Whitworth Threads

Whitworth Threads

British Standard Whitworth

British Standard Fine

System 22 Manufactures a variety of fasteners with 55 Degree B.S.W. (British Standard Whitworth) and B.S.F. (British Standard Fine) Threads

Caution: While some British Standard Thread pitches are identical to Unified National thread pitches and may assemble, the differing thread form will result in a appreciable loss of strength and may lead to failure!

Common British Standard Threads

BSW Whitworth BSF Fine

British Threads
B.S.W B.S.F.
1/8-40 13/16-32
3/16-24 7/32-28
1/4-20 1/4-26
5/16-18 9/32-26
3/8-16 5/16-22
7/16-14 3/8-20
1/2-12 1/2-16
9/16-12 9/16-16
5/8-11 5/8-14
11/16-11 11/16-14
3/4-10 3/4-12
7/8-9 7/8-11
1-8 1-10
1 1/8-7 1 1/8-9
1 1/4-7 1 1/4-9
1 1/2-6 1 3/8-8
1 3/4-5 1 1/2-8
2-4.5 1 5/8-8
2 1/4-4 1 3/4-7
2 1/2-4 2-7
2 3/4-3.5 2 1/4-6
3-3.5 2 1/2-6
3 1/4-3.25 2 3/4-6
3 1/2-3.25 3-5
3 3/4-3 3 1/4-5
4-3 3 1/2-4.5
4 1/2-2.875 3 3/4-4.5
5-2.75 4-4.5
6-2.5 4 1/4-4