Set screw

A set screw is a type of screw generally used to secure an object within or against another object, usually without the use of a nut. The most common application is to secure a collar or hub to a shaft, preventing relative movement between the two parts.

Set screws are typically headless (also known as blind), meaning they are fully threaded and have no head projecting past the major diameter of the screw. This allows them to be completely recessed within a hole. They are driven into the hole via an internal wrenching drive, such as a hex socket (Allen), a square socket, or a slotted head.

The end of a set screw that comes into contact with the object it is securing can have a variety of points designed for different purposes:

• Cup Point: The most common type, providing good holding power and leaving a circular mark on the shaft.
• Cone Point: Offers high holding power, suitable for permanent or semi-permanent applications, and creates a deeper indentation.
• Dog Point (also known as a Half Dog Point or Full Dog Point): Has a cylindrical extension that fits into a matching hole or groove on the mating shaft, providing excellent shear resistance. Requires accurate alignment.
• Flat Point: Minimizes damage to the mating surface, suitable for frequent adjustments.
• Oval Point: Offers a balance between holding power and minimizing surface damage, suitable for softer materials.

Set screws are typically made from hardened steel or stainless steel. The size and grade of the set screw are chosen based on the application and the required holding power. The holding power of a set screw depends on factors such as the screw's size, material, point style, and the torque applied during installation.