Torsion springs are specified differently from compression or extension springs — torque, wind direction, and leg configuration all matter. This guide walks through what to define (and the mistakes to avoid) so you get an accurate quote and a spring that lasts.
Torsion springs are everywhere — in hinges, clips, latches, garage-door mechanisms, and countless return-to-position devices. But they trip up more buyers than any other spring type, because they’re specified by torque and rotation, not by a simple push or pull. Get one detail wrong — especially wind direction — and the spring can fail in a fraction of its expected life.
At GL Springs, torsion springs are one of our core product lines, and over 20 years we’ve seen the same handful of spec gaps again and again. Here’s how to define a custom torsion spring correctly the first time.
This is what the spring has to do: how much torque (N·mm or lb·in) it must deliver, and at what angle of rotation. The clearest way to state it is two points — for example, “20 N·mm at 30° deflection, 40 N·mm at 60°.” If you only know the working torque and travel, that’s enough for our engineers to start.
This is the parameter unique to torsion springs, and the single most common mistake buyers make. A torsion spring must be loaded in the direction that winds the coils tighter, never the direction that opens them up. Loading it to unwind dramatically shortens fatigue life — or breaks it early.
So always specify whether the spring is right-hand or left-hand wound, based on how it mounts and which way the load rotates it. If you’re not sure, describe the motion (“the arm rotates clockwise to close”) and we’ll work out the correct hand.
The legs are how a torsion spring delivers its force, so they’re as important as the coil body:
Tell us how each leg is anchored or what it pushes against; this defines the whole geometry.
As with any spring, wire size is the biggest driver of strength and cost. Provide it if your design fixes it; otherwise give us the torque and space and we’ll select the optimal size.
Torsion springs almost always work over a shaft or arbor that supports the coils. Critically, the body diameter shrinks as the spring winds up — so the inner diameter must leave clearance over the shaft at maximum deflection, or the spring will bind and seize. Always tell us the shaft diameter the spring runs on.
A double (dual-coil) torsion spring uses two coil bodies joined by a bridge to deliver higher torque or balanced loading in a compact width. If your torque is high or your space is wide and shallow, a double torsion spring may be the better design.
A spring held at one position (static) tolerates higher stress than one cycling millions of times (dynamic). Tell us the expected cycles — it shapes material choice, stress levels, and finishing.
Material follows the operating environment and stress level:
| Material | Best for | Notes |
|---|---|---|
| Carbon steel (music wire, 65Mn) | General indoor mechanisms | Economical, high torque capacity; not corrosion resistant |
| Stainless steel (304 / 316) | Corrosion, outdoor, medical, marine | Standard choice when rust is a concern |
| Alloy steel (chrome-silicon, chrome-vanadium) | High stress, heat, high-cycle fatigue | Best fatigue life under demanding loads |
| Phosphor bronze / copper alloys | Electrical contacts, non-magnetic needs | Used in battery contacts and electronics |
If you’re unsure, just describe the environment and we’ll recommend the most cost-effective material that meets it.
Send us as many of these as you have:
You don’t need every line filled in. We regularly reverse-engineer a complete design from a single sample or a rough sketch.
Torsion springs reward careful specification — and a manufacturer who asks the right questions before cutting wire. GL Springs produces precision single and double torsion springs under IATF 16949 quality control, with fast sampling and design support from engineers who do this every day.
GL Springs (Shanghai Guanglei Spring Co., Ltd.) has manufactured precision custom springs in Shanghai, China since 2005, supplying compression, torsion, extension, and wire-form springs to OEMs worldwide under IATF 16949 certification.
