Helical springs are often specified where the large end is meant to work in a bore and the small end is meant to work over a rod. They offer the advantage of a reduced solid height compared to straight compression springs, especially when capable of “telescoping.”
A helical spring is a spiral wound wire with a constant coil diameter and uniform pitch. The most common form of helical spring is the compression spring but tension springs are also widely used. Helical springs are generally made from round wire. it is comparatively rare for springs to be made from square or rectangular sections. The strength of the steel used is one of the most important criteria to consider in designing springs. Most helical springs are mass produced by specialist’s organisations.
P – Pitch means centre distance between two coils.
F – is the deflection.