Threaded inserts are small tubes, which are used to create or repair threaded holes.
Threads can be internal or external and are differentiated by gender. External threads, like screws and bolts, are male, while internal threads, like nuts and holes, are female. Male threads fit into female threads. Though male and female threads are formed using different tools, the structure is the same (if you turn a female thread inside out, it will be the same as a male thread and vice versa).
Female threads can become damaged and may require repair.
Threaded inserts repair existing damaged threads while maintaining the original size of the hole. They also create new female threads by being permanently fixed into a screw hole using varying installation processes – the insert itself then becomes the new female thread.
Threaded inserts also make it possible to create threaded holes in materials other than metal, like plastic and wood.