The World of Fasteners by Gao Grace

Fasteners are widely used in industrial process as well as in our daily life. Although they are small components, they undoubtedly do great help to form manufacturing equipments. In fact, they are classified into many kinds. Different types hold different specifications. How about having a general idea about them?

Generally speaking, threaded fasteners either have a tapered shank or a non-tapered shank. For those with a tapered shank, they are designed to either be driven into a substrate directly or into a pilot hole in a substrate. And for those with a non-tapered shank, they are usually designed to mate with a nut or to be driven into a tapped hole.

Referring to fasteners with a tapered shank, they are wood screws, coach screws (lag screws), concrete screws, self-drilling screws and drywall screws and so on. For example, a wood screw generally has an unthreaded shank below the head which is designed to attach two pieces of wood together. Coach screw is similar to a wood screw, but it is commonly much larger with a hexagonal drive head. This kind of fastener is designed for securely fastening heavy timbers to one another, or to fasten wood to masonry or concrete. And a concrete screw is a stainless or carbon steel screw for fastening wood, metal, or other materials into concrete or masonry. Furthermore, a self-drilling screw has a drill-shaped point to cut through the substrate to eliminate the need for drilling a pilot hole. They are widely used in soft steel or other metals.

For fasteners with a non-tapered shank, they are cap screws, hex bolts, socket cap screws, machine screws, elevator bolts and carriage bolts and so on. For example, a carriage bolt is also named a coach bolt. It has a domed or countersunk head, and the shank is topped by a short square section under the head. The square section grips into the part being fixed (typically wood), preventing the bolt from turning when the nut is tightened. And a machine screw is generally a smaller fasteners (less than 1/4 inch in diameter) threaded the entire length of its shank that usually has a recessed drive type (slotted, Phillips, etc.). What else, a self-tapping machine screw is one similar to a machine screw except the lower part of the shank is designed to cut threads as the screw is driven into an untapped hole. The featured thing is that if the screw is reinstalled, new threads are not cut as the screw is driven.

In words, we can not ignore the convenience brought by these small components. It is important to have some further understanding of each type in order to choose the proper ones under specific circumstances. Hope fasteners continue to favor our industrial process and daily life.