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Many DIY furniture assembly kits include Allen wrenches due to their low cost. Elizabeth Fernandez / Getty ImagesAllen wrenches, also known as allen keys or hex keys, come in various sizes and shapes. They are commonly included with products that require assembly. To use them correctly, understanding allen wrench sizes is essential.
What Are Allen Wrenches?
Allen wrenches are named after the Allen Manufacturing Company, which created them. These "L" shaped tools, made from alloy steel, are designed to work with hex screws [source: Alloy Artifacts]. Their compact size and ease of use make them a popular inclusion in packaging by many furniture manufacturers.
An allen wrench consists of a long arm and a short arm, both of which have the same key sizes. These tools are versatile and are used for much more than product assembly. That's why it's essential to have one or more sets of allen wrenches in your toolbox, covering both SAE and metric sizes.
Allen Wrench Sizes
To ensure you always have the right size, it's advisable to have a variety of allen wrenches. The great thing is that nearly every tool brand offers a selection of hex key sets for purchase.
You can find allen wrench size charts from virtually any manufacturer [source: Truini]. The general range of sizes (though not all sizes are present in every set) is as follows:
- 0.7 mm
- 0.9 mm
- 1.2 mm (3/64 inch)
- 1.3 mm
- 1.5 mm
- 1.6 mm (1/16 inch)
- 2.0 mm (5/64 inch)
- 2.4 mm (3/32 inch)
- 2.5 mm
- 2.8 mm (7/64 inch)
- 3.0 mm
- 3.2 mm (1/8 inch)
- mm (9/64 inch)
- 4.0 mm (5/32 inch)
- 4.4 mm (11/64 inch)
- 4.5 mm
- 4.8 mm (3/16 inch)
- 5.0 mm
- 5.2 mm (13/64 inch)
- 5.5 mm (7/32 inch)
- 6.0 mm (15/64 inch)
- 6.4 mm (1/4 inch)
- 7.0 mm
- 8.0 mm (5/16 inch)
- 9.0 mm
- 9.5 mm (3/8 inch)
- 10.0 mm
- 12.7 mm (1/2 inch)
How to Use Allen Keys Effectively
Smaller allen wrenches tend to require more careful handling than their larger counterparts. They are more prone to stripping the head if not used with caution. Be sure to clean the hex bolt before inserting the allen wrench and ensure that the wrench is aligned with all six sides properly [source: Morgan].
If you opt for a lower-cost set of allen wrenches, the smaller sizes may lack precision, resulting in poor performance or, over time, complete failure when used with corresponding bolts. Never substitute sizes, as doing so may damage the screw head and cause it to strip.
