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 3 (Internal Thread)
| Property |
Minimum |
Maximum |
| Minor Diameter (D1) |
84.927 mm (3.3436 ") |
85.567 mm (3.3688 ") |
| Pitch Diameter (D2) |
86.405 mm (3.4018 ") |
86.622 mm (3.4103 ") |
BSPP G 3-A (External Higher precision)
| Property |
Minimum |
Maximum |
| Major Diameter (d) |
87.45 mm (3.4429 ") |
87.884 mm (3.46 ") |
| Pitch Diameter (d2) |
86.188 mm (3.3932 ") |
86.405 mm (3.4018 ") |
BSPP G 3-A (External Low precision
| Property |
Minimum |
Maximum |
| Major Diameter (d) |
87.45 mm (3.4429 ") |
87.884 mm (3.46 ") |
| Pitch Diameter (d2) |
85.971 mm (3.3847 ") |
86.405 mm (3.4018 ") |
* For More Threadibg Information go to the BSP Thread Calculator
