Hex Bits, Hex Keys, and All the Names They Go By

One of the funny things about tools is how many different names people have for the same thing.

Take hex tools, for example.

Hex bits are also called bit hex, insert bits, or screwdriver bits. Hex keys are commonly called L-wrenches, Allen wrenches, or simply hex wrenches.

If you’ve worked in a shop long enough, you’ve probably heard all of those—and maybe a few more.

In the picture above, the hex key is the tool in the red package at the top. That same tool might be called an L-wrench, an Allen wrench, or a hex wrench depending on who you ask.

The gold-colored tool at the bottom is a hex bit. Those are also called bit hex, insert bits, or screwdriver bits.

If you look closely, the reason for the name “hex” becomes obvious. Both tools have a six-sided shape.

That six-sided geometry is designed to fit into hex sockets in screws and fasteners, allowing torque to be transferred without slipping.

But even though they share the same shape, the two tools are used a little differently.

Hex bits are designed to fit into tool holders—such as screwdrivers, bit holders, or power drivers. They’re meant for situations where you want speed, repeatability, or the convenience of a driver handle.

Hex keys, on the other hand, are designed to be used directly by hand. Their L-shape provides a built-in lever so you can turn the screw without needing a separate handle.

Simple tools, simple idea—but plenty of different names.

These are just a few that came to mind. I’m sure there are others out there.

If you know of a name I missed, I’d enjoy hearing about it.