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