Philips CSK Self-drilling screw, Metal Screw,available for ISO ROHS,SGS
Self-tapping screws are preferable in situations where the screw pattern is not pre-drilled, or there is no specific screw pattern. Self-tapping screws are useful for fastening metals, including steel, aluminum and brass. Although they work with most common material thicknesses, thick steel may require the use of multiple screws to tap the initial hole.
| Screw Thread d | ST2.9 | ST3.5 | (ST3.9) | ST4.2 | ST4.8 | ST5.5 | ST6.3 | |
| P | Pitch | 1.1 | 1.3 | 1.3 | 1.4 | 1.6 | 1.8 | 1.8 |
| a | max | 1.1 | 1.3 | 1.3 | 1.4 | 1.6 | 1.8 | 1.8 |
| dk | max | 5.5 | 6.8 | 7.5 | 8.1 | 9.5 | 10.8 | 12.4 |
| min | 5.2 | 6.44 | 7.14 | 7.74 | 9.14 | 10.37 | 11.97 | |
| k | ≈ | 1.7 | 2.1 | 2.3 | 2.5 | 3 | 3.4 | 3.8 |
| Socket No. | 1 | 2 | 2 | 2 | 2 | 3 | 3 | |
| dp | max | 2.3 | 2.8 | 3.1 | 3.6 | 4.1 | 4.8 | 5.8 |
| M1 | 3 | 4.2 | 4.6 | 4.7 | 5.1 | 6.8 | 7.1 | |
| M2 | 2.8 | 4 | 4.2 | 4.4 | 5 | 6.3 | 7 | |
| Drilling range(thickness) | 0.7~1.9 | 0.7~2.25 | 0.7~2.4 | 1.75~3 | 1.75~4.4 | 1.75~5.25 | 2~6 | |
| Lg | - | - | - | - | - | - | - | |