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When your project demands consistent return force without the risk of rust or fatigue failure, finding the right small compression spring can be frustrating. Undersized wire snaps under load; oversized coils won't fit the bore. These 304 stainless steel compression springs are engineered for makers, engineers, and DIY enthusiasts who need dimensionally accurate, corrosion-resistant springs that perform reliably across repeated cycles.
Each spring is wound from 304-grade stainless steel wire in diameters of 0.9 mm (~0.035 in) or 1 mm (~0.039 in). Outside diameters span 5 mm to 20 mm (approx. 0.20 in to 0.79 in), and free lengths range from 10 mm to 50 mm (approx. 0.39 in to 1.97 in), giving you a broad selection matrix to match your bore and stroke requirements precisely.
These compression springs suit a wide range of use cases: spring-loaded pen mechanisms and retractable tool clips, valve and plunger assemblies in fluid-handling equipment, jig and fixture clamping systems for CNC and woodworking setups, and small appliance or electronics enclosure latches requiring consistent closing force.
| Material | 304 Stainless Steel |
|---|---|
| Wire Diameter | 0.9 mm / 1 mm |
| Outside Diameter | 5 mm – 20 mm (see variant options) |
| Free Length | 10 mm – 50 mm (see variant options) |
| Spring Type | Compression |
| Coil Direction | Right-hand wound (standard) |
| End Type | See variant options |
| Surface Finish | Natural stainless (no coating) |
| Corrosion Resistance | Suitable for mild corrosive environments |
| Operating Temperature | Typically –20°C to +300°C (–4°F to +572°F) |
| Spring Rate | See variant options |
| Quantity per Order | See variant options |
Measure the inner diameter of the bore or housing where the spring will sit. The spring's outside diameter should be slightly smaller than the bore — typically 0.2 mm to 0.5 mm of clearance — to allow free movement without binding. If the spring rides on a post, the post diameter should be smaller than the spring's inner diameter (outside diameter minus twice the wire diameter).
A thicker wire diameter (1 mm) produces a stiffer spring with a higher spring rate, meaning it requires more force to compress the same distance compared to a 0.9 mm wire spring of the same outside diameter and length. Choose 0.9 mm for lighter loads or more sensitive return mechanisms, and 1 mm where a firmer, more robust elastic response is needed.
Yes. 304 stainless steel offers good resistance to atmospheric corrosion, moisture, and mild chemical exposure. It is suitable for outdoor fixtures, marine-adjacent environments (non-saltwater immersion), and humid indoor settings. For direct saltwater or highly acidic environments, 316 stainless steel would be a more appropriate choice.
The free length is the uncompressed length of the spring. You should select a free length that, when compressed to your working length, still provides the required load force without exceeding the spring's solid height (all coils touching). As a conservative rule, avoid compressing a spring beyond 80% of its free length in continuous-duty applications to prevent fatigue and permanent set.
Yes. The small wire diameters (0.9 mm and 1 mm) and compact outside diameters (starting at 5 mm) make these springs well-suited for pen barrels, retractable mechanisms, button actuators, and small electronic enclosure latches. Select the outside diameter and free length that match your housing geometry and required actuation force.
Spring rate (stiffness) depends on wire diameter, outside diameter, number of active coils, and material modulus. If you need a specific spring rate, contact us with your load and deflection requirements and we can help identify the closest matching variant. For general DIY and light mechanical use, selecting by dimensional fit is usually sufficient.
Quantity per order depends on the selected variant. Please refer to the variant options above for pack size information. Bulk quantities may be available — contact us for wholesale or project-volume inquiries.
