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When a worn-out or undersized spring causes your mechanism to fail — whether it's a valve, a latch, a jig, or a precision instrument — finding the exact wire diameter and free length matters. These stainless steel compression springs are designed for makers, engineers, and repair technicians who need reliable elastic return force in a compact, corrosion-resistant form.
Each pack contains 10 identical springs wound from stainless steel wire. Wire diameters range from 0.3 mm to 0.6 mm (approximately 0.012" to 0.024"), outer diameters from 3 mm to 10 mm (approximately 0.12" to 0.39"), and free lengths from 5 mm to 305 mm (approximately 0.20" to 12.0"). Ends are closed and ground for flat, stable seating.
Typical use cases include electronic device button return mechanisms, small appliance spring replacement, precision jig and fixture tensioning, model engineering and robotics prototyping, and laboratory or medical device maintenance where consistent spring force is required.
Wound from stainless steel wire for reliable corrosion resistance in humid, wet, or mildly acidic environments — outlasting carbon steel alternatives in exposed installations.
Wire diameters 0.3, 0.4, 0.5, 0.6 mm × outer diameters 3–10 mm × free lengths 5–305 mm — a broad selection matrix so you can match the exact spring geometry your project demands.
Flat, closed-and-ground end coils provide stable, perpendicular seating against spring pockets and retainers, reducing lateral deflection under load.
Each order ships 10 identical springs — enough for batch repairs, prototyping iterations, or stocking a workshop drawer without over-ordering.
Uniform wire diameter and coil pitch across the batch ensures repeatable elastic return force — critical for mechanisms where spring-to-spring variation would cause functional inconsistency.
From electronics button return and pen mechanisms to valve springs, fixture clamps, and robotics actuators — these small-diameter springs cover a wide range of light-duty compression tasks.
| Material | Stainless Steel |
|---|---|
| Wire Diameter | 0.3 / 0.4 / 0.5 / 0.6 mm (see variant options) |
| Outer Diameter (OD) | 3 / 4 / 5 / 6 / 7 / 8 / 10 mm (see variant options) |
| Free Length | 5 – 305 mm (see variant options) |
| End Type | Closed and Ground |
| Wind Direction | Right-hand (standard) |
| Spring Rate | See variant options |
| Quantity per Pack | 10 pieces |
| Surface Finish | Natural (uncoated stainless) |
| Operating Temperature | Typically –20°C to +200°C (–4°F to +392°F) |
Start with the spring pocket or bore diameter in your assembly — the OD of the spring must be smaller than the bore (typically 0.2–0.5 mm clearance). Then select a wire diameter that gives you the spring rate and load capacity you need. Thicker wire (e.g., 0.6 mm) produces a stiffer spring; thinner wire (e.g., 0.3 mm) gives a softer, more compliant spring. Use the variant selector above to match both dimensions to your design spec.
Free length is the uncompressed length of the spring. Choose a free length that is longer than your required working length by at least the amount of travel (deflection) your mechanism needs. For example, if your mechanism compresses the spring 10 mm and you need 5 mm of working length at full compression, select a free length of at least 15 mm. Available lengths range from 5 mm to 305 mm in this listing.
Yes. Stainless steel provides good corrosion resistance against moisture, humidity, and mild chemical exposure — making these springs suitable for outdoor fixtures, marine-adjacent applications, and food-adjacent equipment where carbon steel would rust. For highly aggressive chemical environments (strong acids, chlorides), consult a materials engineer for a more specialized alloy.
Closed-end springs have the last coil wound tightly against the adjacent coil, creating a flat contact surface. Ground ends take this further by machining the end face flat and perpendicular to the spring axis. This ensures the spring seats squarely in a pocket or against a retainer, reducing side-load and improving load accuracy. These springs feature closed and ground ends for stable, predictable performance.
Yes. The 0.3 mm and 0.4 mm wire diameter variants with small ODs (3–4 mm) are well-suited for button return mechanisms, pen clips, connector contacts, and small instrument components where space is tight and consistent return force is needed. Verify the spring rate matches your actuation force requirement before finalizing your design.
Spring rate (k) can be estimated using the formula: k = (G × d⁴) / (8 × D³ × n), where G is the shear modulus of stainless steel (~68–75 GPa), d is wire diameter, D is mean coil diameter (OD minus wire diameter), and n is the number of active coils. If you need a confirmed spring rate for a critical application, contact us with your selected variant and we can provide additional technical data.
Springs in precision mechanisms wear over time and may need periodic replacement. Having spares on hand eliminates downtime. For prototyping, a 10-pack lets you test multiple configurations and iterate without reordering. The per-unit cost in a 10-pack is also significantly lower than sourcing individual springs from a local hardware store.
