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When a spring fails mid-project, the whole assembly stops. Whether you're a maker rebuilding a mechanism, an engineer prototyping a device, or a technician replacing worn components, finding the exact wire diameter and outer diameter combination matters. These black compression springs are designed for builders who need reliable, consistent spring force across a wide range of sizes — without ordering custom parts.
Each spring is wound from spring steel wire with a black surface finish, available in wire diameters from 0.3mm to 1.5mm (approx. 0.012" to 0.059") and outer diameters from 3mm to 28mm (approx. 0.12" to 1.10"). All springs share a standard length of 305mm (approx. 12"). Select your quantity per order: 1, 3, 5, or 10 pieces.
Typical applications include compression spring replacement in mechanical assemblies, return-force mechanisms in DIY automation projects, tension balancing in jigs and fixtures, and prototype spring selection for engineers testing load requirements across multiple spring rates.
Wire diameters from 0.3mm to 1.5mm; outer diameters from 3mm to 28mm — covering a broad spectrum of mechanical spring needs in a single product listing.
All springs share a consistent 305mm (12") free length, making it straightforward to cut to length or use as-is in longer travel applications.
Wound from spring steel wire for reliable elastic return force and resistance to permanent deformation under repeated compression cycles.
The black coating provides a uniform appearance and a degree of surface protection, suitable for both functional and visible mechanical assemblies.
Order 1, 3, 5, or 10 pieces per variant — ideal for prototyping single units or stocking multiples for ongoing repair and assembly work.
Uniform pitch and closed ends ensure predictable load distribution and straightforward drop-in replacement in standard spring housings.
| Material | Spring Steel |
|---|---|
| Surface Finish | Black |
| Wire Diameter Range | 0.3mm – 1.5mm (0.012" – 0.059") |
| Outer Diameter Range | 3mm – 28mm (0.12" – 1.10") |
| Free Length | 305mm (approx. 12") |
| Spring Type | Compression |
| End Type | See variant options |
| Spring Rate | See variant options |
| Quantity per Order | 1 / 3 / 5 / 10 pieces (select above) |
| Wire Dia × OD Combination | See variant options |
Start with the outer diameter (OD) that fits your spring housing or bore, then select a wire diameter that gives you the spring rate (stiffness) you need. Thicker wire relative to OD produces a stiffer spring. If you're replacing an existing spring, measure the OD and wire diameter with calipers before ordering.
The free length is 305mm — the length of the spring when no load is applied. Spring steel can be cut with an angle grinder or rotary tool, though cut ends should be deburred. Cutting will alter the spring rate and number of active coils, so factor this into your design if precision is required.
These springs are made from spring steel with a black surface finish. The finish provides a degree of surface protection for dry indoor environments. For applications involving moisture, chemicals, or outdoor exposure, consider stainless steel springs or apply additional corrosion protection after installation.
Spring rate varies by wire diameter, outer diameter, and number of active coils. Because these springs are 305mm long with many active coils, they are generally suited for low-to-medium load applications. For precise spring rate values, contact us with your specific wire dia × OD combination and we can provide further guidance.
Yes — the outer diameter values listed (3mm to 28mm) correspond to standard metric spring sizes commonly used in mechanical assemblies, jigs, fixtures, and DIY projects. Verify the OD against your housing bore and the wire diameter against your guide rod clearance before ordering.
Yes. Compression springs work by resisting compression and returning to their free length when the load is released, making them suitable as return springs in mechanisms such as buttons, valves, latches, and actuators. Ensure the compressed length does not exceed the solid height of the spring to avoid permanent set.
Each variant is available in packs of 1, 3, 5, or 10 pieces. For larger quantities beyond what is listed, please contact us directly — we can discuss bulk pricing and availability for your specific size combination.
