Compression Spring Stainless Steel 0.3 - 0.5mm Wire Dia Pressure Coil Springs

Start with the outer diameter (OD) — it must fit inside your spring pocket or bore with a small clearance (typically 0.1–0.3 mm). Then select a free length slightly longer than your required working length to allow for compression. Finally, match the wire diameter to your load requirement: 0.3 mm wire suits very light loads, while 0.5 mm wire handles moderately higher forces. Use the variant selector above to filter by Wire Diameter, Outer Diameter, and Length.

Spring rate depends on wire diameter, outer diameter, number of active coils, and free length. Because this listing covers a wide range of sizes, specific spring rate and load values vary by variant. For precise engineering calculations, use the spring rate formula: k = (G × d⁴) / (8 × D³ × n), where G is the shear modulus of stainless steel (~69 GPa), d is wire diameter, D is mean coil diameter, and n is the number of active coils. Contact us if you need confirmed rate data for a specific variant.

Yes. Stainless steel offers significantly better corrosion resistance than carbon steel or music wire springs. These springs are suitable for humid environments, light moisture exposure, and mild chemical contact. For highly aggressive environments (saltwater immersion, strong acids), consider additional protective measures or a higher-grade stainless alloy.

These small-diameter compression springs are compatible with a wide range of applications including battery contacts, pen and stylus mechanisms, retractable tool clips, sensor mounts, valve assemblies, electronic enclosure latches, miniature jigs and fixtures, and DIY automation components. Always verify the OD fits your bore and the free length suits your travel requirement before installing.

Wire diameter directly affects stiffness and load capacity. The 0.3 mm wire springs are softer and suited for very light-touch applications such as small electronics contacts, pen mechanisms, and delicate sensor mounts. The 0.5 mm wire springs are stiffer and can handle moderately higher compressive loads, making them better for mechanical latches, light valve springs, and similar uses. If in doubt, the 0.5 mm option provides more force for the same geometry.

The outer diameter should be chosen based on the bore or pocket that will house the spring. Leave a radial clearance of approximately 5–10% of the OD between the spring OD and the bore ID to allow free compression without binding. For a 4 mm bore, for example, a 3 mm OD spring with 0.5 mm clearance on each side is a reasonable starting point. Also consider the inner diameter (ID = OD − 2 × wire diameter) if the spring must slide over a guide pin.

Yes. These stainless steel pressure coil springs are well suited for DIY automation projects including 3D printer bed leveling contacts, robotic gripper return mechanisms, linear actuator preload, and CNC machine limit switch plungers. Select the appropriate OD and free length to match your mechanism's travel and force requirements.