Overview of the usual screw connections
Here you will find the necessary tables for identifying the fittings and threaded connections you need.
Thread tables
BSP thread (inch)
| Nominal size |
Outer |
Outer (mm) |
Tap drill (mm) | Pitch |
| G 1/8" | 1/8 | 9,73 | 8,80 | 0,907 |
| G 1/4" | 1/4 | 13,16 | 11,80 | 1,337 |
| G 3/8" | 3/8 | 16,66 | 15,25 | 1,337 |
| G 1/2" | 1/2 | 20,95 | 19,00 | 1,814 |
| G 3/4" | 3/4 | 26,44 | 24,50 | 1,814 |
| G 1" | 1 | 33,25 | 30,75 | 2,309 |
Metric thread
| Nominal size | Outer (mm) |
Tap drill (mm) | Pitch |
| M8x1,0 | 8 | 6,92 | 1,0 |
| M10x1,0 | 10 | 8,92 | 1,0 |
| M12x1,0 | 12 | 10,92 | 1,0 |
| M12x1,5 | 12 | 10,38 | 1,5 |
| M14x1,5 | 14 | 12,38 | 1,5 |
| M16x1,5 | 16 | 14,38 | 1,5 |
| M18x1,5 | 18 | 16,38 | 1,5 |
| M20x1,5 | 20 | 18,38 | 1,5 |
| M22x1,5 | 22 | 20,38 | 1,5 |
| M26x1,5 | 26 | 24,38 | 1,5 |
| M27x2,0 | 27 | 24,84 | 2,0 |
| M30x2,0 | 30 | 27,84 | 2,0 |
| M36x2,0 | 36 | 33,84 | 2,0 |
Thread table for union nuts
Light series 24°
| Size | Wrench size | Thread |
| 6L | 14 | M12x1,5 |
| 8L | 17 | M14x1,5 |
| 10L | 19 | M16x1,5 |
| 12L | 22 | M18x1,5 |
| 15L | 27 | M22x1,5 |
| 18L | 32 | M26x1,5 |
| 22L | 36 | M30x2 |
| 28L | 41 | M36x2 |