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When a loose mechanism, rattling assembly, or under-tensioned component is costing you time and reliability, the right compression spring makes all the difference. These stainless steel compression springs are designed for engineers, hobbyists, and DIY builders who need consistent, repeatable spring force in compact spaces — without sourcing custom parts or settling for imprecise substitutes.
Each pack contains 10 identical springs manufactured from stainless steel wire with a diameter of 0.3 mm, 0.4 mm, or 0.5 mm (select your variant). Outer diameters span 3 mm to 12 mm (approximately 0.12 in to 0.47 in), and free lengths range from 5 mm to 50 mm (approximately 0.20 in to 1.97 in). The tightly wound coil body delivers uniform compression along the full travel length.
Typical use cases include precision instrument assemblies requiring a 0.3×3×10 mm compression spring, electronics enclosure latches calling for a 0.5×6×20 mm small coil spring, and mechanical pen or valve mechanisms where a 0.4×5×30 mm stainless spring ensures smooth, repeatable actuation. The corrosion-resistant alloy also suits outdoor hardware, marine accessories, and humid-environment tooling.
| Material | Stainless Steel |
|---|---|
| Wire Diameter | 0.3 mm / 0.4 mm / 0.5 mm (see variant options) |
| Outer Diameter (OD) | 3 mm – 12 mm (see variant options) |
| Free Length | 5 mm – 50 mm (see variant options) |
| Spring Type | Compression (closed ends) |
| Coil Direction | Right-hand wound |
| Surface Finish | Natural stainless (no coating) |
| Quantity per Pack | 10 pieces |
| Spring Rate | See variant options |
| Max Load Capacity | See variant options |
Match the outer diameter (OD) to the bore or housing it sits in, leaving a small clearance (typically 0.1–0.3 mm). Select the free length based on the travel distance you need plus the compressed height. Choose a wire diameter that provides the spring rate (stiffness) your load requires — thicker wire produces a stiffer spring. Use the variant selector above to browse all available wire diameter × OD × free length combinations.
These are small-format compression springs intended for light-to-medium duty applications such as pen mechanisms, valve returns, electronic latches, and instrument assemblies. They are not rated for heavy structural or high-cycle industrial loads. For load-critical applications, please contact us to confirm the spring rate and maximum load for your chosen variant before ordering.
Stainless steel offers good resistance to oxidation, moisture, and mild chemical exposure, making these springs suitable for humid environments, outdoor hardware, and marine accessories. For highly aggressive chemical environments (strong acids, chlorides at elevated temperatures), additional material verification is recommended.
The three numbers represent: Wire Diameter × Outer Diameter × Free Length, all in millimetres. For example, 0.4×5×20mm means a wire diameter of 0.4 mm, an outer diameter of 5 mm, and a free (uncompressed) length of 20 mm. Select the combination that matches your application from the variant dropdown above.
Yes, provided the wire diameter, outer diameter, and free length match your original spring's specifications. Measure your existing spring carefully before selecting a variant. If you are unsure which size to order, contact us with your measurements and we can help identify the closest match.
Each order includes 10 pieces of the selected size. All 10 springs in a pack are identical in wire diameter, outer diameter, and free length, making them ideal for multi-unit repairs, prototyping batches, or keeping spares on hand.
The inner diameter equals the outer diameter minus twice the wire diameter. For example, a 0.4×5×20mm spring has an inner diameter of approximately 5 − (2 × 0.4) = 4.2 mm. Use this to verify the spring will clear any central guide rod in your assembly.
