GET A GRIP

DIY people make use of sockets and wrenches but are they properly suited to the task of working on your pride and joy? Here is what you need to know

ISTILL have the first full-size socket set I purchased decades ago. It was inexpensive but has served me well. Over the years, I have replaced only a couple of sockets, inevitably misplacing individual pieces. The common set uses a half-inch drive with a socket range of 10 to 32 mm. The drive size is a four-sided square, a half-inch across flats, used with a variety of levers: a ratchet wrench, a T-bar, an impact driver plus many others. There are smaller sets with a 3/8-inch drive, commonly handling sockets up to 19 mm and quarter-inch drives for even smaller sizes, commonly up to 12 mm. Most regular Diyers will have one set of each but there is a lot more to the art of loosening and tightening bolts than meets the ratchet.

HISTORY

The socket wrench was patented by J Richardson of Vermont, USA, in 1863. The first nuts and bolts had a square shape but, as machinery developed, other shapes became easier to manufacture, leading to the hex drive and many more.

METALLURGY

A top-quality steel is necessary because of the extreme forces required for fasteners. Any deformation of the metal will render the tool useless and damage the nuts and bolts. The choice for manufacturers is steel alloyed with chromium and vanadium. More expensive alloys use chrome and molybdenum or chromoly, or a combination of chrome, vanadium and molybdenum.

SIX- AND 12-POINT:

The standard socket is a hex but, with 12 sides, it is sometimes called a double-hex. This grips on a small area around each corner which is fine for general use but, when it comes to highertorqued bolts such as cylinder heads or cardoor hinges, it may round off the corners, causing endless hassles. In this case, a sixsided socket is far superior. Here there are also two options. The cheaper option has flat sides and this will load the nut or bolt only on the corners. The more expensive shape has reduced contact on the corners but increased material on the flats or flanks. This has a much wider surface area of grip. The only disadvantage of the six-sided one is that there are fewer positions in which to place the wrench or T-bar. Since most make use of the ubiquitous ratchet wrench, this does not matter as the ratchet teeth allow for a wide variety of starting spots.

UNIVERSAL:

An interesting tool is the universal socket. This is a more complex item; a socket filled with spring-loaded pins. As you push the socket over the bolt, the pins retract leaving the area outside of the bolt with engaged pins that apply force for loosening. These typically handle bolts from 7 mm to 19 mm.

The two main advantages are: it doesn’t matter if you need a metric or imperial set; and only one socket will work on the full covered range. The downside is it’s quite a complex item that can lack high torque and so should be used on low-torque applications only. However, it is still a handy addition to your toolkit.

METRINCH:

The Metrinch socket set is really neat. This is designed to work on both metric and imperial sizes. It is widely used but, once again, it is a compromise and cannot match the ability of a six-sided hex socket made to fit one size. A socket that should be in all toolboxes is the half-inch/13 mm, as this is the most common metric socket and its equivalent the most common imperial (for motoring purposes, at least).

PASS-THROUGH SOCKETS:

These are handy when you have a nut on a long bolt with restricted access. The socket passes over the bolt and the ratchet grips the outside of the socket to move the nut.

DEEP SOCKET:

The most common of these is the spark-plug socket. With its extended body, the ceramic insulator and tip of the plug are enclosed in the socket with enough space for the half-inch drive. There is an optional rubber insert that grips the plug and prevents it from falling out of the socket after removal.