travel for your design.
These springs are made from carbon steel, which offers good mechanical properties but limited corrosion resistance in humid or wet environments without additional protection. For indoor, dry, or lightly humid applications they perform reliably. If your application involves moisture, chemicals, or outdoor exposure, consider applying a light coat of oil or contact us to confirm whether a coated or stainless steel variant is available for your size.
Carbon steel springs are generally suitable for temperatures up to approximately 120°C (248°F) before the spring rate begins to degrade. For applications above this threshold — such as near heat sources, engines, or industrial ovens — please contact us to confirm suitability or to discuss alternative materials.
To confirm compatibility, measure the bore or pin diameter your spring must fit around or inside, the available travel distance, and the approximate force required at working compression. Cross-reference these with the OD, free length, and wire diameter of the variant you are considering. If you need help calculating spring rate or load, feel free to contact us with your application details and we will assist you in selecting the correct variant.
A compression spring resists being compressed — it pushes back when you press the ends together. A tension (extension) spring resists being stretched — it pulls back when you pull the ends apart. These are compression springs, designed to be loaded axially in compression. They are not suitable for tension applications unless specifically engineered for dual use.
