There are many different types of fasteners, and while most of us are familiar with the more common varieties, it’s certainly worth knowing about the rare, more specialised options available. These kinds of fasteners are designed to perform a specific function and are usually sold in small quantities and only by highly reputable vendors. One of these specialised varieties that is certainly worth investigating if you’re in an industry that uses large quantities of fasteners is the set screw.

Quite simply, a set screw is a headless screw, fully threaded from end to end and designed to secure one object within another object. Used in many industrial and mechanical devices, particularly when securing a gear to a pulley, set screws pass through a threaded hole in the outer object and are tightened against the inner object. Unlike regular fasteners, the design of the set screw allows it to be embedded within the pulley and the gear with no protruding parts. Using regular fasteners in this situation would possibly compromise the assembly.

The headless, hexagonal nature of most set screws is often why they are also referred to as blind fasteners or grub screws. To put them in place, an internal wrenching drive or Allen key is used. Once in place, the set screw works by exerting a clamping or compressional force that will prevent movement between the two objects and hold them connected to each other, as intended. This method is different to regular fasteners that use threads to hold objects together.

Set screws, like regular fasteners, are made from various materials such as aluminium, titanium or steel, with the most popular being alloy steel which is tougher and lasts longer. Set screws also come in several different shapes and sizes, all with varying strengths and features, and all designed with a specific tip. The type of tip you select will depend on the engineering qualities you intend to achieve. For example, if your application requires a smooth flat surface with no protruding parts then a flat point screw is ideal as it presses perfectly flat against the surface. A cup point screw, one of the most common types, works well because the surface is rounded. This feature reduces the contact surface area as well as the stress on a single point of the screw. Other point types include a knurled cup, domed point, cone point, and extended points.

So, the next time your application requires two objects that need to be secured firmly together, consider using a set screw to do the job. If you’re unsure of the type of set screw, don’t hesitate to contact your reliable fastener distributor for advice. At Bearing Centre, we’re available 24/7 to assist with your fastener needs.