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When a worn-out spring causes equipment downtime or a DIY project stalls because you can't find the right size, the frustration is real. Engineers, mechanics, and hands-on makers who need a reliable 400mm compression spring in a specific wire and outer diameter will find exactly what they need here — available in multiple wire-to-outer-diameter combinations and selectable quantities.
These compression springs are manufactured from spring steel (65Mn grade, typically used for high-elasticity applications), finished in black surface treatment for corrosion resistance. The fixed body length is 400mm (~15.75 in). Wire diameters range from 2.3mm to 4mm (~0.091–0.157 in), and outer diameters span 16mm to 38mm (~0.63–1.50 in), covering a wide range of bore and housing fits.
Typical use cases include: replacing return springs in industrial presses and stamping fixtures, restoring tension in custom jigs and clamping devices, and sourcing exact-spec springs for 400mm compression spring DIY automation builds, robotics frames, and mechanical linkage assemblies.
| Body Length | 400mm (~15.75 in) |
|---|---|
| Wire Diameter Range | 2.3mm – 4mm (0.091 – 0.157 in) |
| Outer Diameter Range | 16mm – 38mm (0.63 – 1.50 in) |
| Material | Spring Steel (65Mn) |
| Surface Finish | Black coating |
| Spring Type | Compression (return / push) |
| End Type | See variant options |
| Free Length | 400mm (nominal) |
| Load Capacity | See variant options |
| Spring Rate | See variant options |
| Quantity per Order | 1 / 2 / 3 / 4 / 5 pcs (selectable) |
Match the outer diameter to your spring housing bore (the spring OD should be slightly smaller than the bore ID). Then select the wire diameter based on the load you need — a thicker wire (e.g., 4mm) provides a stiffer spring with higher load capacity, while a thinner wire (e.g., 2.3mm) gives a softer, lighter-duty spring. If you have an existing spring to replace, measure its wire Ø and outer Ø directly.
Load capacity varies by wire diameter and outer diameter combination. Heavier wire gauges (3mm–4mm) and larger outer diameters support significantly higher loads. For precise spring rate and load data for your selected variant, please contact us to confirm — we can provide technical data sheets for specific size combinations.
The black surface coating provides a basic level of oxidation resistance suitable for indoor and semi-protected environments. For prolonged outdoor exposure or high-humidity applications, we recommend applying a light machine oil or grease to the spring surface. These springs are not rated for fully submerged or highly corrosive chemical environments.
Yes — as long as the outer diameter of the spring you select is slightly smaller than your housing bore ID, and the wire diameter matches your load requirements, these springs will seat correctly in standard cylindrical spring housings, guide rods, and bores. Always verify the OD and wire Ø against your housing dimensions before ordering.
Absolutely. The 400mm body length and wide range of wire-to-outer-diameter options make these springs well-suited for custom automation frames, robotic return mechanisms, clamping jigs, and linear actuator assemblies. Select the wire Ø × outer Ø combination that matches your stroke length and force requirements.
For single repairs or prototyping, ordering 1 or 2 springs is sufficient. For production fixtures, multi-spring assemblies, or projects requiring matched spring sets, ordering 3–5 ensures you have spares and consistent spring rates across all positions. Multi-packs are priced to offer better value per spring.
The 2.3mm wire diameter produces a lighter, more flexible spring with lower spring rate — ideal for light return mechanisms, panel latches, or low-load applications. The 4mm wire diameter produces a stiffer spring with a higher spring rate and load capacity, suited for heavier clamping, pressing, or industrial return applications. Choose based on the force your application requires.
