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All About Sockets: Types of Sockets

Revised: 11/3/19
Grainger Editorial Staff

If you work in mechanics or maintenance, you are probably familiar with socket wrenchs and the different types of sockets available.

Socket wrenches are tools that are either manual or electric, and are comprised of two parts - a ratchet and a socket. A ratchet is a tool with a gear that moves when turned in one direction and locks when it is turned the other direction. The ratchet will have square nub that changeable sockets of different sizes can be popped on and off of

What is convenient about a socket wrench is its adaptability. No matter what type of bolt shape or fastener head you have, there is probably a type of socket or bit that fits it perfectly. You can then pop it onto your favorite ratchet and continue working without changing tools. It pays, then, to know the basic types of sockets available for this versatile tool.

What are the different types of sockets?

Hex sockets

A “hex” socket—short for “hexagonal”—is a socket that fits around a hexagonal (six sided) nut or bolt head. There are two types of hex sockets - six point and twelve point. The six-point hex socket has six points (angles) inside the bolt end, making a perfectly even hexagon. The twelve-point socket—also sometimes called a “double hex” or “bi-hex”—has twelve angles in the bolt end. The double hex is able to fit over a hexagonal bolt head in twice as many positions as the regular hex socket, and is therefore a good choice if you are working in a tight space.

Impact Sockets

The first and most noticeable difference between impact sockets and regular sockets is their color. Impact sockets have an industrial surface finish that makes them black, instead of the polished metal of other sockets. Impact sockets are made for power impact wrenches—a strong power tool with an inner rotating hammer that applies more strength and vibration when removing fasteners. Impact sockets must have thicker walls and a non-corrosive finish to manage the extra power and vibration.

Spark Plug Sockets

Spark plug sockets are just what they sound like—they are for removing or fitting a spark plug into an engine. Spark plug sockets are much longer than standard sockets. This type of socket will also frequently come with a rubber insert that prevents the spark plug from becoming damaged while the wrench is working.

Socket Bits

A socket bit is a hex socket with some kind of bit inside it. These bits are frequently screwdriver bits, though they also come in many less common types. Like other sockets, they have a square ratchet end where they attach to the ratchet tool. They frequently come in sets, and can be made to work with impact drivers as well as manual tools.

Pass Through Sockets

If you have a bolt or a stud with an especially long shaft, you may need a pass through socket to tighten or loosen your bolts. This type of socket has a pass through hole in it, making it a hollow tube. Because of this design it can be used on any bolt, without length becoming an issue. A pass through socket requires a pass through ratchet that clamps around the socket, rather than attaching to a square nub on the ratchet head as it does with other types of sockets.

Universal Joint

Sometimes the bolt head you are trying to get to won’t be in a very convenient place. In cases where you need to access a piece of hardware but can’t reach it because of an odd angle or because something is in the way, a universal joint may help. Universal joints have a ball-swivel that give it up to 360-degree turning action. This can help you get into those tight spots your regular sockets just can’t reach.

A Note about Ratchets

In addition to determining the right type of socket for the job at hand, you should consider the ratchet as well. We know there are manual ratchets and power drivers, but there are also many ratchet types for specific applications. There are thumb ratchets, torque wrenches, speed wrenches, socket drivers and many more. When choosing both the best socket and the best tool to couple it with, you should always consider what type of hardware you will be working with, whether you need assistance reaching it and whether you need a power driver to properly tighten or loosen it. With this knowledge you should be able to pick up the right tool every time.


Prime Magazine

The information contained in this article is intended for general information purposes only and is based on information available as of the initial date of publication. No representation is made that the information or references are complete or remain current. This article is not a substitute for review of current applicable government regulations, industry standards, or other standards specific to your business and/or activities and should not be construed as legal advice or opinion. Readers with specific questions should refer to the applicable standards or consult with an attorney.


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