disclosed is an integral one piece plastic fastener for securing belt ends together . the fastener has upper and lower plastic plates clasped to a belt end with integral , hollow rivets projecting from the upper plate through openings in the bottom plate and with hollowed ends of the rivets deformed to form rivet heads for maintaining clasping of the plastic plates on the belt end . also disclosed is a rivet head forming tool which smoothly forms rivet heads by a spinning process in which a rotating tool is forced against the hollow end of the rivet and spun with sufficient velocity and applied with a high force to create a sufficient heat and pressure to cause the end wall of the rivet to curl and turn over radially outwardly to from a rivet head tightly pushing against the lower plate of the fastener .