Concrete screws (often called masonry screws or by trade names like Excaliber bolts) are highly efficient, self-tapping fasteners that thread directly into pre-drilled holes in concrete, brick, block, and stone.
Unlike drop-in, wedge, or shield anchors, they do not use an expansion sleeve or nylon plug to generate friction.
Instead, they feature specialized hardened, saw-tooth high-low threads that cut directly into the masonry walls, forming a direct, expansion-free mechanical interlock.
Because they do not exert expansion pressure, concrete screws can be installed much closer to edges without splitting the concrete.
Core Mechanics & Profile Choices
Concrete screws are engineered from hardened carbon steel or stainless steel to slice through stone aggregates without breaking. As they are driven down, the dust is channelled upward along the screw's relief grooves.
They are available in several common configurations tailored to specific applications:
- Hex Head (Flanged): Features a built-in washer face. It allows for maximum driving torque with a socket driver and is perfect for securing metal brackets, machinery plates, or heavy-duty fixtures where aesthetics matter less.
- Countersunk (Flat Head): Designed with a Torx/TX or Phillips drive recess. The head sinks entirely flush into the fixture, which is ideal for timber framing, battening, and window tracks where a flat surface is required.
