STANDARD SIZES OF MATERIALS

Abstract

This chapter describes standard sizes of materials. It discusses the wire gauge sizes. Many wire gauge standards have been used in the past in the United Kingdom, but the principal ones have been the Standard Wire Gauge (SWG), sometimes referred as the British Imperial Wire Gauge and the Birmingham Gauge (BG). With the advent of metrication, the opportunity has been taken of not only agreeing an International series of wire, sheet, and strip sizes but also to adopt a preferred series of increments based on the R10, R20, and R40 preferred numbers in International Organisation for Standardisation (ISO) Recommendation R3. The basic diameters for wires are shown in ISO Recommendation R388 and BS 4391 and cover the size range 0020–25 mm. In selecting sizes, preference should be given to the R10, R20, and R40 series in that order.