Allen keys are one of the most popular types of wrenches, and they come in a variety of shapes and sizes.
The name "Allen key" is derived from its inventor, Henry A. Allen who patented his design for an allen wrench in 1874.
Allen keys have become widespread due to their ability to turn bolts or screws with hexagonal sockets - often found on bike parts, furniture, musical instruments and electronics equipment.
The shafts can also be manufactured as a ratchet design which allows the user to rotate it clockwise or counterclockwise without having to remove it from the bolt head.
Some of the different types of allen key are:
The L-wrench or "L-shaped" wrench is the most popular and common type of Allen key. It is made out of steel with an alloy steel shaft, and has a hexagonal socket on one end.
The length ranges from 12 inches to 18 inches long, and the width ranges from 1/2 inch to 2 inches wide - making it easy for users to insert it into small spaces. The other end of the allen key is made up of a pointed or flat head which allows for use in different situations, such as Phillips head screwdriver or a slotted tip.
Some examples of places you can find this kind of allen key are: the interior panels on trucks, on the side mirrors of cars, grip heads on guitars and in metalworking.
The key needs to have a long shaft length to make it easier for users to reach bolts that are fastened deep within objects. The hexagonal shape makes the allen key easy to fit into bolt sockets. The shaft is usually made up of solid or hard steel and the rest of the allen key is made up of hardened steel, impregnated with chrome that makes it harder and wear resistant.
Hex keys are another type of allen key and are used for many of the same purposes as L-wrenches. They have a hexagonal shaft that is used to reach bolts that are hard to get at with other wrenches - such as those on an engine or in furniture parts.
They look similar to L-wrenches, but have shorter shafts and a smaller hexagonal socket. The advantage of this is that it can make it easier to tighten or loosen bolts in tight spaces.
'Lever handle (cheater bar)' type
The lever handle allen key has a lever shaped head made of steel, with the same hexagonal shape as L-wrenches. The handle is usually made up of plastic and has a rubber coating for comfortable gripping.
The shaft can also be made up of steel or alloy steel, as well as solid or hard steel with chrome impregnation.
Lever handle wrenches are very similar in design to L-wrenches, but have an extended handle that can make it easier to turn bolts and screws. The longer lever makes it possible for users to get greater leverage when rotating bolts, making it quicker and easier to loosen or tighten those fastened with a hexagonal bolt head.
Other features include a "bottoming out" point where the handle is completely closed against the shaft - which means it will not rotate further, helping prevent the wrench from stripping. It also allows users to more easily reach deep spaces in screws or bolts.
This type of allen key has a longer shaft than regular L-wrenches or hex keys and are often used for rotating furniture construction parts that have hexagonal sockets on them.
This type of allen key has a hexagonal shaft that is used to reach bolts that are hard to get at with other wrenches - such as those on an engine or in furniture parts.
It looks similar to L-wrenches, but have shorter shafts and a smaller hexagonal socket. The advantage of this is that it can make it easier to tighten or loosen bolts in tight spaces.
Buttress keys - or 'handle' type
This type of allen key has a shaft similar to lever handle wrenches, but the hexagonal shaped tip is larger and rounder, with an opening on the end. This makes it easier to rotate bolts that are too small for a hexagonal socket, or when the bolt head is covered by a plate.
The main advantage of this type is that it can reach even further into objects than typical L-shaped or hex key allen keys, but it's not very useful if you need to use the allen key in a tight space.
The cross head type of allen key has a shaft that is straight and flat, with pointed ends at either end. This type is useful for trimming down bolts, fixing small parts and also in places where space is limited.
These types of allen keys are commonly used on bicycles or working on small engines such as those found on motorcycles.
Stud and bolt head
The stud and bolt head type of allen key has a similar design to the cross head, but with an added T-shaped shaft which is used to hold fasteners in place when applying nuts or bolts - such as on bicycle pedals. The main advantage of this tool is that it can be easily stored for future use.
They are also useful for projects like in automotive work, where there may not be enough room to use a normal allen key.
This type of allen key has a shaft with a T-shaped design - with hexagonal bits that can be used to tighten or loosen bolts. It is also useful for gaining leverage when trying to unscrew or screw in hard to reach spaces.
As the handle widens towards the bit, this makes it possible for users to get greater leverage for turning.
The T-shaped handle makes it easier to get at bolts, screws or other fasteners in tight spaces and also allows users to get a better grip when trying to loosen or tighten those that have a hexagonal bolt head.
This type of key has an L-shaped shaft with ridges or rims on the inside of the hexagonal bits, forming an angle. The advantage of this is that it can make it easier to grip bolts in hard to reach spaces or when there is little room for turning.
It can also be helpful when working with very small diameter fasteners, as the bit will have a greater contact area than standard allen keys.
