Which fastening item is NOT typically used in mechanical assemblies?

In mechanical assemblies, the primary function of fastening items is to securely join components together to create a stable structure that can withstand various forces and conditions. Nuts, rivets, and screws are all traditional fastening elements used in a wide range of applications due to their reliability and strength.

Nuts are typically used in conjunction with bolts, providing a threaded counterpart to secure two or more parts together. Rivets are permanent fasteners that are used to join materials together by deforming the end of a metal pin; they are especially useful in applications where welding is not feasible. Screws are versatile fasteners that can be used in many different contexts and are known for their ease of use and ability to create a strong hold by being driven into materials.

On the other hand, wires are not commonly classified as fasteners within mechanical assemblies. Although they may occasionally be used for binding or securing components together, they do not provide the same level of mechanical strength or reliability as the other fastening options listed. Wires can serve supportive roles in specific applications, such as electrical connections, but they lack the characteristics that define the standard fastening items used in mechanical engineering design. Thus, they are not typically recognized as primary fastening components in mechanical assemblies.