Most Common Types of Screws and Bolts
When it comes to any project, screws and bolts are integral components for the proper functions of most operations. While the two are often conflated, it is important to point out their distinguishing properties.
Screws are defined as a type of fastener that can be installed using tools like hammers or screwdrivers with compatible head designs. In general, screws look similar to nails; however, they consist of spiraling ridges around the shaft of the screw. These grooves help keep the screw in place when holding two materials or objects together.
Similarly, bolts are typically used to hold materials or objects together but require the use of a nut for added support. Whereas a screw threads directly into a material, bolts pass through a material and into a nut on the other side. Both screws and nuts come in various shapes and sizes, each equipped with different features. Because of their versatility, there are various screw and bolt types.
Hex Cap Screws
Hex cap screws have hexagonal heads and are typically used to attach wood or metal to wood. They consist of tiny steel threads and a flat washer under their head for increased precision.
Socket-head screws are ideal for applications where a fastener needs to sit below the material’s surface. They are typically made of stainless steel which makes them strong, reliable, and resistant to corrosion.
Thread-rolling screws exert pressure on soft materials like wood, plastic, or nylon to create threads. They consist of a double lead thread style that minimizes torque and enhances pullout power, preventing the material from cracking or becoming damaged.
Set screws are utilized in instances where you need to fasten an object to, or against, another object. Their design lacks a head and the shaft is fully threaded. There are several variations of this kind of screw including flat set screws, knurled cup screws, and cup point screws.
Machine screws are fastened in the tapped hole on a surface with the help of a nut. Moreover, they come in a variety of materials such as nylon, brass, stainless steel, and carbon steel, making them ideal for a number of applications.
Self-drilling screws are mainly used to fasten or join sheet metal or steel to other metals. They come in different lengths of drill tips as well as in varying point sizes based on their diameter.
Eye bolts are one of the more popularly used screws. They consist of a threaded shank and a ring at one end. The ring is designed to lift objects by passing a rope or wire through it.
Shoulder bolts function in a similar fashion to machine screws. They are equipped with a head, shoulder, and threading. These screws are generally used in automotive and wooden furniture making.
Hanger bolts are headless screws that provide an additional external thread to create an internal fastening joint in wood applications. They may also be used to suspend or attach objects to wood.
Carriage bolts are designed to fasten metal onto wood in woodworking projects. Their dome-shaped head prevents the screw from becoming loose or getting pulled through a wooden construction.
Lag bolts consist of a hexagonal head and are typically used in high-impact applications. They are incredibly strong, durable, and have an extended service life. Their core is made of high-carbon steel and their outer surface is coated in zinc which protects the screw from rust or corrosion.