Spring Design Calculator - Free Online Helical Spring Tool
Spring Design Calculator
Design helical springs for compression and extension applications. Calculate spring rate, stress, and dimensions for optimal performance.
Spring Type
Design Requirements
Spring Dimensions
Spring Design Guidelines
Recommended Spring Index
- • Optimal: 5 to 9
- • Acceptable: 4 to 12
- • Difficult: < 4 or > 15
- • Consider manufacturability
Safety Factors
- • Static: 1.2 - 1.5
- • Cyclic: 1.5 - 2.0
- • Critical: 2.0 - 2.5
- • Based on yield stress
How to use this calculator
🌀 How to Use This Calculator
- Select spring type (compression or extension)
- Enter working load and deflection requirements
- Input free length and maximum deflection
- Specify wire diameter, mean diameter, and coils
- Select material and end type
- Calculate to get spring rate, stress, and design verification
📐 Spring Design Formulas
Spring Rate
k = Gd⁴/(8D³n)
Where:
G = Shear modulus
d = Wire diameter
D = Mean coil diameter
n = Active coils
Shear Stress
τ = Kw × 8FD/(πd³)
Kw = Wahl factor
Kw = (4C-1)/(4C-4) + 0.615/C
C = Spring index (D/d)
🌟 Practical Examples
100N load, 10mm deflection, music wire
D=20mm, d=2.5mm, n=8 coils
5000N load, 50mm travel, chrome vanadium
D=120mm, d=15mm, n=6 coils
Extension spring, 50N preload
D=15mm, d=1.5mm, initial tension
💡 Design Tips
- • Keep spring index C between 5-9 for best results
- • Allow 15-20% margin on solid height
- • Consider buckling for L/D > 4
- • Shot peen for fatigue applications
- • Stress relieve after coiling
- • Use closed and ground ends for stability
- • Account for relaxation at high temperatures
⚠️ Important Considerations
- • Never exceed 80% of torsional yield strength
- • Avoid resonance - check natural frequency
- • Consider set removal for precision applications
- • Account for tolerance stackup in assemblies
- • Temperature affects modulus and strength
- • Corrosion can cause premature failure
- • Always proof test critical springs
About this calculator
Design compression and extension springs. Calculate spring rate, stress, and dimensions for helical springs.
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