An Allen key, also known as a hex key or hex wrench, is a small, L-shaped tool used to drive screws and bolts with a hexagonal socket in their heads. They are simple, lightweight, and effective tools commonly used in assembly and maintenance tasks. In robotics we use Hex head screws all of the time for our assemblies and thus we use Allen keys all of the time to tighten and loosen the screws. There are many different types of Allen keys. We will review the different types and their uses below:
The classic, simple design with two arms of different lengths.
The shorter arm is used for high-torque applications, and the longer arm is for better reach or when less torque is needed.
Feature a T-shaped handle for a comfortable grip.
Provide greater torque and are ideal for repetitive tasks or stubborn fasteners.
Resemble a pocketknife, with multiple hex keys of different sizes folding into a single handle.
Convenient for portability and organizing multiple sizes in one place.
Have a rounded end that allows the key to engage the socket at an angle.
Useful for accessing screws in tight or awkward spaces.
Designed to fit into drill drivers or ratchet handles as well as in an electric drill or driver.
Used for tasks that require more speed or force than manual tools.
Metric keys are measured in millimeters, while imperial keys use inches. (In general, FTC uses metric, FRC uses Standard or Imperial.)
Choose the Correct Size: Ensure the key matches the socket size precisely to prevent rounding off the fastener or damaging the tool.
Leverage: Use the longer arm for better reach and the shorter arm for applying more torque.
Ball-End Caution: While ball-end keys provide angular flexibility, they are less capable of handling high torque than standard ends.
Keep Sets Organized: Store Allen keys in labeled holders to quickly find the required size.
In FRC Robotics we use Standard Tools and Fasteners. To make it easy to identify our common use Allen Keys, we mark them with electrical tape. Each color is a particular sized wrench used for a common nut on the robot.
Yellow -> 3/16" -> Standard hex for 1/4-20 Socket Head Screw
Red -> 5/32" -> Standard hex for 1/4-20 Pan Head and 10-32 Socket Head Screws
Blue -> 9/64" -> Standard hex for a #8-32 Socket Head Screw
Green -> 1/8" -> Standard hex for a #10-32 Pan Head Screw
White -> 3/32" -> Standard hex for a #8-32 Pan Head Screw
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