BS 84:1956

Co-operating organizations
Foreword
Specification
1 Scope
2 Nomenclature and definitions
3 Form of Whitworth screw threads
4 Classes of bolts and nuts
5 Standard diameter-pitch series: limits and
     tolerances
6 Plated threads
7 Stainless steel bolts
8 Selected thread series
     a. Basic sizes
     b. Design sizes
     c. Tolerances
9 Tolerances on effective diameter, pitch and flank
     angles
10 Designation of screw threads of Whitworth form
11 Gauges
Tables
Coarse thread series B.S.W.
1 Basic sizes
Limits and tolerances
2 Bolts - Close class
3 Nuts - Medium class
4 Bolts - Medium class
     a. Nominal sizes up to and including 3/4 in.
     b. Nominal sizes above 3/4 in.
5 Nuts - Normal class
6 Bolts - Free class
     a. Nominal sizes up to and including 3/4 in.
     b. Nominal sizes above 3/4 in.
Fine thread series B.S.F.
7 Basic sizes
Limits and tolerances
8 Bolts - Close class
9 Nuts - Medium class
10 Bolts - Medium class
     a. Nominal sizes up to and including 3/4 in.
     b. Nominal sizes above 3/4 in.
11 Nuts - Normal class
12 Bolts - Free class
     a. Nominal sizes up to and including 3/4 in.
     b. Nominal sizes above 3/4 in.
Selected thread series Whit. S.
13 Preferred diameters and pitches - Fractional sizes
13a Preferred diameters and pitches - Decimal sizes
Selected and non-standard threads
14 Depths of thread for various pitches
15 Bolts - Medium and free class allowances
16 Bolts - Close class tolerances
17 Nuts - Medium class tolerances
18 Bolts - Medium class tolerances
19 Nuts - Normal class tolerances
20 Bolts - Free class tolerances
Truncated Whitworth form screw threads with flat crests
21 Basic data
Truncated coarse thread series B.S.W.
22 Bolts and nuts - Limits and tolerances, all classes
Truncated fine thread series B.S.F.
23 Bolts and nuts - Limits and tolerances, all classes
Coarse thread series B.S.W.
24 Nuts - Close class limits and tolerances
Fine thread series B.S.F.
25 Nuts - Close class limits and tolerances
Selected and non-standard threads
26 Nuts - Close class tolerances
Appendices
A Truncated Whitworth form threads with flat crests
B Bases of tolerances and allowances for Whitworth
     form screw threads
C Tolerances on pitch and angle in relation to
     tolerance on effective diameter
D Notes on the form of the crests of Whitworth threads
E Close class nuts, limits and tolerances
       Tables 24-26

Form of thread defined. Tables: basic sizes, limits, tolerances for \'class\' bolts, nuts; BS Whitworth range, ⅛ in to 6 in; BS Fine range, $9C in to 4$9C in (limits and tolerances up to 3 in only). Also a Selected Thread series more suitable than BS Pipe parallel series for extra fine pitch applications. Appendices: limits, tolerances for B.S.W. and B.S.F. truncated bolts and nuts; bases of tolerances and allowances, formulae; effects of pitch and angle errors, acceptability of error combination; form of Whitworth crests; limits and tolerances for (non-preferred) \'close class\' nuts.