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When a failed spring in a precision instrument, pen mechanism, or electronic assembly brings your project to a halt, finding the exact replacement in the right size is half the battle. These miniature compression pressure springs are designed for engineers, hobbyists, and repair technicians who need reliable, dimensionally consistent springs in small form factors — without ordering in bulk or waiting weeks for custom parts.
Each set contains 10 pieces of compression springs manufactured from A2 stainless steel (equivalent to 304 SS), offering a good balance of corrosion resistance and mechanical strength. Wire diameter is 0.5mm (approx. 0.020 in). Outer diameter ranges from 2.5mm to 7mm (approx. 0.098–0.276 in) depending on variant selected, and free length ranges from 5mm to 50mm (approx. 0.197–1.969 in). Ends are typically closed and ground for flat seating.
Typical use cases include: replacing worn springs in ballpoint pens and mechanical pencils, providing return force in miniature switches and push-button assemblies, acting as tension elements in small jigs and fixtures for DIY electronics projects, and serving as light-load compression elements in model engineering and hobby robotics builds.
| Material | A2 Stainless Steel (304-grade equivalent) |
|---|---|
| Wire Diameter | 0.5mm (approx. 0.020 in) |
| Outer Diameter | See variant options (2.5mm – 7mm) |
| Free Length | See variant options (5mm – 50mm) |
| End Type | Closed and ground (typical) |
| Spring Type | Compression |
| Quantity per Pack | 10 pieces |
| Spring Rate | See variant options |
| Surface Finish | Natural stainless (no coating) |
| Operating Temperature | Typically –20°C to +200°C (–4°F to +392°F) |
Measure the bore or housing your spring will sit inside — the spring's outer diameter should be slightly smaller than the bore to allow free movement. For free length, measure the uncompressed gap the spring needs to fill, then add enough extra length to provide the desired preload or working force. If you are replacing an existing spring, measure the old spring's OD and free length directly.
A 0.5mm wire diameter spring is designed for light-duty applications. Exact load capacity depends on the outer diameter, free length, and number of active coils — all of which vary by variant. These springs are suited for pen mechanisms, small switches, light return-force applications, and similar low-load uses. They are not intended for heavy mechanical or structural loading.
A2 stainless steel offers good corrosion resistance in most indoor environments and light outdoor exposure. It performs well in humid conditions and resists rust from water and mild atmospheric exposure. However, it is not recommended for prolonged immersion in saltwater, strong acids, or chlorinated environments, where A4 (316-grade) stainless steel would be more appropriate.
These springs follow standard coil spring geometry and are compatible with any housing or plunger designed for the corresponding outer diameter. Always verify the inner diameter of the housing and the diameter of any guide pin against the spring's OD and inner diameter (ID = OD minus 2× wire diameter) before assembly.
Yes. The small wire diameter and miniature OD range make these springs well-suited for use in PCB test fixtures, battery contacts, push-button switches, and similar electronics applications. A2 stainless steel is non-magnetic and does not introduce significant interference in most low-frequency electronic environments.
A larger outer diameter with the same wire diameter results in a lower spring rate (softer spring), while a smaller outer diameter produces a higher spring rate (stiffer spring) for the same free length. Choose a larger OD when you need a gentler, more compliant force, and a smaller OD when you need a firmer return force in a compact bore.
This listing covers the 0.5mm wire diameter in A2 stainless steel. HomeDIYer carries additional spring families in different wire diameters, outer diameters, and materials. Use the search bar to find the specific combination you need, or contact us if you require a size not currently listed.
