Engineered for hassle-free fastening in metal, wood, and composite materials, these hex head self-drilling screws eliminate the need for pre-drilling—saving time for both DIY enthusiasts and professional installers.
Their key design highlights include:
•Hexagonal head: Enables secure grip with wrenches or socket tools, preventing slippage even under high torque, ideal for tight or heavy-duty connections.
•Self-drilling tip & cutting threads: The sharp, precision-machined tip drills pilot holes automatically, while the aggressive threads ensure fast, firm penetration and long-term holding power, no extra drilling tools required.
Crafted from high-strength carbon steel (with options for zinc plating, galvanization, or stainless steel), they offer excellent corrosion resistance and durability—suitable for indoor/outdoor applications like metal framing, roofing, gutter installation, wooden structure assembly, and appliance mounting.
Available in multiple sizes (e.g., 4.2x16mm, 5.5x25mm) to match different material thicknesses, these screws deliver reliable performance for quick, efficient fastening tasks.
| Thread Size | 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 |
| c | min | 0.4 | 0.6 | 0.6 | 0.8 | 0.9 | 1 | 1 |
| dc | max | 6.3 | 8.3 | 8.3 | 8.8 | 10.5 | 11 | 13.5 |
| min | 5.8 | 7.6 | 7.6 | 8.1 | 9.8 | 10 | 12.2 | |
| e | min | 4.28 | 5.96 | 5.96 | 7.59 | 8.71 | 8.71 | 10.95 |
| k | max | 2.8 | 3.4 | 3.4 | 4.1 | 4.3 | 5.4 | 5.9 |
| min | 2.5 | 3 | 3 | 3.6 | 3.8 | 4.8 | 5.3 | |
| kw | min | 1.3 | 1.5 | 1.5 | 1.8 | 2.2 | 2.7 | 3.1 |
| r | max | 0.4 | 0.5 | 0.5 | 0.6 | 0.7 | 0.8 | 0.9 |
| s | max | 4 | 5.5 | 5.5 | 7 | 8 | 8 | 10 |
| min | 3.82 | 5.32 | 5.32 | 6.78 | 7.78 | 7.78 | 9.78 | |
| dp | 2.3 | 2.8 | 3.1 | 3.6 | 4.1 | 4.8 | 5.8 | |
| 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 | |