A cross peen hammer is a hammer used by blacksmiths to complete metal work. The wedge-shaped end of the hammer allows you to make the metal fuller when used with heat. The main functions of a cross peen hammer is forging and riveting. Forging is a process in which you heat a single piece of metal and use tools to obtain a particular shape. Riveting is the process in which you bind two or more pieces of metal together using a peen hammer. Below is a guide on how to rivet metal. Brass and copper are the best metals to use during riveting because they are softer than other metals and easier to work with. This process can also be used when riveting metal to fabric or leather, the process will be the same. Using brass or copper rivets when working with metal is best because it prevents corrosion and rust damage to the fabric. When doing any metalwork take safety precaution to avoid injury to yourself and others. Always wear protective eyewear and gloves, and read all directions before beginning.