Specifications of International Thread Standards

BSB British Standard Brass Thread. Used brass tubing. BSB has a 26 TPI pitch through the whole range.
The flank angle is 55°.

Nominal
Diameter
Diameter
Inch
Diameter
mm
Tapping Drill Size
mm
TPIPitch
mm
BSB 1/8"0.1253.1751.923260.977
BSB 1/4"0.2505.5565.098260.977
BSB 3/8"0.3759.5258.273260.977
BSB 1/2"0.50012.70011.448260.977
BSB 5/8"0.62515.87514.369260.977
BSB 3/4"0.75019.05017.798260.977
BSB 7/8"0.87522.22520.973260.977
BSB 1"1.00025.40024.148260.977
BSB 1 1/8"1.50028.57527.323260.977
BSB 1 1/4"1.25031.75030.498260.977
BSB 1 1/2"1.50038.10036.848260.977
BSB Thread