• A set screw is a type of screw generally used to secure an object within or against another object. The most common examples are securing a pulley or gear to a shaft. Set screws are generally headless, meaning the screw is fully threaded and has no head sticking out past the diameter of the screw thread.
• The set screw passes through a threaded hole in the outer object and is tightened against the inner object to prevent it from moving relative to the outer object. It exerts clamping force through the bottom tip that projects through the hole.
• Set screws, though, do not come in one shape or size. There are several different variations of this fastener, all with different strengths and positive features. The variety is in the tip types. The different-shaped tips have unique properties that engineers can take advantage of

For example, a cone point type of set screw might be helpful if a detent was used to ensure proper nesting of the screw. A flat point screw could be more helpful if it needed to be pressed perfectly flat against the surface.