There are many types, models and designs of threaded insert. They can be categorised by the material they are imbedded into or the way in which they are inserted. The way they are installed is dependent on the material and the categories greatly overlap.
Threaded inserts for metal
There are two types of insert for metal: solid and coiled. The method to install these is similar (they are both threaded in), it is the actual insert which differentiates the type.
Threaded inserts for plastic
Threaded inserts for plastic are dependent on the plastic, the two main varieties are thermoset and thermoplastic.Press inserts for thermoset plastics are easily installed – as the name suggests they are simply pressed in. Ultrasonic inserts for thermoplastics are installed using a heating process, which is specialised and not generally considered a DIY task.
Threaded inserts for wood
Wood inserts are dependent on the wood, whether it is soft or hard. There are two main varieties: press-in and thread-in. It is possible to use both types on both types of wood, however hardwood is more vulnerable to cracking and so the inserts are usually placed in a slightly larger hole and fixed with glue.
There are some varieties of inserts which can be used on both plastic and wood (thermoplastics and softwoods). These are usually pressed in.