Allen Wrenches and Torx Wrenches

An Allen wrench or hex wrench (A) is a short, metal, six-sided rod that’s used to tighten screws and bolts that contain similar sixsided indentations. A typical Allen wrench has a right-angle bend near one end that forms a handle. Even though most Allen wrenches are shaped with a right-angle bend, tool companies also produce Allen sockets and Allen wrench sets that don’t have this bend. Allen wrenches come in many different sizes—you can buy them individually or in sets.

The Torx wrench is similar to the Allen wrench, except that the end of the Torx wrench is star-shaped (B). Torx wrenches are used when higher fastening strengths are required, because they can handle more turning force without slipping. For this reason, Torx-type bolts are ideal to use with power tools and on assembly lines at manufacturing plants. Therefore, more and more Torx bolts are being used today. Like Allen wrenches, Torx wrenches are also produced as sockets or with screwdriver-type handles on them.
(C) shows how the end of an Allen wrench fits into a set screw, and (D) shows the end of a Torx wrench.