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How to Clean an Allen Wrench

This is a close look at a set of dirty black allen wrenches.

Does your Allen wrench slip in your screw socket? Is it not fitting as snuggly as it used to? Can you see rust forming around the shaft of the tool? There are simple solutions to restore your tool to its previous glory in just a few steps.

Related: Wrench Sizes | Types of Allen Wrenches | Types of Wrenches | Types of Screws | Allen Wrench Sizes | What is Allen Wrench | How to Find Hex Key Size | Allen Wrenches vs. Torx Wrenches | Why Allen Keys Have Ball End | Allen Keys vs. Allen Wrench | Where to Buy Allen Wrenches | How to Remove Rust from Allen Wrench | Allen Wrench Alternatives | Ball Driver vs. Allen Wrench | How to Use Allen Wrench with Drill | Are Allen Wrenches Hardened | How to Measure an Allen Wrench | How to Use Allen Wrench | Allen Wrench Brands | Allen Wrench vs. Hex Key | Best Allen Wrench Sets

What is an Allen wrench?

Black metal allen wrenches with red holder.

Allen wrench is a type of screwdriver used to loosen (or tighten) screws with a hexagonal tip. A simple handheld tool with a long arm serving as a handle and a short arm that fits into the screw top and provides the torque to loosen the bolt or a screw. As a wheelchair user and a budding novice DIY enthusiast, I came across a hexagonal screw and a need for an Allan key rather unexpectedly.

I knew screws had a single groove across the top, and some occasionally had a cross-shaped grove on their head that requires a poshly named Phillips screwdriver to manipulate it. So imagine my surprise when armed with both straight and Phillips screwdriver types, I flipped over my wheelchair, attempting to tighten the main bolt that holds the chair’s frame together, and an unusual hexagonal opening (kind of like a star) in the screw head was staring me in the face.

I have never seen a hexagonal screw before. After a quick call to my trusted hardware store and a meandering explanation to a very smart sales clerk, I discovered that I needed an Allen Key to fit into the unusual screw head. Dumbfounded, I asked, “Allen Key? What is that?”

He patiently explained that an Allen Key, otherwise known as an Allen wrench or Hex key, is a small hand-held screwdriver used to loosen a hex socket screw (the one with the hexagon opening in its head, apparently). Ahhh… of course!

The purpose of the Allen wrench

This is a set of black metal allen wrenches in different sizes.

Most joints can be held together by a normal straight screw or occasionally a Philips head screw to hold together parts that need more strength and stability. However, to hold together parts that experience a large amount of stress, a strong locking screw is needed. If a screw is made to withstand a large amount of force, it requires proportionately more force to remove it from the joint.

However, in items that we use every day like motorbikes, bicycles, or wheelchairs, screws need to be removed or replaced from time to time; therefore, the fastening screws need to be both strong enough to prevent a collapse of the object and malleable enough to remove it should you need to do that.

The hex socket screw fulfills those requirements by providing 6 points of contact for the screwdriver to exert enough power to loosen the screw without damaging the screw socket, and without the need for complicated machines to remove the screw. That is why William G. Allen patented the hexagonal socket and corresponding hex wrench around 1910, revolutionizing the metal fastener industry.

What is Allen wrench made of?

This is a stainless steel allen wrench used to screw in an allen bolt.

The basic component of the Allen wrench is steel. The steel is mixed with other alloys like carbon or Chrome Vanadium to give the tool its required toughness, stability, and ability to stretch. The alloys also give the Allen key its distinct look.

Some are silver, like steel, and some have a black finish. The black-colored ones are made of steel combined with Chrome Vanadium that produces black color. They are also hardened, making them more durable and able to exert more force when manipulating the screw.

How to use an Allen Key?

This is a mechanic repairing a motorcycle with an allen wrench.

Allen keys do come in different sizes to ensure that the tip of the wrench fits snuggly in the screw socket. It needs a snug fit to ensure that the ridges on the key and the corresponding grooves on the screw do not strip when turning.

As the sizes of the screws vary, so do Allen key sizes. They are usually sold in sets that match the most common screw sockets in metric and (SAE) inch sizes.

Some Allen keys are L-shaped, with a short and a long arm. Most of the time, you use the short arm to fit into the screw socket and use the long arm to grip the tool, but in hard-to-reach places, the wrench can be reversed, and you can use the long arm to fit into the screw head.

There are various styles of Allen keys available on the market. Most common is the set of keys in various sizes on a split ring; however, other varieties are available, like the Allen key with one hexagonal tip and a ball at the end of the long arm or a hexagonal tip attached to a T-handle.

How to keep Allen keys clean?

This is a look at the varying sizes of a set of L-shaped allen wrenches.

The two main problems you will encounter as your brand-new Allen wrenches get older are: rust forming on the body and heads of the tool and the wearing of the hexagonal ridges making the head smooth and not fitting snuggly into the hexagonal grooves of the screw socket.

The best way to preserve your set of Allen wrenches is to keep them stored in a toolbox that is dry and dust-free and wipe them off with a soft cloth after each use. To get them looking like new again, follow these tips.

Wiping and lubricating

The best method to care for your Allen key set is to prevent the rust from forming on them in the first place. Store all your tools, not only the set of Allen wrenches, in a dry, clean place (like your toolbox), and remember to wipe and lubricate them after each use.

Use a soft cloth to wipe down dirt and grime from the whole surface of the key and give them a once-over with a light lubricant like WD-40 to prevent surface rust attachment. Clean tools last for much longer and work a lot better than rusty ones.

Removing rust from an Allen key

Once there is a rust patch on the wrench, there are still a couple of things you can do to restore your tool to its former self. You can try to remove the rust by using vinegar and salt solution, submerging them in Coca-Cola, or using steel wool and metal polish.

Vinegar and salt solution method of cleaning

Submerge the Allen key in a salt and vinegar solution for at least three days to soften the rust, and lift it from the surface of the key. The vinegar and salt solution contains a ¼ cup of salt for every liter of vinegar.

Once the soaking is over, use a soft towel to wipe off the rust; you may need to rub quite hard, depending on the amount of rust that needs to be removed. With another cloth, dry and polish the clean Allen key.

Submerge in Coca-Cola method of cleaning

Put your rusty Allen key in a container and pour on enough Coca-Cola to cover the key completely. Leave soaking overnight. The next morning scrub off the rust from the surface with a clean cloth.

Steel wool and metal polish method of cleaning

This one is self-explanatory. Take steel wool and soak it in a metal polish. Rub the steel wool along the surface of the Allen key and, using  “elbow grease,” scrub the rust off in an old-fashioned way. Once the rust is removed, use a soft cloth to polish the gleaming tool to remove the excess metal polish.

Restoring the hexagonal shape of the Allen Key

With time and repeated use, the head of the Allen key will start losing its shape and becoming smooth. A smooth, rounded tool will not fit properly into the hexagonal socket of the screw; therefore, the hexagonal shape will need to be restored from time to time. Using a key with worn ridges will wear down the socket making it very difficult to remove the screw on subsequent occasions.

Putting the rounded edge on a power grinder wheel will restore the proper hexagonal shape. Simply grind off the rounded tip, leaving behind a brand new hexagonal surface. (Kind of like sharpening a pencil.)

Once the tip is ground off, check the surface for any ridges or metal shards that can be present along the edge of the tool after the grinding process. Remove the sharp splinters with a wire brush wheel.

Once you make sure that the Allen key head edges are smooth, use a cloth and a light oil like DW-40 to oil the key and keep it safe for the next use.