To get a better idea of which types of screws to choose, let’s get a quick view of the definition of the screw, in this article, we also introduce different types of screws and their uses, you can know about each kind of screw in detail.
A screw is a type of fastener consists of a threaded shaft and a head on one end, the other end of the shaft can be flat or sharp. The thread on the external surface also called male thread, forms a helical ridge. Screws are used to fasten materials by the engagement of the screw thread with a similar female thread in the matching part, actually, screws are often self-threading, which means that when you turn a screw into the material, the thread will cut into the part and create an internal thread to fasten materials together.
Wood screws are a type of screw with a smooth shank and tapered point used for wood or other soft materials. There are many types of wood screws based on different screw heads, including Phillips flat head screw, Frearson flat head screw, slotted flat head screw, slotted oval head screw, Phillips round head screw, and slotted round head screw. The round head wood screws are suitable for attacking thin materials to wood, the flat head wood screws are ideal for securing hinges. Wood screws are often made from stainless steel or brass.
Machine screws usually are smaller than the average screw and designed with finer, more accurate threads than other fasteners, they are intended to be fastened to an existing tapped hole on the surface of metal parts in various machinery or in conjunction with a corresponding nut. The use of machine screws can be found in machines of all kinds of industries, including manufacturing, engineering, machine tool, and more. They can be used in almost every material such as brass, steel, and nylon. Machine screws also have a wide variety of head types, including Phillips, slotted, star drive, combo, flat, pan, oval, and truss, these head types can form a number of combinations.
A sheet metal screw consists of a fully threaded shank with sharp threads and a tip, and a head. Full threads can increase retention between materials and the sharpness allows it to cut into the material and form its own internal thread easily. Sheet metal screws are often used to fasten metal parts to metal parts, or attach metal pieces to plastic, wood, rubber, or other materials. Sheet metal screws can be classified into self-tapping screws and self-drilling screws. Self-tapping sheet metal screws have a sharp tip to fasten metals with pre-drilled holes, while self-drilling screws can cut through metals that have not been drilled with their drill point tip.
Socket screws are also known as Allen head screws, designed with a hexagonal internal drive built into the head and required to be tightened or loosened with an Allen wrench or hex key. This feature sets socket screws apart from other types. Other than that, socket screws are often squared off at the tip, this type called flat point socket screws and widely used in common applications. Socket screws combine lots of advantages and features of other hex fasteners, it’s convenient and easy to use. They offer higher torque and clamping force than regular screws, so in a given application, fewer socket screws can achieve the desired clamping force and complete the fastening, which allows fewer holes, lower overall weight, and reduced hardware. So socket screws are a preferable choice for applications where require lightweight. Socket screws can be made from aluminum, steel, brass, and more.
Set screws are also known as blind screws or grub screws, they don’t have an obvious head that with a diameter larger than that of the shaft, set screws are used to secure an object within or against another object, usually without a nut. Set screws can create compression forces that hold two loose objects firmly together and do not require a nut. The working principle of set screws is that the screw passes through a threaded hole in a part and butting up tightly against the surface of the second part on the rear side. So the set screw is intended for use of fastening a component that would move or slide around relative to another. Set screws have a cone point, flat point, full dog point, half dog point, oval point, and cup point.
Mating screws have a shoulder that matches the diameter of the sex bolts, they are used with each other. Mating screws have a section of the smooth shaft and an externally threaded portion, which is received by the internally threaded part of the sex screw, they are the companion for sex screws. Mating screws and sex screws are produced in the same material if used together. This group of fasteners is used to assemble fitness apparatus, playground equipment, railing systems, furniture, helmets, knives, fixtures, signs, and many other products.
Lag screws are also known as lag bolts or coach bolts, lag screws are one of the toughest fasteners used to connect heavy materials that need to bear an intense load. Compared to most ordinary screws, lag screws are typically larger. The name lag screw derives from their original use in securing barrel stages. What differentiates lag screws is that it is only available with hex heads. Hex headed fasteners are designed to hold up in applications where a lot of torque is necessary. A lag screw requires a pre-drilled hole at the same diameter as the shaft of the screw in installation. A right driver bit and a power drill are needed for tightening the screw.
Cap screws have a large head and a cylindrical shaft with male threads, the diameter of the head is larger than the threaded shaft, which offers a positive mechanical stop when tightening the screw. Cap screws are usually used without a nut, it is tightened into a threaded or tapped hole directly. The cap screw is available in multiple head types including hex, socket, button, and more. They can be made out of stainless steel, carbon steel, and other alloys. Similar to machine screws, cap screws are commonly used in machines, home appliances, and electronics equipment.