1. Why Do Plastic Parts Often Contain Metal Nuts? Brass Insert Nut Ever had this happen?You’ve tightened a screw into a plastic housing many times — eventually, the screw hole gets loose, won’t grip, and can’t hold anymore. That’s exactly when the Brass Insert Nut comes to the rescue. The concept is simple:Embed a brass nut inside the plastic hole so the plastic part can have a metal-strength threaded anchor. These nuts are installed using heat, ultrasonic vibration, or press