Simple yet highly effective, shaft collars are ring-shaped metal or plastic components that enclose shafts and serve three main purposes: holding components in place, positioning components on the shaft, and providing a point of contact between the shaft and other components. This reference guide provides an overview of shaft collars styles, what you should consider for the installation and disassembly, and the materials, finishes, and surface types that are available today. For more in-depth information, check out our product overview on shaft collars.
Shaft collars come in a diverse range of styles, including set screw, one-piece split, two-piece split, balanced, and hinged. One-piece split, two-piece split, balanced, and hinged models collectively fall into the same category: clamp-type collars. Clamp-type collars are fitted around the shaft and are not screwed to the shaft directly.
When a recessed screw is positioned inside the ring of a shaft collar, the system is called a set screw. To install this collar, the user must first tighten the screw onto the shaft, creating a slight indentation on the shaft material. Once the screw is tightened and the collar is secured, the shaft will become permanently marred with small burrs. The system is relatively easy to use and most effective when the screw is harder than the shaft material.
A one-piece split collar tightens circumferentially around the body of the shaft without breaking the shaft surface. Like a set screw collar, the one-piece split also contains a screw which must be tightened or loosened to move the collar on the shaft—but, unlike the set screw model, the one-piece split can be repositioned and doesn’t damage the shaft. Instead, it distributes pressure evenly across the circumference, providing a more uniform and secure hold.
Made from two semi-circles that combine to form the collar, two-piece split collars are easy to disassemble and rearrange along the length of the shaft. If you have other components on the shaft, using a two-piece split instead of a one-piece split will allow you to reposition the collar without needing to remove anything else.
A balanced collar looks similar to a two-piece split but contains interlocking studs on both sides to help minimize vibration and distribute weight as evenly as possible across the shaft circumference. Just like the one- and two-piece split, this collar won’t mar the surface of a shaft.
As the name suggests, hinged collars contain a hinge that allow the user to install the collar at any point along the shaft. The hinge also ensures both pieces of the collar stay connected. Many users prefer to use a hinged collar over a standard two-piece split because the design makes it impossible to lose a component.