BA also is known as British Association. This standard thread form is recommended for screws smaller than ¼ inch. It is used for small parts instead of BSW and BSF threads. BA threads are similar to Whitworth threads in terms of rounded crests and roots except that the symmetrical angles are 47 degrees and 30 minutes and the crest and root radiuses are proportionately larger. BA thread plug gages conform to S.93. Tolerances are to BS.919 Part 2 2007. BA screw thread plug gages are manufactured to standard class. All BA thread gages are right hand only. This thread form is rarely used in the United States.
WESTport provides a complete line of BA (British Association) Thread Plug Gages. They are available in sizes from BA 0 to BA 16. Free Technical support is available from our core of engineers to assist you with any questions you may have.