Fasten firmly is a term used to describe the process of attaching two objects together in a secure manner. INFIX, RIVET, NAIL, and CLAMP are all methods of fastening firmly. INFIX is a method of fastening by inserting one object into another. RIVET is a method of fastening by using a metal pin with a head on one end. NAIL is a method of fastening by driving a metal spike into two objects. CLAMP is a method of fastening by using a device to hold two objects together.