A ratchet spanner or wrench uses a mechanism which allows an open-ended, flare or ring head to turn a fastener in one direction but not the other while remaining fitted to the fastener head. By turning the spanner over or flicking a lever, it changes the direction of movement. They are an essential tool in any toolbox as it can tighten and loosen a nut or bolt, and by applying the correct amount of torque to the fastening, it can save time and effort. Some manufacturers choose to etch the arrows of the torque direction near the lever, making it easier for the user to identify the direction to tighten or loosen in. Ratchet spanners are available in a variety of metric and imperial sizes
Common ratchet spanner head types:
- Ring Head: The most frequently used type of ratchet head. They are especially useful as they apply force to all sides of the fastener, offering additional grip to avoid coming off the nut or bolt whilst the tool is in use.
- Reversible: The simple reversing mechanism allows to user to adjust the direction of the ratchet simply by moving the lever across on the tool.
- Flare Nut Spanner: Also known as a 'crow's foot' spanner or a 'brake nut' spanner, it provides contact at six points on the fastener, allowing a secure grip.
- Open Ended Spanner: An essential spanner for any tool box, it can also come with a ratchet mechanism meaning this versatile tool can be used across various settings.
- Open Ended Ratchet: This ratchet has an altered profile which can catch the fastening in one direction to apply the torque to loosen or tighten it. It can only move in one direction and can be turned over to change the direction of the torque application.