Types and Applications of Set Collars and Clamping Rings

Set collars and clamping rings are important components in mechanical engineering. Their function is to secure machine components in a specific position on a shaft or axis. This article introduces different versions, selection criteria, and fields of applications.

Set collars and clamping rings

Set collars or clamping rings are used to hold components in a fixed position on shafts or axes. Components to be secured can for example be a gear wheel, a bearing, or a disc. Any axial movement of the components is prevented by locking them on the shaft (axial locking). Clamping rings or set collars can also act as spacers between two components.

Difference between set collars and clamping ring

The difference between set collars and clamping rings is the type of locking action. In most cases, set collars are secured on the shaft with one or more grub screws or set screws threaded into the ring. Unlike the locking action on set collars, a clamping ring is jammed onto the shaft. Omitting the pins or grub screws prevents damage on the shaft. Clamping rings generally achieve a significantly higher holding force compared to set collars.

Applications of set collars and clamping rings

In mechanical engineering, set collars and clamping rings are used to secure bearings, pulleys, gears and other components on shafts and to maintain their positioning. In the electronics industry, set collars and clamping rings are used to secure circuit boards, sensors, motors and other electronic components to shafts or bolts. Conveyor systems also use set collars and clamping rings to accurately position drums, rollers and conveyors.

Advantages of set collars and clamping rings

Set collars and clamping rings offer certain advantages:

• Set collars and clamping rings allow precise positioning and alignment of components on shafts or axes (important in applications that require precise alignment or spacing).
• They are easy to assemble and disassemble, which in turn facilitates maintenance or repairs.
• Given their low profile height, clamping rings and set collars can be used even in small spaces.
• They are very reliable. If selected and mounted correctly, unintended loosening and shifting is virtually impossible.
• Set collars and clamping rings retain their positioning accuracy even after multiple installation and disassembly cycles.
• They offer good resistance to vibration and shock, which is beneficial in applications with motion and vibration.
• Depending on the selected material, they can be corrosion-resistant, which is relevant in wet or aggressive environments.

Versions of set collars and clamping rings

Set collars and clamping rings are available in various versions. MISUMI for example offers the following variants:

• Slotted clamping rings
• Two-piece clamping rings (also called split clamping rings)
• Threaded set collars
• Clamping ring with keyway/damper/slot and clamping lever
• One-sided hinged clamping ring

Materials used

MISUMI lets you choose between different materials for set collars: steel, stainless steel, plastic and aluminum. While steel is appreciated for its robustness, plastic set collars are ideal for applications requiring corrosion protection or electrical insulation. Stainless steel set collars, which are also corrosion-resistant, are particularly appropriate for demanding environments. Low-weight aluminum is preferred for specialized applications.

Various fastening mechanisms

Various fastening mechanisms are used to fasten set collars and clamping rings:

• Screws or nuts: A bore is provided on the open side of the clamping ring for guiding a fastening element such as a screw or a threaded lever. A thread is provided on the opposite side of the clamping opening, in line with this bore, by which the clamping ring can be secured. A threaded insert or nut can be used instead of a threaded hole in the solid material.
• Internal or external threads: Set collars themselves can have an internal or external thread mounted on the shaft. The position of the set collar can be adjusted by rotating the set collar on the shaft. The set collar is then secured with the clamping action of the adjacent threads by tightening the thread.
• Clamping mechanism: Clamping rings have a clamping mechanism that is activated by turning or tightening a screw or lever. This mechanism pushes the clamping ring firmly against the shaft and holds it in place.
• Tensioning ring: A tensioning ring is a special type of clamping ring that uses spring-loaded clamping. Positioning the tensioning ring on the shaft and pushing or engaging the ring will clamp and secure the tensioning ring in its position.
• Keyway: In some cases, a keyway is cut into the shaft or axle, and the set collar is inserted into that groove using a suitably tolerated key. The set collar is now held in position and cannot be moved along the shaft or axis.
• Cotter pin: A cotter pin is a thin-walled piece of metal that passes through bores in the shaft and the set collar and connects them together. The cotter pin prevents the set collar from moving unintentionally.

Selection criteria of set collars and clamping rings

Different selection criteria must be taken into account to select the correct set collar or clamping ring

• Fit selection: The clearance fit must be selected according to the requirements to be fulfilled. Since the mechanism relies on clamping action, a tolerance field selection with noticeable clearance is often sufficient to ensure secure fastening.
• Material: It affects strength, corrosion resistance and temperature resistance. Typical materials are stainless steel, steel, aluminum, and plastics.
• Fastening mechanism: If the components have to be assembled or disassembled frequently, we recommend, for example, using an easy-to-install fastening mechanism and a clearance fit with noticeable clearance. The selected mechanism also depends on the desired joint strength and position adjustability.
• Positioning accuracy: Especially important for high precision requirements. Depending on the design of the connection, it may be appropriate to use clearance fits that can just barely be moved by hand.
• Standards: Some industries or applications may require specific standards or certifications for using set collars or clamping rings. If you have the choice, attempt to select parts that meet the required standards. For example, DIN 703 (heavy-duty series) or DIN 705 (light-duty series ) applies to set collars.

Installation of set collars and clamping rings

Clamping force on set collars and clamping rings is achieved by tightening the set screw, regular screw, or other attachment mechanisms. The clamping force affects the maximum axial load, which is why torque compliance is important. The following is an example table with torque values for slotted set collars.