Compression Spring Wire Dia 3mm OD 20mm-29mm Spring Steel Pressure Coil Springs

Measure the inner diameter of your spring housing or the outer diameter of your guide rod. For a housing fit, the spring OD should be 0.5–1.5mm smaller than the bore. For a rod fit, the spring ID (OD minus twice the wire diameter) should be 0.5–1mm larger than the rod. With a 3mm wire, the ID is approximately OD minus 6mm — for example, a 20mm OD spring has roughly a 14mm ID.

Load capacity depends on the outer diameter, free length, number of active coils, and material. These springs are formed from spring steel and are suited for light-to-medium duty compression loads typical in DIY, robotics, and light industrial fixtures. For precise load and deflection data, contact us with your specific variant and application requirements.

Spring steel provides good mechanical properties but has limited inherent corrosion resistance compared to stainless steel. For dry indoor environments and general mechanical assemblies these springs perform reliably. If your application involves moisture, chemicals, or outdoor exposure, consider applying a protective coating or contact us to discuss alternative material options.

Yes. The 3mm wire diameter and OD range of 20–29mm make these compression springs well suited for CNC axis return mechanisms, end-stop buffers, and robotic joint preload applications. Select the free length that matches your required travel plus compressed length, and verify the spring rate suits your force requirements.

All three packing options contain identical springs — the only difference is quantity per order. The 1 PCS option is ideal for prototyping or replacement of a single spring. The 2 PCS option suits paired or mirrored installations. The 10 PCS option offers a lower per-unit cost for small production runs or stocking spares.

Free length is the overall length of the spring with no load applied — this is the length listed in the variant options (e.g., 50mm). Compressed length (solid height) is the length when all coils are touching and equals the wire diameter multiplied by the total number of coils. For most applications, design your assembly so the spring never reaches solid height during normal operation to avoid coil clash and fatigue.

The listed variants cover wire diameter 3mm with OD 20–29mm and free lengths from 20mm to 400mm. If you need a size outside this range or a different wire diameter, contact us with your specifications and we will advise on availability or alternatives from our catalog.