Figure 1 below shows the cross-sectional profile of the Allen™ wrench or Allen™ key. The important parameter that establishes the size of the Allen™ wrench or Allen™ key is the width across flats, which is the distance between any two of the faces of the tool that are parallel to each other. 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: Torque needed **- When tightening or loosening a fastener (particularly loosening) the amount of torque needed to move the part is key. An L-shape or T-handle have particular leverage in this area, their extended handles allow for greater torque when dealing with fasteners L-Shaped Hex Keys: L Shaped Hex Keys or L Keys are the most common type of hex key with a hexagonal tip at each end

Tether-ready designs – These Allen™ wrenches include an opening on the handle which can be used to attach a tether that can secure the wrench to the user or to a fixed object such as a scaffold. This feature helps prevent the wrench from accidentally falling into a work area and causing injuries or equipment damage. This feature is useful when the tool user is working on an elevated platform. Size of fastener - probably the most important consideration as the wrong sized key either won't fit the fastener or fit loosely resulting in either damaging the tool or rounding off the fastener making it difficult to remove. There are a number of things to take into account when choosing the right hex key for the job, below is a few of the main points of consideration. L-shaped hex keys The most common type of hex key. The L-shaped key is double ended allowing you to use torque to tighten and loosen fasteners with the short end, whilst the long end can be used in the same way as a straight key.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. Hex keys or Allen keys are available in metric sizes and imperial sizes Imperial Allen Keys. They are also available in Allen Key Sets which include a range of popular hex key sizes including 12mm Allen keys. RS also supply Allen keys from leading brands such as Wera Allen Keys, Wera Allen Key Sets and Bondhus Allen Keys 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. 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:

Folding Allen Key Sets: Folding Allen Key Sets consist of an outer casing from which a selection of different sized Allen keys can be unfolded, a bit like a penknife or multi-tool 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. 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:

LifeLine Pro Coloured Allen Key Set

Straight hex keys These resemble screwdrivers and function in much the same way except the head features either a flat or ball ended hex key, instead of the traditional screwdriver bit. Besides the common types described earlier, Allen™ wrenches are available with other features that improve safety or increase convenience for using the tool.

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. Figure 1 – The cross-section of an Allen™ key showing the measurement for width across flats Types of Allen™ Wrenches

What types of long reach Allen keys are available?

Non-sparking designs – While most Allen™ keys use an alloy steel or tool steel material in their fabrication, there are options available that utilize Beryllium Copper in lieu of steel. The Beryllium Copper material will not create sparks if the tool accidentally slips and strikes another metal surface. The non-sparking feature of this material makes these types of Allen™ wrenches suitable for use in applications where the presence of flammable gases or combustible liquids might exist. Access to fastener **- Operating in tight working environments can result in limited access to the fastener you're working on. Ball-end hex keys allow for tightening and loosening of fasteners at a variety of angles, so if you're working in places where space is limited they might be the answer to your troubles.

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). T-Shaped Hex Keys: T-shaped hex keys or T bar Allen Keys have a crossbar or T shaped handle at the end which provides a better gripHex key sets with T-handles are especially popular with mechanics and automobile enthusiasts, thanks in part to the fact that the T-handle Allen wrench offers certain user luxuries that standard hex keys don’t. Allen™ screws and wrenches are not the be-all-end-all in the world of fasteners and tools. Some complaints focus on the tool size being too small to allow for one to apply sufficient torque in all cases. Also, inferior materials used in the manufacturing of either the wrench or the screw can render them easy to damage in spite of the increased number of pressure points. But they are still popular more than 100 years after William G. Allen™ filed for his patent and will likely be here to stay for the foreseeable future. Summary