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14 Different Types of Allen Wrenches

Collage photo of allen wrenches in different types.

If you’re wondering what types of Allen wrenches there are, then you have come to the right place. Allen wrenches are more than effective tools that can make your DIY projects a walk in the park.

At first glance, an Allen wrench doesn’t seem like much of a tool, but as they say, looks can be deceiving. It’s more than a mere L-shaped, small piece of metal.

Allen wrenches are effective hand tools that have the uncanny ability to deliver an exceptional amount of torque, so don’t let its humble appearance fool you. You’ll be surprised to learn that no toolkit is complete without a set of Allen wrenches.

Also known as hex keys/ hex-key wrenches, they have a hexagonal cross-section that’s a snug fit for a barrage of machine screws with hexagonal-shaped recessed holes.

Hex fasteners are increasingly popular in various mechanical devices and equipment such as assemble-it-yourself furniture, motorcycle engines, and bicycles.

With that being said, this guide will walk you through the ins and outs of Allen wrenches, including the types and uses, to permit an informed decision.

Brief History of an Allen Wrench

The first patented use of Allen wrenches dates back to the early 1900s when W.G Allen showcased a safety set of wrenches to the public. Moreover, it was in 1910 that the wrench was first manufactured on a commercial level. As a result, the term ‘Allen wrench’ was coined.

He founded the Allen Manufacturing Company from which the term stemmed from. It’s currently run by the reputable Apex Tool Group that encourages people to use the standard name, ‘Hex key.’

Allen Wrenches vs. Ratchets

For starters, ratchets are mechanical tools that permit movement in one direction. When they’re equipped onto wrenches, they allow users to set two movement directions, one whereby the head is fixed and another where they spin freely.

In turn, you can turn the fastener without requiring the Allen wrench to make a full circle rotation or turning it for a few degrees before lifting it off and resetting it.

While wrenches and ratchets are strikingly similar in functionality (loosening and tightening fasteners), various scenarios call for the use of one over the other. For instance, box-end Allen wrenches are a great alternative to loosen stuck fasteners.

You can apply more torque without the risk of damaging the components compared to using ratchets. However, the fastener comes loose with the application of less torque.

Allen wrenches that indicate or control torque, is armed with ratchets. And, torque wrenches with ratchet heads have a vast assortment of applications and can boost the reliability of repair and assembly projects.

Are There Different Types Of Allen Wrenches?

If you’re wondering how many types of Allen wrenches there are, the answer is several. The truth is they come in different types/ styles (as discussed below) for various applications.

While some are built to pair well with conventional fasteners (Society of Automotive Engineers), others are suitable for metric applications. Keep your eyes peeled for color-coding on some Allen wrenches to quickly identify metric or standard.


EKLIND 10111 Hex-L Key allen wrench - 11pc set SAE Inch Sizes .050-1/4 Short series

As one of the standard Allen wrenches, you can easily find it online or at your local hardware store. Its L-shape design makes it a beast at reaching into tight spots and providing control as needed.

If you’re on the quest for one set, this would be an ideal choice. While there is a wealth of options that have littered the market, a 1.5-10mm L-shaped Allen wrench will give you value for your money.


Capri Tools Sliding T-Handle Hex Wrench, 8 mm

Popularly used in the motorsport industry, T-handle styles allow you to spin the wrench in a jiffy while ushering in, sufficient leverage in common usage. The Capri Sliding Hex Wrench allows it to slide into a position that creates an L-shaped tool. T-Handle wrenches are gaining popularity in bike mechanics.


Park Tool PH-6 P-Handle Hex Wrench - 6mm

Seen in a myriad of professional workshops, P-handle wrenches are oversize versions of the L-shaped counterparts with a comfortable and firm grip that ushers in the same perks as T-handle wrenches.

Folding Hex

TEKTON Folding Hex Key Wrench Set, Metric, 8-Piece | 25142

Soaring in popularity amongst motorbike riders and cyclists, folding Hex wrenches are nearly impossible to lose, compared to other Allen wrenches because they are securely enclosed in the handle.

Furthermore, they are typically folded out at a 90-degree position from the storage handle for optimum torque.

Ratcheting Hex

Ratcheting Hex Wrench Set: Nine Sizes In One Folding Tool; ProTool RHS001

Compared to the generic Allen wrenches, the Ratcheting Hex counterparts deliver superior speed. And, they go hand in hand with sockets and screwdriver bits, thus making them more dynamic.

Available in different varieties, the bits of Ratcheting Hex wrenches are useful in electric drill drivers. Therefore, this makes them the go-to option for those handling rotor bolts.

Torque Wrench

15PCS Bike Torque Wrench Set, Bike Repair Tool Kits for Bicycle Repair Adjustable Torque Wrench Mounting Bolts Torque Wrench

It’s an essential aspect of any workshop, particularly when working with delicate components. But, keep in mind that torque wrenches are not a substitute for the Hex counterparts.

