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When a loose or undersized spring causes your mechanism to fail mid-cycle, the frustration is real — especially for makers, engineers, and hobbyists who need consistent performance from every component. These compression pressure springs are designed for builders who demand repeatable spring force in compact assemblies without hunting through bulk hardware bins for the right size.
Each pack contains 10 springs wound from spring steel wire with a diameter of 0.3mm (approx. 0.012 in). Outer diameter options span 4.5mm to 8mm (approx. 0.177–0.315 in), and free lengths range from 5mm to 50mm (approx. 0.197–1.969 in), giving you precise dimensional control for your application. The close-wound coil geometry provides uniform pitch and consistent load characteristics across the full compression range.
Typical use cases include small electronics enclosures requiring button-return mechanisms, pen and stylus assemblies needing light-load compression springs, miniature valve and latch mechanisms in DIY robotics, and precision instrument housings where compact spring steel coil springs must fit within tight radial clearances.
| Material | Spring Steel |
|---|---|
| Wire Diameter | 0.3mm (approx. 0.012 in) |
| Outer Diameter (OD) | 4.5mm / 5mm / 6mm / 7mm / 8mm (see variant options) |
| Free Length | 5mm – 50mm (see variant options) |
| Coil Type | Compression (close-wound) |
| End Type | See variant options |
| Spring Rate | See variant options |
| Surface Finish | See variant options |
| Quantity per Pack | 10 pieces |
Measure the bore or housing inner diameter where the spring will seat. The spring's outer diameter should be slightly smaller than the bore to allow free movement without binding. For a spring seat (post), the spring's inner diameter (OD minus 2× wire diameter) should be slightly larger than the post. Select the OD variant closest to your target clearance.
Free length is the uncompressed length of the spring. Choose a free length longer than your required working stroke plus any solid-height clearance. For example, if your mechanism compresses the spring by 10mm, a free length of 20–25mm typically provides adequate working range without coil bind.
Spring steel offers good mechanical properties but has moderate corrosion resistance. For indoor, dry, or low-humidity environments these springs perform reliably. For applications exposed to moisture, chemicals, or outdoor conditions, consider adding a protective coating or selecting stainless steel springs instead.
A 0.3mm wire diameter spring is designed for light-load applications. Typical spring rates and maximum loads depend on the specific OD and free length combination. These springs are suited for button returns, pen mechanisms, sensor contacts, and similar low-force applications rather than heavy-duty industrial use. Contact us to confirm load specifications for your chosen variant.
Yes, spring steel compression springs are designed for repeated cycling. Performance longevity depends on operating within the spring's elastic range — avoid compressing to solid height (coil bind) during normal operation, as this causes fatigue and permanent set over time. For high-cycle applications, ensure your design limits maximum deflection to approximately 80% of the available stroke.
These springs are compatible with standard spring seats, plunger bores, and guide posts sized to match the selected OD variant. Verify that your assembly's bore diameter, seat depth, and post diameter align with the spring's OD and inner diameter before installation. The 10-piece pack allows for fit-testing across multiple prototype iterations.
All variants share the same 0.3mm wire diameter and spring steel material. The outer diameter determines the radial footprint of the spring and its inner diameter (ID = OD − 2× wire diameter). A larger OD generally provides a slightly higher spring rate for the same free length. Select the OD that fits your housing bore or guide post with appropriate clearance.
