# Helical Spring Calculators

Calculate Spring Index

C = D/d
C = Spring Index
D = Spring Diameter
d = Wire Diameter

Spring Diameter (D):
m
Wire Diameter (d):
m

Result:

Spring Index (C):

Calculate Total Shear Stress

τ = [8×F×D×K_W]/[π×d^3]
K_W = [4C-1]/[4C-4]+[0.615]/C
τ = Total Shear Stress
F = Axial Force
D = Spring Diameter
d = Wire Diameter
Kw = Wahl Factor
C = Spring Index

Axial Force (F):
Spring Diameter (D):
Wire Diameter (d):

Result:

Total Shear Stress (t):
Newton/Meter2
Spring Index (C):
Wahl Factor (Kw):

Calculate Spring Axial Deflection

δ = [8×F×C^3×N]/[G×d](1+0.5/c^2)
δ = Spring Axial Deflection
F = Axial Force
d = Wire Diameter
N = Number Of Active Coils
G = Modulus of Rigidity
C = Spring Index

Axial Force (F):
N
Spring Diameter (D):
m
Wire Diameter (d):
m
Number Of Active Coils (N):
Modulus of Rigidity (G):
N / m2

Result:

Spring Axial Deflection (δ):

Calculate Spring Rate

K= [G×d]/[8×C^3×N]
K = Spring Rate
d = Wire Diameter
N = Number Of Active Coils
G = Modulus of Rigidity
C = Spring Index

Spring Diameter (D):
m
Wire Diameter (d):
m
Modulus of Rigidity (G):
N / m2
Number Of Active Coils (N):

Result:

Spring Rate (K):
Helical Spring Calculators

Example of use
Input data: spring diameter D: 14 meters; spring steel wire diameter d: 2 meters, click "Calculate" to display the result.

Output result: spring index, winding ratio is 7.
The spring index C affects the strength, stiffness, stability and ease of manufacture of the spring. The value of C is large, the middle diameter D is large, the diameter of the steel wire is small, the spring is soft, the rigidity is small, it is easy to deform, and it is easy to wind. If the C value is small, the opposite is true, the spring is harder, the rigidity is high, and it is not easy to wind. In design, it is generally recommended to take 4≤C≤14.

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