Glossary

In the context of fasteners like bolts and screws, the drive style is the shaped recess or protrusion on the head of the fastener. This is the part of the fastener designed to accept a specific tool, such as a screwdriver or wrench, to apply torque for tightening or loosening. The drive style is a fundamental characteristic of a fastener, and its design has a direct impact on the tool you need and how the fastener performs.

The choice of a drive style is important because it dictates several key factors. First, it determines how much torque can be applied to a fastener without damaging it. Second, it affects cam-out, which is when the tool slips out of the recess. Drives with better cam-out resistance allow for more efficient power tool use and reduce the chance of stripping the fastener head. Finally, some drive styles are designed for specific applications, such as for security or aesthetics, requiring a specialized tool to prevent tampering.

Here are a few of the most common drive styles and their key features:

Slotted: The oldest and simplest design, it has a single slot and is prone to cam-out, making it unsuitable for high-torque applications.

Phillips: This is the most common drive. The cross-shaped recess was originally designed to intentionally cam-out at a certain torque to prevent over-tightening.

Torx (Star): With a six-pointed star shape, this drive offers superior cam-out resistance and can handle very high torque, making it popular in the automotive and electronics industries.

Hex Socket (Allen): This style features a hexagonal recess that is driven by an Allen key. It's well-suited for high-torque needs and is commonly found in machinery and furniture.

Robertson (Square): A square-shaped recess that provides excellent grip and is highly resistant to cam-out. It's a favorite in woodworking because the tapered shape can hold the screw on the driver.