Screw thread standards are amongst the oldest published by BSI British Standards. Standards for machine screw threads have evolved since the early nineteenth century to facilitate compatibility between different manufacturers and users.
Although there are sometimes 50 years between revisions, the longevity of these designs highlight the need for updated standards. A crucial element in manufacturing and engineering, the newly updated standards will be relevant for many years to come.
BSI British Standards offers a wide range of standards which are essential for anyone involved in manufacturing screw threads.
Browse all screw threads products and standards
BS 1580 Unified Screw threads series
Unified screw threads. Screw threads with diameters ¼ in and larger. Requirements
Unified screw threads. Screw threads with diameters below ¼ in. Requirements
BS 919 Screw gauge limits and tolerances series
Specification for screw gauge limits and tolerances. Gauges for screw threads of unified form
Specification for screw gauge limits and tolerances. Gauges for screw threads of Whitworth and BA forms
Screw gauge limits and tolerances. Specification for gauges for screw threads of ISO metric form
Specification for screw gauge limits and tolerances. Limits for size for gauges of screw threads of unified form diameters 1/4 in and larger
BS 3643 ISO metric screw threads series
ISO metric screw threads. Principles and basic data
ISO metric screw threads. Specification for selected limits of size
Parallel screw threads of Whitworth form. Requirements
British Association (B.A.) screw threads. Requirements
BSI Handbook 44. Threaded Fasteners