Choosing The Proper Drive Size

Choosing the proper drive size is important as there are many tasks for various kinds of jobs that can be handled with the unique features of a socket wrench.

Most sockets are available in at least three drive sizes. For example, a 9/16-in. socket is offered in 1/4-, 3/8- and 1/2-inch drives. A 1/4-inch drive socket is the least expensive and will work in the tightest space, but the handles are too short for heavy loads. If the handles were longer, the drive square would twist off before the fastener was fully tight or a tight fastener was removed. The 1/4-inch drive socket is ideal for low-torque applications such as electrical work or in close-quarter automotive dashboards.

A 3/8-in. drive socket is 25 percent stronger, but also .022 inches larger in diameter than the 1/4-inch drive socket. A 1/2-inch drive socket is an additional 21 percent stronger and .027 inches larger in diameter.

Most of the time, the best way to choose a drive size is by choosing a drive with handles long enough to provide the required leverage, but not so long that the fasteners will break from overloading. Ideally, sockets should be designed so that each consecutive larger drive has stronger and larger sockets. This provides a wide choice of tools for a variety of fastener strengths from copper electrical fasteners to hardened alloy steel fasteners. Hitting the handle with a hammer or lengthening it with a cheater bar may overload both the socket and the handle and is never recommended.

Special care should be taken when using the smallest sockets of a particular drive. A hard pull on the handle may overload the socket and/or the fastener. Remember, too, that the strength of larger sockets of a particular drive are limited by the drive square and are, therefore, not appropriate for high-strength fasteners such as Grade 8 bolts or 12-point fasteners.

Proper drive size selection combined with proper usage will ensure that you can safely and effectively complete a variety of tasks with a socket wrench.