What Is a Wrench?
A wrench is a tool used to tighten or loosen a hexagonal bolt or nut. The wrench is inserted into the two parallel hexagonal surfaces of the bolt or nut and force is applied by hand to transmit torque. A wrench is also known as tools for tightening and loosening hexagonal bolts and nuts. “Spanner” is the British English word and “Wrench” is the American English word. There is no difference in their original meanings, and the difference between a wrench and a spanner is not clearly defined.
Uses of Wrenches
Wrenches are used to fasten or loosen hexagonal bolts, nuts, and other screws with two parallel sides. They are indispensable fastening tools for machinery and equipment, precision instruments, vehicles, engines, construction, furniture, DIY, and all other situations. They are highly versatile and their range of use is very wide. One method of preventing nuts from loosening is the double nut method, in which two nuts are stacked on top of each other, but wrenches are always required for double nut fastening. In most cases, two wrenches are used for fastening.
Characteristics of Wrenches
Wrenches are not suitable for turning a bolt or nut 360°, because it requires a large space to do so. Therefore, they are often tightened first by hand or with other tools, such as a screwdriver, to the point of temporary tightening, and then finally tightened with a wrench. Since wrenches tighten on two sides, applying excessive force can deform the bolt/nut or damage the tool. When tightening with a large torque, spectacle wrenches (which receive force at the six apex points) should be used. For parts that require a wrench with a large amount of force, a striking wrench is used. This wrench can apply large force instantaneously by striking the tip of the handle with a hammer or the like. It can be used when retightening is necessary or for nuts that are rusted and cannot be loosened.
The nominal dimensions and sizes of wrenches are expressed in terms of the dimension of the 2-sided width (the dimension of the open part). Therefore, even if it is not a bolt or nut, the wrenches can be used by matching its dimensions. With a round shaft, the wrenches can be used by taking out two sides, and with a small torque, the wrenches can be used by only taking out one side (so-called “D cut”).