Compression Spring Steel 0.4mm Wire Dia 2mm - 10mm OD Small Pressure Springs

Measure the bore or housing your spring will sit inside, then select an OD that is slightly smaller than the bore to allow free movement. For a shaft-guided spring, measure the shaft and choose an ID (inner diameter) that clears the shaft with a small gap. The OD options for this product range from 2mm to 10mm — pick the one that fits your housing or shaft constraint first, then select the free length.

Free length is the uncompressed length of the spring. Choose a free length that is longer than your required compressed length by the amount of travel (deflection) you need. For example, if your assembly compresses the spring by 10mm and you need 5mm of working length at full compression, select a free length of at least 15mm. Available lengths run from 5mm to 50mm in this listing.

With a 0.4mm wire diameter, these are light-duty compression springs suited for low-force applications such as pen mechanisms, small switches, sensor preloads, and model assemblies. They are not intended for heavy industrial loads. If you need a specific spring rate or load capacity, please contact us to confirm before ordering.

These springs are made from steel wire. Steel springs can be susceptible to surface oxidation in humid or wet environments over time. For applications exposed to moisture, consider applying a light coat of oil or grease, or contact us to inquire about stainless steel alternatives if corrosion resistance is a critical requirement.

Yes. The small OD range (2mm – 10mm) and short length options (starting at 5mm) make these springs well-suited for use in battery contacts, push-button PCB switches, probe tips, and similar electronics applications where a compact, low-force return spring is needed.

A larger OD at the same wire diameter generally produces a softer spring (lower spring rate), while a smaller OD produces a stiffer spring. If you need more force in a given deflection range, choose a smaller OD. If you need gentler, more compliant action, choose a larger OD. Match the OD to your housing constraint first, then evaluate whether the resulting spring rate meets your force requirements.

Each variant is sold as a pack of 10 identical springs. The pack quantity is indicated in the "Length & Pack Quantity" option (e.g., "15mm & 10 Pcs" means a free length of 15mm, 10 pieces per pack). There is no single-piece option for this listing.