HEX HEAD SELF TAPPING SCREW

Self tapping roofing screws are a screw that taps its own hole as it is driven into a material. More narrowly, self tapping roofing screws is only used to describe a specific type of thread-cutting screw used to create threads in relatively soft or sheet materials, excluding wood screws. 

The tips of roofing screws with washers are described as thread-forming, thread-cutting, or thread-rolling. If the screw is pointed, it will be thread-cutting – tapping and creating threads in a pre-drilled hole. If the tip is flat, it will be thread-rolling – rolling out or extruding threads, creating zero clearance between the screw and the material.

The most important difference between self tapping roofing screws and self-drilling screws is that self-drilling screws cannot go through metal without a pilot hole, which must be pre-drilled or punched.

The exact size of the drilled or punched hole is also important. If the hole is too large, the screw will become loose and will not penetrate properly and safely. If the hole is too small, the screw will break or cause the material to split or crack.

Roofing screws with washers are suitable for metals, various types of plastics (plywood, fiberglass, polycarbonate) and cast or forged materials such as iron, aluminum, brass or bronze. Self tapping roofing screws are also suitable for surfaces where the rear end cannot be fixed with a nut. Common applications include fastening aluminum profiles, fixing metal brackets to wood, or inserting screws into plastic housings.