BS 8726-1:2002

Cylindrical helical springs made from rectangular and square section wire and bar. Guide to calculation and design. Compression springs | Status: Confirmed, Current

1 Scope This British Standard provides guidance on the design of parallel sided helical compression springs manufactured from rectangular and square section wire and bar. This standard applies only to springs made from rectangular section material where the ratio of radial dimension, b, to the axial dimension, h, termed the shape factor, m, is not greater than 2.5 and not less than 0.4.

NOTE 1 This applies because, outside the shape factor range 2.5 to 0.4, it is difficult to coil a spring accurately.

NOTE 2 There are numerous methods of calculating the parameters necessary for the design of springs and initially the designer is free to use any one of these.

Three types of end coils are provided for, i.e. open end, closed end and closed and ground end, the last of these being applicable only to springs where the axial dimension of material is 0.5 mm or greater. This British Standard differentiates between springs that have or have not been stress relieved after forming, designated group A springs, and springs, the material of which has undergone a structural change by heat treatment after forming, designated group B springs. This British Standard gives two methods of specifying springs for general purposes and one method of testing springs.