Intro to Millwright 2025 – 400 Free Practice Questions to Pass the Exam

The correct answer is an expansion anchor, which works by driving a wedge that expands the anchor body within a pre-drilled hole in a solid substrate. When the anchor is installed, a tool or fastener is used to drive the wedge into the anchor, causing it to expand outward against the walls of the hole. This mechanical action secures the anchor in place and allows it to hold significant loads in tension.

Expansion anchors are commonly used in concrete or masonry applications, where a strong and reliable anchoring solution is required. The principle of expansion provides a firm grip, making them ideal for heavy-duty fastening applications. This capability distinguishes them from other types of anchors that function differently.

For instance, drop-in anchors are designed specifically for use with a setting tool and provide a flush installation but do not work by wedging. Screw anchors rely on the threads of a screw to hold in softer materials, offering a different kind of attachment method. Toggle anchors operate by using a spring-loaded mechanism that opens inside a hollow wall as it's inserted, relying on a completely different action for securing.