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When a mechanism fails because a tiny spring loses its tension or snaps under repeated cycling, the frustration is real — especially when the replacement is hard to source in the exact size you need. These wire dia. 0.5mm compression springs are designed for hobbyists, electronics repair technicians, model makers, and precision DIY builders who need reliable, correctly-sized small springs without ordering in bulk from industrial suppliers.
Each spring is formed from carbon steel wire with a nominal wire diameter of 0.5mm. Outer diameters span from 3mm to 12mm (approximately 0.12" to 0.47"), and available lengths range from 5mm to 120mm (approximately 0.20" to 4.72"). The close-wound coil geometry provides consistent spring force across the compression stroke, with a natural finish typical of carbon steel spring wire.
Typical use cases include replacing worn return springs in mechanical keyboards and switches, restoring tension in small appliance mechanisms and pen clickers, and providing preload force in precision jigs, fixtures, and hobby robotics assemblies where a compact 0.5mm wire dia. compression spring is required.
Consistent 0.5mm wire diameter across all size variants ensures predictable spring rate and reliable fit in tight-tolerance housings.
Outer diameters from 3mm to 12mm (0.12"–0.47") cover a broad spectrum of small-spring applications in a single product line.
Available in lengths from 5mm to 120mm, letting you match the exact free length your mechanism requires without cutting or shimming.
Formed from carbon steel spring wire for consistent elastic return force and resistance to permanent set under normal operating loads.
Choose 5-piece or 10-piece packs to match your project needs — ideal for prototyping, repair stock, or small-batch production.
Close-wound ends provide stable seating on flat spring seats and even load distribution across the compression stroke.
| Wire Diameter | 0.5mm (0.020") |
|---|---|
| Outer Diameter (OD) | 3mm – 12mm (0.12" – 0.47") |
| Inner Diameter (ID) | See variant options |
| Free Length | 5mm – 120mm (0.20" – 4.72") |
| Material | Carbon Steel Spring Wire |
| Finish | Natural / Uncoated |
| Spring Type | Compression Spring |
| Coil Style | Close-Wound |
| Spring Rate | See variant options |
| Pack Quantity | 5 pcs or 10 pcs (select above) |
Measure the bore or housing your spring sits in to determine the maximum allowable outer diameter, then subtract 0.2–0.5mm for clearance. For free length, measure the uncompressed gap the spring must fill. Select the OD and length combination from the variant options that best matches your measurements.
The inner diameter equals the outer diameter minus twice the wire diameter. For example, a 0.5mm wire dia. spring with 5mm OD has an approximate ID of 4mm. Exact IDs vary by OD — refer to the variant options or contact us to confirm for your specific size.
These springs are made from carbon steel with a natural finish and are not coated or plated. They are best suited for dry indoor environments. For applications exposed to moisture or corrosive conditions, consider stainless steel springs or apply a protective coating after installation.
Carbon steel spring wire provides good fatigue resistance under normal operating loads within the elastic range. Avoid compressing the spring to solid height (coil bind) repeatedly, as this accelerates fatigue. For high-cycle applications, ensure the working deflection stays within 70–80% of the maximum deflection.
Yes. The close-wound coil ends seat stably on flat spring seats. Verify that your plunger or guide rod diameter is smaller than the spring ID, and that your housing bore is larger than the spring OD, to ensure smooth operation without binding.
For single repairs or initial prototyping, the 5-piece pack provides spares without excess. For production runs, small-batch manufacturing, or stocking multiple sizes, the 10-piece pack offers better value per unit. Both pack sizes are available for most OD and length combinations.
Spring rate for a compression spring is calculated as: Rate = (G × d⁴) / (8 × D³ × n), where G is the shear modulus of steel (~80,000 N/mm²), d is wire diameter, D is mean coil diameter, and n is the number of active coils. If you need a confirmed spring rate for your specific variant, please contact us with your size requirements.
