What Are Set Screws?

When you are interested in using fasteners, you may come across some that you may not be very familiar with. Most of the time, these turn out to be highly specialized fasteners that are designed to perform a specific function, and which are usually sold by a limited number of high quality vendors. However, just because they are not very commonly used does not mean that you should not know anything about them.
If you are in an industry where you use a large number of fasteners, it would be a good idea to know something about some of these rare fasteners, since you may find out that you actually need them to improve the quality of your products. One of such fasteners is the set screw.

What is a set screw?

In a nutshell, a set screw is defined as a type of screw that is designed to secure one object within another one. An example of this is when you need to secure a gear to a pulley. In such cases, regular fasteners such as aluminum hex head cap screws may not be ideal, since the jutting head could end up compromising the function of the gear and pulley assembly. However, due to the design of the set screw, it can be embedded within both the pulley and the gear without having any protruding parts.

How can you identify one?

The most obvious feature about set screws is the fact that they are usually headless. Such fasteners, also known as blind fasteners, are usually fully threaded throughout the whole body. On account of this, they are usually put in place using a machine known as an internal wrenching drive, or an Allen key. In addition to that, Robertson sockets and slots can also be used to put them in place. Once in place, this fastener exerts a clamping force that will hold the two items it is connected to together.

 

Common set screw materials

Set screws can be made in any material that a regular fastener can be made in, such as aluminum, titanium and steel. You may therefore need to figure out which type of metal will be most ideal for a particular application, so that you can get a set screw made out of that material.
Most commonly, set screws are made out of alloy steel. Alloy steel socket set screws are usually tougher than other types of fasteners, and thus last longer.

The different point types

Set screws are all designed to have a specific point type, which is the type of tip the fastener has. Which tip you select will depend on the engineering qualities you hope to achieve. For instance, if you want a screw that will press on a flat surface, you could get one that has a flat point. You can also get screws with cup points if you want the screw tip to have a reduced surface area of contact without experiencing huge stresses. Other point types include the domed points, cone point, knurled cup point and extended points.