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When a repair stalls because you can't find the right spring rate or length, the whole project grinds to a halt. Whether you're a hands-on DIYer rebuilding a mechanism, a maker prototyping a device, or a technician replacing worn-out components, having a reliable selection of compression coil springs on hand makes the difference between a finished job and a frustrating delay. These 305mm long compression coil springs are engineered to deliver consistent, repeatable force across a wide range of applications.
Each spring is formed from round wire with a diameter ranging from 0.3 mm to 5 mm (approximately 0.012" to 0.197"), wound into a cylindrical coil body with an overall length of 305 mm (approximately 12.0"). Coil outer diameters range from 3 mm to 50 mm (approximately 0.12" to 1.97") depending on the selected size variant. Two material options are available: Stainless Steel A2 (304-grade equivalent, corrosion-resistant) and Spring Steel (high-carbon, higher tensile strength for demanding mechanical loads).
Typical use cases include custom suspension mechanisms, jig and fixture clamping systems, valve return assemblies, drawer and door damping hardware, robotics and automation prototypes, and general-purpose compression applications in workshop or light industrial settings. The 305 mm body length allows the spring to be cut to a shorter working length if needed, or used full-length where extended travel is required.
| Free Length | 305 mm (≈ 12.0 in) |
|---|---|
| Wire Diameter Range | 0.3 mm – 5 mm (≈ 0.012" – 0.197") |
| Outer Diameter Range | 3 mm – 50 mm (≈ 0.12" – 1.97") — See variant options |
| Material Options | Stainless Steel A2 (304-grade) / Spring Steel (high-carbon) |
| Spring Type | Cylindrical compression coil spring |
| End Style | See variant options |
| Spring Rate | See variant options |
| Surface Finish | Natural / uncoated (Stainless Steel A2); Natural / uncoated (Spring Steel) |
| Pack Quantity | See variant options |
| Operating Temperature | Stainless Steel A2: typically –20 °C to +200 °C; Spring Steel: typically –20 °C to +120 °C |
Wire diameter directly affects spring rate and load capacity — a thicker wire produces a stiffer spring. For light return or damping duties (e.g., small levers, drawer mechanisms), wire diameters of 0.3 mm – 0.8 mm are typically sufficient. For moderate clamping or valve return applications, 1 mm – 2 mm wire is a common starting point. For heavy mechanical loads or high-cycle industrial use, 2.5 mm – 5 mm wire diameters are more appropriate. If you know the required load at a specific deflection, use the spring rate formula (Rate = (G × d⁴) / (8 × D³ × n)) or contact us for guidance.
Stainless Steel A2 (equivalent to 304 stainless) offers good corrosion resistance in damp, outdoor, or mildly corrosive environments. It is the better choice when rust prevention is a priority — for example, in marine-adjacent, food-handling, or outdoor enclosure applications. Spring Steel (high-carbon steel) has a higher tensile strength and can store more elastic energy per unit volume, making it preferable for high-load or high-cycle mechanical applications where corrosion is not a concern. Spring Steel springs should be kept dry or protected with a light oil film to prevent surface rust.
Yes, compression coil springs can be cut to a shorter free length using an angle grinder or spring-cutting tool. After cutting, the cut end will be open (not ground flat), which may cause slight lateral instability under load. For precision applications, grinding the cut end flat is recommended. Keep in mind that shortening the spring reduces the number of active coils, which increases the spring rate — the shorter the spring, the stiffer it becomes for the same wire and coil diameter.
Measure the inner diameter of the bore or housing that the spring will sit inside. The spring's outer diameter should be 0.5 mm – 2 mm smaller than the bore to allow free compression without binding. For example, if your bore is 12 mm, look for a spring with an outer diameter of 10 mm – 11.5 mm. The variant size label shows wire diameter × outer diameter × length (e.g., "1 x 8 x 305mm" means 1 mm wire, 8 mm outer diameter, 305 mm long).
The Stainless Steel A2 variants are suitable for outdoor and damp environments — A2 stainless resists atmospheric corrosion and light moisture exposure well. The Spring Steel variants are not inherently corrosion-resistant and will develop surface rust if left exposed to moisture without protection. If you need Spring Steel performance in a wet environment, apply a thin coat of corrosion-inhibiting oil or grease, or consider a protective sleeve or housing.
The three numbers in the size label follow the format: Wire Diameter × Outer Diameter × Free Length, all in millimetres. So "1.5 x 12 x 305mm" means the spring wire is 1.5 mm thick, the outer coil diameter is 12 mm, and the uncompressed (free) length is 305 mm. Use these three dimensions to match the spring to your application's bore size, shaft diameter, and available travel space.
The "Pack of Quantity" option in the variant selector shows the number of springs included per order. Select the quantity that suits your project — single pieces are available for one-off repairs, while multi-piece packs offer better value for ongoing use or stocking a workshop. If you need quantities larger than those listed, please contact us to confirm availability.
