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When a mechanism fails because a worn-out spring can no longer hold its load, finding an exact replacement fast is critical. Whether you are a hobbyist repairing a tool, a technician servicing machinery, or a maker prototyping a new device, these steel compression springs give you the precise dimensional control you need to get the job done right the first time.
Each spring is formed from steel wire with a nominal wire diameter of 3 mm (0.118 in). Outer diameters range from 16 mm to 30 mm (0.63 in – 1.18 in), and free lengths span 20 mm to 100 mm (0.79 in – 3.94 in). Springs are wound in a closed-end, ground configuration typical of this wire gauge, providing stable seating on flat surfaces.
These compression coil springs suit a wide range of applications: light-load return mechanisms in power tools and jigs, valve and plunger assemblies in pneumatic or hydraulic fixtures, tension-balancing components in DIY automation projects, and replacement springs in furniture hardware or industrial equipment maintenance.
Consistent 3 mm wire gauge across all variants ensures uniform spring rate characteristics and reliable seating in standard 3 mm wire spring pockets.
Outer diameters from 16 mm to 30 mm and free lengths from 20 mm to 100 mm let you match the exact dimensional envelope of your application without custom fabrication.
Wound from steel wire, these springs deliver the load-bearing capacity and fatigue resistance needed for repetitive cycling in mechanical assemblies.
The closed and ground ends provide a flat, stable bearing surface that reduces lateral deflection and keeps the spring aligned under compression.
From return mechanisms and valve springs to DIY automation and equipment repair, these coil springs adapt to a broad spectrum of light-to-medium load scenarios.
Available in 1-piece quantities so you can order exactly what you need — ideal for prototyping, repair, or testing before committing to larger quantities.
| Wire Diameter | 3 mm (0.118 in) |
|---|---|
| Outer Diameter (OD) | 16 mm – 30 mm (0.63 in – 1.18 in) — See variant options |
| Inner Diameter (ID) | OD − 6 mm (varies by variant) |
| Free Length | 20 mm – 100 mm (0.79 in – 3.94 in) — See variant options |
| Material | Steel |
| End Type | Closed & Ground (typical for this wire gauge) |
| Wind Direction | See variant options |
| Spring Rate | See variant options |
| Surface Finish | See variant options |
| Quantity per Order | 1 piece |
Measure the bore or housing that the spring sits inside. The spring's outer diameter should be slightly smaller than the bore — typically 0.5 mm to 1 mm of clearance — so it can compress freely without binding. For a shaft-guided spring, the inner diameter (OD − 6 mm for 3 mm wire) should be slightly larger than the shaft diameter.
The free length is the uncompressed height of the spring. Choose a free length that, when compressed to your working height, delivers the load you need. As a starting point, the free length should be at least 20–30% longer than your intended compressed (working) length to keep the spring within its elastic range.
Load capacity depends on the outer diameter, free length, number of active coils, and material. For 3 mm wire steel springs in this size range, typical spring rates fall in the light-to-medium range. If you have a specific load requirement, contact us with your OD, free length, and working deflection and we can help confirm suitability.
These springs are made from steel wire. Standard steel offers good mechanical properties but limited corrosion resistance in wet or chemically aggressive environments. For outdoor or humid applications, consider applying a protective coating (e.g., light oil or spray lacquer) after installation, or contact us to confirm if a coated variant is available.
The inner diameter (ID) equals the outer diameter minus twice the wire diameter. For a 3 mm wire spring: ID = OD − 6 mm. For example, a 3 × 20 mm spring has an ID of approximately 14 mm. Use this to verify shaft clearance in guided-spring applications.
Yes. Springs stacked in series (end-to-end) increase total deflection while reducing the effective spring rate. Springs arranged in parallel (side-by-side on the same axis) increase the combined load capacity. Ensure the outer diameters and end types are compatible with your housing when stacking.
Check three dimensions against your application: (1) outer diameter vs. bore clearance, (2) inner diameter vs. shaft clearance, and (3) free length vs. available space. If you are replacing an existing spring, measure the old spring's wire diameter, OD, and free length directly. Our variant selector lets you match all three parameters precisely.
