How does a socket work?
Sockets are fitted around or inside a fastener head of a corresponding size and turned with the aid of a turning tool such as a wrench.
For instance, a 13mm socket is designed to fit around the head of a 13mm bolt head and, when attached to a wrench or ratchet, can be used to turn the bolt head, thus tightening or loosening it.
If the fastener has a standard thread, then turning it in a clockwise direction with a socket will tighten the fastener, whilst turning it in an anti-clockwise direction will loosen the fastener.
In order to turn a fastener, the socket is first attached to a turning tool using a ‘drive socket’.
The ‘drive socket’ size must match the size of the ‘drive square’ of the turning tool.
There are a wide range of turning tools for use in different circumstances and applications. Some, such as a breaker bar, allow a large turning force (torque) to be applied to the fastener. Torque wrenches allow a more precise torque to be applied to the fastener, while ratchets allow a fastener to be tightened or loosened with just a small angular movement instead of complete turns.
See Which turning tools can be used with sockets? for more information.
Do all sockets work in the same way?
The answer to this question is both yes and no. Once the socket has been attached to the turning tool, the other end of the socket (the drive) is usually placed onto the head of the fastener to be turned. All sockets work by turning the head of a fastener either clockwise (tightening), or anti-clockwise (loosening).
However, while some sockets, such as hex sockets are designed to fit around the outside of the fastener head, others such as socket bits, fit into the fastener head.
There is also a difference between the way different sockets can turn a fastener. The heads of cheaper or poorer quality sockets tend to have flat internal walls. This leads to the turning force (or torque) being applied to the corners or points of the fastener head.
This part of the fastener head is not as strong as the flats (or land) and by applying the torque here, you run the risk of rounding the head of the fastener. In some cases, this makes the fastener almost impossible to remove.
High-quality sockets have curved internal walls, that are designed to make contact with the head of the fastener on the flats (or lands), thus applying the turning force (torque) to this area of the fastener head. As this area is stronger, it greatly reduces the chance of the fastener head being rounded off, and also means that more torque can safely be applied to the fastener.
The curved walls also help reduce the stress on the socket walls, and so make the socket itself stronger too.
There are several different names given to sockets that apply the torque to flats of a fastener, by different manufacturers.
Some common names used by manufacturers for this feature are: ‘Hip-Grip design’, ‘Anti-slip drive’, ‘OGV’, ‘Opti-Torque’, ‘OZAT’ and ‘AF’.