Basic Thread Dimensions
*Â The below values are nomoinal (without tolerances) and are valid for both external and internal threads.
| Thread Family |
BSPP (G) |
| Relevant Standards |
ISO 228-1, ISO 228-2 |
Tolerances for all Classes
BSPP G 1 1/8 (Internal Thread)
| Property |
Minimum |
Maximum |
| Minor Diameter (D1) |
34.94 mm (1.3756 ") |
35.58 mm (1.4008 ") |
| Pitch Diameter (D2) |
36.418 mm (1.4338 ") |
36.598 mm (1.4409 ") |
BSPP G 1 1/8-A (External Higher precision)
| Property |
Minimum |
Maximum |
| Major Diameter (d) |
37.537 mm (1.4778 ") |
37.897 mm (1.492 ") |
| Pitch Diameter (d2) |
36.238 mm (1.4267 ") |
36.418 mm (1.4338 ") |
BSPP G 1 1/8-A (External Low precision
| Property |
Minimum |
Maximum |
| Major Diameter (d) |
37.537 mm (1.4778 ") |
37.897 mm (1.492 ") |
| Pitch Diameter (d2) |
36.058 mm (1.4196 ") |
36.418 mm (1.4338 ") |
* For More Threadibg Information go to the BSP Thread Calculator
