Compression Pressure Spring Wire Dia 0.3mm - 4.0mm Length 300mm Springs

Start with your bore or housing inner diameter — the spring's outer diameter (OD) should be slightly smaller than the bore to allow free movement. Then select a wire diameter that provides the spring rate (stiffness) you need: thicker wire = stiffer spring. For shaft-guided applications, the spring's inner diameter (ID = OD minus 2× wire dia) should be slightly larger than the shaft. Use the size selector above to find the combination that fits your clearance requirements.

Spring rate depends on wire diameter, outer diameter, number of active coils, and material modulus. Because these springs are 300mm long, the number of active coils varies by size. Exact spring rate values are not listed here — for critical load applications, we recommend measuring deflection under a known load after receiving the spring, or contacting us with your load/deflection requirements so we can confirm suitability.

These springs are made from spring steel with a bright natural finish, which offers limited corrosion resistance. For outdoor, humid, or wet environments, we recommend applying a light coat of oil or grease after installation, or considering stainless steel springs for your application. Contact us to confirm if a coated or stainless variant is available for your required size.

Yes. The 300mm free length is designed to give you working stock. You can cut the spring to your required free length using a rotary cutting tool or spring cutter. After cutting, lightly grind or deburr the cut end to ensure stable seating. Note that cutting changes the number of active coils and therefore the spring rate — the shorter the cut length, the stiffer the spring will be.

The inner diameter is calculated as: ID = Outer Diameter − (2 × Wire Diameter). For example, a 1.0mm wire dia × 10mm OD spring has an ID of 10 − 2 = 8mm. Use this formula with the size options listed above to verify shaft clearance before ordering.

Yes. The wide size range — from ultra-fine 0.3mm wire dia springs for micro mechanisms up to 4.0mm wire dia springs for heavier-duty fixtures — makes this catalog well suited for DIY automation jigs, robotic end-effectors, latch returns, and fixture clamps. The 300mm length also provides flexibility for custom-length cuts in iterative prototyping builds.

At the same outer diameter, a larger wire diameter produces a stiffer spring with higher load capacity but less deflection range before solid height. A smaller wire diameter gives a softer spring with more travel. Choose based on your required force at working deflection: if you need a light touch return force, go with a smaller wire dia; for firm clamping or heavy-duty return, select a larger wire dia.