ESDU 83003 provides a comprehensive guide to the concepts and principles relating to the design and operation of helical springs. After a detailed description of the prestressing process@ the considerations governing choice of material such as operational reliability@ corrosion@ temperature@ electrical conductivity etc.@ are discussed. Values of the operating temperature ranges of 27 spring materials are tabulated. Consideration is given to the manner of loading including cyclic@ transverse@ impact and eccentric loading@ and buckling is discussed. Different designs of end forms for compression and tension springs are described with their effect on manufacturing costs and the free and solid lengths. Surface finish and treatment processes are examined. An approach to optimum design that minimises the weight@ volume or closed length is described together with an example calculation. The information required by the manufacturer is discussed and a blank table for completion by the user is provided listing the essential items that must be specified to the manufacturer. Some alternative spring types are briefly described and a glossary of spring terminology is appended.