Tapping Drill Sizes for BA Threads

The following tables show the range of drill sizes suitable for tapping BA (British Association) screw threads.

The first table gives general information about BA threads - the thread angle, and, for each size, the nominal diameter and thread pitch.

Please also read the general comment on the Tapping Index page.

BA table BA tapping 1 BA tapping 2 BA tapping 3 BA tapping 4 BA tapping 5 BA tapping 6