Constant Force Spring
Constant Force Spring
A flat strip of pre-stressed steel coiled on a drum. Delivers near-constant force across long extension distances.
A constant force spring is a coiled strip of spring steel on a drum. As it unwinds, it exerts the same force throughout its travel — unlike a regular extension spring, where force scales with stretch. Used wherever you need predictable force over long extension: counterbalances, tape measures, motor brushes, cable retractors.
We supply constant-force springs in stainless and high-carbon strip stock, in standard and custom widths and forces.
Specifications
| Strip width | 5mm – 50mm |
| Strip thickness | 0.1mm – 1.0mm |
| Force output | 0.5N – 50N typical |
| Extension length | up to 3m |
| Materials | Stainless steel strip, high-carbon strip |
| Lead time | Production runs 2–4 weeks |
| MOQ | None — single piece available |
Common applications
- Cable and hose retractors
- Counterbalance mechanisms
- Motor brush spring tension
- Window blinds and shades
- Tape measure return
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.