BA thread are metric based, 0BA is 6mm diameter x 1mm pitch with 47.5
degree included angle IIRC. The BA number is used as a power in a
formula to produce the thread details.

Nick Müller wrote:

Jordan wrote:

BA is metric, sort of.


Oh no, not again. BA is not metric.
The "B" in BA stands for "British", so this _can't_ be metric. :-)

Nick