Breaker bar

A breaker bar is a long non-ratcheting bar that is used with socket wrench style sockets. Breaker bars are used to break loose very tight fasteners because their additional length allows the same amount of force to generate significantly more torque than a standard length socket wrench. The use of a breaker bar also prevents damage to the ratcheting mechanism of a socket wrench. Often, after the first 1/2 turn of a fastener, the fastener is then loose enough to be turned with a socket wrench.

The long handle on the breaker bar compared to shorter wrench allows a larger torque to be generated with the same amount of force.

An improvised breaker bar can be made by inserting a wrench into a length of metal pipe to increase the available torque. A pipe used for this purpose is called a cheater bar or snipe.

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Wikipedia