A Complete Guide to Socket Sets

Impact driver socket sets function much like any other socket set, except they’re designed for use with power tools such as electric or pneumatic air wrenches.

To withstand use in these high-demand applications, impact sockets are generally forged from slightly softer but thicker (and therefore less shatter-prone) alloys such as chrome molybdenum steel, frequently dipped or coated to provide enhanced anti-corrosion properties.

Socket sets in imperial measurements are designed to tackle fasteners whose heads are measured in inches and fractions of inches. While this was once the accepted standard (and is still widely referred to as the SAE standard, an acronym for the US-based Society of Automotive Engineers), the majority of other countries around the world today prefer the metric system.

• Note: while metric values are often used for the socket head opening these days, the drive socket recess - the part that attaches a socket to a ratchet spanner - is always given in imperial measurements (see ‘socket set sizes’ further on in this guide).

Measured in millimetres, metric is broadly seen as tending to be somewhat more precise for many uses. However, it’s not at all common to encounter nuts and bolts that still conform to imperial standards, particularly in older or machinery. In most cases, you should be able to find a roughly equivalent metric/imperial socket that will do the job in a pinch (e.g. 5/16” and 8 mm, or 7/8" and 22 mm), but this isn’t an ideal approach.

If you know you’re likely to be encountering fasteners that use both standards at some point, it’s sensible to invest in both types of kit - or, as is the case with a good number of reasonably priced socket sets, one that includes options for either system.

They’re also more widely available in smaller sets or as individual attachments than regular sockets - outside of automotive environments, it’s fairly common to see toolkits with a full complement of standard-length sockets, plus a narrower selection of deep sockets for more occasional uses.

A hex socket set, also called a 6-point socket set, is designed to fit over a standard 6 sided hexagonal shaped nut or bolt head. These are the most common type of socket.

They’re generally preferred for everyday use because they’re extremely versatile, fitting a majority of fasteners in most applications, and the fact that the socket forms six points of contact with the nut or bolt means it tends to offer very reliable purchase for tightening and loosening.

Some hex socket sets - generally the higher-end ones - feature slightly convex internal socket faces, which allow for more torque to be applied while reducing the risk of stripping or rounding-out the head of the fastener at its corners.

12-point socket sets, often called ‘bi-hex’, work on the same principle as their 6-point hex cousins, but the recessed openings of the sockets feature twice as many inner faces.

Collectively, they provide 12 points of potential contact with the fastener, which can deliver some important benefits: as well as making it quicker and easier to seat the socket over most fastener types, a 12-point socket set allows for square-head nuts and bolts to be accommodated (these cannot be fitted into a 6-point hexagonal recess at any angle).

The possible downside of a 12-point or bi-hex socket is that the force tends to be exerted more directly on the corners of the fastener head, leading to higher risk of rounding or stripping if too much torque is applied.

Bahco is a tool manufacturing brand originally founded in Sweden. Now a leading pan-European name in hand tool design and production, its key innovations over the years have included the adjustable spanner, the bi-metal hacksaw blade and the ergonomic screwdriver. Bahco socket sets are known for their high-performance steel alloy construction.

DeWALT is among the top-regarded brands for hand and power tools across all manner of worldwide construction, manufacturing and engineering fields. Like all of the company’s products, DeWalt socket sets are rigorously tested by genuine professionals under the most demanding job site conditions.

Wera is a German brand widely seen as one of the more innovative designers of hand tools on today’s market. They specialise in turning and torque tools, including Wera socket sets, which are rightly lauded for their lasting quality and precision.

Stanley socket sets are equally prized by hobbyists and professionals for their ruggedness and consistency of build quality - a brand synonymous with reliability, innovation and value for more than 170 years.

Headquartered in Japan, Makita needs no introduction to professional mechanics, engineers and craftspeople of all stripes, being extremely highly regarded for its market-leading standards in manufacturing, performance and safety. Makita socket sets are no exception, made from high-quality alloy steel for long life, durability, impact resistance and ease of use.

Gedore is among the global market leaders when it comes to hand tool branding, having expanded dramatically from its German roots since forming in 1919. Gedore socket sets are designed by established experts in the field, and chosen primarily for their rugged build quality.

Yet another leading German manufacturer that still makes all of its tools on home soil, STAHLWILLE today exports to more than 90 nations. STAHLWILLE socket sets are crafted from high-grade steel alloys to deliver exacting standards of performance and longevity.

CK tools are engineered to offer leading performance, durability, accuracy and strength, and the company’s product development is driven by panel of cross-trade professionals. CK socket sets reflect input from both metallurgical and hand tool design engineers, which shows in their manufacturing quality and range of robust finishing treatments.

France-based manufacturer Facom is recognised for quality craftsmanship at competitive prices. Solid design mechanics and consistent ease of use make Facom socket sets a popular brand choice among both professionals and home users alike.

US brand GearWrench is a highly regarded name among professional mechanics, especially well-known for its patented five-degree-turn and X-Beam ratcheting wrenches. GearWrench socket sets have gained a deserved reputation for ruggedness, speed and convenience, available in a range of both SAE and metric configurations.