British Standard Square and Hexagon Bolts


British Standard Square and Hexagon Bolts, Screws and Nuts.—Important dimensions of precision hexagon bolts, screws and nuts (BSW and BSF threads) as covered by British Standard 1083:1965 are given in Tables 1 and 2. The use of fasteners in this standard will decrease as fasteners having Unified inch and ISO metric threads come into increasing use.

Dimensions of Unified precision hexagon bolts, screws and nuts (UNC and UNF threads) are given in BS 1768:1963 (obsolescent); of Unified black hexagon bolts, screws and nuts (UNC and UNF threads) in BS 1769:1951 (obsolescent); and of Unified black square and hexagon bolts, screws and nuts (UNC and UNF threads) in BS 2708:1956 (withdrawn). Unified nominal and basic dimensions in these British Standards are the same as the comparable dimensions in the American Standards, but the tolerances applied to these basic dimensions may differ because of rounding-off practices and other factors. For Unified dimensions of square and hexagon bolts and nuts as given in ANSI/ASME B18.2.1-1996 and ANSI/ASME B18.2.2-1987 (R1999).

ISO metric precision hexagon bolts, screws and nuts are specified in the British Standard BS 3692:1967 (obsolescent) (see British Standard ISO Metric Precision Hexagon Bolts, Screws and Nuts), and ISO metric black hexagon bolts, screws and nuts are covered by British Standard BS 4190:1967 (obsolescent).

British Standard Screwed Studs.—General purpose screwed studs are covered in British Standard 2693: Part 1:1956. The aim in this standard is to provide for a stud having tolerances which would not render it expensive to manufacture and which could be used in association with standard tapped holes for most purposes. Provision has been made for the use of both Unified Fine threads, Unified Coarse threads, British Standard Fine threads, and British Standard Whitworth threads as shown in the table on page 1573. Designations: The metal end of the stud is the end which is screwed into the component. The nut end is the end of the screw of the stud which is not screwed into the component. The plain portion of the stud is the unthreaded length.

In general, it will be found that the amount of oversize specified for the studs will produce a satisfactory fit in conjunction with the standard tapping as above. Even when interference is not present, locking will take place on the thread runout which has been carefully controlled for this purpose. Where it is considered essential to assure a true interference fit, higher grade studs should be used. It is recommended that standard studs be used even under special conditions where selective assembly may be necessary.


British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Bolts, Screws, and Nuts
British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Bolts, Screws, and Nuts


Table 1. British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Slotted and Castle Nuts BS 1083:1965 (obsolescent)
British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Slotted and Castle Nuts


Table 2. British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Slotted and Castle Nuts BS 1083:1965 (obsolescent)
British Standard Whitworth (BSW) and Fine (BSF) Precision Hexagon Slotted and Castle Nuts



Table 3. British Standard ISO Metric Precision Hexagon Bolts, Screws and Nuts
BS 3692:1967 (obsolescent)
British Standard ISO Metric Precision Hexagon Bolts, Screws and Nuts


Table 4. British Standard ISO Metric Precision Hexagon Bolts and Screws BS 3692:1967 (obsolescent)
British Standard ISO Metric Precision Hexagon Bolts and Screws BS 3692:1967 (obsolescent)


Table 5. British Standard ISO Metric Precision Hexagon Nuts and Thin Nuts BS 3692:1967 (obsolescent)
British Standard ISO Metric Precision Hexagon Bolts and Screws BS 3692:1967 (obsolescent)


You may see also the other related topics:
Metric Threaded Fasteners - List of Standard ANSI for Metric Screws
Unified Screw Threads - American Standard for Unified Screw Threads
Engineering Books - Mechanical Engineering Books