How Ratchets and Sockets Work
A ratchet is a handle that snaps into one end of a socket by means of a square-drive connector. The other end of the socket fits over a fastener. A mechanism in the ratchet allows the handle to engage and tighten the fastener when you swing it in a clockwise direction and turn freely when you swing it counterclockwise. A switch on the ratchet reverses the action to loosen the fastener.
Ratchets and Sockets vs. Wrenches
You choose the best tool for your project.
Ratchets and sockets are among the different types of wrenches designed for specific tasks. They perform the same functions as a conventional wrench — tightening and loosening fasteners. However, there are some tasks that suit a ratchet and socket particularly well. A ratchet and socket combination (sometimes called a socket wrench) lets you turn a nut or bolt without repositioning the tool on the fastener — like you need to do with a wrench when there isn't enough room to turn it in a full circle. This can make the work quicker. Also, since a socket fits completely around a fastener, it's less likely to slip off than some types of wrenches. See the list below for more details on socket tools and their uses. For more information on wrenches, see The Wrench Guide: Types of Wrenches, Uses and Features. Make sure the tool you use is suited for the task.
Types of Ratchets, Sockets and Accessories
Here's an overview of the available sockets, ratchets and accessories. They're often sold individually, but you may prefer a socket set or ratcheting wrench set to be prepared for a variety of jobs.
Ratchet
- Available with different drive sizes — 1/4 inch, 1/2 inch and 3/8 inch — to operate different size sockets.
- Most operate with a geared drive; those with a higher tooth count let you operate the tool with a smaller swinging motion, which is useful when there's little room to move the handle.
- Gearless models operate with a roller bearing and require smaller movements to turn fasteners than a geared drive.
- Many have a lock that keeps the socket from falling off or sticking on the fastener; a quick-release button disengages the lock.
- Jointed or flexible-head ratchets (bottom image) allow you to adjust the angle of the handle to work in tight areas.
Socket
- Attaches to a ratchet to tighten and loosens nuts and bolts.
- Also works with torque wrenches and breaker bars.
- Available in standard (SAE) and metric sizes; some are color-coded to help you quickly distinguish between the two types.
- Fits either a 1/4-inch, 1/2-inch or 3/4-inch ratchet; smaller sizes fit smaller fasteners, while larger fasteners usually need sockets with larger drive sizes.
- Shallow, low-profile sockets (left image) fit spaces where there's little clearance above the head of the fastener.
- Deep sockets (right image) can reach the nut on a longer, threaded bolt; they also allow you to reach recessed fasteners.
- 6-point sockets (left image) and 12-point sockets (right image) are available to fit a variety of fastener heads; universal sockets work with more fastener types, including spline, star and square.
- Flex or flexible sockets have a built-in joint that allows you to use the handle at different angles, which is a useful feature in tight spaces.
Pass-Through Socket
- Turns a nut on a longer, threaded bolt, allowing the bolt to extend through the socket and ratchet.
- Has a low-profile design.
- Reduces the need to have both low-profile and deep sockets.
- Works only with specially designed ratchets.
Driver Socket
- Tightens/loosens fasteners, such as flathead, Phillips, hex or star-head screws.
- Available in sets with standard sockets.
Spark Plug Socket
- Has a deep socket design to fit over the body of a spark plug.
- Lined with a rubber insert that grips the plug, helping you pull it out once loosened.
Impact Socket
- Designed to work with pneumatic or cordless impact wrenches.
- Made with a material that can handle the impact action without breaking.
- Darker finish distinguishes them from standard chrome sockets.
- Typically has a thicker wall than a standard socket.
- Available in low-profile and deep designs.
Socket Adapter
- Drive adapters (left image) allow you to fit a socket to a ratchet handle with a different drive size.
- Hex-shank adapters (right image) fit a square drive socket to the hex drive found on impact drivers and drill/drivers.
U-Joint Adapter
- A jointed attachment that connects a socket to a ratchet, allowing you to use the ratchet at different angles relative to the fastener.
- Gives you the flexibility to turn fasteners where a standard ratchet/socket combination wouldn't have clearance to swing back and forth.
Socket/Ratchet Extension Bar
- Attaches between a socket and ratchet to increase the reach of the socket and turn recessed fasteners.
- Available in various lengths.
- Locking extensions prevent the socket from dropping off or sticking on the fastener.
- Extensions with a wobble feature have a socket-end shaped to give you the option of pivoting the ratchet handle a few degrees relative to the fastener for a better working angle.
- A knurled or crosshatch pattern on some extensions allows for hand-tightening or loosening.
Torque Wrench
- Turns sockets to tighten nuts and bolts.
- Can be set to a specific amount of torque (rotational force) and indicates when you tighten a fastener to that point.
- Helps prevent overtightening.
- Different models have different torque ranges.
- Electronic models (bottom image) are available.
Breaker Bar
- Turns sockets to loosen nuts and bolts.
- Doesn't have a ratcheting mechanism.
- Designed to break free tight or stuck nuts and bolts; once you loosen the fastener with the breaker bar, you can use a ratchet to remove it without the risk of damaging the ratchet mechanism.
- An extended handle provides greater torque than the shorter ratchet handle.
- May have a jointed drive end to allow a variety of working angles.
Socket Tool and Mechanic Tool Sets
- Ratchet and socket sets provide ratchets and several socket sizes.
- Mechanic tool sets (image to right) often provide socket and ratchet sets plus tools such as wrenches and pliers.
- Options range from smaller 11-piece sets to collections with 300 or more pieces.
Socket Lengths and Special Features
Even if you have the right size socket, it may not work for every type of job. Working in tight spaces or on difficult tasks, you may need a special socket length or type to get the job done efficiently. Ratchets and sockets also have special features that can make work easier.
Socket Lengths
- Standard length sockets: Best for basic projects.
- Deep sockets: Help you reach bolts that are far down on a vehicle or machinery. Also, they are often needed when the bolt extends from the nut, or the fastener is recessed.
- Low-profile sockets: Best for tight spaces that can be difficult to maneuver in.
- Mid-length or intermediate sockets: Useful for projects in tighter spaces that require additional reach.
Special Features and Additional Tools
- Socket extensions: Extensions go between the socket and ratchet to reach parts that are unreachable with a regular socket. Locking extensions help keep your socket secure to the ratchet.
- Socket adapters: Socket adapters let you use a socket with a ratchet of a different drive size.
- Breaker bars: A breaker bar is designed to provide extra leverage to help break free a stuck or difficult nut or bolt.
Ratchet and socket sets, along with specialty tools like breaker bars, are especially helpful for all sorts of vehicle repairs, construction tasks, and electronic and machinery maintenance. A set that has both SAE and metric sockets is ideal for most tasks.