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All About Sockets: Types of Sockets

Revised: 5/23/22
Grainger Editorial Staff

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

Socket wrenches are tools that are either manual or electric and comprise 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 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

There are two types of hex sockets — six-point and 12-point. The six-point hex socket has six points or angles inside the bolt end. The 12-point socket, also called a double-hex or bi-hex, has 12 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, so it's a good choice for working in tight spaces.
Impact Sockets

Impact sockets have an industrial, black surface finish. They 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 As their name implies, spark plug sockets remove or fit a spark plug into an engine. Spark plug sockets are longer than standard sockets, and 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 a bit inside. Socket bits are frequently screwdriver bits, but they also come in less common types. They have a square ratchet end where they attach to the ratchet tool. They frequently come in sets, and can work with impact drivers as well as manual tools.
Pass-Through Sockets A bolt or a stud with an especially long shaft may require a pass-through socket to tighten or loosen bolts. The pass-through socket's hollow- tube design makes it useful on any bolt, without length being an issue. A pass-through socket requires a pass-through ratchet that clamps around the socket.
Flex Sockets If you need to access a piece of hardware but can’t reach it because of an odd angle or obstruction, a flex socket, also called a universal adapter, may help. Flex sockets have a ball swivel that provides up to 360-degree turning action, allowing you to get into tight spots.

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. There are manual ratchets and power ratchets, 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.


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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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