Heat staking, which is also known as metal-to-plastic insertion, involves preheating an insert with induction and then pressing it into a hole in a plastic part. This is accomplished by positioning the induction coil over the hole and then holding the insert in the coil for a short period of time. When the correct temperature is achieved, the insert is pressed into the plastic. A narrow zone of plastic then melts and flows into the knurls of the insert. The plastic re-solidifies resulting in a complete assembly that often has much better mechanical properties than what results from alternative heating methods. The inserts are often brass or steel.