A Fastener is a tool or a mechanical device that joins two surfaces together. You can classify them into two categories: Permanent fasteners and Temporary fasteners. The permanent fasteners, once fixed, can only be removed after leaving a mark at the joint place. Nails and Rivets are examples of Permanent fasteners. Temporary fasteners, as the name suggests, hold the surfaces together temporarily. Nuts and Screws hold the fastened objects temporarily and may need occasional tightening. There are many different fasteners classified under the following categories. Let us look at them one by one in detail.