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When a hinge creaks, a clip loses its snap, or a mechanism fails to return to position, the culprit is almost always a worn or incorrectly specified torsion spring. Engineers, repair technicians, and hands-on DIYers who need a reliable, dimensionally consistent small torsion spring will find this range covers the most common compact applications without compromise.
Each spring is formed from 0.7mm wire diameter carbon steel, with outer diameters spanning 3.5mm to 9mm (approximately 0.138 in to 0.354 in) and coil counts of 3, 6, or 9 turns. Angle selections of 60°, 90°, 120°, and 180° are available, and both left-hand and right-hand wind orientations are stocked to match your assembly direction.
Typical applications include small torsion springs for hinges in electronic enclosures, return springs in precision instruments, clip and latch mechanisms in consumer products, and replacement springs for DIY repair of eyeglass frames, cabinet latches, and hobby robotics joints.
| Wire Diameter | 0.7 mm (0.028 in) |
|---|---|
| Outer Diameter Range | 3.5 mm – 9 mm (0.138 in – 0.354 in) |
| Coil Count Options | 3 Coil / 6 Coil / 9 Coil |
| Leg Angle Options | 60° / 90° / 120° / 180° |
| Wind Direction | Left spring / Right spring |
| Material | Carbon steel |
| Surface Finish | See variant options |
| Inner Diameter | See variant options |
| Free Leg Length | See variant options |
| Spring Rate | See variant options |
| Quantity per Order | 1 piece |
Match the outer diameter to the bore or housing your spring sits in, leaving a small clearance. The coil count affects angular travel and stiffness — 3 coils give a stiffer, shorter-travel spring, while 9 coils allow more angular deflection with a softer rate. If you are replacing an existing spring, measure the OD and count the coils on the original.
Wind direction determines which way the spring loads. A left-hand (left spring) winds counter-clockwise when viewed from the front; a right-hand (right spring) winds clockwise. Installing the wrong wind direction causes the spring to unwind under load instead of storing energy. Check your assembly's rotation direction before selecting.
The leg angle is the angle between the two straight legs of the spring in its free (unloaded) state. Select the angle that matches your assembly's geometry so the legs seat correctly against their stops without pre-stressing the spring beyond its design range. 90° and 180° are the most common for hinge and latch applications.
These springs are made from carbon steel, which provides good mechanical properties but limited corrosion resistance on its own. They are suitable for dry indoor environments. For applications exposed to moisture or humidity, consider applying a light protective coating after installation, or contact us to confirm if a treated variant is available for your requirement.
Common uses include return springs in hinges, clips, latches, and clasps; reset mechanisms in precision instruments and sensors; spring-loaded joints in hobby robotics and RC models; and replacement springs in eyeglass frames, cabinet hardware, and small consumer electronics enclosures. The compact OD range of 3.5–9mm makes them ideal wherever space is limited.
The inner diameter of the spring must be slightly larger than the shaft or pin diameter to allow free rotation without binding. The inner diameter equals the outer diameter minus twice the wire diameter (ID = OD − 2 × 0.7mm). For example, a 0.7 × 5 × 6 Coil spring has an approximate ID of 3.6mm. Verify this against your shaft size before ordering.
Each listing is sold as 1 piece (single spring), as indicated by the "x1" suffix in the SKU. This allows you to source the exact specification you need without committing to a large quantity, which is ideal for prototyping, repair, or low-volume production.
