Compression Spring 2mm Wire Dia OD 21-30mm Spring Steel Pressure-Coil Springs

Measure the inner diameter of your spring housing or bore, then select an OD that provides a small clearance fit — typically 0.5mm to 1mm smaller than the bore ID. For guide rod applications, measure the rod OD and select a spring ID (OD minus 2× wire diameter) that clears the rod with 0.3–0.5mm of play. Use the variant selector to choose from OD 21mm through 30mm in 1mm increments.

Free length determines the unloaded height of the spring. Your working length (compressed height under load) should be at least 20–30% shorter than the free length to stay within the elastic range. For example, if your assembly compresses the spring to 20mm, a free length of 25–30mm is a reasonable starting point. Available lengths range from 15mm to 305mm — select the variant that matches your stroke and preload requirements.

Spring rate (force per unit of deflection) depends on wire diameter, OD, and number of active coils, which varies by free length. With a 2mm wire diameter and ODs of 21–30mm, these springs are suited for light-to-medium duty applications — typically return-force mechanisms, detents, latches, and spring-loaded assemblies rather than heavy structural loads. For specific load requirements, contact us to confirm the spring rate for your chosen variant.

These springs are made from carbon spring steel, which provides excellent elastic properties but has limited inherent corrosion resistance compared to stainless steel. For indoor, dry, or lightly humid environments they perform reliably. For outdoor, wet, or chemically exposed environments, consider applying a light coat of oil or grease, or contact us about stainless steel spring options if corrosion resistance is a primary requirement.

Yes — the smaller OD variants (21–23mm) and shorter free lengths (15–25mm) are commonly used in 3D printer bed leveling spring replacements, while mid-range lengths (30–60mm) suit RC vehicle suspension tuning and light robotics. Verify the OD fits your spring pocket and the free length matches your travel before ordering. The 5-pack and 10-pack options are cost-effective for prototyping multiple configurations.

All packs contain identical springs — the only difference is quantity per order. The 10 PCS packs are available for shorter lengths (15–50mm) where multiple springs are commonly needed in a single assembly. The 5 PCS packs cover the full length range including longer springs (60–305mm). The 2 PCS option is available for the longest variants (305mm) where fewer pieces are typically required per project. Select the pack size that matches your build quantity.

Yes — these compression springs are well-suited for CNC workholding fixtures, spring-loaded clamps, ejector pins, and automation jig return mechanisms. The closed ends provide stable seating in spring pockets, and the consistent wire diameter ensures repeatable spring rates across a batch. For high-cycle applications, ensure the spring is not compressed beyond 80% of its free length to avoid fatigue and permanent set.