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Engineers, makers, and repair technicians who need a consistent, repeatable return force often struggle to find torsion springs in the exact wire diameter, outside diameter, coil count, angle, and wind direction they require. This listing solves that problem with a comprehensive selection matrix covering 0.5mm wire diameter across outside diameters from 2.5mm to 6mm (approx. 0.098″ to 0.236″), available in 3, 6, or 9 active coils, four leg angles (60°, 90°, 120°, 180°), and both left-hand and right-hand wind directions.
Each pack contains 10 torsion springs manufactured from spring steel wire. Wire diameter is 0.5mm (approx. 0.020″). Outside diameters span 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, 5mm, 5.5mm, and 6mm. Coil counts of 3, 6, and 9 provide short, medium, and long body lengths respectively. Leg angles of 60°, 90°, 120°, and 180° cover the most common mechanical configurations.
Typical applications include small appliance mechanisms requiring a compact torsion spring for door latches, pen clips, and hinged covers; electronics enclosure clasps where a 0.5mm wire torsion spring delivers controlled closing torque; and precision instrument assemblies where a left-wind or right-wind torsion spring must match an existing shaft rotation direction. The wide outside-diameter range also suits miniature robotics joints and model engineering projects.
All variants share a consistent 0.5mm (0.020″) wire cross-section, giving a uniform spring rate baseline across the entire size range for straightforward design calculations.
Choose from 2.5, 3, 3.5, 4, 4.5, 5, 5.5, or 6mm OD to match your bore or housing precisely, covering a span of approximately 0.098″ to 0.236″.
Select 3, 6, or 9 active coils to control body length and angular deflection capacity — more coils allow greater angular travel before reaching the elastic limit.
Pre-formed leg angles of 60°, 90°, 120°, and 180° eliminate the need for manual bending and ensure repeatable geometry across all 10 springs in the pack.
Both rotate-left (LH) and rotate-right (RH) wind directions are stocked, so you can match the spring to the rotation direction of your shaft or mechanism without modification.
Each order ships as a pack of 10 identical springs, giving you spares for testing, iterative prototyping, or batch repairs without needing to reorder frequently.
| Wire Diameter | 0.5mm (approx. 0.020″) |
|---|---|
| Outside Diameter Options | 2.5 / 3 / 3.5 / 4 / 4.5 / 5 / 5.5 / 6mm |
| Active Coil Options | 3 / 6 / 9 coils |
| Leg Angle Options | 60° / 90° / 120° / 180° |
| Wind Direction | Rotate left (LH) / Rotate right (RH) |
| Material | Spring steel |
| Surface Finish | See variant options |
| Inside Diameter | See variant options |
| Free Leg Length | See variant options |
| Spring Rate | See variant options |
| Pack Quantity | 10 pieces per pack |
| Unit Price | $6.80 per pack |
The outside diameter (OD) of the torsion spring should be slightly smaller than the bore or housing it sits in, with enough clearance to allow free rotation. Measure your bore ID and select the next smaller OD option. For shaft-mounted springs, the spring's inside diameter (ID = OD minus 2× wire diameter) must be larger than the shaft OD to avoid binding.
More active coils increase the body length of the spring and allow greater angular deflection before the spring reaches its elastic limit. A 3-coil spring is compact and suited to tight spaces with limited angular travel. A 9-coil spring can absorb more angular displacement and is better for applications requiring a larger rotation range. Spring rate (torque per degree) decreases as coil count increases for the same wire and OD.
Wind direction must match the direction in which the spring is loaded. A left-hand (rotate left) spring tightens — and therefore strengthens — when its body is rotated clockwise when viewed from the leg end. A right-hand (rotate right) spring tightens when rotated counter-clockwise. Check your mechanism's rotation direction and select accordingly. Using the wrong wind direction will cause the spring to unwind under load rather than store energy.
0.5mm wire diameter is suited to light-duty applications such as pen clips, small hinges, latches, electronics enclosures, and miniature mechanisms. It is not intended for heavy-load industrial applications. If your application requires significant torque or repeated high-stress cycling, consider a larger wire diameter. For light return-force and positioning tasks, 0.5mm spring steel wire provides reliable performance.
These springs are made from spring steel, which offers good mechanical properties but limited inherent corrosion resistance. For indoor, dry environments they perform well without additional treatment. For humid or outdoor environments, consider applying a light coat of oil or using a corrosion-inhibiting spray after installation. If your application requires stainless steel, please contact us to confirm availability.
Torsion springs are designed to be loaded in one direction only — the direction that tightens the coil. Loading a torsion spring in the opposite direction (unwinding direction) reduces its effective spring rate and can cause permanent deformation or failure. Always select the wind direction that matches your mechanism's loading direction.
The leg angle is the angle between the two straight legs of the spring in its free (unloaded) state. Choose the angle that matches your mechanism's geometry when the spring is at rest. For example, if your mechanism holds two arms at 90° when unloaded, select the 90° variant. The spring will then exert return torque as the arms are deflected away from that rest angle. If you are unsure, 90° is the most common configuration for general-purpose applications.
