Compression Spring Various Size 18-32mm Diamete & 20-305mm Length Pressure Small

Measure the inner bore or housing that will contain the spring. The spring's outer diameter should be 0.5–1.5 mm smaller than the bore to allow free movement without binding. If you're using a guide rod, the spring's inner diameter (OD minus twice the wire diameter) should clear the rod by at least 0.5 mm. Select from the 18–32 mm OD range to match your assembly.

The free length is the uncompressed length of the spring. Choose a free length that is longer than your required working stroke plus the compressed (solid) height. As a conservative rule, the working stroke should not exceed 70–80% of the difference between free length and solid height to avoid coil bind and premature fatigue.

These springs are designed for light-to-medium duty loads typical of DIY automation, fixture clamping, and return mechanisms. The 3.5 mm wire diameter provides a moderate spring rate. For precise load requirements, contact us to confirm the spring rate and maximum load for your selected OD and length combination before ordering.

These springs are made from carbon steel wire, which can oxidize in high-humidity or wet environments over time. For indoor or dry-environment applications they perform reliably. If your application involves moisture exposure, consider applying a light coat of machine oil or grease, or contact us to inquire about stainless steel alternatives.

Yes, provided you match the OD to your housing bore and verify the inner diameter clears your guide rod. The inner diameter of each spring equals the outer diameter minus twice the wire diameter (OD − 7 mm for 3.5 mm wire). For example, an 18 mm OD spring has an inner diameter of approximately 11 mm. Always verify fit before final assembly.

Springs with free lengths of 180 mm, 200 mm, and 305 mm are typically used in single-axis or prototype applications where one spring per assembly point is standard. Selling them individually keeps your per-unit cost lower and avoids surplus stock for low-quantity builds. Shorter lengths (20–150 mm) are sold in packs of 5 to support multi-point installations common in fixtures and automation rigs.

Yes. Compression springs in the 18–22 mm OD range and 20–40 mm free length are commonly used in 3D printer bed leveling mounts. Select an OD that fits your existing spring seat and a free length that gives you adequate adjustment travel. The 3.5 mm wire diameter provides enough stiffness to hold the bed level under normal printing forces.