Allen Screwdriver

REXBETI Hex Head Allen Wrench Screwdriver Bit Set, SAE 1/4 Inch Hex Shank S2 Steel Magnetic 3 Inch Long Drill Bits, 1/16-3/8 Inch, 12 Piece

It’s a handy tool to have within arm’s reach when your project involves tight clearance and low torque. An Allen screwdriver set is perfect for adjusting disc brake and other types of levers. And, the most common size you’ll find ranges from 1.5 mm to 5mm.

Ball Hex

AmazonBasics Hex Key Allen Wrench Set with Ball End - Set of 26

With ball molded head at tight edges, Ball Hex wrench sets can get to tight spots that are out of reach for the L-shaped counterparts. Thus, this sets them apart from the pack.

Key Ring

It’s a simple L-shaped Hex mounted on a key ring with a spring retaining clip. A Key Ring set is affordable and can be conveniently stored in your car. For long term use, you’ll need to pull the key from the retaining clip. And, for replacement, push and twist the key.


Allen 66894g 10" Adjustable Wrench

It’s a versatile tool that is also known as a network wrench and pairs well with metric and standard fasteners. It has a moveable jaw to adjust the wrench size and a fixed jaw point that is placed at the wrench’s top position.

Used for loosening or tightening angled nuts or screws, adjustable wrenches come in three types (200mm, 300mm, and 250mm), and are typically used by plumbers, electricians, self-assembly furniture, and car repairs. Furthermore, they are chosen according to the nut size and are not designed for use in reverse.



It’s a double-ended tool that has a box-end on one side and an open-end on the other. The box-end comprises a closed ring with different diameters on the inside, depending on the Allen wrench’s size.

As a multi-purpose tool, the open-end comes in handy for loosening and tightening bolts and nuts in small spaces, whereas the box-end provides a firm grip around them. Combination Allen wrenches are used in bicycle repairs, for instance.


Allen 11/16'' x 13/16'' Wrench Open End Black 21013B USA RO

Designed as a double-ended one-piece tool, open-end Allen wrenches come in handy for narrow project areas that are inaccessible to thicker or larger wrenches. And, they have varying size openings for opposite faces of nuts or bolts. The U-shaped opening on each end delivers a firm grip for objects by flipping over the wrench to use the opposite side.


14 Pc Extra Long Hex Bit Sockets Allen Wrench Mm+SAE

Used to turn a fastener, an Allen socket wrench has a hollow cylinder that is attached to the end of the handle. And, it’s fitted over bolts and buts to loosen or tighten them.

Socket wrenches are detachable, which makes them useful for different-sized objects. They’re also known as ratchet wrenches and provide unmatched efficiency and speed. Moreover, they are useful at a myriad of angles.


Craftsman 10 Piece Standard Crowfoot Wrench Set, 9-4362

It’s strikingly similar to a box-end or open-end wrench, with the only difference being the lack of a shaft or handle. And, it has an opening at the back of the wrench’s mouth.

Williams 10772 3/8 Drive Crowfoot Wrench, 22mm

Crowfoot Allen wrenches are a snug fit onto a bolt or nut’s side as opposed to the top as seen in the socket counterparts. In turn, they are ideal for tight spaces. Crowfoot wrenches are useful in valve adjustments, different fittings such as clutch or brake, power steering, and abs modulators.

Mechanics in the aviary department use this type of wrench nearly daily. And, they are used with ratchets or torque wrench handles.

Tips When Using Allen Wrenches

It’s no secret that hex keys and Allen wrenches seem durable enough. However, they can result in damage if you use the wrong size on a socket screw head. Smaller-sized Allen wrenches can easily be stripped down or strip hex bolts.

Before you place the hex key into the bolt, ensure the head is spick and span. Therefore, a quick swipe using a Q0tip dipped in rubbing alcohol will pick up any debris and dirt that can accumulate at the hexagon’s corners.

Always ensure that each edge of the Allen wrench is well-aligned before you loosen or tighten any bolts. Otherwise, there’s a high likelihood of damaging the wrench or stripping the bolt head.

Common Applications of Allen Wrenches

Here’s a breakdown of the five most popular uses of Allen wrenches that will infuse efficiency to your build, repair, or maintenance DIY projects.


These are the dominant tools that come in handy for a broad range of bike repairs coupled with size adjustments. The vast assortment of sizes makes them useful in various applications.

Furthermore, their compact size makes them a breeze to carry. If you’re an avid cyclist, you can opt for a set of folding hex wrenches.


Allen screwdrivers are an important piece of hardware to secure furniture in place. They allow you to assemble or disassemble different types of furniture, such as coffee tables, without the addition of unnecessary and bulky components.

The compact nature of Allen screwdrivers makes them easily go unnoticed and strong in fastening bolts and nuts. And, given that furniture pieces typically have small crevices that are difficult to reach, a set of long arm Allen wrenches are your holy grail.

