Allen™ wrenches are available as individual keys of a given size but are also sold in sets that contain a range of standard sizes. Allen™ keys are identified as being either metric-sized keys in millimeter sizes or SAE (Imperial) sized keys in fractions of an inch or decimal equivalents. Besides the common types described earlier, Allen™ wrenches are available with other features that improve safety or increase convenience for using the tool. This chrome-plated hex keys has a degree of corrosion resistance, however, correct storing of your tools will increase their useful life. It is recommended that the tools are stored in a clean and dry environment. Moving over to the right-hand side, we’ve provided the metric to SAE guide for Allen wrench conversions. Similar to the metric hex keys, the SAE hex wrenches don’t always have a perfect substitute as seen for SAE size 3/16″. Thus, we recommend that those with only a metric Allen wrench set add a separate SAE hex key set to their stable. Substituting Uncommon Hex Sizes

In particular, the T-handle design provides a more comfortable grip than the standard L-shaped hex key, but importantly it can also allow for significantly increased torque (provided the gauge of the hex wrench itself is high enough), because the additional weight of the T-handle acts as a counterbalance that can help to seat the tool more firmly and securely in the head of the fastener. Allen™ wrenches or Allen™ keys are generally available in several different styles or types. The most common Allen™ wrench type is the one mentioned earlier – the L-shaped hex key – but there are other variations that incorporate different handle designs, utilize different materials, or add special features. A summary of the most common Allen™ wrench types is found below:Where the additional access provided by a long-reach hex wrench is needed, you'd use the more elongated side as the ‘driver', and the shorter side therefore becomes the handle that you turn to tighten or loosen the fastener. However, when a hex bolt is within easy reach and there's plenty of space to work in, long-arm Allen keys can also be handy used in the reverse configuration - the longer side can help provide better grip and torque when operating as a handle. What types of long reach Allen keys are available?

Lastly, there’s one other added benefit to having both SAE & metric hex keys. In the United States, larger metric half sizes like 6.5 mm aren’t standard in most hex key sets. However, the 1/4″ SAE hex wrench will likely work in place of a 6.5 mm wrench. In scenarios like these, use the chart to estimate the correct alternative. You can test different sizes till you find the best match. We do recommend starting slowly to ensure that you don’t damage the hardware. Long-reach Allen keys are a common feature of most good quality hex key sets, which tend to include a useful range of common wrench sizes and diameters (typically from around 1-1.5mm, up to 12mm and beyond).

Hex keys have a number of important characteristics that make them particularly well suited to the straightforward, user-friendly fastening role that has made them so popular among operators of all experience levels. These include the fact that hex keys: This article will present information on Allen™ wrenches, what they are, their advantages, and the common sizes that are available in the marketplace. To learn more about other types of fastener products, see the list of related articles at the end of this article. What is an Allen™ Wrench? Like all hex wrenches, long-reach Allen keys are also sold with a variety of head and handle types for various more specialised applications - these can include:

Are typically double-ended, thus offering a ‘spare’ hex driver in case of damage or rounding to one end of the tool Size and weight – Allen™ keys tend to be smaller and lighter than the equivalent tools used to apply other fastener types, making them easier to carry. This can be an advantage for applications where mobility is important such as with cyclists that might want to carry a bike tool kit along on a ride. Figure 1 – The cross-section of an Allen™ key showing the measurement for width across flats Types of Allen™ WrenchesFrom RS PRO, this high-quality hex key set is a handy way to keep differing allen key sizes all in one place. The L-shaped key has a long arm, and so is ideal for deep-set bolts. A ball end Allen key set is also an increasingly popular choice for both professional and hobbyist users alike, and with good reason - ball end hex wrenches (sometimes known as ball end hex keys, or ball point hex keys) offer a far greater degree of versatility and flexibility in terms of access to smaller spaces. They achieve this by dramatically increasing the range of positions the user can stand in relative to the fastener they’re working on at the time. This article provided a summary of the commonly available sizes of Allen™ wrenches/keys and explained the different types of Allen™ wrenches as well as the advantages of these tools. For information on other topics, consult our additional guides or visit the Thomas Supplier Discovery Platform where you can locate potential sources of supply for over 70,000 different product and service categories, including suppliers of Allen™ wrenches and other hex key wrenches.