The following is a comparison of BSP threaded hydraulic fittings ID and OD data:

1/8 inch:

Outer diameter: 9.73mm
Inner diameter: 8.56mm
Teeth per inch: 28

1/4 inch:

Outer diameter: 13.16mm
Inner Diameter: 11.43mm
Teeth per inch: 19

3/8 inch:

Outer diameter: 16.64mm
Inner Diameter: 14.92mm
Teeth per inch: 19

1/2 inch:

Outer diameter: 20.96mm
Inner Diameter: 18.63mm
Teeth per inch: 14

3/4 inch:

Outer diameter: 26.42mm
Inner Diameter: 24.10mm
Teeth per inch: 14

1 inch:

Outer diameter: 33.34mm
Inner Diameter: 30.24mm
Teeth per inch: 11

1 1/4 inches:

Outer diameter: 41.98mm
Inner Diameter: 38.90mm
Teeth per inch: 11

1 1/2 inches:

Outer diameter: 47.86mm
Inner Diameter: 44.80mm
Teeth per inch: 11

2 inches:

Outer diameter: 59.66mm
Inner Diameter: 56.60mm
Teeth per inch: 11

2 1/2 inches:

Outer diameter: 75.16mm
Inner Diameter: 72.16mm
Teeth per inch: 11

3 inches:

Outer diameter: 87.80mm
Inner Diameter: 84.84mm
Teeth per inch: 11

Please note that actual production will also take into account materials, manufacturing processes and specific application requirements.