Helical Spring Mandrel Design Calculator

This calculator determines the mandrel diameter needed to render a given spring diameter.

Equation:

\( D_m = kD - d \)

Where:

\( D_m \) is the diameter of the mandrel,

\( k \) is the diameter coefficient,

\( D \) is the final diameter of the spring, measured from the center of the wire (not the outer or the inner spring diameter),

\( d \) is the diameter of the wire.