Guide to Shaft Collars
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.
Clamp-style collars can have additional features, including, for example:
Featuring weighty clamping screws and large diameters, heavy-duty collars provide exceptional holding power but are slightly bulkier than other models.
Weldable collars are lead-free, offer permanent holding power, and are heavyweight bearing.
Installation and Disassembly
A set screw collar is the oldest type of collar with the simplest design but has a few notable drawbacks. First, if you use a set screw collar, it will damage the shaft, which could make it challenging to reposition the collar later. The set screw collar also isn’t as secure as clamp-based models.
If you plan to reposition the collar along the shaft, a two-piece hinged collar will probably be the most convenient option. Rearranging or removing one-piece collars by sliding them along the shaft can be burdensome, especially if you’re working with a long, unwieldy shaft. A two-piece hinged collar is easy to move along the length of the shaft without separating the components.
The collar material significantly affects its overall performance. The material’s durability, holding power, and resistance to corrosion should all factor into your decision, in addition to its relative hardness compared to the shaft material.
At Stafford, we manufacture products from a wide range of materials, including aluminum and stainless steel.
Finish and Surface Treatment
Manufacturers can add surface treatments to change the collar’s appearance and increase its slip-resistance, anti-corrosive properties, and durability. Certain types of finishes are also chemically inert or specially engineered for food processing, the pharmaceutical industry, and other applications that require a sterile environment.
If you’re using a non-standard screw instead of the one that was provided with the collar, it’s also critical to determine how the material will interact with the shaft and collar.
Shaft Collars from Stafford Manufacturing Corp.
When selecting the right shaft collar for a job, consider the style, intended application, material, and surface treatments at your disposal. If you’re not sure what options are best-suited to your needs, talk to the experts at Stafford Manufacturing Corp. in Wilmington, MA. With over 45 years of experience manufacturing shaft collars, we have the expertise to answer all your questions and help you choose the best solution. We are ISO 9001:2015-certified and dedicated to complete customer satisfaction.
Contact us today to learn more about our precision-manufactured collar shafts and coupling components.