Wire Dia 0.3mm OD 16mm-40mm Small Springs Compression Spring Steel Coil Springs

Measure the bore inner diameter (ID) your spring will sit in — the spring OD should be slightly smaller than the bore ID, typically 0.5–1mm clearance. For free length, measure the available cavity depth and subtract your desired compressed length to determine the required travel. Select the variant whose OD and free length best match these measurements.

Spring rate varies by OD and free length combination. Longer free lengths and larger ODs at the same wire diameter generally result in lower spring rates (softer springs). Specific spring rate values are not confirmed for all variants — if your application requires a precise rate, please contact us to confirm before ordering.

These springs are formed from steel wire. Standard steel springs are not inherently corrosion-resistant and are best suited for dry, indoor environments. For applications exposed to moisture or chemicals, consider adding a protective coating or selecting a stainless steel alternative. Contact us to confirm finish options if corrosion resistance is a requirement.

These springs are compatible with pen and stylus mechanisms, small electronic push-button and tactile switch assemblies, miniature valve and plunger mechanisms, hobby robotics linkages, and precision instrument components. They are designed for light-duty return and actuation applications where a 0.3mm wire diameter provides the appropriate force range.

Yes. For bore mounting, ensure the bore ID is at least 0.5–1mm larger than the spring OD. For post mounting, the post OD should be slightly smaller than the spring inner diameter (ID = OD minus 2× wire diameter, approximately OD minus 0.6mm). Verify clearances with your selected variant before assembly.

Each order is for one (1) spring per unit. Select your exact Wire Diameter × OD × Length combination from the variant dropdown. If you need multiple springs of the same or different sizes, simply adjust the quantity or add multiple variants to your cart.

Travel (deflection) = Free Length minus Compressed Length. The minimum compressed length (solid height) is approximately equal to the wire diameter multiplied by the total number of coils. For a 0.3mm wire spring, solid height is typically very small. Ensure your assembly allows the spring to compress without reaching solid height under normal operating loads to avoid permanent set.