How to Measure an Allen Wrench - Home Stratosphere

How to Measure an Allen Wrench

Many times when putting together exercise equipment, a bed, or a multitude of other items, you will be required to use an Allen wrench which is also known as a hex key or an Allen key. You will need to know how to measure an Allen wrench.

This is a mechanic holding a set of stainless steel allen wrenches.

Many times when putting together exercise equipment, a bed, or a multitude of other items, you will be required to use an Allen wrench which is also known as a hex key or an Allen key. Sometimes manufacturers will include the right size of an Allen wrench inside the box of the product you have purchased but if not, you will need to know how to measure an Allen wrench.

When most people think of a wrench, they are referring to a common wrench but an Allen wrench is quite different and you need to know and understand how they work and what they are used for as well as how to measure an Allen wrench which we will explain in this article.

Table of Contents

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 | Top Allen Wrench Brands | How to Use Allen Wrench | How to Clean Allen Wrench | Allen Wrench vs. Hex Key | Best Allen Wrench Sets

What is an Allen Wrench?

This is a close look at a screw being screwed in with appropriate allen wrench.

I remember the first time someone asked me to get them an Allen wrench out of the toolbox. It was my dad and it took me a long time to find a wrench. When I handed it to him, he said that was not an Allen wrench, went to the toolbox himself, and fetched one out.

I had no idea that an Allen wrench actually looks nothing at all like a regular wrench since it is L-shaped and takes on the form of a hexagonal key, also known as a hex key. I now own several of them myself after realizing that the reason I could not get my electric drill to fit into holes of place where the screws are located in a daybed I have in my home is that it requires an Allen wrench to put it together or take it apart.

What is Allen Wrenches Used For?

This is a close look at someone assembling a furniture with screw using allen wrench.

The reason that I could not take my day bed apart with a regular screwdriver or a drill is due to the fact that it is put together with what is known as hex screws. A hex screw is used quite often when fascinating together metal like my day bed frame is made of, wood and even plastic. The Allen wrench got its name from the company that registered the trademark before these tools which is the former Allen Manufacturing Company that was located in Hartford, Connecticut.

In today’s world, the company that produces Allen wrenches is the Apex Tool Group (ATG) and company officials would prefer that they be referred to by their standard name of a hex key instead of an Allen wrench or Allen key but many people, especially in the United States, still refer to them as Allen wrenches.

Allen wrenches are considered to be hand tool essentials since an Allen wrench is the only hand tool that can fit in the bolt head of a hex screw. When it comes to bolt size, there are many different hex screw sizes which means you will need an Allen wrench that is the proper size for the job at hand but how do you measure an Allen wrench?

How to Measure an Allen Wrench

To know which wrench size you need for the job you are doing, you will need to know the hex size of the hex screw that is used for the object you are attempting to put together or take apart since the Allen wrench size will depend upon it.

The best way to measure an Allen wrench, or the hex socket, is to use a caliper. It will give you the right size, including the metric or imperial size. This allows you to determine pretty quickly if you need a larger size of Allen wrench to fit into the hexagonal bolt or a smaller size of the hex key to get the job done. A caliper will give you the metric size for your hex head as well or can be used to determine an inch style measurement.

Allen wrenches can be purchased in a variety of sizes and you can even purchase them singular or in an Allen wrench set that includes a variety of sizes. They are small, light, and simple to work and they provide six different contact surfaces that are between the driver itself and the Allen bolt that you are working with on the object at hand. It allows for you to have really small bolt heads to be accommodated, especially when the hexagonal socket is located inside of an area that is hard to reach.

The nut, bolt, and Allen head screws are protected from external damage when they are placed this way. The Torx key allows for the use of recessed-head screws as well as a headless screw in the hexagonal cross-section of your object.

In other words, the hex screw is held in place with the hex key while it is being inserted or taken out of the hole it is inside of. The amount of torque that is applied to the screw is limited by the thickness, as well as the length, of the key.

Many times, as in the case with a treadmill I recently purchased, a metric Allen wrench was included in the box which made it very convenient since I did not have to hunt down the proper size of an Allen wrench in my house. They are cheap to manufacture which is the reason that companies can afford to simply include them in the assembly tools of many items you purchase.

The hex key size of my treadmill is larger than the small Allen wrench that was needed for my daybed frame. The screw an even be held by the socket wrench as I put it into the hole which made it so much easier to work with and to get the job done so I could use my treadmill right away.

The fun part for me when using an Allen wrench since I am not that mechanically inclined is the fact that I can utilize either end of the metric hex key to still be able to have the proper reach or torque when putting together or taking apart an object like my daybed or treadmill and working with a hex bolt. The other convenient thing about a hex wrench is that it can be reconditioned and put back into great working order by simply grinding the end that is worn out from many uses over time.

Allen wrenches are a great option when working with a fastener that is located in a place that is hard to reach for a screwdriver or a drill so they are super convenient.

FAQs About How to Measure an Allen Wrench

What is an Allen wrench used for?

An Allen wrench, also known as an Allen key or hex key, is used to turn screws and bolts that have hexagonal sockets.

What can I use instead of an Allen wrench?

Sometimes you can use a small type of flat-headed screwdriver although it is so much easier to use an Allen wrench for these types of situations that require one.

What does an Allen screw look like?

The Allen wrench is an L-shaped tool that has six sides to it. The cross-section of the Allen wrench really does resemble a hexagon. You can simply put the short end of the L-shape into the bolt head you are working with then press down on the longer part of the L-shape to turn the hex bolt or screw.

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