To many people, all sockets look similar. However, if you speak with professionals, you’ll likely find that each one has a strong preference for a particular brand or design of socket. That’s because there are a variety of small differences in features and manufacturing processes of this simple, but important tool.

We highlight these differences below so you can properly build and maintain your socket collection for many decades of use.

6 Point vs. 12 Point Sockets

Six-point sockets (also called “single hex” sockets) have a hexagon-shaped opening with six points, or vertices, and six edges at 60-degree angles. These provide a tight fit on six-point fasteners, which makes the socket less likely to slip or round-off the fastener’s corners. This makes six-point sockets a great choice for stubborn fasteners that require a lot of force to remove.

12-point, or double hex, sockets are easier to connect to fasteners that are hidden, difficult to see or in tight spaces. Professionals will carry both six- and 12-point sockets in their toolboxes to handle all situations.

Drive Size

Located at the opposite end of the opening, the socket end drive is where the socket contacts the ratchet, extension or other accessories. The most popular drive sizes are 1/4", 3/8", 1/2" and 3/4". Industrial-grade brands like Gray Tools offer drive sizes as large as 2 ½". Even though sockets are available in imperial and metric sizes, the drive size is always expressed in imperial units.

The drive end is often beveled to guide the ratchet into the socket. Four dented grooves help provide a secure connection with the retaining ball of the socket or extension. It is very important to ensure a good connection between sockets, ratchets and extensions to help prevent setbacks from the socket falling to the ground, dropping in an engine or other undesirable outcomes.

Wall Thickness

Not only does the socket wall display its size and part number, but it also contributes to the overall strength of the socket. Some sockets also have a knurl for easy removal, even with greasy hands.

Regular sockets are highly durable and offer the strength needed to handle industrial applications, such as heavy-duty machinery. Thin-walled sockets, on the other hand, are more popular for narrower, deeper spaces. As a result, they are used more in the automotive industry, but the drawback is they are not as strong as regular sockets.

Socket Finish

Sockets can be found in three different finishes:
1. Chrome Plated: This is the most popular finish in North America because these sockets are easy to clean and corrosion resistant. However, never use one of these if the chrome finish flakes off because it is very sharp. Many sockets come with a lifetime warranty and should be replaced if this happens.
2. Satin: The satin finish is typically less expensive than chrome and is very common outside of North America. Satin provides a slightly better grip and makes some imperfections less visible.
3. Black Oxide: A black oxide finish is usually only found on impact sockets. However, it’s important to never assume that a socket is an impact socket just because it has a black oxide finish. Black oxide sockets are easy to clean and typically less expensive than chrome. The size markings are highly visible on the black surface, especially if they are laser-etched, but may be more difficult to see in low light.

Material

Most sockets are made from alloyed steel, but manufacturers use different materials to enhance the hardness, strength and ductility of their sockets. Chromium-molybdenum (CRMO) and chromium-vanadium (CRV) are most often used, and there are strong opinions as to which is better.

A common perception is that sockets imported from Asia are made of CRV, since most of them have a CRV symbol stamped on them, while domestic manufacturers use CMO. However, the chemical composition is very similar, and both CRMO and CRV can make high-quality sockets. The difference in quality comes down to the manufacturing process and quality control.

Manufacturing Process

Although each manufacturer may use slightly different processes, below are the most important steps of making a socket:
1. Cutting Steel Bars: First, a steel bar is fed through a die and cut to the desired lengths, creating small cylindrical sections.
2. Hex Shape Formation: The cylindrical sections are cold formed in forging machines. Metal is shaped near room temperature to improve tensile strength, while allowing high levels of manipulation.
3. Cleaning and Machining: The sockets are tumbled through a washer/dryer system to remove lubricating oil. Machines then remove sharp edges and cut a bevel on the inner rim.
4. Stamping: Rolling stamps engrave information on the sockets. This includes the company name, part number, size and more.
5. Heat Treating: This process increases the hardness of the base material. The manufacturer specifies the required hardness and type of material, and then the appropriate heat treatment process is used to achieve the desired result. The amount of time a socket spends in the furnace depends on the required hardness and material used. This is followed by a rapid cooldown called “quenching,” in which the sockets are submerged in oil or another cooling medium. The quenching process is tightly controlled. The heating temperature, cooling method, cooling medium and cooling speed are all dependent on the type of material being quenched and the desired hardness. Generally, cooling is much faster than heating, since the desired result is to set the hardness as quickly as possible.
6. Shot Blasting: Next, sockets are typically sent into a chamber where they are blasted with fine steel particles to remove imperfections and to polish them. The chamber has a rotating belt, and steel shot is blasted at the parts as the belt rotates. This process takes about 10 to 15 minutes.

7. Rotobarrel: Sockets then go into a tub of ceramic stones and mild acid in a rotobarrel process to create a smooth finish prior to chrome adhesion. This takes about six hours per lot of sockets. The chemical recipe, as well as the quality and type of media, determines the quality of the finish. The rotobarrel process also helps remove inconsistencies, remaining dirt, burrs and rough spots off the surface of the socket. It results in a shinier product and cleaner surface to receive plating. Leaving a product too long in the rotobarrel can result in acid etching the surface, while removing it prematurely can result in a dull finish.
8. Wash and Rinse: Sockets are washed and rinsed as part of the electroplating process to prepare for chrome plating.
9. Chrome Plating: Some manufacturers, like Gray Tools, use a nickel chrome plating process. Nickel, which is the main protection against wear and corrosion, is deposited first. Chrome is then deposited over the nickel to provide added protection and a cosmetically pleasing finish. Each step in the plating process is precisely timed, and there may be many steps, depending on the product. If the surface isn’t properly prepared before this step, the chrome finish will appear unacceptable, or there will be poor adhesion. The chrome and nickel layers are only a few microns thick.
10. Rust Proofing: This is part of the electroplating process to ensure protection from rust.
11. Spinning: Part of the drying process during electroplating, the sockets are spun to remove excess rust. This is done differently among various manufacturers.

Identifying a High-Quality Socket

A person can often use sight and touch to help identify the difference between a high- and low-quality socket. Is the inside forging smooth and level? Does the socket feel solid in your hands? Pay attention to the exterior and interior finish to identify imperfections, such as chrome peeling or signs of rust. Also, the socket markings should be durable, so they don’t wear off easily.

Next, a high-quality socket opening should feature radiused corners to help prevent fastener round-off, and it should connect securely with ratchets and extensions. Finally, the brand is a good indicator of socket quality. Is it made by a reputable manufacturer known to stand behind its products?

Proper Maintenance

Even the highest quality sockets must be maintained and used properly in order to ensure many years of reliable service. Follow these simple steps to help get the most out of your socket collection:
1. Always use the exact size socket to match the fastener to prevent damage or injury.
2. Do not use metric sockets on imperial bolts, and vice-versa.
3. Do not use hand sockets on an impact gun.
4. Do not weld attachments on your sockets to improve leverage.
5. Do not store sockets in a moist environment.
6. Clean your sockets regularly.

More engineering has been put into sockets than most people realize. And, for such a simple tool, a lot of steps go into manufacturing them. But each step of the process plays an important role to provide you with a quality socket collection that should last a lifetime.