A pipe wrench is an aluminum or steel tool used for gripping and then tightening or loosening rounded metal objects, such as bolts, pipes or rods.
A pipe wrench is made of an upper hook jaw and lower heel jaw piece connected to a flat handle.
The jaw pieces have small teeth or grooves for gripping rounded objects when turned, and the lower jaw can be adjusted either up or down to fit the size of the metal object.
Pipe wrenches come in a variety of sizes and types.This type of wrench should not be used on hard metals, such as steel, or on square objects, as the teeth of the wrench can cause damage to the surface.
Also, there should be a 0.5-inch (12-mm) space between the back of the hook jaw and the surface for the proper amount of gripping to be applied and to prevent damage to either the object, the wrench or the person.
Other types of wrenches include the compound leverage wrench, the chain pipe wrench and the strap wrench.