Types of Screws: A Practical Selection Guide
Quick answer: Common screw families include wood, machine, sheet-metal, self-tapping, self-drilling, drywall, deck and pocket-hole screws. The correct family is determined first by the materials being joined and how the receiving hole is formed.
What matters most
- Wood and deck screws use threads suited to timber.
- Machine screws fit a nut or tapped hole.
- Sheet-metal and tapping screws form threads in suitable material.
- Self-drilling screws add a drill-point feature.
- Drywall and pocket-hole screws are optimized for specific systems.
How to choose or use it
Define the base material, thickness, exposure, required strength, head clearance and whether the joint will be removed. Then confirm diameter, length, thread standard, material and coating. For structural or safety-critical work, follow the project specification.
Before buying, verify the screw diameter, length, thread, head style, drive, material and finish against the mating parts. A correct-looking screw can still be incompatible if its thread standard or corrosion performance is wrong.
Installation checklist
- Inspect the parts and confirm the required hole or mating thread.
- Use a correctly fitting driver and keep it aligned with the screw axis.
- Tighten only until the joint seats or to the specified torque; overtightening can strip threads or damage the workpiece.
- For structural, overhead or safety-critical joints, follow the approved drawing, code or fastener manufacturer’s data.