Specifies the dimensions for bolts and screws with British Standard Whitworth threads in diameters from ¼ in to 6 in, and the material requirements for steel bolts, screws and nuts for general use.

This Standard specifies the requirements for hexagon bolts and screws with British Standard Whitworth (BSW) thread in diameters from 1/4in to 2 in inclusive and nuts with BSW thread in diameters from 1/4in to 6 in inclusive.The Standard is intended primarily to cover steel bolts, screws and nuts used within the temperature range of -50¦C to +300¦C, and does not make provision for products requiring special properties such as weldability or corrosion-resistance.The dimensional requirements of this Standard may also be applied to hexagon nonferrous and stainless steel bolts, screws and nuts.NOTES:1 The range of sizes included in this Standard is considered adequate for most of the applications for which this series is likely to be employed.2 To provide for the time when imperial measuring equipment is no longer available, dimensional and mechanical property requirements in metric units are given in Appendix A.3 If the purchaser requires other pitch series, i.e. BSF or other thread classes, these should be the subject of agreement between the purchaser and the manufacturer.

First published in Australia as AS (E)B506-1943.Revised and redesignated AS B100-1948.Second edition 1958.Revised and redesignated AS 2451-1981.Jointly revised and designated AS/NZS 2451:1998.Reconfirmed 2016. Originated in Australia as AS (E)B506-1943. Previous Australian edition AS 2451-1981. Jointly revised and designated AS/NZS 2451:1998.