1 Scope
This British Standard relates to the Heavy Series of Unified black hexagon bolts,
screws and nuts having Unified screw threads in a range of nominal sizes from ½ in.
to 2 in. inclusive.
NOTE It is considered that the range of nominal sizes included in this standard is adequate for most of the applications for which this series is likely to be employed, but for the convenience of users requiring larger sizes, the formulae from which the proportions for bolt heads and nuts are derived are given in Appendix A.