BS 93:2008

This standard BS 93:2008 British Association (B.A.) screw threads. Requirements is classified in these ICS categories:

• 21.040.30 Special screw threads

This British Standard specifies limits of sizes, and tolerances, for single start parallel screw threads of British Association (B.A.) form. It is not applicable to screw threads associated with interference fits, such as those on the “metal ends” of studs and in the corresponding tapped holes.

This British Standard specifies the following:

1. basic sizes for B.A. threads, sizes 0 B.A. to 16 B.A.;

2. limits of size, and tolerances, for close class and normal class external threads of sizes 0 B.A. to 10 B.A.;

3. limits of size, and tolerances, for normal class external threads of sizes 11 B.A. to 16 B.A.;

4. limits of size, and tolerances, for a single class of internal threads of sizes 0 B.A. to 16 B.A.