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When a project demands a compact, reliable compression spring that won't corrode or fatigue under repeated cycling, finding the right wire diameter and free length in one place is a real challenge. Whether you're a hobbyist repairing small mechanisms, a maker prototyping a device, or a technician sourcing replacement springs, these 304 stainless steel compression springs give you the exact geometry you need without over-engineering your build.
Each spring is formed from 0.4mm wire diameter 304 stainless steel, with outside diameters ranging from 3mm to 12mm (approximately 0.12–0.47 in) and free lengths from 5mm to 305mm (approximately 0.20–12.0 in). Packing options of 10 or 50 pieces per order let you stock up for production runs or grab a small quantity for a one-off repair.
Typical use cases include small electronics enclosures requiring spring-loaded contacts, pen and stylus mechanisms needing a consistent return force, miniature valve assemblies in fluid control systems, and DIY robotics or automation projects where a compact compression spring for precision mechanisms is essential.
| Material | 304 Stainless Steel |
|---|---|
| Wire Diameter | 0.4mm (0.016 in) |
| Outside Diameter Range | 3mm – 12mm (0.12 – 0.47 in) |
| Free Length Range | 5mm – 305mm (0.20 – 12.0 in) |
| End Type | Closed ends (typical for this wire gauge) |
| Spring Rate | See variant options |
| Load Capacity | See variant options |
| Surface Finish | Natural stainless (no coating) |
| Packing Quantity | 2 / 5 / 10 / 50 Pcs (see variant options) |
| Operating Temperature | Typically –20°C to +200°C (–4°F to +392°F) |
Measure the bore or housing your spring will sit in and select an outside diameter (OD) that fits with a small clearance — typically 0.5–1mm less than the bore ID. For free length, choose a spring that is longer than your required compressed length so it maintains positive force at full compression. Use the variant selector above to pick your OD and length combination.
Spring rate varies by outside diameter and free length. Shorter springs with smaller OD tend to have higher rates; longer springs with larger OD tend to be softer. Exact spring rate data is not listed per variant — if your application requires a specific rate, please contact us to confirm before ordering.
Yes. 304 stainless steel offers good resistance to atmospheric corrosion, moisture, and mild chemicals. It is suitable for most indoor and light outdoor applications. For highly corrosive environments (saltwater immersion, strong acids), consider 316 stainless steel instead.
These springs are widely used in pen and stylus mechanisms, spring-loaded electrical contacts, miniature valve assemblies, robotics and automation actuators, model engineering, 3D printer components, and general DIY mechanical projects. The 3–12mm OD range covers most compact mechanism needs.
If you are prototyping or need springs for a single repair, the 10-piece pack is ideal. For small production runs, recurring maintenance kits, or if you want spares on hand, the 50-piece pack offers a lower per-unit cost. For very long springs (60mm and above), smaller pack quantities (2 or 5 pcs) are also available.
Yes. Compression springs are designed to resist compressive loads and return to their free length when the load is removed, making them suitable as both compression elements and return/reset springs in mechanisms. Ensure the spring is not compressed beyond its solid height to avoid permanent set.
The 305mm free length variants are significantly longer and are suited for applications requiring extended travel or a long spring column, such as certain valve stems or custom fixtures. These longer variants are available in smaller pack quantities (2 or 5 pcs) due to their size. All other specifications (wire dia, OD, material) remain the same.
