Date : 2016-06-23 12:24:21

Design procedure for helical compression spring of circular cross section

1) Diameter of wire:

Shear stress

Wahl’s stress factor

Also refer for k value from DHB Figure

Where d = diameter of spring wire

‘c’generally varies from 4 to 12 for general use


2. Mean Diameter of Coil

Mean coil diameter D = cd

Outer diameter of coil Do= D d

Inner diameter of coil Di= D - d

3. Number of coil or turns

Axial Deflection

where i = Number of active turns or coils

4. Free length


y = Maximum deflection

Clearance ‘a’ = 25% of maximum deflection or a = xdi, for x value refer figure in DHB Assume squared and ground end


Number of additional coil n = 2


5. Stiffness or Rate of spring

6. Pitch



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