Extension Spring
Extension Spring
A coil that pulls back. Loaded axially in tension, with hooks or loops on the ends. Returns to length when released.
Extension springs store energy when stretched and pull back to their original length on release. They handle tension forces — anywhere a mechanism needs to spring closed, retract, or hold under pull.
We coil extension springs with German-style hooks, English-style hooks, screw-in plugs, or custom-formed ends. Initial tension specified to your drawing.
Specifications
| Wire diameter | 0.2mm – 8mm |
| Outer diameter | 2mm – 80mm |
| Body length | up to 400mm |
| End types | German hook, English hook, side loop, swivel hook, screw-in |
| Initial tension | specified per drawing |
| Materials | Stainless spring steel, high-carbon spring steel |
| Tolerance | ±0.05mm wire, ±1% length |
| Lead time | 2–5 days for stock items · production runs 1–3 weeks · walk-in single-piece custom often within an hour |
| MOQ | None — single piece available |
Common applications
- Garage door counterbalance
- Trampolines and exercise equipment
- Clamping mechanisms
- Door and gate closers
- Industrial weighing equipment
Materials & finishes
Materials & finishes
Stainless spring steel and high-carbon spring steel for most spring types. Chrome silicon and chrome vanadium for die-spring grades. Polyurethane elastomer for urethane springs. Finishes available: zinc plating, black oxide, phosphate, passivated stainless.
Dimensions & tolerances
Dimensions & tolerances
Wire diameter range: 0.1mm – 10mm. Tolerance: ±0.05mm wire, ±1% free length, ±10% load. Squareness: 3° or less. Custom geometries to drawing — send a sample or a sketch.
Lead time & ordering
Lead time & ordering
Walk-in single-piece custom: often within an hour at our Valenzuela factory for standard geometries. Stock items: 2–5 days. Production runs: 1–3 weeks. No minimum order — single piece available.
QC & documentation
QC & documentation
Every batch is sample-tested before pack-out. Mill certificates, dimensional reports, and full material traceability available on request — at no extra charge for production runs above 500 pieces.
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Have a sample?
Get directionsBring it to our factory in Valenzuela. Walk-ins welcome Mon–Sat 08:30–16:00 — we'll quote on the spot for standard work.
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2–5 days standard
Most stock springs ship in 2–5 days. Custom runs in 1–3 weeks. Same-day pickup at our Valenzuela factory available.
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Material certs included
Mill certificates, dimensional reports, and material traceability documentation provided at no charge for production runs above 500 pieces.