Types of Security Screws
The screw comes in different types and sizes for different purposes. Below comes some types in daily uses.
• Cap screw has a convex head, usually hexagonal, designed to be driven by a spanner or wrench.
• Wood screw has a tapered shaft allowing it to penetrate undrilled wood.
• Machine screw has a cylindrical shaft and fits into a nut or a tapped hole, a small bolt.
• Self-tapping screw has a cylindrical shaft and a sharp thread that cuts its own hole, often used in sheet metal or plastic.
• Drywall screw is a specialized self-tapping screw with a cylindrical shaft that has proved to have uses far beyond its original application.
Shapes of Security Screw Head
• Pan head: disc with chamfered outer edge.
• Cheese head: disc with cylindrical outer edge.
• Countersunk: conical, with flat outer face and tapering inner face allowing it to sink into the material, very common for wood screws.
• Button or dome head: flat inner face and hemispherical outer face.
• Mirror screw head: countersunk head with a tapped hole to receive a separate screw-in chrome-plated cover, used for attaching