Do It Yourself: When And How To Use Hex Keys

A guide to what hex keys are and how to use them.

Hex keys (also known as Allen wrenches) are useful little tools that are often misunderstood in regards to their usage and purpose. Their name comes from the fact that they have six sides of the same size, and they are inserted into a hole in the bolt or object that they are being used to tighten or loosen.

Most hex key sets come with a variety of different sized wrenches, usually with the characteristic "L"-shaped wrenches that usually look like a piece of wire that has been bent at a 90 degree angle. Of course, there are also "straight" wrenches, hex keys with plastic handles attached at the top for you to use when turning them, instead of the simple bend that the others have.

So, how do you use a hex key or Allen wrench? Well, it's actually really simple. All that you do is insert the appropriate hex key into the hex-shaped hole on the surface of the bolt that you're loosening or tightening, and then turn the hex key to the left or right (depending upon whether you're tightening or loosening.) The principle is the same as using a socket wrench, but instead of placing the wrench around the bolt, you're placing the bolt around the wrench.

The real question with hex keys is when, not how, they should be used. Well, obviously, they should be used whenever you find a hex key bolt (defined here as a bolt that has a six-sided hole in the middle of it, not a bolt that has a six-sided head) that needs to be tightened or loosened. A more pertinent question arises when you are building something yourself and need to decide whether to use hex key bolts in it, or to use some other form of bolt.

To determine whether you should use hex key bolts, look at the material that you're building, especially the area around where the bolt needs to go. Is the hole for the bolt inside of another piece, or surrounded so that it cannot be accessed from the sides? Is the piece small enough that a small bolt should be used, especially one that wouldn't fit most standard wrenches? Does the bolt need to be inserted so that it's flush with the material around it, or perhaps even at a lower level than the surrounding material? If any of these situations are the case, you might do well to use hex key bolts in your project.

The main advantages of using hex keys and hex key bolts is that the wrench is inserted into the top of the bolt, so there is no need to have room around the bolt for a standard wrench (or even the room needed for a socket wrench.) The bolt can be inserted into a narrow or recessed opening, and can range in size from exceedingly small to large (depending upon the size of the hex key used.) It can also be easily inserted flush or even recessed into a material that requires it.

In closing, hex keys can be exceedingly useful in a variety of situations. In addition to everything mentioned above, they can also be used to add a bit more security to a project, since hex key bolts are difficult to remove without a wrench of the proper size. Best of luck with your projects!

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