Compression Spring 30-40mm Diameter & 20-100mm Length Pressure Big 3mm Wire Dia

Measure the inner diameter of the housing or bore where the spring will sit. The spring's outer diameter should be 1–2mm smaller than the bore to allow free movement without binding. For a shaft-guided setup, the spring's inner diameter must clear the shaft by at least 1mm. Use the Size selector above to match your required OD (30, 32, 34, 35, 36, 38, or 40mm).

Free length is the uncompressed length of the spring. Choose a free length that, when compressed to your working height, still leaves the spring above its solid height. As a general rule, working deflection should not exceed 80% of the difference between free length and solid height. Available lengths range from 20mm to 100mm — select via the Size option above.

A 3mm wire diameter produces a substantially higher spring rate than 1–2mm wire springs of the same OD and length. This makes them well-suited for applications requiring firm return force, such as industrial press platens, heavy valve returns, or robotic joint mechanisms. If your application requires a softer, more compliant spring, consider a lighter wire gauge.

These springs are manufactured from spring steel, which offers good mechanical properties but moderate corrosion resistance in dry or mildly humid environments. For outdoor, wet, or chemically aggressive environments, consider applying a protective coating (e.g., zinc plating or oil) after installation, or contact us to confirm finish options for your specific size.

Yes. The 3mm wire diameter and closed-ground ends make these springs suitable for automotive jig fixtures, machinery damping, hydraulic valve returns, and similar industrial uses. Always verify the spring rate and solid height against your load and travel requirements before installation in safety-critical assemblies.

Many assemblies use springs in symmetric pairs (e.g., both sides of a press platen or dual-return mechanisms). Selling in 2-piece packs ensures you receive a matched set in one order, reducing the risk of mismatched dimensions from separate purchases. If you need larger quantities, simply adjust the quantity at checkout.

Spring rate depends on wire diameter, outer diameter, free length, and number of active coils. Because coil count varies by size, exact spring rates are not listed universally across all variants. If you need a specific spring rate for an engineering application, please contact us with your size selection and load requirements and we will provide confirmation.