BS 1769:1951

This standard BS 1769:1951 Specification. Unified black hexagon bolts, screws, nuts (UNC & UNF threads). Heavy series is classified in these ICS categories:

• 21.060.20 Nuts
• 21.060.10 Bolts, screws, studs

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.

Dimensions, general requirements for sizes ½ in to 2 in. Dimensions of bolts, screws, ordinary nuts, lock nuts, slotted nuts, bolts faced under the head and machined on shank, machined nuts. Formulae for calculation of dimensions for bolts, screw heads, nuts in intermediate sizes, and sizes larger than 2 in.