The Torx key has a six pointed star-shaped head - which looks like the letter T.
This is designed to prevent the bit from slipping when being used with fasteners that have a hexagonal bolt head on them, as well as increasing the contact area between user and tool and preventing slippage.
The shape of the head also means that there is less chance of the tool slipping, which can damage fasteners or even injure users.
This type of key has a screw-shaped bit - but with six points instead of two and with a hexagonal opening in the middle to make it easier to grab onto screws or bolts with ridged or rims.
Double ended allen keys have a bit at each end, with one size phillips and one hexagonal.
This is useful for repairing things like bicycles, where both sizes will often be needed in order to make repairs or adjustments.
As the tool has two different sized bits on it, it is more versatile than other tools - but it is also more difficult to store since it will take up double the space.
This design has an L-shaped shaft that forms a 'T' when viewed from above, with six pointed openings in the end to make it easier to grip hexagonal bolts and screws.
These types of keys are also available for use with torx fasteners.
This type of allen key has a long handle with a hexagonal bit at one end.
The advantage of this is that it's easier to apply pressure when tightening bolts or screws, without feeling like your hands will cramp up, because they are far away from where the main force is being applied.
They are also very useful for use in hard to reach places, as they can be attached to a ratcheting wrench or even another tool with an allen key hole. This type of key is designed for turning screws that have flat heads on them - each bit includes three sides, so it will fit in the screw holes without slipping out.
Folding Hex Tools
These tools have a hollow handle and a folding bit on them - which means that they can be stored in the most compact locations, like tool kits.
They are very useful for working in narrow or otherwise tight spaces, as they can easily be folded and unfolded to get at bolts or screws.
This makes it easier to access hard to reach locations such as under a sink or underneath car seats, where there is little room to manoeuvre.
Flat handle hex key
This is designed to be held like a screwdriver - the end of it has an arched surface that users will grip over and onto the bolt head, while the bit rests on top.
The advantage of this type of key is that it can be used in tight spaces to get at bolts and screws, without requiring a lot of turning room.
It is also useful for reaching fasteners that are positioned on the edge of shelves or tables, where there might not be as much space to manoeuvre.
Ball Hex Key
A ball hex key has a curved bit that is designed to be easier for users to get at bolts and screws in tight spaces, as it can pick up the bolt more easily. The different design of the head makes it much easier to use than standard keys - however, this effect is reduced for large diameter fasteners.
The ball hex key has a large head that makes it easier for users to manipulate, which is especially useful if the space is tight or otherwise difficult to reach. A flattened portion on the side of the hexagonal bit allows users to apply pressure when turning bolts and screws without worrying about their hands slipping off.
This type of key can also be fitted to socket wrenches for this purpose, which makes it possible to apply more pressure when tightening bolts or screws.
1. How do I choose the correct size allen key?
Check the documentation for your product to make sure that you have the right size key - but as a general rule, most products only need 'regular' sized keys.
2. What are the disadvantages of allen keys?
The main disadvantage is that they can't be used in tight spaces, unless users own a folding or hexagonal bit key.
Although these types of keys are more expensive, they can be used for various different jobs around the house as well.
3. Are there any disadvantages to using a torx key?
No - in fact, some people find them much easier to use than other key styles because the bit head is angled, rather than flat or concave.
This makes it easier for users to see where the bit is and what they are trying to turn, without having to squint or bend over.
4. What can I use an allen key for?
Allen keys are commonly used on bicycles and car wheels - but they are also used in furniture assembly, electrical wiring and even mounting a TV to the wall.
They can also be used with a screwdriver to get at screws in furniture or computers, so they are really useful to have around the house.
Although there are cheap alternatives, it's best for users to invest in a quality brand - otherwise, the bit can fracture while being used.
5. Are allen keys stronger than torx ones?
No - in fact, torx keys are designed so that they don't slip off as easily when pressure is applied to them, meaning that users can use them for many different jobs.
The only disadvantage is that these types of keys are more expensive, but it's worth the expense in the long run.
6. Is there a type of allen key that I can use with smaller screws?
Yes - screwdrivers are available with a size called 'tiny', which has a head that measures just 3mm in diameter.
This is a good option for users who are replacing small screws, rather than working on major repairs or renovations.
Allen keys are effective at getting hard to reach screws and bolts loose - but they aren't as strong or flexible as torx ones, so users will need to choose the right key for the job before starting. Folding hexagonal and flat handle keys can be used in tight spaces, which is a big advantage over other types of allen key.
Check the size and type of key that is required, before choosing one to ensure that it will work with your product. If you have to remove a lot of screws or bolts over time, then investing in a quality brand makes sense - otherwise the bit will break while being used. It's also worth considering using screwdrivers for smaller tasks, as they are cheaper to buy and easier to work with.