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When a mechanism fails because a spring loses tension, snaps under load, or simply doesn't fit the geometry of your design, the entire project stalls. Engineers, hobbyists, and repair technicians who need consistent, repeatable torque in compact assemblies rely on torsion springs with exact wire and coil specifications. This listing is designed for those users — offering a 10-piece pack of left-hand wound torsion springs in spring steel, configurable across wire diameter, outer diameter, coil count, and leg angle.
Each spring is wound from 0.5mm spring steel wire with outer diameters ranging from 3mm to 6mm (approximately 0.118" to 0.236"). Coil counts span 3 to 9 turns, and leg angles are available in 60°, 90°, 120°, and 180°, allowing precise fit across a wide range of mechanical configurations. The left-hand wind direction means the spring tightens when rotated counterclockwise.
Typical applications include small appliance hinges, electronic enclosure latches, precision instrument return mechanisms, RC model components, and DIY automation projects requiring controlled angular return force. Long-tail use cases include torsion spring replacement for cabinet door hinges, clock mechanism repair, and custom robotics joint assemblies.
| Wire Diameter | 0.5mm (0.020") |
|---|---|
| Outer Diameter (OD) | 3mm / 3.5mm / 4mm / 4.5mm / 5mm / 5.5mm / 6mm |
| Inner Diameter (ID) | OD − 1.0mm (e.g., 3mm OD → 2mm ID) |
| Number of Coils | 3 / 4 / 5 / 6 / 7 / 8 / 9 Coils |
| Leg Angle | 60° / 90° / 120° / 180° |
| Wind Direction | Left-hand (counterclockwise) |
| Material | Spring Steel |
| Finish | See variant options |
| Quantity per Pack | 10 pieces |
| Spring Rate | See variant options |
| Free Angle | See variant options |
The outer diameter (OD) should be selected based on the bore or housing your spring sits in, or the shaft it wraps around. The inner diameter (ID) equals OD minus twice the wire diameter — for this spring, ID = OD − 1.0mm. For example, a 5mm OD spring has a 4mm ID, suitable for a shaft up to approximately 3.8–3.9mm to allow clearance.
Left-hand wound means the coils spiral counterclockwise when viewed from the front. The spring tightens (stores energy) when the load rotates it counterclockwise. If your mechanism applies torque clockwise, you need a right-hand wound spring instead. Using the wrong wind direction will cause the spring to unwind rather than store energy.
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 mounting geometry so the legs contact their stops at the correct position without pre-stressing the spring beyond its design range. Common choices: 90° for right-angle brackets, 180° for parallel-leg configurations, 60° or 120° for angled housings.
More coils reduce the spring rate (making it softer) and increase the angular deflection capacity before the spring reaches its stress limit. Fewer coils produce a stiffer spring with less travel. If you need a gentle, long-travel return force, choose more coils. For a firm, short-travel snap-back, choose fewer coils.
These springs are made from spring steel, which offers good mechanical properties but moderate corrosion resistance. For environments with moisture, humidity, or mild chemical exposure, consider applying a light coat of oil or grease after installation. For highly corrosive environments, stainless steel torsion springs would be a more suitable choice.
Spring steel can rust if exposed to prolonged moisture without protection. For outdoor use, apply a corrosion-inhibiting lubricant or consider housing the spring in a protected enclosure. If long-term outdoor exposure is required, a stainless steel variant is recommended for extended service life.
This listing provides 10 identical springs per order. This is ideal for batch repairs, prototyping multiple units, or keeping spares on hand. All 10 springs in a pack share the same wire diameter, OD, coil count, and leg angle as selected in the variant options above.