Motorcycles and Cars

You’d require an Allen wrench key set for ideal car maintenance. They’re a lifesaver for accessing tight spaces below the seats or under the glove compartment. T-handle Allen wrenches are the go-to for excellent motorcycle and car repairs.


Aside from other uses, Allen wrenches or Hex Keys, come in handy in repair and maintenance of heavy machinery and tools. The Drill bits depend on them to remain safely in place.

Similarly, power saws of all tool varieties need short arm Allen keys to replace the blades or make a few minor adjustments.


Allen wrenches are soaring in popularity with a multitude of people dealing with the repair and maintenance of electronics. Furthermore, as electronics are becoming increasingly compact, Allen wrenches come in handy.

Large TV screens and PCs are held together with these screws from the backside. Therefore, torque wrenches get the job done as they’re the main components in an electrician’s toolkit.

How to Use Allen Wrench

Before you proceed to tighten or loosen the nuts and bolts, it’s essential to figure out if your Allen wrench is the ideal size for them. Keep mind that if the wrench isn’t a perfect fit, don’t force it. Doing so could damage the hexagonal shape of the bolt or wrench.

Once you find the snug fit, simply stick the short arm of the wrench into the bolt then turn it anticlockwise for loosening or clockwise to tighten it.

Are there different types of Allen wrenches With Regard To Size?

A set of differently-sized allen wrench.

Yes! They are designed in metric and standard sizes, as discussed below.

Standard-Size Allen Wrenches

The inch-based Allen wrench set is standard. And, it usually contains a vast assortment of inch sizes as discussed below.

  • 5/32
  • 3/16
  • 7/64
  • 1/8
  • 7/32
  • 5/32
  • 1/4
  • 3/32

European Standard-Size Allen Wrenches

Metric sizes are used as the norm in Europe. Therefore, below are the standard sizes (in mm) per European set of Allen wrenches.

  • 4
  • 8
  • 3
  • 6
  • 2.5
  • 5
  • 10

The smaller-sized Allen wrenches demand more maintenance compared to the larger counterparts. It’s easier to strip the head on a small wrench of you’re not careful.

So, ensure that the hex bolt is clean before inserting the Allen wrench. And, insert it with all six edges well-aligned.

If you opt for a cheaper Allen wrench set, remember that the small ones may not be 100% accurate in their measurements, which means they won’t get the job done to perfection within their size bolts.

Things to Remember When Buying Allen Wrenches

For starters, you’ll need to conduct your due diligence to know the type of Allen wrench set you need at your home or workshop. Is it the T-shape, Folding Hex, or L-shape?

If you’re on the quest for the simplest and most popularly used, then it’s advisable to settle for the L-shape Allen wrenches.

If you require increased torque to better loosening and tightening of the nuts and bolts, then a T-shape would be a better option.

Secondly, if you’re outgoing or a tad bit clumsy that you at times lose items without realizing, then choose the Folding Hex Key to diminish the likelihood of losing a single Allen wrench. It also comes in handy for avid travelers as it’s a snug fit in most pockets.

How to Choose the Best Allen Wrenches

Hand holding an allen wrench.

With the wealth of options in the market, selecting the right Allen wrench for your project can be an uphill battle. Luckily, the factors below will help steer you in the right direction.

After all, the last thing you need is to buy a set of products that won’t get the job done.


Most Allen wrenches are made of steel, which varies in grade and quality. Those built from lower-quality grades that are lacking in stress relief, material hardness, and surface treatments have reduced longevity and tensile strength. In turn, this means more frequent replacements.

Topnotch products with unmatched durability have a high tensile strength that ushers in superior torque capabilities. These have a minimum Rockwell Hardness rating of C5 that’s often specified by the respective manufacturers.

Surface Treatments

These directly affect the performance and lifespan of Allen wrenches. Those with zinc or black oxide finishes are more susceptible to rust and flake off easily.

So, when comparing tools from various manufacturers, keep your eyes peeled for chrome-plated options as they provide reduced friction, which enhances durability.


It can be crucial based on the application. Long Allen wrenches are more suitable when there’s limited accessibility, or greater torque is required. Contrarily, shorter counterparts are preferred for confined spaces that are inaccessible to longer wrenches.

End Geometry

Generic affordable Allen wrenches have an end with sharp corners meant to fit the hardware with some play. They must be used perpendicularly to the screw, which makes it more challenging to guarantee full engagement and creates awkward wrist angles that provide discomfort to users.

Fortunately, the solution to this is to opt for Allen wrenches that have a ball end. They’re built to be inserted into the screw socket at an angle, thus paving the way for a firmer yet more natural grip coupled with smoother torque.

Ball ends are typically just on the long end of Allen wrenches and are time efficient during the disassembly or installation process. This is because they don’t demand perfect alignment to mate with the screw head.

Closing Remarks

Now that you know different types of Allen wrenches, how to use them, and much more, selecting the ideal options for your DIY projects will be a breeze. So, get yours today and enjoy the perks that these handy tools have to offer for years to come.