305mm Long Compression Spring 304 Stainless Steel Pressure-Coil Springs

Wire diameter directly determines the spring rate and load capacity. Thinner wire (e.g., 0.3mm–0.8mm) produces lighter, more flexible springs suited for delicate mechanisms, sensors, or light-duty return functions. Thicker wire (e.g., 2.0mm–4.0mm) yields stiffer springs capable of handling heavier loads in industrial or structural applications. As a starting point, calculate the required spring force and deflection, then use standard spring design formulas (or a spring rate calculator) to identify the wire diameter that meets your load and travel requirements.

For a housing bore, the spring's outer diameter should be slightly smaller than the bore ID to allow free movement — typically 0.5mm to 1.5mm clearance on each side. For a guide rod, the spring's inner diameter (outer diameter minus twice the wire diameter) should be slightly larger than the rod OD to prevent binding. Measure your housing bore or rod diameter first, then select the OD variant that provides the appropriate clearance.

304 stainless steel has a tensile strength typically in the range of 515–860 MPa depending on temper and wire diameter. The actual spring load capacity depends on the specific wire diameter, outer diameter, and number of active coils. Larger wire diameters and smaller outer diameters generally produce higher spring rates and load capacities. For precise load data, refer to the variant-specific specifications or contact us to confirm.

Yes. 304 stainless steel offers solid resistance to atmospheric corrosion, moisture, and mild chemical exposure, making it suitable for outdoor enclosures, garden equipment, marine-adjacent applications (non-saltwater immersion), and humid workshop environments. For direct saltwater or highly acidic exposure, 316 stainless steel would be a more appropriate choice.

Cutting a compression spring is possible but will alter its spring rate, load capacity, and end condition. If you need a shorter free length, it is generally more reliable to select a spring designed to the required length rather than cutting. If cutting is necessary, use a rotary tool with a cutting disc and be aware that the cut end will need to be ground flat to maintain consistent seating.

Compression springs resist being compressed and push back when force is applied along their axis — they are used in applications where you need a return force when two surfaces come together (e.g., button mechanisms, valve returns, shock absorption). Extension springs, by contrast, resist being stretched and pull two components together. If your application requires a spring to push apart or absorb impact between two surfaces, a compression spring is the correct choice.

Spring rate (k) can be estimated using the formula: k = (G × d⁴) / (8 × D³ × n), where G is the shear modulus of 304 stainless steel (approximately 69 GPa), d is the wire diameter, D is the mean coil diameter (OD minus wire diameter), and n is the number of active coils. If you need confirmed spring rate data for a specific variant, please contact us with your selected wire diameter and outer diameter and we will provide the specification.