Wire forming and springs: design rules
Bending and coiling wire into springs, clips, hooks and wire forms.
Typical tolerance
Specify only what matters (free length, diameters, spring rate); wire forms vary by a fraction of a millimetre.
Files to send
Drawing with wire diameter, material, dimensions and, for springs, free length, diameters and rate or load.
Common materials
Music wire, stainless (302/304), oil-tempered steel, phosphor bronze.
The rules, with reasons
- Minimum bend. Inside bend radius at least about 1× the wire diameter. Why: Tighter bends crack the wire.
- Spring index. Keep the ratio of coil diameter to wire diameter between about 4 and 12. Why: Outside this range springs are hard to make or unstable.
- Material. Choose by load, corrosion and temperature: music wire for strength, stainless for corrosion. Why: The wrong wire fails or rusts.
- Stress relief. Ask for stress relief after coiling for springs under load. Why: It stabilises dimensions and life.
- Cycles. State the expected number of load cycles. Why: It decides wire, stress level and surface treatment.
Before you ask for a quote
- Wire material and diameter
- Dimensions and tolerances
- Spring rate or load
- Quantity
- Finish (plating, coating)
Common mistakes
- Bends tighter than the wire allows
- No load or cycle information
- Missing end-type specification on springs
Request a quote Find manufacturers
Typical rules of thumb, not a guarantee. The manufacturer's own design guidelines override them: ask for them and check your design against both before ordering.