When fastening metal to metal, which screw is the most effective?

The machine screw is specifically designed for fastening metal to metal, which makes it the most effective choice in this context. Machine screws feature a uniform diameter shaft and threads that are often designed to fit into nuts or pre-tapped holes in metal. This design allows for a strong and secure connection, as they create a tight fit that can handle higher torque loads typically associated with metal fastening.

In contrast, wood screws are primarily intended for joining wood, which has different material properties and requires a different kind of thread design to grip into the fibers of wood. Lag bolts, while effective for heavy-duty applications in wood or concrete, are not ideally suited for metal-to-metal connections. Lastly, roundhead stove bolts, which typically include a washer and are often used in situations requiring tight fastening with a larger head, are less versatile when it comes to applications that require the specific dimensions and strength found in machine screws.

Therefore, when considering effectiveness for fastening metal components, machine screws are the preferred option due to their design and compatibility with metal hardware.