Bent Allen Wrench
- Allen wrenches or Allen keys are hexagon-shaped (six-sided) metal shafts that are bent into an L-shape for leverage. Hex drivers are “straight Allen wrenches” that have a screwdriver-type handle. These are different from the other wrenches since they fit inside a recessed hexagonal hole in screw heads instead of around a nut or bolt.
Fixed wrenches fit single, specific sizes. Metric wrench sizes are expressed as whole numbers (e.g., 8, 10, 14, 32) that correspond to the sizes in millimetres. Non-metric sizes used widely in the U.S. are also called S.A.E (Society of Automotive Engineers) sizes and are expressed as fractions of an inch; e.g., 1/4, 1/2, 3/4, 1 1/4. Since both metric and S.A.E. fasteners (nuts, bolts, etc.) are used in Canada, users must select the correct type and size of wrench to prevent injuries and damage to equipment in case of slippage when force is applied to the wrench.